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Principles of Anatomy and Physiology Thirteenth Edition Chapter 18 The Endocrine System Copyright © 2012 by John Wiley & Sons, Inc. Gerard J. Tortora Bryan.

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Presentation on theme: "Principles of Anatomy and Physiology Thirteenth Edition Chapter 18 The Endocrine System Copyright © 2012 by John Wiley & Sons, Inc. Gerard J. Tortora Bryan."— Presentation transcript:

1 Principles of Anatomy and Physiology Thirteenth Edition Chapter 18 The Endocrine System Copyright © 2012 by John Wiley & Sons, Inc. Gerard J. Tortora Bryan H. Derrickson

2 Thyroid gland Trachea PARATHYROID GLANDS PARATHYROID GLANDS (behind thyroid glands) SKIN Lung ADRENAL GLANDS PANCREAS SMALL INTESTINE Scrotum Male TESTES Female OVARY Uterus KIDNEY STOMACH HEART THYMUS Trachea THYROID GLAND PITUITARY GLAND HYPOTHALAMUS PINEAL GLAND LIVER

3 Hormone receptor Endocrine cell Circulating hormone Blood capillary Distant target cells (a) Circulating hormones

4 Paracrine receptor Autocrine receptor Autocrine cell (b) Local hormones (paracrines and autocrines) Autocrine Paracrine Paracrine cellNearby target cell

5 Aldosterone Steroid hormones

6 Triiodothyronine (T3) Thyroid hormones

7 Norepinephrine Amines

8 Oxytocin Peptides and proteins

9 A leukotriene (LTB4) Eicosanoids

10 Nucleus Cytosol Receptor DNA mRNA Ribosome New protein Activated receptor– hormone complex alters gene expression Newly Formed mRNA directs synthesis of specific proteins on ribosomes New proteins alter cell's activity Target cell Lipid-soluble hormone diffuses into cell Blood capillary Free hormone Transport protein 2 3 4 1

11 Activated protein kinases phosphorylate cellular proteins 4 Phosphodiesterase inactivates cAMP 6 Activated adenylate cyclase converts ATP to cAMP 2 Second messenger Binding of hormone (first messenger) to its receptor activates G protein, which activates adenylate cyclase 1 Adenylate cyclase Water-soluble hormone Receptor G protein ATP cAMP Protein kinases Activated protein kinases cAMP serves as a second messenger to activate protein kinases 3 Protein ATP ADP Protein - P Millions of phosphorylated proteins cause reactions that produce physiological responses 5 Blood capillary Target cell

12 POSTERIOR PITUITARY ANTERIOR PITUITARY Infundibulum Sagittal section of pituitary gland Hypothalamus Pituitary gland Primary plexus of hypophyseal portal system HYPOTHALAMUS Median eminence Superior hypophyseal artery Hypophyseal portal veins Sphenoid bone ANTERIOR PITUITARY Secondary plexus of hypophyseal portal system Anterior hypophyseal veins ANTERIORPOSTERIOR Inferior hypophyseal artery (a) Relationship of hypothalamus to pituitary gland Hypophyseal fossa Capillary plexus of infundibular process POSTERIOR PITUITARY Posterior hypophyseal veins Infundibulum

13 Hypophyseal portal veins Hypothalamic neurosecretory cell (b) Path of releasing and inhibiting hormones Primary plexus of hypophyseal portal system

14 Corticotroph (c) Histology of anterior pituitary Lactotroph Gonadotroph Thyrotroph Somatotroph LM all about 65x

15 Corticotropin-releasing hormone (CRH) Elevated cortisol inhibits release of CRH by hypothalamic neurosecretory cells Elevated cortisol inhibits release of corticotropin by anterior pituitary corticotrophs Cortisol Adrenal cortex Corticotropin stimulates secretion of cortisol by adrenal cortex Corticotropin (ACTH) Anterior pituitary CRH stimulates release of corticotropin (ACTH) Hypothalamus

16 A low level of hGH and IGFs decreases the rate of glycogen breakdown in the liver and glucose enters the blood more slowly 16 27 38 49 5 10 hGH and IGFs speed up breakdown of liver glycogen into glucose, which enters the blood more rapidly Blood glucose level falls to normal (about 90 mg/100 mL) Blood glucose level rises to normal (about 90 mg/100 mL) If blood glucose continues to decrease, hypoglycemia inhibits release of GHIH If blood glucose continues to increase, hyperglycemia inhibits release of GHRH GHIH inhibits secretion of hGH by somatotrophs GHRH stimulates secretion of hGH by somatotrophs hGH Anterior pituitary GHRH GHIH Low blood glucose (hypoglycemia) stimulates release of High blood glucose (hyperglycemia) stimulates release of

17 Human growth hormone (hGH), also known as somatotropin Liver (and other tissues) Thyroid-stimulating hormone (TSH), also known as thyrotropin Thyroid gland Ovaries Follicle-stimulating hormone (FSH) Testes Ovaries Luteinizing hormone (LH) Testes Mammary glands Prolactin (PRL) Adrenal cortex Adrenocorticotropic hormone (ACTH), also known as corticotropin Brain Melanocyte-stimulating hormone (MSH)

18 Hypothalamus Infundibulum Pituitary gland Neurosecretory cells HYPOTHALAMUS Optic chiasm Capillary plexus of the posterior pituitary ANTERIOR PITUITARY Axons of neurosecretory cells Axon terminal POSTERIOR PITUITARY

19 Target tissues 1 High blood osmotic pressure stimulates hypothalamic osmoreceptors 5 Low blood osmotic pressure inhibits hypothalamic osmoreceptors Osmoreceptors 2 activate neurosecretory cells that synthesize and release ADH 6 Inhibition of osmoreceptors reduces or stops ADH secretion Hypothalamus 3 Nerve impulses liberate ADH from axon terminals in posterior pituitary into bloodstream ADH Sudoriferous (sweat) glands decrease water loss by perspiration from skin Arterioles constrict, which increases blood pressure Kidneys retain more water, which decreases urine output 4

20 Oxytocin (OT) UterusMammary glandsKidneysSudoriferous (sweat) glands Arterioles Antidiuretic hormone (ADH) or vasopressin

21 Hyoid bone Superior thyroid artery Superior thyroid vein Thyroid cartilage of larynx Internal jugular vein LEFT LATERAL LOBE OF THYROID GLAND Common carotid artery ISTHMUS OF THYROID GLAND Vagus (X) nerve Trachea Inferior thyroid veins Sternum Pyramidal lobe of thyroid gland RIGHT LATERAL LOBE OF THYROID GLAND Middle thyroid vein Inferior thyroid artery Subclavian artery Thyroid gland Trachea (a) Anterior view of thyroid gland

22 Parafollicular (C) cell Follicular cell Thyroid follicle Thyroglobulin (TGB) (colloid) Basement membrane 500x (b) Thyroid follicles LM

23 LEFT LATERAL LOBE (c) Anterior view of thyroid gland RIGHT LATERAL LOBE ISTHMUS

24 Thyroid cartilage of larynx (d) Anterior view Cricoid cartilage of larynx RIGHT LATERAL LOBE OF THYROID GLAND LEFT LATERAL LOBE OF THYROID GLAND ISTHMUS OF THYROID GLAND Trachea Right lung Arch of aorta

25 Portion of thyroid follicle Follicular cell Blood capillary Colloid Iodination of tyrosine 4 Coupling of T 1 and T 2 5 Oxidation of iodide 3 Pinocytosis and digestion of colloid 6 Synthesis of TGB 2 Iodide trapping 1 Secretion of thyroid hormones 7 Transport in blood 8 Tyrosine T1T1 T2T2 T4T4 T3T3 Colloid TGB I2I2 Secretory vesicles Lysosome Golgi complex T3T4T3T4 T3T3 T4T4 Rough ER I–I– I–I– I–I– I–I– I–I– I–I– I–I– I–I– I–I– I–I– I–I– Blood plasma T3T3 T4T4 TBG Blood capillary Key: I – = Iodide; I 2 = Iodine TGB = thyroglobulin TBG = thyroxine-binding globulin

26 Elevated T 3 inhibits release of TRH and TSH (negative feedback) 5 T 3 and T 4 released into blood by follicular cells 4 Anterior pituitary TSH TRH Hypothalamus Low blood levels of T3 and T4 or low metabolic rate stimulates release of 1 TRH, carried by hypophyseal portal veins to anterior pituitary, stimulates release of TSH by thyrotrophs 2 TSH released into blood stimulates thyroid follicular cells 3 Thyroid follicle

27 T 3 (triiodothyronine) and T 4 (thyroxine) or thyroid hormones from follicular cells Calcitonin (CT) from parafollicular cells Thyroid follicle Follicular cells Blood vessel Thyroid follicle Parafollicular cells

28 Parathyroid glands (behind thyroid gland) Trachea

29 Right internal jugular vein Right common carotid artery Middle cervical sympathetic ganglion Thyroid gland RIGHT SUPERIOR PARATHYROID GLAND Inferior cervical sympathetic ganglion RIGHT INFERIOR PARATHYROID GLAND Vagus (X) nerve Right brachiocephalic vein Brachiocephalic trunk Trachea LEFT SUPERIOR PARATHYROID GLAND (a) Posterior view Esophagus LEFT INFERIOR PARATHYROID GLAND Left inferior thyroid artery Left subclavian artery Left subclavian vein Left common carotid artery

30 Venule Capillary Arteriole Chief cell Oxyphil cell 240x (b) Parathyroid gland LM

31 Blood vessel Parafollicular cell Follicular cell Thyroid gland (c) Portion of thyroid gland (left) and parathyroid gland (right) Chief cell Oxyphil cell Parathyroid gland Parathyroid Thyroid Capsule

32 Thyroid gland (d) Posterior view of parathyroid glands PARATHYROID GLAND PARATHYROID GLAND

33 PARATHYROID HORMONE (PTH) promotes release of Ca 2+ from bone extracellular matrix into blood and slows loss of Ca 2+ in urine, thus increasing blood Ca 2+ level. CALCITONIN inhibits osteoclasts, thus decreasing blood Ca 2+ level. Low level of Ca 2+ in blood stimulates parathyroid gland chief cells to release more PTH. High level of Ca 2+ in blood stimulates thyroid gland parafollicular cells to release more CT. 13 42 CALCITRIOL stimulates increased absorption of Ca 2+ from foods, which increases blood Ca 2+ level. 6 PTH also stimulates the kidneys to release CALCITRIOL. 5

34 Parathyroid hormone (PTH) from chief cells Chief cell

35 Inferior phrenic arteries Celiac trunk LEFT ADRENAL GLAND Left middle suprarenal artery Left inferior suprarenal artery Left suprarenal vein Left renal artery Left renal vein Right superior suprarenal arteries RIGHT ADRENAL GLAND Right middle suprarenal artery Right inferior suprarenal artery Right renal artery Right renal vein Kidney Adrenal glands Inferior vena cavaAbdominal aorta Superior mesenteric artery (a) Anterior view

36 CAPSULE ADRENAL CORTEX ADRENAL MEDULLA (b) Section through left adrenal gland

37 Kidney ADRENAL GLAND (c) Anterior view of adrenal gland and kidney

38 Zona glomerulosa secretes mineralocorticoids, mainly aldosterone Capsule (d) Subdivisions of adrenal gland Adrenal cortex: Zona fasciculata secretes glucocorticoids, mainly cortisol Zona reticularis secretes androgens Adrenal medulla chromaffin cells secrete epinephrine and norepinephrine (NE) 50x LM

39 Dehydration, Na + deficiency, or hemorrhage Decrease in blood volume Decrease in blood volume Angiotensinogen Increased renin Increased angiotensin I Increased angiotensin II Blood pressure increases until it returns to normal Vasoconstriction of arterioles Increased blood volume Increased K + in extracellular fluid In kidneys, increased Na + and water reabsorption and increased secretion of K + and H + into urine Increased aldosterone Juxtaglomerular cells of kidneys Liver ACE Lungs (ACE = angiotensin converting enzyme) Adrenal cortex Adrenal cortex 1 2 3 6 8 7 9 5 4 15 10 11 12 16 13 14

40 Some stimulus disrupts homeostasis by Decreasing Glucocorticoid level in blood Neurosecretory cells in hypothalamus Receptors Input Increased CRH and decreased cortisol Corticotrophs in anterior pituitary Control center Return to homeostasis when response brings glucocorticoid level in blood back to normal OutputIncreased ACTH Cells of zona fasciculata in adrenal cortex secrete glucocorticoids Effectors Increased glucocorticoid level in blood

41 Androgens (mainly dehydroepiandrosterone, or DHEA) from zona reticularis cells Epinephrine and norepinephrine from chromaffin cells Adrenal cortex Adrenal medulla

42 Common hepatic artery Abdominal aorta Celiac trunk Splenic artery Spleen (elevated) TAIL OF PANCREAS BODY OF PANCREAS Inferior pancreatic artery Superior mesenteric artery Inferior pancreaticoduodenal artery Gastroduodenal artery Dorsal pancreatic artery Anterior pancreaticoduodenal artery Duodenum of small intestine HEAD OF PANCREAS (a) Anterior view Pancreas Kidney

43 Blood capillary (b) Pancreatic islet and surrounding acini Exocrine acini Alpha cell (secretes glucagon) Beta cell (secretes insulin) Delta cell (secretes somatostatin) F cell (secretes pancreatic polypeptide)

44 Pancreatic islet 40x LM 200x LM Exocrine acinus Beta cell Alpha cell Pancreatic duct (c) Pancreatic islet and surrounding acini

45 Duodenum (cut open) Pancreas (d) Anterior view of pancreas dissected to reveal pancreatic duct

46 Low blood glucose(hypoglycemia) stimulates alpha cells to secrete 1 High blood glucose (hyperglycemia) stimulates beta cells to secrete 5 Glucagon acts on hepatocytes (liver cells) to: 2 Glucose released by hepatocytes raises blood glucose level to normal 3 If blood glucose continues to rise, hyperglycemia inhibits release of glucagon 4 convert glycogen into glucose (glycogenolysis) form glucose from lactic acid and certain amino acids (gluconeogenesis) Insulin acts on various body cells to: accelerate facilitated diffusion of glucose into cells speed conversion of glucose into glycogen (glycogenesis) increase uptake of amino acids and increase protein synthesis speed synthesis of fatty acids (lipogenesis) slow glycogenolysis slow gluconeogenesis Blood glucose level falls If blood glucose continues to fall, hypoglycemia inhibits release of insulin 6 7 8 INSULINGLUCAGON

47 Glucagon from alpha cells of pancreatic islets Insulin from beta cells of pancreatic islets Pancreatic polypeptide from F cells of pancreatic islets Somatostatin from delta cells of pancreatic islets Alpha cell Delta cell Beta cell F cell

48 Estrogens and progesterone Ovaries Testosterone Testes

49 STRESS RESPONSES 1. Increased heart rate and force of beat 2. Constriction of blood vessels of most viscera and skin 3. Dilation of blood vessels of heart, lungs, brain, and skeletal muscles 4. Contraction of spleen 5. Conversion of glycogen into glucose in liver 6. Sweating 7. Dilation of airways 8. Decrease in digestive activities 9. Water retention and elevated blood pressure STRESSORS stimulate Hypothalamus CRH GHRH TRH Nerve impulses Sympathetic centers in spinal cord Anterior pituitary Sympathetic nerves TSH hGH ACTH Adrenal medulla Epinephrine and norepinephrine Visceral effectors ACTHhGHTSH CortisolIGFs Thyroid hormones (T3 and T4) STRESS RESPONSES Lipolysis Gluconeogenesis Protein catabolism Sensitized blood vessels Reduced inflammation STRESS RESPONSES Lipolysis Glycogenolysis STRESS RESPONSES Increased use of glucose to produce ATP Adrenal cortex LiverThyroid gland Supplement and prolong “fight-or- flight” responses (a) Fight-or-flight responses(b) Resistance reaction Key: CRH = Corticotropin-releasing hormone ACTH = Adrenocorticotropic hormone GHRH = Growth hormone–releasing hormone hGH = Human growth hormone TRH = Thyrotropin-releasing hormone TSH = Thyroid-stimulating hormone

50 Stomodeum Hypophyseal (Rathke’s) pouch Neurohypophyseal bud Hypothalamus Thyroid diverticulumRespiratory diverticulum Esophagus Pharyngeal pouches 4 3 2 1 (a) Location of neurohypophyseal bud, hypophyseal (Rathke’s) pouch, thyroid diverticulum, and pharyngeal pouches in 28-day embryo

51 Neurohypophyseal bud Mouth cavity Hypophyseal (Rathke’s) pouch Infundibulum Pars intermedia Hypothalamus Infundibulum Anterior pituitary Posterior pituitary Mesenchyme (b) Development of pituitary gland between 5 and 16 weeks

52 (a) A 22-year-old man with pituitary giantism shown beside his identical twin

53 (b) Acromegaly (excess hGH during adulthood)

54 (c) Goiter (enlargement of thyroid gland)

55 (d) Exophthalmos (excess thyroid hormones, as in Graves’ disease)

56 (e) Cushing’s syndrome (excess glucocorticoids)


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