Physiology Endocrine System Behrouz Mahmoudi www soran edu

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

Overview of the Endocrine System • What are the Properties of the Endocrine System? – Controls longer term metabolic processes – Shares some functions with nervous system – Releases hormones from endocrine cells • • www. soran. edu. iq 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 2

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

• 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) www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 4

• 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. www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 5

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

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

• 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. www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 8

• 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 www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 9

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

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

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

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) www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 13

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 (h. GH) • Stimulates cell growth • Melanocyte Stimulating Hormone (MSH) www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 14

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 www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 15

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

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). www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 17

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 www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 18

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 www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 19

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

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 www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 21

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

Increased excretion of calcium in kidneys Thyroid gland produces calcitonin Calcium deposition in bone (inhibition of osteoclasts) Blood calcium levels decline Uncertain significance in a healthy nonpregnant adult HOMEOSTASIS DISTURBED Rising calcium levels in blood HOMEOSTASIS DISTURBED HOMEOSTASIS RESTORED HOMEOSTASIS Normal calcium levels (8. 5 -11 mg/dl) HOMEOSTASIS RESTORED Falling calcium levels in blood Release of stored calcium from bone (stimulation of osteoclasts, inhibition of osteoblasts) Parathyroid glands secrete parathyroid hormone (PTH) Enhanced reabsorption of calcium in kidneys Stimulation of calcitriol production at kidneys; enhanced Ca 2+, PO 43 absorption by digestive tract www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Blood calcium levels increase 23

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

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. www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 25

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) www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 26

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

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

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 www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 29

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. www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 30

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

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 www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 32

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

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

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

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

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

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

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

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

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 www. soran. edu. iq Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 41