Essentials of Anatomy and Physiology Fifth edition Seeley, Stephens and Tate Slide 2.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 10: Endocrine System

Thyroid Gland Slide 9.23a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Found at the base of the throat  Consists of two lobes and a connecting isthmus  Produces two hormones  Thyroid hormone  Calcitonin

Thyroid Gland Slide 9.23b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 9.6

Thyroid Hormone Slide 9.24 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Major metabolic hormone  Composed of two active iodine- containing hormones  Thyroxine (T 4 ) – secreted by thyroid follicles  Triiodothyronine (T 3 ) – conversion of T 4 at target tissues

Thyroid Hormone Slide 9.24 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Target: all body cells  Action:  Regulation of cell metabolism  Oxygen utilization

Calcitonin Slide 9.25 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Antagonistic to parathyroid hormone  Produced by C (parafollicular) cells Figure 9.9

Calcitonin Slide 9.25 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Target: osteocytes  Action:  Decreases blood calcium levels  Stimulates Ca ++ deposition in bone Figure 9.9

Parathyroid Glands Slide 9.26 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Tiny masses on the posterior of the thyroid  Secrete parathyroid hormone (PTH)

Parathyroid Glands Slide 9.26 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Target: Osteoclasts  Action:  Stimulate osteoclasts to remove calcium from bone  Stimulate the kidneys and intestine to absorb more calcium  Raise calcium levels in the blood

Adrenal Glands Slide 9.27 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Paired glands above kidneys  Cortex  outer glandular region  in three layers  Medulla – inner neural tissue region

Hormones of the Adrenal Cortex Slide 9.28a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Mineralocorticoids (mainly aldosterone)  Target: the kidneys  Action:  Regulate mineral content in blood  Water, electrolyte balance (Na + retention)  Increase blood pressure

Hormones of the Adrenal Cortex Slide 9.28b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 9.10

Hormones of the Adrenal Cortex Slide 9.29a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Glucocorticoids (including cortisone and cortisol)  Target: Most body cells  Actions:  Promote normal cell metabolism  Help resist long-term stressors  Depress immune response

Hormones of the Adrenal Cortex Slide 9.29b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Sex hormones  Produced in the inner layer of the adrenal cortex  Androgens (male) and some estrogen (female)  Target: gonadal tissue  Action: development of secondary sex characteristics

Hormones of the Adrenal Medulla Slide 9.30 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Produces Epinephrine, Norepinephrine  Target: Sympathetic nervous system  Action:  Prepare the body to deal with short-term stress  Potentiate sympathetic response

Roles of the Hypothalamus and Adrenal Glands in the Stress Response Slide 9.31 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 9.12

Pancreatic Islets Slide 9.32a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  The pancreas is both endocrine and exocrine  The islet cells produce hormones  Insulin – produced by ß cells  Target: all cells, esp. muscle, adipose  Action: enhances glucose transport across plasma membranes

Pancreatic Islets Slide 9.32a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Glucagon – produced by  cells  Target: the liver  Action:  breakdown of glycogen to glucose  Increases blood sugar  These hormones are antagonists that maintain blood sugar homeostasis

Pancreatic Islets Slide 9.32b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 9.13

Pancreatic Hormones and Blood Sugar Slide 9.33 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 9.14

Pineal Gland (“Third Eye”) Slide 9.34 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Found above third ventricle of the brain  Secretes melatonin  Target: Sleep centers in brain, gonads  Action:  Helps establish the body’s Circadian rhythms  Affects timing of puberty

Thymus Slide 9.35 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Located posterior to the sternum  Largest in infants and children  Produces thymosin, thymopoietin  Target: immature white blood cells  Action:  Maturation of T-cells  Important in developing the immune system

Hormones of the Ovaries Slide 9.36 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Estrogens  Produced by Graafian follicles or the placenta  Targets:  Gonadal tissue  Female reproductive organs

Hormones of the Ovaries Slide 9.36 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Actions:  Stimulates the development of secondary female characteristics  Matures female reproductive organs  Helps prepare the uterus to receive a fertilized egg  Helps maintain pregnancy  Prepares the breasts to produce milk

Hormones of the Ovaries Slide 9.37 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Progesterone  Produced by the corpus luteum  Target: Uterus, breast tissue  Action:  Acts with estrogen to regulate the menstrual cycle  Helps maintain pregnancy

Hormones of the Testes Slide 9.38 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Interstitial cells produce several androgens  Testosterone is the most important  Target:  Male reproductive organs  Skeletal muscle  Skeletal system  Larynx

Hormones of the Testes Slide 9.38 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Actions:  Responsible for adult male secondary sex characteristics  Promotes growth and maturation of male reproductive system  Required for sperm cell production

Other Hormone-Producing Tissues and Organs Slide 9.39 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Parts of the small intestine  Parts of the stomach  Kidneys  Heart  Many other areas have scattered endocrine cells

Endocrine Function of the Placenta: FYI Slide 9.40 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Produces hormones that maintain the pregnancy  Some hormones play a part in the delivery of the baby  Produces HCG in addition to estrogen, progesterone, and other hormones

Developmental Aspects of the Endocrine System: FYI Slide 9.41 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Most endocrine organs operate smoothly until old age  Menopause is brought about by lack of efficiency of the ovaries  Problems associated with reduced estrogen are common  Growth hormone production declines with age  Many endocrine glands decrease output with age