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CLEMSON / Biology / MICR 2230 / What is the difference between neural system and nervous system?

What is the difference between neural system and nervous system?

What is the difference between neural system and nervous system?

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School: Clemson University
Department: Biology
Course: Human Anatomy and Physiology II
Professor: John cummings
Term: Fall 2015
Tags: Human, anatomy, Physiology, Clemson, Cummings, exam, 1, one, Endocrine, Reproductive, and system
Cost: 50
Name: COMPLETE Unit 1 Exam Study Guide for Human Anatomy and Physiology II on Endocrine and Reproductive Systems
Description: Here is the completed study guide for the exam on Thursday on the endocrine and reproductive systems.
Uploaded: 01/27/2016
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What is the difference between neural system and nervous system?



Spring 2016

Human Anatomy and Physiology II

Unit 1 Exam Study Guide

Endocrine System 

1. Discuss the differences between neural and endocrine mechanisms of control  of body functioning.

• Both the nervous and endocrine systems function in maintaining  homeostasis in the body

• Nervous System:

- The nervous system creates an electrical impulse to respond to stimuli  - Able to activate excitable tissue (Ex: Muscles- Cardiac and skeletal  and some glands)

- Responds very quickly to stimuli (Within milliseconds)

- Responses are generally short-lived


What is the difference between exocrine and endocrine glands?



• Endocrine System:

- Can activate a target cell using a chemical messenger (Ex: Hormone) - Chemical messenger: Goes into blood stream and travels throughout  the body until it reaches a target cell with the specific receptor for that  hormone

- Target cell: Cell that possesses the receptor for the hormone  

- Hormones are chemical secretions produced by glands that change  cellular metabolic activity  

- Has a lag time in a response to a stimulus (Can take from a few  

seconds to days)

2. Differentiate exocrine and endocrine glands.

• Exocrine Glands:

- Produce secretions that are not hormones (These secretions are not part  of the endocrine system)


What is the neuroendocrine system and its role?



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- Have a duct for the most part where the secretions are secreted into in  order for them to go to the appropriate site where its going to execute  its activity  

- Examples: Sweat glands, salivary glands, digestive enzymes  Don't forget about the age old question of What does humanistic refer to?

• Endocrine Glands:

- Endocrine glands produce hormones and are ductless  

- The hormones are secreted on the surface and are picked up in Don't forget about the age old question of What is the meaning of deductible?

circulation and transported throughout the body until they reach a  

target cell with the specific cell receptor

- Endocrine glands are highly vascularized to increase efficiency in  circulation  

3. Identify the neuroendocrine link, and discuss its functioning. • Neuroendocrine link refers to the conjunction of the nervous and  endocrine systems working together to function in the body

• The nervous system is able to activate endocrine glands via a nervous  impulse that travels to the endocrine gland to stimulate it to start secreting  its corresponding secretions We also discuss several other topics like The chemical name means what?

• The presence of a hormone also has the ability to turn on or off nervous  impulses  

• Specific example of a strong neuroendocrine link: Hypothalamus - Part of the midbrain (Neural tissue) We also discuss several other topics like What is the behavioral exposure theory?

- Connected to the pituitary gland that has some strong endocrine  functions  

- Mechanism: Signal is sent from the hypothalamus to the pituitary  gland to release hormones  

4. List and differentiate the types of chemical messengers.

• Hormones:

- Chemical secretion produced in one part of the body but has an effect  somewhere else in the body

- Long-distance chemical messenger

• Autocrines:

- Chemical produced by a cell that changes the activity of that cell - Short-distance chemical messenger  

- “Self-regulator”

- Only affects the cell that produces the chemical  

• Paracrines:

- Chemical that is secreted by cells that affect the neighboring cells in  that area

- Key to understand that they only affect the area where it was produced • Pheromones:

- Chemical secretion that alters behavior of another individual  - Ex. of non-human functions: Marking territory, mate attraction, etc. - 1970’s: Research on mate attraction showed that humans due produce  pheromones and was seen in perspiring women  

5. Identify the cells at which hormones exert their effects, and discuss the  generalized effects hormones can produce.

• Hormones affect target cells, which are defined as anything that has a  receptor

• Hormone action:  

- When a hormone is secreted on the surface of the endocrine structure,  it moves into circulation in the blood stream so that is transported  throughout the body and will only have an effect on cells with the  receptor specific to that hormone

• Different effects of hormone action:

a) Open or close ion channels:

When the hormone binds to its specific receptor of a cell, it  

changes the permeability of the cell membrane, which is what  

allows the changes in ion flow  

b) Stimulates protein synthesis:

o Hormones can stimulate the cell to start producing proteins  

(Structural or functional)

o Ex: Hormone could stimulate the muscle cell to produce actin  or myosin to increase muscle mass; an enzyme could be  

produced to catalyze a reaction; protein could be packaged for  

export to have an effect elsewhere, etc.  

c) Activate or deactivate enzymes:

Hormones are able to stimulate the production of new proteins or  change the activity of an existing protein within a cell

d) Promote secretion: (Ex: Mucous, a different enzyme, etc.)

e) Stimulate mitosis:

Hormones can cause cells to start dividing with the stimulation of  mitosis for growth to occur  

6. Describe the chemical classifications of hormones.

• Amino Acid Based:

- Derivative of AA  

- Water soluble  

- Cannot diffuse across the plasma membrane because of its  

hydrophobic properties due to lipids (Chemical composition helps us  understand where receptors are located for that cell)

- Majority of the hormones produced in the body are AA derivatives  (Non-steroids) and almost all the hormones produced are water soluble • Steroid:

- Steroid: A derivative of cholesterol which is fat soluble  

- Can diffuse across the plasma membrane by itself

- Steroid hormones are only produced by the gonads (Testes and  ovaries) or cortex of the adrenal gland; Otherwise, the hormone is AA  based if it is not produced by these

• Eicosanoid (NOT a real hormone):

- Eicosanoid: Biologically active lipid that is a chemical secretion that  has a localized effect – What makes it not a true hormone (Similar to a  paracrine but is not exactly the same)

- The 2 most common types of eicosanoids:

a) Prostaglandins:

o Biologically active lipids  

o Ex: When there is damage to a tissue, the tissue releases  

prostaglandins that cause other cells to migrate to the site  

and can disrupt the action of the action potential in the  

nervous system so that won’t have a pain signal

o Ex: One ovulating ovary secretes prostaglandins so that the  

sperm know which one to go to  

b) Leukotrines

7. Describe the two major mechanisms by which these two classes of hormones  bring about their effects.

• Steroid Action:

- When stress (or another type of stimuli) is applied to the body, an  endocrine gland (In this case, a gonad or adrenal gland) produces a  secretion that goes into the blood stream where it encounters a cell  with its specific receptor and then diffuses across the membrane  

- With steroid hormone activity, the hormone diffuses across the plasma  membrane and binds with the intracellular receptor (If there isn’t a  receptor inside the cell, the steroid hormone crosses back out of the  cell and won’t have any effect on it)

- When the steroid hormone binds to the receptor, the complex is now  activated which will then bind to a second receptor that is located on  the DNA inside the nucleus

- When the activated complex binds to the DNA, it acts as a promoter  and starts transcription (Taking gene and using genetic code to  

produce mRNA to then be translated and go out of the nucleus and  find the ribosome to begin producing the protein) ???? Demonstrates  direct activation of protein production by steroid hormones

- Note: the receptor for the steroid hormone could also be located in the  cytoplasm which then can cross into the nucleus and bind to the DNA  activator which then causes the cascade of the production of a protein  (Transcription and translation processes, more specifically)

• Amino-Acid Hormones:  

- AA based hormones attach to specific receptors on the surface of the  cell that use secondary messenger mechanisms to change the activity  of the cell  

- 2 Mechanisms (General Introduction):

a) Cyclic AMP Mechanism: Cyclic AMP is the secondary messenger  to cause something to happen in the cell

b) PIP-Calcium Mechanism: PIP causes something to happen in the  cell and then calcium follows with its effect

8. Discuss the two models of amino acid-based action.

• AA based hormones attach to specific receptors on the surface of the cell  that use secondary messenger mechanisms to change the activity of the  cell  

• **Note: Most of the hormones produced in our body are non-steroid • 2 Mechanisms involving Secondary Messengers:  

a) Cyclic AMP Mechanism:

o Hormone binds to a receptor located on the exterior surface  

of the plasma membrane, which modifies the receptor

o A second protein associated with the now modified  

receptor known as a G protein is activated  

o The activated G protein is used to activate adenylate  

cyclase, which is an enzyme that causes the production of  

cyclic AMP (cAMP) from ATP  

o cAMP then stimulates the protein kinases enzymes, which  

phosphorylate proteins (Addition of a phosphate group to a  

protein)

o Phosphorylation by protein kinases to already existing  

proteins inside the cells either 1) Activates the protein or 2)  

Deactivates the protein  

o At some point, it will be necessary to have a way to break  

down cAMP ???? Occurs through phosphodiesterase  

(Hormone response has a duration time)

b) PIP-Calcium Mechanism:

o Hormone binds to the membrane bound receptor, which  

becomes the modified receptor and activates the G protein

o The activated G protein causes the activation of  

phospholipase (PLP) inside the cell, which splits PIP2 into  

DAG and IP3

o DAG activates protein kinases, which phosphorylate  

proteins  

o IP3 causes calcium to be released from the ER in the cell,  

which can act as another secondary messenger to be  

released to promote other changes in cellular activity

• Overall idea: These mechanisms demonstrates that only one hormone  affected the cell but it causes hundreds of different responses due to the  effect of changing the proteins inside the cell to be either turned on or off  

• The benefit of second messenger signaling is the amplification that occurs  inside of the cells; small amounts of signal create a large response— Secondary messengers do not have to do with conducting a rapid response  with communication

9. Identify the factors that control hormone action.

• Hormonal activity is affected by the amount of hormones circulating in the  blood stream ???? The higher the concentration, the higher the response to  the hormones

• The human body is capable of adapting to stress (For example) through: 1) Up regulation in the number of receptors as a result so that there will  be a greater hormonal response with continued stress ???? More  

receptors allows for more binding of the specific hormones that  

produce the necessary proteins

2) High levels of stress can also cause the number of receptors on target  cells to be reduced if that particular hormone’s response is not needed  ???? Decreased numbers of receptors leads to decreased response to that  hormone

3) Receptor Affinity: Can change the way the receptor binds to the  hormone—Ex: May be necessary for an increase in speed in the  

response of a hormone on a cell and body can accompany this need • Hormone producing structures can be working at the same time so  hormones are able to interact amongst themselves as a result

10. List three kinds of interaction that different hormones acting on the same  target cell can have.

• Permissiveness:

- A hormone, such as FSH (Follicle-Stimulating Hormone), will affect  reproductive development so that as it is secreted it will cause  

development of the reproductive organisms but if there are higher  levels of thyroid hormone present, for example, FSH will have a  greater effect  

- In this example, thyroid hormone isn’t necessary for FSH to work  properly, but it enhances FSH’s effect

• Synergism:

- When more than one hormone produces the same effect so when that  when these multiple hormones are present together, a greater effect is  experienced

- Ex: Glucagon and epinephrine both increase blood glucose levels and  together, this is experienced even more

• Antagonism:

- Hormones that have opposite effects

- Ex: Insulin vs. glucagon  

11. Explain how hormone release is regulated.

• Humoral: (Humors are liquids)

- Concentrations of something in the blood stream can stimulate  endocrine secretions

- Ex: Increase in blood sugar level can cause the pancreas to produce  insulin in order for cells to take up glucose and reduce the  

concentrations in the blood stream  

• Neural:

- Nervous impulses directly stimulate glands to start producing  hormones  

- Ex: Sympathetic nervous stimulation of the adrenal gland causes the  production of epinephrine  

• Hormonal:

- Hormones in the blood stream bind to target cell to cause it to produce  another hormone

• Modified by Nervous System:

- The previously discussed modes of endocrine gland stimulation can be  fine tuned by nervous system activity because the endocrine and nervous  system work together

• Inhibited by negative feedback:

- Most hormones will function through negative feedback mechanisms  - Ex: Stress causes the hormone to be released to reduce stress and once  the stress is successfully reduced, the hormone will be shut off

• Both "turn on" factors (hormonal, humoral, and neural stimuli) and "turn  off" factors (feedback inhibition and others) may be modulated by the  activity of the nervous system 

12. List the major endocrine organs, and describe their body locations. • Pituitary: Extends off of the hypothalamus via what is called the  infundibulum = pituitary gland’s funnel-shaped stalk + it is divided into 2

parts ???? posterior (neurohypophysis) and anterior (adenohypophyseal)  pituitary glands

• Thyroid: Located around the trachea by the isthmus across the front • Parathyroid Glands: Embedded in the posterior portion of the thyroid  gland

• Adrenal Glands: Paired glands located on top of the kidneys

• Pancreas: Located in the abdominal cavity behind the stomach  • Gonads: Ovaries and testes

• Pineal: Extends from roof of third ventricle in diencephalon of the brain • Thymus: Located beneath the sternum and on top of the heart (Deep to  sternum in thorax)

13. Discuss the structure of the neurohypophysis, and describe the effects of its  two hormones.

• Neurohypophysis (Posterior Pituitary Gland):  

- Part of the pituitary gland, which extends off the hypothalamus via  what is called the infundibulum (Pituitary gland’s funnel-shaped stalk) - The posterior pituitary gland is comprised of nervous tissue

- It does NOT produce hormone structures but is instead responsible for  storing hormones made originally in the hypothalamus  

- Releases the hormones into circulation when signaled to do so by the  hypothalamus

• Hormones:

a) ADH (Anti-Diuretic Hormone):

- AA based hormone that uses the PIP-calcium mechanism (Activates  proteins that are already inside the cell)

- Stimulates smooth muscle contraction ???? Childbirth, milk ejection - Promotes the ejection of milk (NOT production but the release itself) - Example of its involvement in a positive feedback mechanism: Giving  

birth to an infant ???? Stimulation of the contraction of muscles in labor,  increase in pressure, baby pushed out and released

- Involved with sexual arousal and satisfaction ???? Associated with  climax response

- High levels of oxytocin promote nurturing behavior; This is seen  especially immediately after the mother finishes giving birth (“Cuddle  hormone”)

- NOT produced by the posterior pituitary gland itself  

b) Oxytocin:

- AA based hormone that uses the PIP-calcium mechanism (Activates  proteins that are already inside the cell)

- Regulates water balance by affecting the kidney tubules and prevent  urine formation

- The kidneys are stimulated by ADH to reabsorb water so that it goes  back into circulation to reduce urine production

- Important to monitor tonicity of blood as a result of this

- Alcohol suppresses ADH ???? Leads to release of lot of fluids that cause  dehydration  

- NOT produced by the posterior pituitary gland itself  

14. List and describe the adenohypophyseal hormones and their effects. • Adenohypophyseal (Anterior Pituitary Gland):

- Part of the pituitary gland, which extends off the hypothalamus via  what is called the infundibulum (Pituitary gland’s funnel-shaped stalk) - Anterior pituitary gland is not directly part of the nervous brain, but it  is fused to the neural tissue of the posterior pituitary gland

- Made up of glandular tissue, which is secretory tissue  

- Starts out as out-pouching (Rathke’s pouch) of the oral cavity and this  piece breaks off the oral cavity and travels until it comes in contact  with neural tissue and fuses together  

- Produces many hormones that are all AA based and use the cyclic  AMP mechanism  

- The hormones the anterior pituitary gland produces are tropic  hormones ???? A hormone whose target cells are other endocrine glands  so that it causes the production of another hormone

• Hormones:

a) GH (Growth Hormone):

- GH is an anabolic hormone that builds tissue (Seen with muscle and  bone tissue for example)

- GH stimulates cell growth and division, protein synthesis, fat  metabolism and glucose conservation

- GH’s target cell could be skeletal muscle, for example, and when it  binds to the receptor it stimulates the production of myosin/actin,  which make the muscle larger  

- With increasing glucose concentrations and storing glucose, the cells  get bigger inclusions as a result

- GH Malfunctions:  

o Pituitary Dwarfism: Insufficient concentrations of GH lead to  smaller and maintain younger looking features

o Giantism: Excess concentrations of GH lead to bigger and older  looking features

o Acromegaly: Where GH levels are normal until adulthood where  an excess amount is produced and there are effects of enlargement  of hands, feet, longer face etc.; Simple diagnostic test: Taking had  and putting around wrist to see if the thumb overlaps the fingers by  a great extent  

- GH Cascade:

o Cascade: What causes the anterior pituitary gland to start  

producing hormones and also includes what shuts it back off  

o The anterior pituitary is generally stimulated by the hypothalamus  (But not always) = Chemical hormonal stimulus to cause anterior  pituitary cells to start to produce the wanted hormone (Example of  the hormonal mechanism)

o Many kinds of cells are in the anterior pituitary with each cell  having different receptors and responding to different signals from  the hypothalamus

o GH Cascade:

o The hypothalamus secretes growth hormone releasing hormone  (GHRH) that signals the somatotrope cells in the anterior pituitary  gland which causes the production of GH (On switch)

o GH is released then by the anterior pituitary and travels in the  blood stream to affect any cells with the GH receptor  

o GH is AA based so it binds on the surface of the cell with its  specific receptor and then causes a 1) Direct effect on the cell or 2)  Indirect effect on the cell through use of a secondary component

o This is a negative feedback system so as GH levels increase in  circulation, growth hormone inhibiting hormone (GHIH) is  triggered which shuts off GHRH which stops GH production  GHIH is also known as somatostatin and this hormone can shut off  other hormones too, such as digestive enzyme production  - Direct Actions of GH:  

o GH that is released from the anterior pituitary gland travels in the  blood stream until it reaches a cell with its specific receptor that it  binds to and causes an increase in blood levels of fatty acids (FA)  ???? This means that fat is being taken out of storage and is going to  

be made available for energy  

o GH decreases cellular uptake of glucose so that it is kept in  circulation to be used for energy elsewhere instead of glucose  coming out of the blood stream to be stored in a cell  

o Glucose and FA function as energy sources ???? By taking fat out of  storage and preventing glucose from being stored, energy is being  provided for the body  

o GH encourages the breakdown and release of glucose from  glycogen in the liver = diabetogenic effect (Releasing glucose from  the storage of glycogen)

o GH demonstrates the changing of membrane permeability where it  closes off the in-flow of glucose into cells and opens up the out flow of glucose out of cells so that more energy is available and is  in circulation  

- Indirect Actions of GH:

o Indirect actions of GH function through IGF (Insulin-like Growth  Factors)

o IGFs are produced by the liver and require GH presence for  activity  

o GH stimulates an increase in IGFs by the liver

o GH binds to IGFs and stimulates the uptake of AA from the blood  into cells that stimulates protein synthesis  

o GH stimulates uptake of sulfur through IGF binding which is  important for making the matrix of cartilage ???? In an embryo,

when cartilage matrix is being made, this is the foundation for  where bone comes from and in order to do this, the GH has to  interact with IGF

b) Thyroid Stimulating Hormone (TSH)

- TSH is produced by the anterior pituitary gland

- Stimulates the development of the thyroid gland and secretion from the  thyroid gland  

- TSH Cascade:

o The hypothalamus secretes TRH (Thyrotropin Releasing  Hormone) which stimulates the thyrotrope cells of the anterior  pituitary gland which produces TSH (Thyrotropin) and secretes it  into the blood stream to bind to specific receptors

o High levels of TSH inhibit the pituitary gland and hypothalamuas  and it also stimulates the production of GHIH which blocks the  production of TRH and therefore the production of TSH  c) ACTH (Adrenocorticotropic Hormone)

- ACTH is an AA based hormone that stimulates the adrenal cortex to  secrete its steroid based hormones (corticosteroids) using the cyclic  AMP mechanism  

- The adrenal gland produces 3 classes of steroid hormones and of these  3, ACTH primarily causes the production of mostly glucocorticoids  - All of the steroids that are secreted by the adrenal cortex help the body  

relieve stresses (Ex: Fever, blood pressure, external stresses, etc.) - ACTH Cascade:

o The hypothalamus secretes CRH (Corticotropin Releasing  Hormone) which stimulates the corticotrope cells of the anterior  pituitary gland to release/produce ACTH which binds to receptors  on cells of the adrenal cortex where the production of  

glucocorticoids primarily occurs

o Increased levels of glucocorticoids shut off CRH which stops the  production of ACTH which stops the production of glucocorticoids o Fever, hypoglycemia, and other stressors cause CRH to be  produced in the hypothalamus  

d) Gonadotropins  

- Gonadotropins are anterior pituitary gland secretions that help regulate  and develop the functioning of the gonads (Ovaries/testes) - 2 types of gonadotropins:  

a) FSH (Follicle-Stimulating Hormone): Stimulates the production of  gametes (Sex cells- sperm/eggs)

b) LH (Luteinizing Hormone): Stimulates the production of gonadal  hormones (Testosterone, estrogen, progesterone)

- Male

o FSH: Stimulates sperm production

o LH: Stimulates production of testosterone, which is produced in the  tests by the interstitial cells  

o Testes: Produce gametes (sperm) and testosterone

- Female

o FSH: Stimulates production of ova (eggs) = gametes

▪ Women are born with all the gametes that are going to be  produced in the ovaries which means that FSH is producing  the ova prior to birth and the ova are then maintained in the  follicles

▪ Normally 3-5 follicles develop each month with normally  one finishing development in making it into a mature egg  o LH: Triggers ovulation and development of the female sex hormones  (estrogen and progesterone)

o After puberty, the FSH and LH work together to cause maturation of  some of the ova in the follicles, cyclically  

- Gonadotropin Cascade

o At puberty, the hypothalamus secretes GnRH (Gonadotropin Releasing  Hormone) that stimulate the gonadotrope cells of the anterior pituitary  gland to secrete FSH and LH

o FSH and LH cause the gonads to mature and produce their own  hormones  

o The production of these hormones by the gonads are then what shut off  the production of LH and FSH when there are increased levels  e) Prolactin Cascade (Cycling)

- During a woman’s cycle, an ovum begins to develop in the ovary and  as the follicle where the ovum is located in matures, this causes an  increase in estrogen and this causes prolactin to be released form the  lactotrope cells of the anterior pituitary gland

- Key to understand that a chemical is NOT being released from the  hypothalamus to stimulate prolactin release from the lactotropes—It is  high estrogen levels that stimulate the lactotropes to secrete prolactin  by suppressing PIH (Prolactin Inhibiting Hormone) production  

- Decreased estrogen levels stimulate PIH production from the  hypothalamus  

- Prolactin production then stops from the lactotropes

- Prolactin Cascade (Pregnant)

o PIH is produced by the hypothalamus and high estrogen levels causes  suppression of PIH in order to start the production of prolactin from  the lactotropes in the anterior pituitary gland

o Estrogen levels don’t get very high until the end of pregnancy so then  the production of milk begins at this point

o Oxytocin then kicks in to deliver the baby and milk is released here o Suckling is what maintains the production of prolactin so as long as  breast feeding is occurring, prolactin is being produced

o When the mother weans the baby and the suckling stops, the PIH is  produced by hypothalamus and prolactin production stops

Hormone-Producing Structures

15. Identify the hormone producing organs, list the hormones each produces,  and discuss the actions of each product.

a) Thyroid Gland: Thyroid Hormone (Thyroxin)

• Two lobes connected by isthmus across the front

• Located around the trachea beneath the larynx  

• Largest pure endocrine gland ???? Meaning that it only produces hormones • TH is actually 2 separate hormones:

a) T3: Thryoglobulin + 3 iodine

b) T4: Thyroglobulin + 4 iodine

• Almost every cell in the body has a receptor for Thyroxin (TH) except the  brain, spleen, testes, uterus, and the thyroid gland itself

• TH is a major hormone that regulates metabolic activity—Oxidation of  glucose

• Bringing it together: Hypothalamus releases TRH that stimulates that  anterior pituitary gland to release TSH that stimulates the thyroid to  release T3 and T4 into the blood stream to bind to specific receptors  (Negative feedback mechanism)

• TH stimulates the oxidation of glucose so that it is broken down by the  cell to produce energy (Increases basal metabolic rate) and liberates heat  - Calorigenic effect: Heat produced when glucose is broken down by the  cell for energy

• TH helps maintain blood pressure ???? It causes can increase of adrenergic  receptors  

- TH binds to norepinephrine that then binds to the adrenergic receptors on  the blood vessels that causes vasoconstriction so that blood pressure is  increased  

• Regulates tissue growth and development, especially with skeletal and  nervous systems  

- Ex: Permissiveness ???? Gonadotropins (LH and FSH) cause the development of sex organs and if TH is circulating at the same time as  these, great sex organ development is stimulated  

• The thyroid is unique in that it can store hormones (2-3 months supply  worth)

• TSH normally is secreted around the time one gets tired (Peaks before  sleep and remains high at night)

• Produced TH is stored in the extracellular colloid

• When energy is needed during the day, the thyroid secretes TH  • Effect of sleep deprivation: Not producing as much TH and therefore  energy is lost  

b) Thyroid Gland: Calcitonin

• Hormone produced by the parafollicular cells = C cells (C is for  calcitonin)  

• Its effects are to lower blood calcium levels ???? It takes calcium out of  circulation and stores it in bone and muscle

• Calcitonin is most important during rapid skeletal growth and reformation  ???? Plays the biggest role in childhood (And does not have as big of a role  once one hits puberty)

• Inhibits osteoclast activity ???? Shuts off osteoclasts so that the breaking  down of bone to release calcium is inhibited  

c) Parathyroid Gland: Parathyroid Hormone (PTH)

• Embedded in the posterior portion of the thyroid gland  

• Has 2 types of cells: Oxyphil and Chief  

• PTH is the most important hormone in controlling blood calcium balance  of blood  

• Calcitonin causes a reduction in blood calcium

• PTH is an antagonist so that is causes an increase in blood calcium • Therefore, triggers for PTH to be produced by the chief cells is low blood  calcium

• PTH stimulates the osteoplasts to release calcium and some phosphates  into the blood stream (Breaking down bown)

• PTH also enhances reabsorption of calcium in the kidneys so that it is kept  in the body and not excreted out via urination  

• PTH increases absorption of calcium in the intestines

• Promotes the kidneys to convert Vitamin D to its active form, calcitriol  (D3)—Necessary to be present in the intestines in order for calcium to be  absorbed by the body

d) Adrenal Glands: General Information

• Paired glands located atop each kidney  

• Each is comprised of a cortex and medulla

• Cortex: Glandular epithelium = secretory epithelial cells

• Medulla: Part of the sympathetic nervous system  

• Norepinephrine is a neurotransmitter that is released by post-ganglionic  sympathetic fibers (Secreted by the medulla)

• The cortex secretes steroid hormones  

• All adrenal secretions help fight off stress

• 3 classes of steroids (Corticosteroids) are produced by the cortex:  Mineralocorticoids, glucocorticoids, gonadocorticoids

• This means that there are 3 different regions and different types of cells  that correspond with each steroid as a result

• ATCH (Adrenocorticotropic Hormone) is secreted from the anterior  pituitary gland and affects the cortex which causes the production of many  of the steroids

e) Adrenal Glands: Mineralocorticoids (Aldosterone)

• Major hormone from mineralocorticoids is aldosterone (95%)  • Aldosterone helps regulate electrolyte concentrations of extracellular  fluids in our body—Particularly the sodium-potassium combination that  are involved in membrane potentials

• As aldosterone regulate concentration of electrolytes, water will follow  concentration gradients so aldosterone is very important with regulating  blood pressure

• Aldosterone stimulates reabsorption of sodium in the kidneys ???? As blood  is filtered, substances are in the filtrate that will go out as urine unless they  are reabsorbed into the circulatory system  

• An osmotic gradient is created with the reabsorption of sodium back into  the blood stream by the kidneys so that there is more sodium in the blood  stream than in the filtrate that is to be urinated out of the body ???? Water  follows the sodium and this regulates blood volume and therefore blood  pressure

• Other ions are also linked to sodium and play a role in blood pressure and  blood volume control  

• Essentially, with the reabsorption of sodium by the kidneys, the blood volume changes and this affects the blood pressure  

• Reabsorption of sodium in the kidneys is aldosterone’s primary action but  the corticosteroid is able to affect other glands as well: Sweat, saliva,  gastric juice glands for example

f) Adrenal Glands: Glucocorticoids (Cortisol)

• The major hormone is cortisol  

• Cortisol regulates energy metabolism of most cells in the body and helps  resist stress  

• Examples of stimulants of stress for cortisol: Cold weather, emotional  stresses, etc.  

• Cortisol affects energy metabolism by maintaining blood glucose levels by  promoting gluconeogenesis (This is not the main way to regulate blood  glucose levels though)

• Gluconeogenesis: The production of new carbohydrate from non carbohydrate sources – FA and proteins are broken down to be used for  making glucose and therefore for energy

• Cortisol also is related to blood volume and maintaining it ???? It prevents  water from leaving the blood and going into body cells (Inhibits water  uptake by body cells)  

g) Adrenal Glands: Gonadocorticoids (DHEA)

• Gonadocorticoids are produced by zona reticularis of the adrenal cortex • The major hormones of the gonadocorticoids are weak androgens ???? DHEA

• DHEA is a precursor for testosterone or estrogen

• Glucocorticoids (DHEA included) contribute to the onset of puberty; Prior  to puberty there is little produced by the adrenal cortex

• DHEA also provides sex drive for women

h) Adrenal Medulla: Epinephrine and Norepinephrine

• The adrenal medulla is sympathetic nervous tissue ???? It uses  norepinephrine and epinephrine as a neaurotransmitter that also work as

hormones too by making sugars available for energy, increasing  circulation, and increasing heart rate

• Essentially the adrenal medulla produces modified sympathetic neurons  that are released into the circulatory system to the liver and throughout the  body (They are not sent to a synapse)

• Epinephrine and norepinephrine together makeup adrenaline  • Stress promotes sympathetic nervous activity (Fight or flight response)  which leads to the release of epinephrine and norepinephrine because the  nervous tissue has been activated which has also led to an increase in  blood sugar as a result

• Fight or flight: Means the body is getting ready to fight stress or flee from  it and to do this, there has to be energy available which is accomplished by  stimulating the release of glucose into the bloodstream  

• Norepinephrine especially causes the constriction of blood vessels ???? increase in blood pressure  

• The fight or flight response causes blood to be sent from the extremities to  the brain, heart, and skeletal muscles and circulation is also geared  primarily more towards preganglionic sympathetic nerve endings  

• The release of epinephrine and norepinephrine is also a much shorter  response for stress and demonstrates the link between the nervous and  endocrine systems

i) Pancreas: General Information

• The pancreas is located in the abdominal cavity behind the stomach  • Has both endocrine and exocrine functions ???? Therefore, more than one  type of cell is present

• Exocrine part: Secretes enzymes into a duct that dumps into the small  intestine where there is digestion involvement  

• Endocrine part: Secretes hormones that go to the surface and get into the  blood stream (Insulin and glucagon)

j) Pancreas: Glucagon

• Functions on the liver to release glucose into the blood stream as free  glucose via taking the glucose out of storage (Most glucose is stored in the  liver as glycogen)

• First, glycogen is broken down into glucose that is released into the bloods  stream

• Glucagon also stimulates glucose to be synthesized from lactic acid: - When muscles are being used a lot, lactic acid is produced and then  circulates throughout the body until it reaches the liver

- Liver uses lactic acid as an energy source which can then be converted  back into glucose and be used by muscle (or other cells) again for  energy

- Overall: The waste product of lactic acid from muscle contraction =  food source for liver = food source for muscle again  

• Glucagon essentially function sin increasing blood glucose levels by  releasing it into the blood

k) Pancreas: Insulin

• Insulin decreases blood glucose levels by signaling cells to take up  glucose out of the blood stream

• Influences protein and fat metabolism (Anabolic hormone so signals for  the build up of these)

• Signals for glucose to be taken out of the blood stream via enhancing  membrane transport of glucose into cells  

• Inhibits the breakdown of glycogen into glucose (Left as storage) • Inhibits the conversion of AA or FA (Fats) to glucose

• Promotes glycogen production predominantly in the liver when there is  excess glucose

• Rest of excess glucose goes to fatty acid synthesis and further triglyceride  storage in adipose tissue

• It is important to note that there is some oxidation of glucose when cells  take up glucose by the cell for the needed amount of energy by the cell at  that time  

• Glucocorticoids play a similar role with blood sugar levels l) Gonads: Testosterone, Estrogen, and Progesterone

• Testes  

• Ovaries

• Both produce the same sex hormones that the adrenal cortex produces  (Acts as precursors at this point in the adrenal cortex) ???? Testosterone and  estrogen  

• Male: Testosterone

• Female: Estrogen, progesterone

• Both genders produce all but in different amounts

• Testosterone:

- Stimulates the maturation and maintenance of male reproductive  organs  

- Secondary sex characteristics ???? Enlarged muscle mass, increased  body hair, oil production, deeper voice, etc.  

- Promotes sex drive

- Stimulates male gamete (sperm) production  

• Estrogen:

- Stimulates the maturation and maintenance of the female reproductive  organs

- Female secondary characteristics ???? Accumulation of fat in  hips/breasts, smoother skin, less oil, higher voice, less hair, etc. • Progesterone:

- Functions with estrogen to promote breast development

- Functions with estrogen to cause cyclic changes in the uterine lining  (menstrual cycle)

m) Pineal Gland: Melatonin

• Pea size gland that extends from the third ventricle of diencephalon and is  made up of pinealocytes

• Promotes drowsiness

• Inhibits sexual maturation ???? Prior to puberty almost no gonadotropin is  produced because melatonin shuts it off

• Therefore, melatonin helps time puberty (Reduces in levels when puberty  is about to occur)

• Melatonin is continued to be produced in adulthood and is instead used to  make us feel drowsy ???? Sunlight (UV radiation) inhibits the pineal gland  so when the sun sets, inhibition is lost and melatonin levels increase so we  sleep (Sleep-wake cycle)

n) Thymus: Thymoproteins, Thymic Factor, Thymosins

• Located beneath the sternum an don top of the heart (Deep to sternum in  thorax)

• Size diminishes with age ???? It’s very active in an embryo and child • 3 classes of hormones are produced that all influence the development of  T lymphocytes (Specialized white blood cells that function to give us  immunity):

a) Thymoproteins

b) Thymic Factor

c) Thymosins

• When there is an embryo/small child, the thymus produces these  hormones that cause the T lymphocytes to be produced to get the body  ready to have an immune system before they come in contact with  pathogens  

• With age, immunity declines so it is important to have a strong immunity  as a child because it will have to be carried with us until death  

16. Describe the histological composition of each of the endocrine glands to  illustrate how the hormones are produced.

a) Thyroid Gland: Thyroid Hormone

• The thyroid gland is composed of follicles that are made up of epithelial  cells (cuboidalepithelium) that produce thyroglobulin protein which is  stored in the follicles as colloid substance  

• Thyroid hormone is derived from colloid

• TSH (Thyroid Stimulating Hormone) stimulates the follicles to produce  thyroglobulin, which is a component of thyroid hormone (TH)  

• Thyroglobuilin will combine with iodine to make TH = thyroxin  • The thyroid gland is unique because it is the only endocrine gland that can  store its secretions ???? All other endocrine gland secrete hormones that are  immediately released into the blood stream  

• The anterior pituitary gland secretes TSH which travels to the thyroid  gland via blood vessels

• TSH triggers the production of thyroglobulin by cuboidal cells that  accumulates in the follicles as colloid

• TSH also stimulates active transport of iodine into the follicles

• Thyroglobulin is then iodized in 2 different circumstances: (Occurring in  the colloid)

a) Thyroglobulin + 1 iodine = T1 ???? Leads to form T3 

b) Thyroglobulin + 2 iodine = T2 ???? Leads to form T4 

• T3 and T4 are still in the colloid at this point and the thyroid will secrete  both from the colloid so that they move back into the follicular cells to be  packaged into lysosomes  

• The lysosomes transport T3 and T4 to where they are released into the  bloodstream via lysosomal enzymes  

• Most TH is produced at night  

b) Thyroid Gland: Calcitonin

• The thyroid gland also contains other cells located between the follicles  called parafollicular cells that produce calcitonin (A different hormone) • Calictonin shuts off osteoplasts (Cells in bones)

c) Parathyroid Gland: Parathyroid Hormone (PTH)

• 2 Types of Glandular Cells:

1. Oxyphil: It is not clear what these cells do

2. Chief: Secrete parathyroid hormone (PTH)

• Able to tell the difference between the thyroid and parathyroid because  each have different follicles and tissues  

d) Adrenal Glands: Mineralocorticoids (Aldosterone), Glucocorticoids  (Cortisol), Gonadocorticoids (DHEA)

• 3 zones where each zone produces a different class of corticosteroids: a) Zona glomerulosa (Mineralocorticoids)

b) Zona fasiculata (Glucocorticoids)

c) Zona reticularis (Gonadocorticoids)

e) Adrenal Medulla: Epinephrine and Norepinephrine

• Chromaffin cells are modified ganglionic sympathetic neurons that secrete  epinephrine and norepinephrine (catecholamines)

f) Pancreas: Glucagon and Insulin

• Most of the pancreas is composed of the acinar pancreas that is made up of  acinar cells = exocrine portion that produces enzymes for digestion  • The Islets of Langerhans (Pancreatic islets) are located throughout acinar  portion  

• 2 types of cell sin the Islets of Langerhans: Alpha (Produce glucagon) and  beta (produce insulin) ???? Both of these hormones are antagonists  g) Gonads: Testosterone, Estrogen, Progesterone ???? Information not provided  on power point

h) Pineal Gland: Melatonin

• Pinealocytes are the hormone producing cells in the pineal gland • Responsible for the production of melatonin

i) Thymus: Thymoproteins, Thymic Factor, Thymosins ???? Information not  provided on power point

17. Outline the feedback mechanisms that control endocrine gland activity.

a) Thyroid Gland: Thyroid Hormone

• T3 and T4 are released into the blood stream and must bind to transport  proteins in order to reach specific cell receptors where they are going to  have an effect

• TBG (Thyroxin Binding Globulin) is the major transport protein where it  delivers TH to target cells

• TH is an AA based hormone that binds to intracellular receptors (An  exception of AA based hormones normally binding to receptors on the  surface of cells) ???? TH functions like a steroid then which is why TBG is  so important so that it helps with getting TH inside the cell to its receptors  • Transcription by TH is then promoted like a steroid  

• Increasing levels of T4 (Thyroxine) inhibit TSH production while falling  levels reversibly stimulate TSH production that produces the T4 (Negative  feedback)

• An increase in body energy needs stimulate the release of TRH that  stimulates TSH that stimulates TH release  

a) Thyroid Gland: Calcitonin

• High calcium levels are humoral stimuli for C cell (parafollicular cell)  activity  

• Low calcium levels inhibit C cell activity ???? As take out calcium out of  circulation, levels get lower so the C cells shut off and calcitonin  production stops

b) Parathyroid Gland: Parathyroid Hormone (PTH) ???? Information not  provided on power point

c) Adrenal Glands: Mineralocorticoids (Aldosterone)

• The anterior pituitary gland secretes ATCH that stimulates the adrenal  cortex to produce hormones (This is one method of aldosterone  production that is not the major method)

• Aldosterone secretion by the adrenal cortex is stimulated by: a) Humoral effects: High potassium levels and low sodium levels in the  bloodstream  

b) Low blood volume

c) Low blood pressure

• ** ATCH functions predominantly on glucocorticoids and not  mineralocorticoids (Review)

d) Adrenal Glands: Glucocorticoids (Cortisol)

• The hypothalamus secretes CRH which stimulates the anterior pituitary  gland to secrete ACTH which stimulates the adrenal cortex to produce  cortisol (Zona fasiculata)

• ** ACTH results are predominantly in the production of glucocorticoids • As cortisol is produced and levels rise, it inhibits CRH and therefore  ACTH release that shuts cortisol production off

e) Adrenal Glands: Gonadocorticoids (DHEA)

• CRH from the hypothalamus stimulates ACTH from the anterior pituitary  gland to stimulate the production of gonadotropins

• There does not seen to be an inhibitor for the production of gonadotropins  ???? Therefore, one the gonadotropins being producing, they continue to do  so throughout life

f) Adrenal Medulla: Epinephrine and Norepinephrine ???? Information not  provided on power point

g) Pancreas: Glucagon

• Humoral control: Low blood glucose (sugar) levels and high AA levels  stimulate the pancreas to produce glucagon from the acinar cells of the  Islets of Langerhans

• High blood glucose and low AA levels shuts off the production of  glucagon

• Sympathetic stimulation of the adrenal medulla promotes the release of:  Epinephrine and norepinephrine ???? Help increase blood glucose levels as  well and will stimulate glucagon production by the pancreas

• Somatostatin (GHIH) production also shuts off glucagon – In terms of not  needing as much energy when one is done growing

h) Pancreas: Insulin

• High blood sugar levels stimulate the beta cells of the Islets of Langerhans  in the pancreas to produce  

• High levels of AA and FA also stimulate insulin production  

• Parasympathetic release of acetylcholine stimulates the release of insulin  as well  

• Hormonal influences also exist

• ** Sympathetic nervous activity relates to glucagon and parasympathetic  nervous activity relates to insulin  

i) Gonads: Testosterone, Estrogen, Progesterone

• Production of the sex hormones (gonadic hormones) are stimulated by  gonadotropins  

• As high levels of gonadotropins are present, they shut themselves off j) Pineal Gland: Melatonin ???? Information not provided on power point k) Thymus: Thymoproteins, Thymic Factor, Thymosins ???? Information not  provided on power point

18. Other Hormones:

a) Heart

• Releases ANP (Atrial Natriuretic Peptide) that shuts off aldosterone  production by inhibiting renin production so that there is an increase in  urinary output ???? Sodium is not reabsorbed

• ANP production is promoted by high blood pressure, which is reduced by  getting the fluids out of the blood via increasing urine production  b) Gastrointestinal Tract

• Many places along the GI tract secrete hormones that affect the digestive  activity  

• Ex: Hormone produce by the small intestine will affect stomach activity;  hormone produced by the stomach affects small intestine activity, etc.

c) Placenta

• Both the female and embryo produce the placenta organ  

• Hormone producing structure of estrogen, progesterone, and hCG (Human  Chorionic Gonadotropin)  

• hCG = what pregnancy tests detect

• All of these hormones produced by the placenta will influence the  development of the fetus and ovary maintenance

d) Kidneys

• Produce erythropoietin that stimulates the production of red blood cells e) Skin

• Produces cholecalciferol that is an inactive form of Vitamin D3

• It is converted to the active form of Vitamin D3 = calciferol under the  influence of sunlight

• Vitamin D3 is also important for the absorption of calcium in the digestive  tract

f) Adipose Tissue

• Produces leptin

• As one takes in excess calories, it is put into storage in adipose tissue, and  as adipose tissue increases in amount, the production of leptin increases  which reduces appetite and encourages an increase in energy expenditure  to try to reduce the amount of energy stored

• Also produces resistin that is an antagonist of insulin  

**Endocrine Gland Development

• Endocrine glands can arrive from all 3 embryonic germ layers  

• Mesoderm: Gives rise to the steroid producing endocrine glands

• Ectoderm and endoderm: Give rise to the AA derived hormones

• Endocrine gland activity changes with age (Excellent ex: Thymus,  reproductive hormone activity, etc.)

• Endocrine gland activity can be influenced by environmental cues???? Ex: If  one is cold, the thyroid gland can release more thyroid hormone to  

increase metabolic activity to increase heat production  

19. Discuss four mechanisms of mineralocorticoid secretion.

a) Renin-Angiotensin Mechanism  

• This is main method in which aldosterone is stimulated by  

• The liver is continuously producing a protein called angiotensinogen that is an  inactive form of a protein  

• The kidneys, when stimulated properly, will produce renin that converts the  inactive angiotensinogen into the active form called angiotensin

• Angiotensin stimulates the adrenal cortex to produce aldosterone that has  effects on the kidneys to reabsorb sodium  

• Low blood pressure also stimulates the kidneys to start producing renin  • Because the liver is producing the inactive angiotensinogen all the time, the  production of renin is key for aldosterone production

• Overall, there are many other ways that stimulate aldosterone production:  Combined effects of the nervous and endocrine activity that maintain  homeostasis in the body so there’s a lot of interaction to fine tune all of the  complexities that go into relations with aldosterone  

b) Plasma Concentration Mechanism  

• High potassium and low sodium in the blood have a direct effect on the zona  glomerulosa (Where the mineralocorticoids are produced ???? stimulate  aldosterone production)

• Low potassium and high sodium in the blood inhibit the zona glomerulosa c) ACTH Mechanism

• Stress stimulates CRH production in the hypothalamus ???? Stimulates  corticotrope cells in the anterior pituitary gland to release ACTH ???? Stimulates aldosterone production in the zona glomerulosa of the adrenal  cortex (Not much though with this mechanism)

d) Atrial Natriuretic Peptide (ANP)

• ANP is a hormone produced by the heart and is secreted due to high blood  pressure

• High blood pressure puts a lot of stress on the heart so ANP is secreted to  inhibit renin which in turn inhibits aldosterone production  

Reproductive System 

20. Describe the structure and function of the testes, and explain the importance  of their location in the scrotum.

• The testes are where gametes (Sperm) are produced

• There are 2 testis that are divided into different compartments called  lobules

• Seminiferous tubules: Site of sperm production (Spermatogenesis) but are  not capable of fertilization at this site  

• The seminiferous tubules have a hollow center = lumen containing cells  on the edges that allows for the passage of immature sperm to pass  through to the tubulus rectis ???? rete testis ???? efferent ductules ????

epididymis  

• Epididymis: Where sperm is stored and maturation occurs  

• Sperm will only be released via sexual stimulation; otherwise, sperm is  able to be stored for several months and then it will be phagocytized if not  released

• The interstitial cells of the testes are not related to the testes tubules but  produce testosterone and other hormones that stimulate sperm production  in the seminiferous tubules

• In order for the testes to produce viable sperm, the testes must be 3  degrees below body temperature (34 degrees C) – Testes are located  outside of the pelvic cavity  

• Testicular blood flow to maintain lower temperature:

- Testicular arteries supply blood to the scrotum and they pass out of the  body cavity, pass through the pampiniform plexus, and then are

drained by the testicular veins  

- How the lowering of the blood temperature works: When the testicular  arteries pass through the pampiniform plexus, the heat is transferred  from the arterial supply to the drain of the testicular veins to ensure  that the blood is cooled before reaching the testes

• Scrotum:  

- Sac-like structure composed of skin and superficial fascia that houses  the testes

- The testes are separated into 2 different compartments

- Allows the maintenance of optimal temperature via the dartos and  cremaster muscles ???? Able to contract and relax to change how close  the testes are to the abdominal cavity based on temperature changes

21. Describe the structure of the penis, and identify the physiological changes  that occur during the reproductive process.

• The penis is a specialized copulatory organ that deposites sperm inside the  female reproductive tract and is the pathway for urine flow

• Base: Root of the penis

• Most of the penis is the shaft

• Glans: Head of the penis and covered with prepuce (foreskin) • Erectile Tissue: Composed of cavernous tissue that is spongy epithelial  and connective tissue + highly vascularized  

- Made up of corpora cavernosa (2 units that make up mass of penis)  and corpus spongiosum (1 unit that surrounds the urethra)

- Sexual arousal causes blood to be diverted towards the penis that fills  the cavernous tissue so that it becomes erect (Due to parasympathetic  response to nitric oxide when sexually aroused)  

- Both of the erectile tissue is composed of smooth muscle and vascular  space

- As blood fills the cavernous tissue, the arteries that supply blood and  the veins that drain blood of the penis get squeezed so that the blood  cannot leave (Leaves when sexual arousal removed)

- Referring to slide 8 in the Reproductive System PPT: In the front in  the figure, there is a separate body of corpus spongiosum tissue so that  as the blood fills the cavernous tissue, the corpus spongiosum body  prevents crushing of the urethra in order to keep it open so sperm can  be released from the male’s body  

• Penis and scrotum together = external genitalia

• Male Reproductive Physiology Erection:

- Sexual arousal in the male is divided into two components:  

a) Parasympathetic portion (Erection phase):

o Sexual stimulation will stimulate parasympathetic nervous  

activity to release nitric oxide as the base of the penis that

causes the blood flow to increase the penis size (Dilation of  

the arterioles)

o As blood is delivered to the penis, the erectile bodies fill  

with blood  

o Corpora cavernosa expands, which compressed the  

drainage veins so that the blood is trapped

o Parasympathetic stimulation also releases the pre

ejaculatory fluid by the bulbourethral glands

b) Sympathetic portion:

o Continued tactile stimulation provokes massive  

sympathetic nerve discharge which will result in  

ejaculation

o Smooth muscle contraction, peristaltic contractions, and  

accessory gland contraction (Ex: Prostate releasing fluid)  

is the result of the sympathetic nervous activity and is what  

pushes the sperm out of the epididymis into the ductus  

(vas) deferens

o Because the urethra in males is the path for both urine and  

reproductive fluid, the bladder sphincter muscle must  

constrict to prevent sperm being pushed up into the bladder  

(Otherwise it wouldn’t be released form the body)

o Smooth muscle contractions then occur rapidly, which  

causes the semen and sperm to be expelled = ejaculation

22. Describe the location, structure and function of the male accessory  reproductive organs.

• Accessory Ducts:

a) Epididymis:  

- Sperm is produced in the seminiferous tubules in the lobules of the  testis and is then stored here in the epididymis  

- In the epididymis, the sperm develops and matures  

- But even the sperm that leave the epididymis upon sexual arousal  aren’t mature yet ???? Full maturity occurs inside the woman  

- It takes 20 days for sperm to learn how to swim in the epididymis  (Able to be stored here for several months though)

- Male is able to make 400 million sperm per day everyday  

b) Ductus (vas) deferens:  

- Sperm that is stored in the epididymis will leave upon continued  sexual stimulation and once this occurs, the sperm will be moved to  the ductus (vas) deferens

- Vasectomy: Surgical separation of the vas deferens and the two ends  of the cut tubules are sealed off so that the sperm isn’t able to leave the  epididymis

c) Ejaculatory duct:

- From the ductus (vas) deferens (2- from each testis), the sperm moves  to the ejaculatory ducts that is a short connection where both from

each testis connect to the urethra that transcends the penis and then the  sperm is released from the body  

• As sperm is being propelled out of the epididymis and through the ductus  (vas) deferens and out of the urethra, it passes accessory glands along the  way  

• Accessory Glands: Secrete fluid upon sexual climax

a) Seminal Vesicles (Glands):

- There are 2  

- Where the ductus (vas) deferens meets the ejaculatory duct, the  seminal vesicles (a gland) secrete alkaline fluid that is especially  important when the sperm enters the vagina of the female reproductive  tract ???? Acidic environment so the alkaline fluid surrounds the sperm  to protect it  

- Secrete alkaline fluid upon sexual arousal  

b) Prostate Gland:

- Located at the beginning of the urethra  

- Upon sexual arousal, it will release nutrient sources and enzymes  - The sperm in the epididymis are activated at this point and will have  energy to start swimming

c) Bulbourethral Glands (Cowper’s glands)

- 2 pea sized glands that secrete mucous that will cleanse the urethra to  get rid of crystals of urine left behind (Toxic to sperm)

- Bulbourethral glands are actually stimulated before the rest of the  process of releasing sperm with the accessory ducts and other  

accessory glands occurs ???? Meaning that it provides the pre  

ejaculatory fluid that helps cleanse the urethra + the mucous is viscous  so acts a lubricant  

• Secretions from the seminal vesicles, prostate gland, and bulbourethral glands =  semen ???? Therefore, sperm and semen are what is released from the male body

23. Discuss the components of semen and the contribution each makes to the  reproductive process.

See above question for details on the 3 accessory glands and how they all together  make up semen.  

24. Outline the events of spermatogenesis.

• Spermatogenesis is the sperm production process that starts at puberty and then  continues until death

• Site of spermatogenesis: Seminiferous tubules ???? Have the outer membrane of the  seminiferous tubules with the lumen on the inside; The spermatogenesis process  goes from the basal membrane, and as it gets closer to the lumen, the closer it is to  have the sperm produced  

• All cells in the body has a diploid number of chromosome (Half female and half  male) ???? The cell that begins the spermatogenesis process is a diploid cell called a  spermatogonia

• Spermatogonia undergoes mitosis and produces type A and type B daughter cells  (These are diploid cells—no reduction occurs with mitosis)

• Type A cell: Replaces the spermatogonia and remains at the basal membrane so  that it will be there next time for division

• Type B cell: This is the primary spermatocyte (A diploid cell) ???? It undergoes  meiosis I and produces 2 secondary spermatocytes (These are haploid- underwent  reduction and division in meiosis)

• Each secondary spermatocyte undergoes meiosis II to produce spermatids that are  haploid

• The spermatids don’t look like sperm and have to go to the epididymis to  finishing maturing (Some of the maturation process starts in the seminiferous  tubules)

• Overall: In the production of sperm, it started with one cell (spermatogonia) that  produced 4 gamete cells  

• Spermiogenesis: Change in the morphology of the cell – maturation  - Spermatid decreases cytoplasmic volume and forms a tail (flagellum) - Finished product is known as spermatozoan  

- Spermatids eliminate most of the cytoplasm (It is phagocytized) and  get most of the organelles ???? spermatozoan  

- Spermatozoan as a head, mid-piece, and tail  

- Head: Contains male genetic material (haploid) + tack—Acrosome  that is a vesicle with enzymes that specifically digest the coverings  around the egg to make it available for fertilization  

- Mid-piece: Collection of many mitochondria that will use the nutrient  source and enzymes secreted from the prostate gland to cause the  flagellum to start to whip to be able to swim  

- Tail (Flagellum): Propellant device to deliver the genetic material  - Sperm in the epididymis is not capable of fertilization because the  acrosome is what is changed when it is in the female body and is what  makes the sperm completely mature

25. Discuss the hormones involved in reproduction for the male. • The hypothalamus releases GnRH (Gonadotropin Releasing Hormone)  that stimulates the anterior pituitary gland to release gonadotropins (LH  and FSH) that will affect the male reproductive tract

• FSH stimulates the Sertoli cells to release androgen-binding protein (ABP) - Sertoli cells = Sustencacular cells = nurse cells that protect the  developing spermatocytes from the immune system ???? They provide a  blood-testis barrier (Connection between the circulatory system and  the testes)

- Also nourish dividing cells to help them move to the lumen of the  seminiferous tubules and once they are in the lumen, they will help  them get to the epididymis by secreting testicular fluid (Functions as a  transport medium in the lumen)

- Dispose of eliminated cytoplasm of the spermatids via phagocytosis

- Also involved in partial phagocytosis if the sperm haven’t been used in  the duration of their storage time

- Help regulate spermatogenesis—It takes 72 days for spermatogonia to  become spermatozoan  

• ABP on the spermatogonia binds to testosterone that causes an accumulation of  testosterone

- Testosterone stimulates the division process of the spermatogonia, but  this process can’t start until the testosterone has something to bind to - Therefore, FSH causes these testosterone receptors to be produced • LH causes the interstitial cells to secrete the testosterone that stimulates the  division process

• LH also causes the production of a small amount of estrogen

• Role of testosterone:

- Stimulates spermatogenesis  

- As testosterone levels increase, GnRH is shut off which inhibits the  gonadotropin release of FSH and LH  

- Testosterone has an anabolic effect on the male accessory reproductive  organs ???? Causes them to develop

- Promotes male secondary characteristics: Hair development over most  of the body, deeper voice, oily skin, increase in bone density, increase  in muscle mass

- Increases basal metabolic rate ???? It causes the breakdown in a lot more  of the reserves to produce all this energy

- Influences behavior—Increases sex drive and aggression  

• Role of inhibin:

- Produced by the Sertoli cells (Help regulate spermatogenesis) when  sperm count is high in the epididymis (Secreted when sperm is not  being released as much)

- Inhibits the release of FSH and GnRH to slow down sperm production  

26. Describe the location, structure and function of each of the organs in the  female reproductive system.

• Ovaries:

- Gametes (eggs) form in the cortex of the ovaries (Form before birth  but are immature at this point)

- Gametes exist as ovarian follicles ???? Oocyte + follicular or granulosar  cells

- One layer of cells that surround the gamete = follicular cells

- More than one layer of cells that surround the gamete = glanulosar  cells

- Women are born with all the follicles (and eggs) that they’re going to  possess

• Ovarian Follicles:

- Oocyte with one layer of cells around it (follicular) = what is in the  ovary when the female is first born and each one is called a primordial  follicle???? Born with 2 million primordial follicles to begin with

- Most primordial follicles will be absorbed by the woman’s body and  lose most of them before puberty

- At puberty, some primordial follicles will be stimulated to start  maturing ???? Therefore generally 4 or 5 that begin the process each  month

- When the process starts (Maturation), a primordial follicle changes to  a primary follicle with granulosar cells (The difference between the  two is the number of layers of the cell that surrounds the oocyte)

- Continued stimulation of hormones leads to the production of  secondary follicles from primary follicles

- Secondary follicles have many layers around the oocytes and have a  fluid-filled component called an antrum ???? The secondary follicle  continues to develop and gets larger + the fluid portion (antrum) itself  also continues to get bigger

- Next, the Graafian follicle (Antrum (Liquid )+ oocyte suspended on a  stalk) has developed after the secondary follicle ???? The Graafian  follicle pushes off like a cyst or abscess on the surface of the ovary and  continues to have increase in liquid  

- The Graafian follicle will then eventually rupture = ovulation and there  is the release of fluid along with the release of the egg

- Generally only one follicle reaches the Graafian phase out of the 4-5  that begin the maturation process each month  

- If more than one egg ovulates, more than one can be fertilized  - After the Graafian follicle ruptures open, the corpus luteum develops,  which is a glandular product that can secrete hormones

- The corpus luteum degenerates if the female is not pregnant and it  becomes scar tissue

• Oviducts:

- AKA fallopian tubes

- Ovulated oocyte is released into the peritoneal cavity  

- Between the ovary and oviducts, there is not direct connection  - Fimbriae are fingers of the oviduct that have cilia that begin to vibrate  due to hormonal stimulation and beat to create a current to draw the  oocyte towards the oviduct

- First entry point of the ovum into the oviduct: Infundibulum ???? Then  the egg moves through the ampulla of the oviduct???? then to the  isthmus of the oviduct that connects ultimately to the uterus  

- The natural/usual site of fertilization occurs in the ampulla portion of  the oviducts

- The unfertilized oocyte gets pushed along the same path  - If fertilization occurs elsewhere and in any place that it implants other  than the uterus, this is known as an ectopic pregnancy and can be life  threatening for the mother

• Uterus:

- The ovum is transported into the uterus via cilia on the oviducts that  beat along with peristaltic contractions that push it towards the uterus  where it will be stored

- The location oviducts that enter the uterus are known as the fundus - The ovum that is not fertilized will only be stored for about 14 day sin  the uterus  

- The uterus is a thick-walled muscular organ that receives, retains, and  nourishes the fertilized ovum

- It contains smooth and involuntary muscle in the body of the uterus,  making a thick wall

- Cervix: “Neck”; The portion that connects to the vagina - Os: Canal that transverses through the cervix with an internal os on the  uterine side and external os on the vaginal side ???? The os is what dilates at 10 cm during delivery

- Cervical canal has mucous that lines it ???? When the fertilized ovum  implants in the uterus, the mucous becomes thick and forms a plug to  act as a barrier in keeping foreign cells out

- When not pregnant, women still have cervical mucous that will change  its consistency based on the hormones produced ???? Ex: During  ovulation, it is slippery which makes it easier for sperm to travel  through

- Uterine Wall Layers:

a) Perimetrium: Outer layer of the uterus  

b) Myometrium: Thick muscular layer

c) Endometrium:  

o Lining of the uterus where the fertilized egg implants

o This makes it a highly vascularized region as a result

o Part of the endometrium sloughs off as a result if there isn’t  implantation of a fertilized egg

o Endometrium Strata:

▪ Stratum basalis: Stimulated by hormones to stimulate  

the functional layer of the stratum functionalis to be  

produced

▪ Stratum functionalis: Produced by the basal layer and is  what is sloughed off and is expelled through  

menstruation if not fertilization of the egg occurs

• Vagina:

- Female copulatory organ

- Birth canal: Where the baby is pushed through after gestation, and it is  mostly used as the canal for the blood flow from the shedding of the  lining of the uterus in menstruation  

- Maintains an acidic environment to prevent pathogen entry that could  destroy a developing embryo

- Hymen: A thin membrane of tissue that covers the external vaginal  orifice; It is very fragile and can be easily torn (Used to be used as a  measure of chastity and purity though)

• External Genitalia (Vulva):

- Mon pubis:  

o A pad of fat located on top of the pubic synthesis that protects  the pubic synthesis during intercourse

o Associated with having hair follicles

- Labia majora:  

o External most layer of the lips  

o Have hair follicles associated with it

- Labia minora:  

o Layer of lips under the labia majora  

o Has no hair follicles associated with it

o * All humans sexually develop as females first, but this is the  tissue that fuses together in males to create the scrotum; In  

females, the tissue remains apart to make an orifice  

- Great vestibular glands:

o Homologous to the bulbourethral glands of the male

o Upon sexual arousal, parasympathetic stimulation stimulates  these glands to secrete mucous that aids in the insertion of the  

penis

- Clitoris:

o Homologous to the penis in males

o Comprise of spongy tissue  

o During parasympathetic stimulation due to sexual arousal, it  will engorge with blood to make it more sensitive

- Perineum:

o Typically not seen as part of the vulva

o The tissue between the vulva and anus

o Often times it tears during child birth, so doctors perform an  episiotomy now where a surgical incision is made so it is easy  

to stitch the perineum back together and it won’t tear on its  

own  

27. Discuss the structure and function of the mammary glands. • The mammary glands are not technically considered to be a part of the  reproductive system

• Both males and females have mammary glands, but they only develop in  females and are suppressed in males

• Mammary glands function to produce milk and nourish a newborn baby  • Prolactin levels increase right before childbirth (Due to high estrogen  levels inhibiting the secretion of PIH by the hypothalamus) so milk is  produced and this will continue as long as suckling occurs

• Mammary gland is essentially a modified sweat gland

• It is divided into lobes that are divided into lobules

- Alveoli: Small sacs that produce the milk secretions (Site of milk  production)

- The alveoli are connected the lactiferous ducts that run through each  lobule

- All the ducts merge at the lactiferous sinus that is located behind the  nipple (Point of suckling)

- Areola: Ring of pigmented tissue that surrounds the nipple

- Similar to the anatomy of the testis that also has compartments  Female Reproductive Physiology 

28. Describe the process of oogenesis, and compare it to spermatogenesis. • Oogenesis (Pre-puberty):

- Production of female gametes

- Before birth, the gametes have already been produced + located in the  ovaries and are in suspension until puberty

- Oogonia = diploid cell that undergoes mitosis first to produce the  primary oocyte (Diploid) that has the follicular cell layer (1 layer of  cells surrounding the oocyte in the cortex of the ovary)

- Primary oocyte + follicular cell layer = primordial follicle (What  females are born with)

- Approximately 2 million primordial follicles are found in females’  ovaries before birth; by the time puberty occurs, there is only 400,000  primordial follicles left due to the absorption of many

- Females only ovulate about 500 potential viable gametes in a lifetime  - Primary oocytes (Part of the primordial follicle) will start but do NOT  finish meiosis I ???? Stop at prophase I until puberty begins where the  development of a few primordial follicles occurs each month

• Oogenesis (Post-Puberty)

- Under hormonal influence, some of the primordial follicles will  continue to develop and finish meiosis I ???? production of 1) Polar  body: Provides nourishment to the egg 2) Secondary oocyte ‘

* Both are haploid cells at this point

- The first polar body undergoes meiosis II and produced 2 more polar  bodies

- The secondary oocyte starts but doesn’t finish meiosis II if it is not  fertilized and will be expelled along with the endometrium lining of  the uterus  

- The secondary oocyte is what will be ovulated  

• Oogenesis (Post-ovulation):

- If fertilization occurs, the secondary oocyte (Haploid) completes  meiosis II ???? Production of ovum (But really a zygote since is has  been fertilized—same thing here according to Dr. Cummings) +  another polar body

- In total: Oogonium: Produces 1 gamete (ovum) + 3 polar bodies  • Spermatogenesis comparison: (See above notes for more explicit  differencs)

- Sperm is not produced until puberty

- Spermatogonia = diploid cell that first undergoes mitosis

- Results are 4 haploid gametes = spermatozoan (Sperm)

29. Describe the phases of the ovarian and uterine cycles, then related them to  one another and to the events of oogenesis.

** See question 30 for uterine cycle discussion involving events + hormone  incorporation  

A) Ovarian Cycle: 3 Phases

• Regulates the oogenesis process  

• On average, is 28 days long but can vary from 21-40 days ???? Variation  depends on the follicular phase in how fast the response of the follicle is to  the hormonal signals

• Follicular Phase:

- Associated with the development of the follicles in the ovaries  - Females are born with primordial follicles that development into  primary and later secondary follicles after puberty

- Secondary follicles ???? Graafian follicles

- Primordial follciles: 1 layer of follicular cells ???? Primary follicles - Primary follicles: 2 layers of granulosar cells (Or can be more than 2) ???? Secondary follicles

- Secondary follicle:

o Theca folliculi: A connective tissue layer of the secondary  

follicle that forms

o The theca and granulosa cells produce estrogen  

o Zona pellucida: Transparent membrane enriched with  

glycoproteins that are often receptor sites for sperm in this case  

that forms with the secondary follicle  

o Antrum: The single most identifiable characteristic of the  

secondary follicle that forms  

- Secondary follicle ???? Graafian follicle

o Have oocyte located on a stalk called the corona radiate

o At this point, there is a bulging on the surface of the ovary that  opens and releases the oocyte from the Graafian follicle  

• Ovulation:

- The ovary wall ruputures, releases the secondary oocyte and corona  radiate into the peritoneal cavity  

- The fimbriae move the oocyte into the oviduct

- Ways to tell when a female is ovulating:

o Increase in basal body temperature due to inflammation in the  rupturing of the Graafian follicle

o Viscosity of the cervical mucous: Thin

o Experience of pain that is associated with ovulation

o Female sexual receptivity increases

- There is a genetic component to the number of oocytes a female  ovulates and the number of oocytes increases with age ???? Therefore,  twins are more likely the older a female gets

o Identical Twins: When one oocyte is ovulated and there is one  sperm that fertilizes that oocyte + for chemical reasons, the  

fertilized ovum divides and one placenta is shared so  

genetically identical offspring are produced  

o Fraternal Twins: When more than one oocyte is ovulated, and  different sperm fertilize each one so that each have their own  

placenta and 2 different offspring are produced

• Luteal Phase:

- Anything that happens after ovulation and is associated with the  corpus luteum (Structure that the Graafian follicle turns into + is a  hormone secreting structure)

- When a ripened follicle releases an oocyte from the ovary, the ovary  experiences changes after ovulation  

- Corpus hemorrhagicum forms: Term for when ruptured ovarian tissue  has caused the antrum to fill with blood due to the ovulation process  o Corpus hemorrhagicum forms as a result but the blood is  

quickly absorbed and this leaves the granulosar cells and theca  

cells, which cause the remaining follicle to become the corpus  

luteum (Takes about 4 days)

- The corpus luteum begins to secrete progesterone and estrogen  - Progesterone keeps the uterus ready to except an embryo  

- The corpus luteum will be maintained and continue to produce  hormones until the placenta takes over 3 months into a pregnancy  - If fertilization does not occur, the corpus luteum degenerates and  becomes scar tissue = corpus albicans (Takes about 10 days)

- Luteal phase lasts a total of 14 days as a result

30. Identify the hormones involved in regulating these cycles, and discuss the  role each plays.

A) Ovarian Cycle:

• Prior to puberty, the ovaries produce estrogen that shuts off GnRH from  the hypothalamus (Which restricts the release of gonadotropins- LH and  FSH- from the anterior pituitary gland)

• At puberty, the sensitivity/receptivity of the hypothalamus to estrogen  reduces, so GnRH begins to be produced in rhythmic pulses  

• The resulting LH and FSH release from the anterior pituitary gland is  extremely irregular for the first 3 years on average

• Role of FSH:  

- Stimulates the follicle cells to grow and mature  

• Role of LH (Early Cycle):

- Produces androgens such as DHEA that are converted to estrogen via  thecal cells

- Estrogen conversion from DHEA is via granulosa cells

• Role of Estrogen:

- An initial rise in estrogen level inhibits the release of FSH and LH so  these gonadotropins are building up in the anterior pituitary

- Continued stimulation of estrogen stimulates follicle development - So, the more the follcilles develop, the more estrogen is produced - Eventually, the increasing estrogen levels get to a point where they are  very high and this causes a burst of LH (LH surge)

• Non-cyclic Role of Estrogen:

- Anabolic effects on female reproductive tract  

- Support short-term growth spurt of girls at puberty

- Promotes female secondary characteristics  

• Role of LH (Mid-Cycle):

- The LH surge as a result of high estrogen levels stimulates the  completion of meiosis I by the dominant primary follicle + stimulates  ovulation

- Therefore, the conversion of the primary oocyte to the secondary  oocyte in the dominant follicle is what ruptures and is the gamete that  is released from the ovary

- The stimulation of ovulation inhibits estrogen production since there  no longer is a follicle producing estrogen

- LH also stimulates the transformation of the ruptured follicle into the  corpus luteum, which begins the production of progesterone after estrogen is shut off  

• Progesterone:

- Progesterone inhibits FSH and LH (No more follicles are ripening at  this point)

- Progesterone production shuts off after 10 days if fertilization hasn’t  occurred

- The end of the ovarian cycle (Day 1 of period) is when hormone levels  are the lowest in a woman  

• Inhibin:

- Produced by the corpus luteum  

- Inhibits FSH and LH production of another gamete in the ovary - All the hormones are at the lowest level at this point, as already  mentioned

- FSH and LH start over and the ovarian cycle begins again (28 day  average)

B) Uterine Cycle: 3 Phases

• AKA menstrual cycle ???? Changes occurring with the lining  (endometrium) of the uterus due to hormones

• Menstrual Phase:

- Menstruation- bleeding

- Takes up about the first 5 days in cycle  

- Ovarian hormones are in the lowest levels at this point (FSH and LH  are turned off + corpus luteum is degenerating)

- The stratum functionalis detaches from the uterus and is expelled  through the vagina with menstruation  

- By day 5, the follicles are starting to produce estrogen  

• Proliferative Phase:

- Estrogen levels continue to increase ???? Effect of endometrium starting  to rebuild itself

- Endometrium becomes highly vascularized and begins to develop  many progesterone receptors in the endometrial cells – Continues until  ovulation occurs

• Secretory Phase:

- Progesterone causes the endometrium to prepare and thicken for  implantation if the oocyte is fertilized

- There is a change in cervical mucous so that a thick plug is formed and  will stay like this as long as there is progesterone present

- Decreasing progesterone and LH levels initiate the breakdown of the  endometrium

31. Differentiate the female sexual response to that of the male. • Arousal is similar to male  

• When stimulation occurs ???? excitement phase where parasympathetic  nervous activity causes the release of blood near the sex organs

• Erectile tissue:

- Clitoris, vagina walls, and labia will engorge with blood  

- Breasts will also engorge with blood and all listed are more sensitive  to touch

• Parasympathetic stimulation stimulates the vestibular glands to secrete  mucous for insertion (Like bulbourethral glands secreting pre-ejaculatory  fluid)

• With continued stimulation, there could be a climax

• For males to ejaculate, they must reach orgasm; This is not required for  conception to occur in females

• Female orgasm does not include ejaculation or refractory period—Males  do have a refractory period ???? Once they have ejaculated, they cannot be  stimulated again for a while

• Orgasm in females: Discharge of sympathetic neurons that causes a lot of  smooth muscle contractions + increase heart rate, blood pressure, and  oxytocin release for the sensation of pleasure  

32. Identify how sex is determined, and discuss the processes of sexual  differentiation.  

• Gender is determined by the genetic contribution of sperm

• Females have 2 X chromosomes = homologous

• Males have 1 X and 1 Y chromosome = heterozygous  

• SRY gene: On chromosome that promotes testes development via  stimulating testosterone production so the embryo becomes male • Embryo is sexually indifferent for the first 2 most post-conception: - Starting on week 5, the embryo develops gonadal ridges - Mullerian (Female) and Wolffian (Male) ducts develop at first but only  one will be maintained and the other will degenerate

- All the primordial germ cells are deposited = diploid cells that either  become spermatogonia or oogonia later

- Genital tubercle develops later intot he external genitalia ???? Contains  the urethral groove, folds, and labioscrotal swellings

• Sexual Differentiation (Male):

- Seminiferous tubules form in the gonadal ridges and link with  Wolffian ducts

- The developing testes secrete AMH which causes the Mullerian duct  to degenerate

- Genital tubercle enlarges to form the penis  

- Urethral folds fuse to form the urethra

- Labioscrotal folds fuse to form the scrotum

- Testosterone production guides secondary sexual development - Testes descend into the scrotum approximately 2 months before birth • Sexual Differentiation (Female)

- Gonadal ridges form the ovaries

- Follicles form in the cortex of the ovaries

- Mullerian ducts differentiate (There is no specific hormone to get rid  of the Wolffian ducts, so female ducts are dependent on AMH to make  this work)

- Wolffian ducts degenerate

- Genital tubercle gives rise to the clitoris

- Urethral groove become vestibule (Inner opening of the vagina) - Urethral folds stay unfused and become labia minora

- Labioscrotal folds stay unfused and become labia majora - Ovaries also descend but only to the pelvic brim from the abdominal  cavity

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