1. www.soran.edu.iq Physiology Behrouz Mahmoudi Endocrine System 1

2. www.soran.edu.iq What are the Properties of the Endocrine System? – Controls longer term metabolic processes – Shares some functions with nervous system – Releases hormones from endocrine cells Hormones are chemicals Hormones change metabolism of many cells Release controlled by negative feedback Hormones act on target cells Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Overview of the Endocrine System 2

3. www.soran.edu.iq An Overview of the Endocrine System Overview of the Endocrine System Figure 10-1 3

4. www.soran.edu.iq What is the Structure of Hormones? – Three chemical families Amino acid derivatives Peptides and proteins – Chains of amino acids Lipid derivatives – Steroids (e.g., testosterone) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 4

5. www.soran.edu.iq Target Cells Peripheral cells that can respond to a particular hormone Hormone receptor A protein in the cell membrane, or within the cytoplasm or nucleus, to which a hormone specifically binds to trigger its actions on a target cell. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 5

6. www.soran.edu.iq The Role of Target Cell Receptors in Hormonal Action Figure 10-2 6

7. www.soran.edu.iq Mechanisms of Hormone Action Figure 10-3(b) 7

8. www.soran.edu.iq Key Note Hormones control cells on a sustained basis. They circulate in the blood and bind to specific receptors on or in target cells. They change membrane permeability, activate or inactivate key enzymes, or change genetic activity. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 8

9. www.soran.edu.iq What is the Hypothalamus and Endocrine Control? – Three steps of action Hypothalamus releases hormones as an endocrine organ Hypothalamus releases regulatory hormones to control pituitary gland endocrine cells Autonomic centers cause direct neural control of adrenal medullae Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 9

10. www.soran.edu.iq Three Mechanisms of Hypothalamic Control over Endocrine Organs Figure 10-4 10

11. www.soran.edu.iq The Pituitary Gland What is the Pituitary Gland? – Also called the hypophysis – Releases nine important hormones All are peptide hormones Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 11

12. www.soran.edu.iq The Pituitary Gland Figure 10-5 The Location and Anatomy of the Pituitary Gland 12

13. www.soran.edu.iq The Pituitary Gland What are the Anterior Pituitary Hormones? – Thyroid-Stimulating Hormone (TSH) Triggers thyroid hormone release – Adrenocorticotropic Hormone (ACTH) Stimulates glucocorticoid release from adrenal gland – Follicle-Stimulating Hormone (FSH) Stimulates estrogen secretion, egg production (females), sperm production (males) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 13

14. www.soran.edu.iq The Pituitary Gland What are the Anterior Pituitary Hormones? (continued) – Luteinizing Hormone (LH) Triggers ovulation, progestin production (females), androgen production (males) – Prolactin (PRL) Stimulates mammary gland development and milk secretion – Growth hormone (hGH) Stimulates cell growth Melanocyte Stimulating Hormone (MSH) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 14

15. www.soran.edu.iq The Pituitary Gland What is the Posterior Pituitary Gland? – Antidiuretic Hormone (ADH) Reduces water loss in the urine Increases thirst – Oxytocin Stimulates uterine contraction, milk delivery Stimulates prostate gland smooth muscle Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 15

16. www.soran.edu.iq The Pituitary Gland Pituitary Hormones and Their Targets Figure 10-8 16

17. www.soran.edu.iq The Pituitary Gland Key Note Hypothalamic regulatory factors control the anterior pituitary (source of seven hormones). Most of these control other glands (thyroid, adrenal, gonads). It also produces growth hormone. The posterior pituitary releases two hormones produced in the hypothalamus, ADH (restricts water loss) and oxytocin (stimulates contractions in the mammary glands and uterus, and the prostate gland). Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 17

18. www.soran.edu.iq The Thyroid Gland What is the Anatomy of the Thyroid Gland? – Lies near thyroid cartilage of larynx – Has a rich blood supply – Contains numerous thyroid follicles Produce, store, release thyroid hormones Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 18

19. www.soran.edu.iq The Thyroid Gland What are the Thyroid Follicles and Thyroid Hormones? – Production requires adequate iodine in the diet – Occurs in two forms, thyroxine (T 4 ) and triiodothyronine (T 3 ) – Increases metabolism and heat production (calorigenic effect) – Required for normal development Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 19

20. www.soran.edu.iq The Thyroid Gland Figure 10-9 20

21. www.soran.edu.iq The Thyroid Gland What is the function of the C Cells of the Thyroid Gland? – Secrete calcitonin Lowers blood Ca 2+ levels Increases urinary calcium loss – Caused by high blood Ca 2+ level Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 21

22. www.soran.edu.iq The Parathyroid Glands What are the Parathyroid Glands? Chief cells produce parathyroid hormone Low blood Ca 2+ triggers secretion PTH raises blood Ca 2+ Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 22

23. www.soran.edu.iq Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Thyroid gland produces calcitonin Increased excretion of calcium in kidneys Calcium deposition in bone (inhibition of osteoclasts) Uncertain significance in a healthy nonpregnant adult Blood calcium levels decline HOMEOSTASIS DISTURBED Rising calcium levels in blood HOMEOSTASIS RESTORED HOMEOSTASIS Normal calcium levels (8.5-11 mg/dl) HOMEOSTASIS RESTORED HOMEOSTASIS DISTURBED Falling calcium levels in blood Release of stored calcium from bone (stimulation of osteoclasts, inhibition of osteoblasts) Enhanced reabsorption of calcium in kidneys Stimulation of calcitriol production at kidneys; enhanced Ca 2+, PO 4 3- absorption by digestive tract Parathyroid glands secrete parathyroid hormone (PTH) Blood calcium levels increase 23

24. www.soran.edu.iq The Parathyroid Glands Figure 10-11 The Parathyroid Glands 24

25. www.soran.edu.iq The Parathyroid Glands Key Note The thyroid gland produces (1) hormones that adjust tissue metabolic rates, and (2) a hormone that usually plays a minor role in calcium ion homeostasis by opposing the action of parathyroid hormone. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 25

26. www.soran.edu.iq The Adrenal Glands What is the Adrenal Gland Anatomy? – Lie along superior border of each kidney – Made of two parts Adrenal cortex (outer) Adrenal medulla (inner) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 26

27. www.soran.edu.iq The Adrenal Glands The Adrenal Gland 27

28. www.soran.edu.iq The Adrenal Glands What is the Adrenal Cortex? – Makes steroid hormones (corticosteroids) Glucocorticoids (e.g., cortisol) Mineralocorticoids (e.g., aldosterone) Androgens (male hormone) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 28

29. www.soran.edu.iq The Adrenal Glands What is the Adrenal Medulla? – Produces two related hormones Epinephrine (adrenaline) Norepinephrine (noradrenaline) – Increases heart rate and force, releases glucose, fatty acids into blood, opens airways Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 29

30. www.soran.edu.iq The Adrenal Glands Key Note The adrenal glands produce hormones that adjust metabolic activities at specific sites, affecting either the pattern of nutrient utilization, mineral ion balance, or the rate of energy consumption by active tissues. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 30

31. www.soran.edu.iq The Pineal Gland What is the Pineal Gland? – Produces melatonin Stops reproductive function Allows daily wake-sleep cycle Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 31

32. www.soran.edu.iq The Pancreas What is the Overview of the Pancreas? – Lies behind stomach and beneath liver – Endocrine cells organized into islets of Langerhans – Islet cells secrete insulin and glucagon Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 32

33. www.soran.edu.iq The Pancreas The Endocrine Pancreas 33

34. www.soran.edu.iq The Pancreas The Endocrine Pancreas 34

35. www.soran.edu.iq The Pancreas What are the Actions of Insulin and Glucagon? – Insulin Lowers blood glucose concentration – Glucagon Raises blood glucose concentration Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 35

36. www.soran.edu.iq Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Beta cells secrete insulin Increased rate of glucose transport into target cell Increased rate of glucose utilization and ATP generation Blood glucose concentration declines HOMEOSTASIS DISTURBED Rising blood glucose levels HOMEOSTASIS RESTORED HOMEOSTASIS Normal glucose levels (70-110 mg/dl) HOMEOSTASIS RESTORED HOMEOSTASIS DISTURBED Declining blood glucose levels Increased breakdown of glycogen to glucose (liver, skeletal muscle) Increased breakdown of fats to fatty acids (adipose tissue) Increased synthesis and release of glucose (liver) Alpha cells secrete glucagon Blood glucose concentration rises Increased conversion of glucose to glycogen (liver, skeletal muscle) Increased amino acid absorption and protein synthesis Increased fat synthesis (adipose tissue) 36

37. www.soran.edu.iq Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Beta cells secrete insulin Increased rate of glucose transport into target cell Increased rate of glucose utilization and ATP generation Blood glucose concentration declines HOMEOSTASIS DISTURBED Rising blood glucose levels HOMEOSTASIS RESTORED HOMEOSTASIS Normal glucose levels (70-110 mg/dl) Increased conversion of glucose to glycogen (liver, skeletal muscle) Increased amino acid absorption and protein synthesis Increased fat synthesis (adipose tissue) 37

38. www.soran.edu.iq Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 10-14 15 of 16 HOMEOSTASIS Normal glucose levels (70-110 mg/dl) HOMEOSTASIS RESTORED HOMEOSTASIS DISTURBED Declining blood glucose levels Increased breakdown of glycogen to glucose (liver, skeletal muscle) Increased breakdown of fats to fatty acids (adipose tissue) Increased synthesis and release of glucose (liver) Alpha cells secrete glucagon Blood glucose concentration rises 38

39. www.soran.edu.iq Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Beta cells secrete insulin Increased rate of glucose transport into target cell Increased rate of glucose utilization and ATP generation Blood glucose concentration declines HOMEOSTASIS DISTURBED Rising blood glucose levels HOMEOSTASIS RESTORED HOMEOSTASIS Normal glucose levels (70-110 mg/dl) HOMEOSTASIS RESTORED HOMEOSTASIS DISTURBED Declining blood glucose levels Increased breakdown of glycogen to glucose (liver, skeletal muscle) Increased breakdown of fats to fatty acids (adipose tissue) Increased synthesis and release of glucose (liver) Alpha cells secrete glucagon Blood glucose concentration rises Increased conversion of glucose to glycogen (liver, skeletal muscle) Increased amino acid absorption and protein synthesis Increased fat synthesis (adipose tissue) 39

40. www.soran.edu.iq Patterns of Hormonal Interaction What Hormones are Needed for Normal Growth? – Growth Hormone – Thyroid Hormones – Insulin – Parathyroid Hormone – Calcitriol – Reproductive Hormones Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 40

41. www.soran.edu.iq Patterns of Hormonal Interaction What are Hormones and Behavior? – Sex hormones Testosterone causes aggressiveness Estrogen causes sexual receptivity – Thyroid hormones Excess leads to nervousness, restlessness Deficiency leads to sluggishness – Antidiuretic hormone Leads to feeling of thirst, water intake Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings 41