BIOL_2312___exam_3_study_guide_part_2.pdf BIOL 2312
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This 6 page Study Guide was uploaded by Anu on Sunday July 17, 2016. The Study Guide belongs to BIOL 2312 at University of Texas at Dallas taught by Dr. Mehmet Candas in Summer 2016. Since its upload, it has received 53 views.
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Date Created: 07/17/16
BIOL 2312 – MODERN BIOLOGY II - EXAM 3 STUDY GUIDE CHAPTER 49: Chemical Signals in Animals 15. What are the types of chemical signals? CHEMICAL SOURCE TARGET EXAMPLES SIGNAL Autocrine Signals Cell that On itself Cytokines – amplify response of a cell to a secretes stimulus Interleukin 2 – secreted by T cells to fight off infections Paracrine signals Cell that Nearby cells Insulin, Glucagon and Somatostatin- Islets secretes of Langerhans in the pancreas – control blood sugar levels ** also an autocrine (maybe endocrine because they can be secreted into blood stream) Endocrine Signals Cell that Transported to Oxytocin- induces labor and milk release secretes OR other cells by from mammary glands in females By discrete blood and other Refer to figure 49.2 in textbook (or slide 19 organs called body fluids in lecture notes) glands Neural Signals From To post synaptic Neurotransmitters presynaptic cell – membrane Acetylcholine (Ach) cell potential Neuroendocrine From neurons Carried by Neurohormones – do not act on or at the Signals blood/ other synapse body fluids to Antidiuretic hormone – produced by distant cells hypothalamus but acts on duct of kidney to regulate excretion of water 16. What is the chemical nature of hormones? Ans. Hormones belong to one of 3 chemical families: 1. Polypeptides 2. Amino acid derivatives 3. Steroids ** Animal hormones present in extremely small concentrations, yet have large effects. Below are some of the hormones of the human body. There are many more!!! POLYPEPTIDES AMINO ACID STEROIDS DERIVATIVES Not lipid soluble Most not lipid soluble lipid soluble Bind to receptors on surface of Bind to receptors on surface of bind to receptors inside target target cell target cell cell Examples: Examples: Examples: Hypothalamus: Thyroid Glands: Adrenal Glands: Growth-hormone-releasing Thyroid hormones Cortisol hormone Thyroxine (T4) Aldosterone Corticotropin-releasing Triiodothyronine (T3) Ovaries: hormone (CRH) Adrenal Glands: Estradiol Thyrotropin-releasing hormone Epinephrine Progesterone Gonadotropin-releasing Pineal Gland: Testes: hormone (GnRH) Melatonin Testosterone Antidiuretic hormone (ADH) Oxytocin Parathyroid glands: Parathyroid hormone (PTH) Kidneys: Erythropoietin (EPO) Anterior Pituitary Gland: Growth Hormone (GH) Adrenocorticotropic hormone (ACTH) Thyroid-stimulating hormone (TSH) Follicle-stimulating hormone (FSH) and Luteininzing hormone (LH) Prolactin (PRL) Pancreas: Insulin Glucagon ** Know the functions of the highlighted hormones!!! 17. What does endocrine, exocrine, and paracrine mean? Ans. Endocrine denotes to the glands or specialized cells that secrete hormones or other products directly into the blood stream to act on distant cells. Exocrine denotes to the glands that secrete their hormones through ducts opening into the epithelium rather than through the blood stream. Paracrine denotes to the hormones that has an effect only in the vicinity of the gland secreting it, and not to distant cells. 18. What are the main endocrine glands in human body? Where are they located in the body? Ans. There are 7 main endocrine glands in the human body, including: 1. Pituitary gland: distinct anterior and posterior regions, sits just below hypothalamus 2. Thyroid gland: situated in the neck 3. Parathyroid glands (4): embedded in thyroid gland 4. Kidneys: lie in posterior part of abdominal cavity 5. Adrenal glands: sit atop kidneys 6. Pancreas (endocrine part): located in anterior part of abdominal cavity 7. Ovaries/ testes: suspended below pelvic cavity. 19. What gland is also known as master gland in human body? Ans. The Pituitary gland is known as the master gland in the human body because its hormones control other parts of the endocrine system, namely the thyroid gland, adrenal glands, ovaries, and testes. 20. Why do hormones exert action only specific cells/tissues in the body? Ans. Hormones are broadcast throughout the body via the bloodstream, but they act only on cells that express the appropriate receptor. Target cells respond to a particular hormone because they contain a receptor for that hormone. 21. What is the function of epinephrine? Ans. Epinephrine, also known as adrenaline, is secreted by the adrenal gland by the sympathetic nerves. In dangerous situations, the short-term reaction, known as fight-or-flight response is triggered by the sympathetic nervous system. Epinephrine produces many effects related to short- term stress response. 22. What is the function of testosterone? Ans. Testosterone is a hormone produced by testes that induces the male reproductive system. Also in human males, testes also produces Mullerian inhibitory substance, which inhibits the female reproductive system development. 23. What is the function of aldosterone? + Ans. Aldosterone is released by the adrenal glands (a steroid), and increases the reabsorption of Na by kidneys. It is released when ion concentrations in body fluids are low, resulting in increased reabsorption of Na ions in the distal tubes of the kidney. Adrenal hormones are also known as Mineralocorticoids. 24. What is the function of secretin? Ans. Secretin is a hormone secreted by the small intestines that signals cells in the pancreas via bloodstream to secret buffers that neutralize the acid. 25. What is the function of cholecystokinin? Ans. Cholecystokinin plays a key role in facilitating digestion within the small intestine. It is secreted from mucosal epithelial cells in the first segment of the small intestine (duodenum), and stimulates delivery into the small intestine of digestive enzymes from the pancreas and bile from the gallbladder. 26. What is the function of insulin? Ans. Insulin decreases blood glucose. 27. What is the function of corticosterone? Ans. Corticosterone is a steroid hormone of the adrenal cortex. It is classified as a gluticocorticoid. Corticosterone is converted to aldosterone by aldosterone synthase. It is the precursor molecule to the mineralocorticoid aldosterone, one of the major homeostatic modulators of sodium and potassium levels. 28. What is the function of cortisol? Ans. Cortisol produces many effects related to short-term and long term stress responses. IT is produced by the adrenal gland. The hormone ensures the continued availability of glucose for use by the brain. It is also referred to as glucocorticoid because of its importance in regulating blood glucose. Cortisol manages three processes for the maintenance of glucose production: 1. Induces liver to produce enzymes that generate glucose from amino acids 2. Changes adipose tissue and resting muscles resistant to insulin so they will not take in glucose 3. Promotes release of fatty acids for use by heart and muscles. 29. What is the function of antidiuretic hormone? Ans. When an individual is dehydrated, antidiuretic hormone (ADH) is released by pituitary gland. ADH increases permeability of kidney’s collecting ducts to water, so water is reabsorbed from urine (concentrated urine). 30. What is the function of progesterone? Ans. Progesterone prepares uterus for pregnancy 31. What is the function of erythropoietin? Ans. Erythropoietin (EPO) is a crucial element in the homeostatic system for blood oxygen levels. When blood oxygen levels falls, kidneys and other tissues releases EPO, which stimulates production of more red blood cells. 32. What is the function of estrogen? Ans. The primary function of estrogens is development of female secondary sexual characteristics. These includes breasts, endometrium, regulation of the menstrual cycle etc. It is required for further development of the female reproductive tract. 33. What is the function of testosterone? Ans. Testosterone regulates development and maintenance of secondary sex characteristics in males and induces development of male reproductive system. 34. What is the function of leptin? Ans. Leptin was found to be a polypeptide-type hormone secreted into blood by adipocytes. It interacts with various tissues and part of the brain to control feeding behavior and influence metabolism. When there are sufficient food supplies, and triglyceride levels have risen, homeostasis is achieved by this feedback mechanism. Leptin triggers hypothalamus to suppress appetite in response to increases in adipose tissue mass. According to the experiment with the mice, ob/ob mice do not produce leptin and db/db mice do not have leptin receptors although they do produce leptin. 35. What is catecholamine? Ans. Epinephrine and Norepinephrine are members of a family of molecules called catecholamine, which function as neurotransmitters as well as hormones. Two modes of control include: 1. Neurotransmitters change gene expression in neurons 2. Hormones change gene expression in target cells. 36. Why do coffee-drinkers urinate more frequently? Ans. Caffeine is a diuretic. Opposite to an ADH, a diuretic does not reabsorb water in the kidneys and urine is more dilute. 37. What is the hallmark of goiter? Ans. When you have Hashimoto's thyroiditis, your immune cells mistakenly attack your healthy thyroid tissue. When this occurs, your thyroid can become inflamed and enlarged to the point that you develop a goiter. The primary sign of a goiter is visible swelling in the front of your neck. At first, the bulge may be painless. But if left untreated, it can put pressure on your lower neck. In advanced stages, a goiter can interfere with proper breathing and swallowing. ** Source: http://www.endocrineweb.com/conditions/hashimotos-thyroiditis/symptoms-hashimotos- thyroiditis 38. What are the second messengers? How are they generated? Ans. Second messengers are non-protein signaling molecules that increases in concentration inside a cell in response to a received signal- a molecule that binds at the surface. Second messengers serve to greatly amplify the strength of the signal. Binding of a ligand to a single receptor at the cell surface may end up causing massive changes in the biochemical activities within the cell. There are 3 major classes of second messengers: 1. cyclic nucleotides (e.g., cAMP and cGMP) 2. inositol trisphosph2+e (IP )3and diacylglycerol (DAG) 3. calcium ions (Ca ) 39. Where do second messengers act? How do second messengers act? Ans. The second messengers act inside the cell, amplifying the hormones signal by attaching to various proteins. For example, in the case of epinephrine, cAMP binds to cAMP-dependent protein kinase A to activate it, further activating other proteins. The second messenger initiates chain of events called as signal transduction cascade, by binding to an enzymes. End of study guide
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