Slide 2.1

Human Anatomy Human Anatomy

Endocrine System

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Slide 9.23a

Thyroid GlandThyroid Gland

Found at the base of the throat Consists of two lobes and a connecting

isthmus Produces two hormones

Thyroid hormone Calcitonin

Slide 9.23b

Thyroid GlandThyroid Gland

Figure 9.6

Slide 9.24

Thyroid HormoneThyroid Hormone

Major metabolic hormone Composed of two active iodine-

containing hormones Thyroxine (T4) – secreted by thyroid

follicles Triiodothyronine (T3) – conversion of T4 at

target tissues

Slide 9.24

Thyroid HormoneThyroid Hormone

Target: all body cells Action:

Regulation of cell metabolism Oxygen utilization

Slide 9.25

CalcitoninCalcitonin

Antagonistic to parathyroid hormone

Produced by C (parafollicular) cells

Figure 9.9

Slide 9.25

CalcitoninCalcitonin

Target: osteocytes Action:

Decreases blood calcium levels

Stimulates Ca++ deposition in bone

Slide 9.26Parathyroid GlandsParathyroid Glands

Tiny masses on the posterior of the thyroid

Secrete parathyroid hormone (PTH)

Slide 9.26

Parathyroid GlandsParathyroid Glands

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

Slide 9.27

Adrenal GlandsAdrenal Glands

Paired glands above kidneys Cortex

outer glandular region in three layers

Medulla – inner neural tissue region

Slide 9.28a

Hormones of the Adrenal CortexHormones of the Adrenal Cortex

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

Slide 9.28b

Hormones of the Adrenal CortexHormones of the Adrenal Cortex

Figure 9.10

Slide 9.29a

Hormones of the Adrenal CortexHormones of the Adrenal Cortex

Glucocorticoids (including cortisone and cortisol)

Target: Most body cells Actions:

Promote normal cell metabolism Help resist long-term stressors Depress immune response

Slide 9.29b

Hormones of the Adrenal CortexHormones of the Adrenal Cortex 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

Slide 9.30

Hormones of the Adrenal MedullaHormones of the Adrenal Medulla

Produces Epinephrine, Norepinephrine Target: Sympathetic nervous system Action:

Prepare the body to deal with short-term stress

Potentiate sympathetic response

Slide 9.31

Roles of the Hypothalamus and Adrenal Roles of the Hypothalamus and Adrenal Glands in the Stress ResponseGlands in the Stress Response

Figure 9.12

Slide 9.32a

Pancreatic IsletsPancreatic Islets

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

Slide 9.32a

Pancreatic IsletsPancreatic Islets

Glucagon – produced by cells Target: the liver Action:

breakdown of glycogen to glucoseIncreases blood sugar

These hormones are antagonists that maintain blood sugar homeostasis

Slide 9.32b

Pancreatic IsletsPancreatic Islets

Figure 9.13

Slide 9.33

Pancreatic Hormones and Blood SugarPancreatic Hormones and Blood Sugar

Figure 9.14

Slide 9.34

Pineal Gland (“Third Eye”)Pineal Gland (“Third Eye”)

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

Slide 9.35

ThymusThymus

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

Slide 9.36

Hormones of the OvariesHormones of the Ovaries Estrogens

Produced by Graafian follicles or the placenta Targets:

Gonadal tissue Female reproductive organs

Slide 9.36

Hormones of the OvariesHormones of the Ovaries 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

Slide 9.37

Hormones of the OvariesHormones of the Ovaries

Progesterone Produced by the corpus luteum

Target: Uterus, breast tissue Action:

Acts with estrogen to regulate the menstrual cycle

Helps maintain pregnancy

Slide 9.38

Hormones of the TestesHormones of the Testes Interstitial cells produce several

androgens Testosterone is the most important

Target: Male reproductive organs Skeletal muscle Skeletal system Larynx

Slide 9.38

Hormones of the TestesHormones of the Testes

Actions: Responsible for adult male secondary sex

characteristics Promotes growth and maturation of male

reproductive system Required for sperm cell production

Slide 9.39

Other Hormone-Producing Tissues Other Hormone-Producing Tissues and Organsand Organs

Parts of the small intestine Parts of the stomach Kidneys Heart Many other areas have scattered

endocrine cells

Slide 9.40

Endocrine Function of the Placenta: Endocrine Function of the Placenta: FYIFYI

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

Slide 9.41

Developmental Aspects of the Developmental Aspects of the Endocrine System: FYIEndocrine System: FYI 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