Endocrine System Hormone is a chemical messenger secreted

Endocrine System

Hormone is a chemical messenger secreted by one endocrine gland or cell into the bloodstream and targeted toward cells in another organ. - specificity - receptor - distribution

Chemical Identity of Hormones 1) Steroid hormones 2) Biogenic amines 3) Peptide hormones

1) Steroid hormones Estrogens Progesterone Androgens glucocorticoids aldosterone - derived from cholesterol

2) Biogenic amines Epinephrine Norepinephrine Dopamine Serotonin Melatonin thyroid hormones - Synthesized from amino acids

3) Peptide hormones Hypothalamic hormones Pituitary hormones Pancreatic hormones GI hormones - are peptides

Water Solubility and Membrane Permeability Steroid + thyroid hormones All other hormones Hydrophobic Membrane-permeable Hydrophilic Membrane-impermeable

Effects after hormones bind to their receptors 1) Synthesis of new proteins (enzymes) 2) Alterations of activities of proteins that are already present

Effects of Hormone Concentration

Effects of Hormone Concentration

Hormone Deactivation Hormones have short half-life (< 2 min) in the plasma.

Hormone Interactions Synergistic effects Two hormones act together to produce an effect that is greater than the sum of their separate effects. Permissive effects Only in the presence of one hormone, the target organ responds to a second hormone. Antagonistic effects One hormone opposes the action of another hormone.

Posterior Pituitary Hormone Target Organ Principal Effects 1) ADH Kidneys blood vessels reducing urine output vasoconstriction 2) Oxytocin Uterus, Labor contractions mammary glands, milk ejection

Anterior Pituitary Hormone Target Organ 1) FSH Principal Effects Ovaries and Testes (Follicle-Stimulating Hormone) follicle/egg or sperm development 2) LH Ovaries and testes Ovulation/growth of corpus luteum (Luteinizing Hormone) 3) TSH (Thyroid-Stimulating Hormone) Thyroid gland Growth of thyroid gland Secretion of thyroid hormone

Anterior Pituitary Hormone Target Organ Principal Effects 4) ACTH Adrenal cortex Growth of adrenal cortex (Adrenocorticotropic secretion of Hormone) glucocorticoids 5) PRL Mammary gland milk synthesis (Prolactin) Testes enhance secretion of testosterone

Anterior Pituitary Hormone 6) GH (Growth hormone or somatotropin) Target Organ Principal Effects Most tissues tissue/organ growth, cell mitosis and differentiation

Hypothalamus hormones

Hypothalamus Hormone 1) TRH Target Organ Pituitary Thyrotropin-releasing hormone 2) CRH Pituitary Corticotropin-releasing hormone 3) Gn. RH Pituitary Gonadotropin-releasing hormone 4) PRF Pituitary Prolactin-releasing factor Principal Effects Promotes TSH and PRL secretion Promotes ACTH secretion Promotes FSH/LH secretion Promotes PRL secretion

Hypothalamus Hormone 5) PIF Target Organ Pituitary Principal Effects Inhibits PRL secretion Prolactin-inhibiting factor Dopamine 6) GHRH Pituitary Promotes GH secretion Growth hormone-releasing hormone 7) GHIH Pituitary Growth hormone-inhibiting hormone somatostatin Inhibits GH/TSH secretion

Pineal Gland Hormone Target Organ Principal Effects 1) Melatonin Brain Regulate timing of puberty; influence mood 2) Serotonin Brain Regulate timing of puberty; influence mood

Thymus Hormone Target Organ Principal Effects Thymopoietin/ T lymphocytes Promote T lymphocyte Thymosins development/activation

Thyroid Gland Hormone Target Organ 1) Triiodothyronin Most tissues (T 3) 2) Throxin (T 4) 3) Calcitonin Principal Effects Stimulate Na+-K+ pumps, metabolic rate, heat production, alertness, protein synthesis, fetal and childhood growth, and CNS development Stimulates calcium Osteoblasts deposition and ossification; reduces blood calcium concentration

Parathyroid Gland Hormone PTH Parathyroid hormone Target Organ Small intestine, Kidneys, and Osteoclasts Principal Effects Stimulates calcium absorption and retention; promotes bone resorption; elevates blood calcium concentration

Adrenal Gland

Adrenal Medulla Hormone Target Organ 1) Epinephrin 2) Norepinephrin 3) Dopamine Most tissues Principal Effects Complement action of sympathetic nervous system

Adrenal Cortex Hormone 1) Aldosterone Target Organ Kidneys 2) Glucocorticoids Most tissues Cortisol/Corticosterone Principal Effects Promotes Na+ retention and K+ excretion; maintains blood pressure and volume Promote fat and protein catabolism, gluconeogesis, stress resistance, and tissue repair; inhibit inflammation

Adrenal Cortex Hormone 3) Androgen Target Organ Principal Effects Bone, muscle, Integument, many other organs Stimulate growth of pubic and axillary hair in both sexes; stimulate libido; negligible effcts in males compared to teststerone from testes

Pancreatic Islets Hormone Target Organ Principal Effects 1) Glucagon Primarily liver Stimulates glycogen and fat hydrolysis, mobilization of glucose and fatty acids, and gluconeogenesis 2) Insulin Promotes glucose and amino acid uptake and synthesis of glycogen, fat, and protein Most tissues

The Ovaries Hormone Estradiol Estragen Target Organ Ovaries, uterus, mammary glands, brain, many other tissues Principal Effects Regulates egg production; stimulates adolescent growth; promotes development of female secondary sex characteristics; prepares mammary glands for lactation; prepares uterus for pregnancy

The Ovaries Hormone Target Organ Progesterone Ovaries, uterus, mammary glands, many other tissues Principal Effects Stimulates mammary development in puberty and pregnancy; prepares uterus for pregnancy Inhibin Anterior pituitary Suppresses FSH secretion

The Testes Hormone Target Organ Testosterone Most Tissues Principal Effects Regulates sperm production; promotes development of male reproductive system and physique; stimulates adolescent growth, libido, and sexual behavior

Heart Hormone Target Organ ANF Kidneys Principal Effects Increases Na+ excretion and urine output; lowers blood pressure

Kidneys Hormone Target Organ Calcitriol Intestines Erythropoietin Renin Red Bone marrow angiotensinogen Principal Effects Increase absorption of calcium Stimulate RBC production Stimulate production of angiotensin I

Liver Hormone Angiotensinogen Target Organ Blood vessels, adrenal cortex, hypothalamus Erythropoietin Principal Effects Stimulates vasoconstriction, aldosterone secretion, and thirst

GI tract Hormone Gastrin Secretin Target Organ GI tract and its accessory glands CCK (cholecystokinin) GIP (gastric inhibitory peptide) Principal Effects Coordinate secretion and motility in digestion

Placenta Hormone Estrogen Progesterone Target Organ Maternal and fetal tissues Principal Effects Promotes fetal growth; regulate pregnancy; prepare mammary glands for lactation

Exercise

11. Digestion is a process to ___. A. take food into the mouth B. take absorbable nutrients into blood stream C. break ingested food into absorbable forms D store food in the digestive tract

1. W 2. Which of the following forms of nutrients cannot be directly absorbed into blood without digestion? A. Proteins B. fatty acids C. vitamin A D. glucose

33. The primary dietary carbohydrates are starch, which are ____. A. Monosaccharides B. polymers of glucose C. polymers of amino acids D. polymers of fatty acids

44. Fats or triglycerides ___. A. can be absorbed without digestion B. are digested into monoglycerides and fatty acids, then absorbed in the small intestine C. are digested into glucose, then absorbed in the small intestine D. are digested into amino acids, then absorbed in the small intestine

55. Which of the following is not secreted by gastric glands? A. pepsinogen B. trypsinogen C. HCl D. intrinsic factor

66. Which of the following is not a function of gastric acid? A. activating pepsinogen. B. digesting connective tissues in the ingested food C. destroying ingested pathogens D. activating pancreatic enzymes

77. Intrinsic factor has the function of ___? A. activating pepsinogen B. helping absorb vitamin B 12 C. helping absorb vitamin B 6 D. activating pancreatic enzymes

88. Pepsinogen is able to digest ___. A. proteins B. fats C. starch D. none of the above

99. Food digestion is completed primarily in ____. A. stomach B. small intestine C. large intestine

110. Gastric motility and secretion is ____. A. inhibited when food is ingested into the mouth B. stimulated when food enters the stomach C. strongly stimulated after chyme have entered the small intestine

111. Bile is produced by ____. A. hepatocytes B. gallbladder C. pancreas D. small intestine

112. Bile salts are needed for digestion and absorption of ____. A. carbohydrates B. proteins C. fats D. minerals

113. Which component of bile is reabsorbed via enterohepatic circulation? A. bile salts B. bile pigments C. cholesterol D. minerals

114. Pancreatic juice is ____. A. acidic (low p. H) B. basic (high p. H) C. neutral

115. Which of the following cannot be digested and absorbed by human pancreatic enzymes? A. starch B. proteins C. fats D. cellulose

116. Bile and pancreatic juice are released into duodenum when ___. A. chyme is not present in duodenum B. cholecystokinin is secreted by duodenal mucosa C. hepatopancreatic sphincter constricts D. gallbladder relaxes

117. Pancreatic zymogens are ___. A. active when stored in pancreatic duct B. activated after being released into duodenum

118. Proteins and carbohydrates can be digested into amino acids and glucose by ___. A. pancreatic enzymes alone B. pancreatic enzymes plus brush border enzymes C. brush border enzymes alone

119. Which of the following is not a hormone? A. gastrin B. cholecystokinin C. secretin D. intrinsic factor

220. Which type of the movement of the small intestine can push chyme towards the large intestine? A. peristalsis B. segmentation C. both peristalsis and segmentation

221. Which of the following is a function of gastrin? A. to stimulate the secretion of HCl and pepsinogen B. to inhibit gastric motility C. to inhibit motility of the large intestine

222. The functions of cholecystokinin include ___. A. to stimulate constriction of gallbladder B. to stimulate relaxation of hepatopanreatic sphincter C. to inhibit gastric secretion of motility D. all of the above

223. Bacterial flora ____. A. are present primarily in small intestine B. synthesize vitamins C. are harmful to human health

224. The large intestine primarily absorbs ___. A. glucose B. fatty acids C. amino acids D. water

225. Glucose is taken into intestinal epithelial cells directly by ____. A. Na+-K+ ATPase B. sodium-dependent glucose transporters C. potassium-dependent glucose transporters D. all of the above

226. Emulsification is required to complete digestion of ___. A. fats B. proteins C. carbohydrates D. water

227. Hunger and satiety are regulated by ____. A. the feeding center and satiety center at hypothalamus B. cholecystokinin C. appetite-stimulating hormones released by adipocytes D. all of the above

228. Which of the following nutrients is more often used to produce ATP? A. glucose B. fats C. proteins D. vitamins

229. Which of the following can be stored in human body? A. ATP B. Glucose C. Glycogen and fats D. All of the above

330. Which of the following fuel do neurons normally use? A. glucose B. amino acids C. fatty acids

31. Absorption of blood glucose by most tissue cells depends on ____. A. insulin B. insulin receptors C. both of the above

332. During absorptive state, ____. A. blood glucose is absorbed by all tissue cells B. excessive blood glucose is converted to glycogen or fat C. both of the above take place

333. Glycogen is synthesized and stored primarily in ____. A. liver B. kidneys C. neurons

34. Gluconeogenesis is a process that ____. A. glucose is synthesized from fats or amino acids B. occurs normally during absorptive state when blood glucose is abundant C. glycogen is hydrolyzed into glucose

335. During postabsorptive state, ____. A. blood glucose comes from glycogen and fats. B. blood insulin level is high C. blood glucagon is low D. all of the above take place

336. In which temporal order (first to last), are the following nutrients used to produce ATP when food is not available. A. Glycogen --- fats --- skeletal muscle proteins --- cardiac muscle proteins B. skeletal muscle proteins --- glycogen --- fats --- cardiac muscle proteins C. fats --- skeletal muscle proteins --- glycogen --- cardiac muscle proteins D. cardiac muscle proteins --- skeletal muscle proteins --- fats --- glycogen

337. Body heat is produced during ___. A. synthesis of ATP B. consumption of ATP C. both of the above

338. Thermoregulation center is located in ___. A. medulla oblongata B. hypothalamus C. spinal cord D. cerebral cortex

339. The body heat can be lost via ___. A. conduction B. radiation C. evaporation D. all of the above

440. The sex of an individual is determined by ____. A. sex chromosomes B. primary sex organs C. secondary sex organs D. secondary sex characteristics

441. Sperm cells are produced in ____. A. seminiferous tubules B. epididymus C. seminal vesicles D. vas differens

442. Sperm cells are stored in ____. A. seminiferous tubules B. epididymus C. seminal vesicles D. vas defferens

443. Semen contains ___. A. spermatozoan B. fructose C. prostaglandins D. all of the above

444. Sperm cells ___. A. start to migrate towards uterus immediately after being ejaculated into vagina B. are not able to fertilize an egg without capacitation C. can all find the egg

445. In which part of the female reproductive tract is an egg usually fertilized by a sperm cell? A. uterus B. vagina C. one third of uterine tube that is proximal to the uterus D. one third of uterine tube that is distal to the uterus

446. During which of the following period does a sexual intercourse have the maximum chance of resulting in pregnancy? A. starting at 48 hours before ovulation and ending at 14 hours after ovulation B. starting at 48 hours before ovulation and ending at 24 hours after ovulation C. starting at 48 hours before ovulation and ending at 48 hours after ovulation D. starting at 48 hours before ovulation and ending at 72 hours after ovulation

447. Which of the following statement is incorrect? A. Only one egg is released by two ovaries in each ovarian cycle B. Ovulation is triggered by a sudden increase of blood FSH level at day 14 C. FSH stimulates the development of follicles

448. Which of the following statements about corpus luteum is incorrect ? A. Corpus luteum normally secrets progesterone and estrogen B. Corpus luteum secrets progesterone and estrogen for only ~10 days, then undergo degeneration, no matter if the egg is fertilized or not. C. Corpus luteum is formed after the oocyte is ovulated.

449. Which of the following statement about uterus is incorrect? A. The growth and secretion of uterus depends on progesterone B. The uterus harbors embryo C. The uterus secrets nutrients D. The uterus does not contract at labor.

550. The p. H of vagina is usually ___. A. low (acidic) B. high (basic) C. neutral

551. Which of the following statements about HCG is correct? A. HCG is secreted by ovaries. B. HCG is found in blood 8 -10 days after fertilization C. HCG inhibits the secretion of progesterone from corpus luteum D. HCG stimulates the development of follicles.

552. In which of the following events, are the chemical messengers transported by the blood? A. endocrine B. paracrine C. autocrine D. synaptic communication

553. Hormones fall into the following chemical classes except ____. A. steroids B. biogenic amines C. fatty acids D. peptides

554. Which of the following hormone classes has their receptors located in the nucleus? A. steroid hormones B. peptide hormones C. biogenic amine hormones (except thyroid hormones)

555. Which of the following hormone classes stimulates synthesis of new proteins? A. steroid hormones B. peptide hormones C. biogenic amine hormones (except thyroid hormones)

556. Long-term exposure to high levels of a hormone causes ____ in the number of receptors and sensitivity to the hormone A. a decrease B. an increase C. no change

557. Which of the following statements is correct? A. Most hormones remain active for several hours after being released into the blood. B. About 50% of most hormones are deactivated a couple of minutes after being released into the blood. C. Hormones are primarily deactivated in muscles.

558. Which of the following hormones is not secreted by pituitary? A. luteinizing hormone (LH) B. thyrotropin releasing hormone (TRH) C. adrenocorticotropic hormone (ACTH) D. growth hormone (GH)

559. Which of the following hormones is synthesized in hypothalamus and secreted from pituitary? A. antidiuretic hormone B. prolactin C. follicle-stimulating hormone D. growth hormone

660. Which of the following hormones stimulates gluconeogenesis ? A. insulin B. vasopressin C. glucagon D. gastrin

661. Which of the following hormones has the strongest stimulatory effect on metabolic rate or heat production? A. thyroid hormone B. ADH C. Aldosterone D. oxytocin

662. Which of the hormone stimulates uterine labor contractions? A. thyroid hormone B. ADH C. Aldosterone D. oxytocin

663. Adrenal medulla secrets ____. A. catecholamines B. glucocorticoids C. aldosterone D. androgen