Endocrine System Notes for Final
Endocrine System Notes for Final BIOL 2510 - 001
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This 5 page Study Guide was uploaded by Brooke Polinsky on Saturday April 30, 2016. The Study Guide belongs to BIOL 2510 - 001 at Auburn University taught by Dr. Shobnom Ferdous in Spring 2016. Since its upload, it has received 31 views. For similar materials see Human Anatomy & Physiology II in Anatomy at Auburn University.
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Date Created: 04/30/16
Endocrine System Final Exam Notes: • What are all the types of endocrine glands? ◦ pituitary,thyroid,parathyroid,adrenal,and pineal glands • What kind of organ is the hypothalamus? ◦ neuroendocrine • Which organs have endocrine and exocrine functions? ◦ pancreas,gonads,and placenta • What are other tissues and organs that produce hormones? ◦ adipose cells,thus,and cells in walls of small intestine,stomach,kidneys,and heart • What are endocrine glands? ◦ ductless glands that secrete chemical messengers (hormones) into the blood stream o run extracellular ﬂuid then diffuse into bloodstream ◦ pituitary gland,pancreas,ovaires,testes,thyroid gland,adrenal glands • What are exocrine glands? ◦ secrete non-hormonal products to a membrane surface (body cavity,lumen of organ or body surface) through ducts ◦ salivary glands,mammary glands,chef cells in stomach,liver,pancreas ◦ PANCREAS IS BOTHTYPES OF GLANDS • What are hormones? ◦ chemical messengers related into bloodstream or ECF and then diffuse into bloodstream • What are autocrines? ◦ chemical messengers,exert effect on cells then secrete them • What are paracrine? ◦ chemical messengers,exert effect on nearby cells • How is the endocrine system different from the nervous system? ◦ releases hormones (vs.neurotransmitter) ◦ has a systemic effect (vs.localized) ◦ takes minutes or hours to have their effects (vs.milliseconds) ◦ effects canals for days,hours,years (vs.short lived) ◦ regulates long term ongoing metabolic function (vs.short term muscle/gland activity) • What are the four functions of the endocrine system? ◦ maintains the internal environment in body (the optimum biochemical environment) ◦ inﬂuences metabolic activities ◦ integrates and regulates growth and development ◦ controls,maintains,stimulates sexual reproduction, including gametogenesis,coitus,fertilization,fetal growth and development and nourishment of the newborn • What are three types of hormones? ◦ amino acid derivatives (amines)- constructed from the amino acid,tyrosine ‣ are water soluble ‣ ex:thyroid hormones and epinephrine and norepinephrine from adrenal medulla ◦ peptide hormones- consist of short or long chains of amino acids ‣ are water soluble ‣ thyrotropin-relaseing hormone (TRH from hypothalamus),ADH from posterior pituitary,oxytocin from posterior pituitary,growth hormone from anterior pituitary,LH,FSH both from anterior pituitary ◦ Lipid derivatives- are lipid soluble • What are the two types of lipid derivatives? ◦ steroid hormones- constructed from cholesterol ‣ ex:estrogen,testosterone,progesterone (from gonads) and glucocorticoids (from adrenal cortex) ◦ eicosanoids- made from fatty acids ‣ ex:prostaglandins (from cells throughout body) • What are target cells? ◦ cells whose activity is altered by hormone • The activation of the target cell depends on what three factors? ◦ Blood levels of the hormone which depend on: ‣ rate of synthesis/secretion ‣ levels of binding plasma proteins for lipid soluble hormones ‣ clearance rate (half-life) ◦ Relative number of receptors on the target cell ‣ up-regulation- target cells from more receptors in response to increasing blood levels of hormone ‣ down-regulation- target cells lose receptors in response to high levels of hormones ◦ Afﬁnity of those receptors for the hormone • In what two ways can hormones act on target cells? ◦ Activate second messengers (involves G proteins)- for amino acid derived and peptide hormones (water soluble) ◦ Activate Genes- for steroid and thread hormones (lipid-soluble) • What are the steps to activate second messengers? ◦ 1.hormone binds to a G-protein linked receptor on the plasma membrane ◦ 2.hormone binding activates G-protein ◦ 3.G-protein binds to enzyme,activating the enzyme to produce second messenger,such as cAMP ◦ 4.second messenger activates or inactivates enzymes in the cell • What are the steps to activate genes? ◦ 1.hormones diffuse through plasma membrane of target cells ◦ 2.bind to receptor in the cytoplasm or in the nucleus ‣ if bind to receptors in the cytoplasm,the hormone-receptor complex then enters the nucleus ◦ 3.in the nucleus,hormone-receptor complex binds to speciﬁc region of the DNA ◦ 4.either turns genes ON or OFF • What cellular changes in target cells do hormones produce? ◦ alter plasma membrane permeability by opening or closing ion channels ‣ Ex:Epi,Norepi open Ca channels on heart ◦ Increase or decrease there ate of synthesis of enzyme or proteins ◦ Activate or deactivate enzymes ‣ Ex:glucagon activates enzymes that carbolize glycogen ◦ Induce secretory activity ‣ Ex:progesterone on cervical mucus production during secretory phase of uterine cycle ◦ Stimulate Mitosis ‣ Ex:growth hormone on skeletal muscles • What three things that hormones released in response to? ◦ Humoral stimuli- a direct response to changes in blood levels of certain ion or nutrient ‣ Ex:low blood Ca causes secretion of parathyroid hormone ◦ Neural Stimuli- nerve ﬁbers stimulate hormone release ‣ sympathetic NS stimulates epinephrine and norepinephrine secretion from adrenal medulla ◦ Hormonal Stimuli- endocrine organ secrete hormones in response to hormones from another endocrine organ ‣ GnRH from hypothalamus-->LH and FSH from anterior pituitary-->estrogen from ovaries • What is most hormone relate controlled by? ◦ negative feedback mechanism- target cell response inhibits further hormone release • The pituitary gland is connected to the hypothalamus by what? ◦ infundibulum • What are the two major lobes of the pituitary glands? ◦ anterior pituitary- composed of glandular tissue,produce/secrete many hormones ◦ posterior pituitary- composed of neural tissue,CONTAINING supporting cells and nerve ﬁbers • Does the pituitary gland make its own hormones? ◦ no,it stores and releases hormones produced by hypothalamus • What is the hypothalamic-pituitary relationship with the anterior pituitary? ◦ no direct neural connection to hypothalamus,but has vascular connection- hypophyseal portal system (2 capillary beds in tandem,connected by veins) ◦ 1.secretion of the regulatory hormones from hypothalamic neurons ◦ 2.regulatory hormone travel through hypophyseal portal system into the anterior pituitary ◦ 3.hormones from anterior pituitary released into capillaries • What are the 6 hormones produced in the anterior pituitary in relation to the hypothalamic- pituitary relationship? ◦ all protein ◦ LH, FSH, PROLACTIN, ACTH, TSH, growth hormone • What is the hypothalamic-pituitary axis relationship with the posterior pituitary ◦ maintains neural connection with hypothalamus- hypothalamic-hypophyseal tract ◦ 2 hormones released=ADH,oxytocin ◦ 1.hypothalamic neurons synthesize oxytocin andADH ◦ 2.ADH and oxytocin stored in posterior pituitary within axon terminals of hypothalamic neurons ◦ 3.ADH or oxytocin released in response to action potentials from the hypothalamic neurons • What are pathologies that deal with growth hormones? ◦ Giagantism= hyper secretion of GH in children ◦ Acromegaly= hyper secretion of GH after epiphyseal plates are closed ‣ over growth of hands,feet,face ◦ Pituitary dwarﬁsm= hypo secretion of GH ‣ slows bone growth ‣ may coincide with deﬁciencies in other pituitary hormones • Where are the thyroid glands located? ◦ located on teaches,just inferior to the larynx • What are two structures inside thyroid glands? ◦ follicles= secrete thyroid hormones ‣ follicular cells= epithelial cells making up the walls of follicles synthesize thyroglobulin and secrete it into the cavity ‣ follicular cavity= stores colloid (ﬂuid with thyroglobulin and attached iodine atoms- forTH synthesis) ◦ Parafollicular cells ‣ secrete calcitonin= decreases blood Ca levels in animals,role not clear in humans • What are thyroid hormones? ◦ body's major metabolic hormones- affects almost every cell in the body except adult brain,spleen,testes,uterus,and thyroid gland itself • What are two active forms of thyroid hormones? ◦ thyroxine (T4)- lees potent form,has 4 iodine ions,predominantTH secreted by thyroid gland,mostT4 is converted to T3 at the target tissue ◦ triiodothyronine (T3)- more potent form,has 3 iodine ions,small amount is produced by thyroid hormone • What are the effects of the thyroid hormone on the body? ◦ promote glucose catabolism,mobilizes fats ◦ increases basal metabolic rate and body heat production ◦ increase adrenergic receptor in blood vessels (increase sensitivity to sympathetic NS activity) ◦ regulate tissue growth and development,including muscular,skeletal growth,development of NS • What are the steps to thyroid hormone synthesis? ◦ 1.follicular cell synthesizes enzymes and thyroglobulin,which are secreted not follicular cavity ◦ 2.iodide ions are transported into follicle cells ◦ 3.iodide ions then move into follicular cavity and are oxidized to iodine ◦ 4.enzymes add iodine to thyroglobulin to makeT1 andT2 ◦ 5.Enzymes linkT1 andT2 ‣ T1+T2 yieldsT3 ‣ T2+T2 yieldsT4 ◦ 6.Thyroglobulin endocytose back into follicular cell ◦ 7.enzymesT3 andT4 from thyroglobulin,hormones secreted into bloodstream • How does the body control thyroid hormone secretion? ◦ 1.stimuli for release ‣ decreased thyroid hormone levels in blood ‣ low body temperature ◦ 2.Thyrotropin-releasing hormone (TRH) from hypothalamus-->Thyroid stimulating hormone (TSH) from anterior pituitary-->T3 andT4 from thyroid gland ◦ 3.T3 andT4 exert negative feedback onto hypothalamus and anterior pituitary • What is hyperthyroidism? ◦ caused by Grave's Disease- autoimmune disease,abnormal antibodies mimcTSH ◦ Symptoms:increased BMR,heat production,sweating,muscle weakness,weight loss,hyperexcitable reﬂexes and psychological disturbances,rapid and irregular heartbeat,bulging eyeballs ◦ Treatment:surgically remove thyroid gland and consume radioactive iodine • What is hypothyroidism? ◦ cause:removal of thyroid gland and lack of iodine in diet ◦ symptoms:feeling cold,low metabolic rate,slowed reﬂexes,slow speech and thought process,slow heart rate,Goiter (enlarged thyroid gland,follicular cells produce colloid,but insufﬁcient iodine to makeT3 andT4) ◦ Treatment:iodine supplements and thyroid hormone replacement therapy • Where are parathyroid glands located? ◦ posterior of thyroid gland • What do parathyroid glands produce? ◦ parathyroid hormone (PTH) ◦ stimulate bone reabsorption by osteoclasts ◦ increase Ca reabsorption in kidneys ◦ involved in vitamin D metabolism: ‣ PTH stimulates kidneys to convert inactive vitamin D into active vitamin D3 in kidneys ‣ activated vitamin D needed for Ca absorption in intestines ◦ stimulus for release is low Ca levels • What is the adrenal medulla? ◦ inner portion,part of sympathetic NS ◦ secrete epinephrine and norepinephrine • What is the adrenal cortex? ◦ outer portion,glandular tissue ◦ secrete corticosteroids • What three corticosteroids does the adrenal cortex secrete? ◦ mineralocorticids= regulate ion concentrations in extracellular ﬂuid ◦ glucocorticoids= involved in stress response,inﬂuence metabolism of most body cells ‣ maintain glucocorticoid in humans= cortisol ◦ gonadocorticoids= adrenal sex hormones • What are adrenal glands stimulated by? ◦ physical,physiological ,and psychological stressors • What are the effects of stress on the body? ◦ Enhance essential systems for survival ‣ cardiovascular system,respiratory system,nervous system ◦ Suppress non-essential systems ‣ reproductive system,immune system,digestive system • What do epinephrine and norepinephrine do in response to stress? ◦ 1.Activation of NS ‣ secretes norepinephrine ‣ triggers adrenal medulla to secrete E and NE viaAch • What do epinephrine and norepinephrine affect? ◦ increases heart rate and blood pressure ◦ increases blood ﬂow to muscles ◦ increases respiration rate,bronchodialation ◦ decreases digestion ◦ decreases urine production • What is the adrenal glands stress response in the HPA axis? ◦ 1.hypothalamus secrete corticotropin-releasing hormone ◦ 2.CRH causes anterior pituitary to secrete ACTH ◦ 3.ACTH causes adrenal cortex to secrete glucocorticoids (mainly cortisol) and mineralocorticoids (mainly aldolsterone) ◦ 4.Cortisol causes:decrease in immune function,increase glycogenesis from liver (fat and protein-->glucose),breakdown of muscles,lipolysis in adipose tissues,decrease in Ca+ absorption in intestines,and decrease in HPG axis ◦ 5.Cortisol exerts negative feedback to reduce CRH andACTH ◦ 6.Aldosterone causes:increase of Na+ and water-->increases blood pressure • What is cushing's syndrome (hypercortisolism)? ◦ causes: ‣ adrenal tumor,excess secretion of cortisol ‣ pituitary tumor,excess secretion ofACTH ‣ iatrogenic Cushing's syndrome- caused by cortisol therapy ◦ Symptoms:high plasma glucose levels,loss of protein from muscles,hypertension/edma,redistribution of fat to face, neck,abdomen,poor wound healing • What is addison's disease? ◦ cause= hypo secretion of adrenal steroids ◦ symptoms= low plasma glucose and Na+,high plasma K+,dehydration and hypotension ◦ effects of chronic stress= hypertension,infertility,reduction in disease resistance,insulin resistance • What is the pineal gland? ◦ major hormone produced:melatonin ◦ stimulus for secretion ‣ light/dark-detected by photoreceptors in retina--> suprachiasmatic nucleus of hypothalamus-->pineal gland ‣ secretion follows daily cycle:low during day,highest at night
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