1. Slide 2.1
Human AnatomyHuman Anatomy
Endocrine System
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2. 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

3. Slide 9.23b
Thyroid GlandThyroid Gland
Figure 9.6

4. 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

5. Slide 9.24
Thyroid HormoneThyroid Hormone
• Target: all body cells
• Action:
• Regulation of cell metabolism
• Oxygen utilization

6. Slide 9.25
CalcitoninCalcitonin
• Antagonistic to
parathyroid
hormone
• Produced by C
(parafollicular)
cells
Figure 9.9

7. Slide 9.25
CalcitoninCalcitonin
• Target: osteocytes
• Action:
• Decreases blood
calcium levels
• Stimulates Ca++
deposition in
bone

8. Slide 9.26
Parathyroid GlandsParathyroid Glands
• Tiny masses on
the posterior of
the thyroid
• Secrete
parathyroid
hormone (PTH)

9. 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

10. Slide 9.27
Adrenal GlandsAdrenal Glands
• Paired glands above kidneys
• Cortex
• outer glandular region
• in three layers
• Medulla – inner neural tissue region

11. 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

12. Slide 9.28b
Hormones of the Adrenal CortexHormones of the Adrenal Cortex
Figure 9.10

13. 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

14. 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

15. 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

16. Slide 9.31
Roles of the Hypothalamus and AdrenalRoles of the Hypothalamus and Adrenal
Glands in the Stress ResponseGlands in the Stress Response
Figure 9.12

17. 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

18. Slide 9.32a
Pancreatic IsletsPancreatic Islets
• Glucagon – produced by α cells
• Target: the liver
• Action:
•breakdown of glycogen to glucose
•Increases blood sugar
• These hormones are antagonists that
maintain blood sugar homeostasis

19. Slide 9.32b
Pancreatic IsletsPancreatic Islets
Figure 9.13

20. Slide 9.33
Pancreatic Hormones and Blood SugarPancreatic Hormones and Blood Sugar
Figure 9.14

21. 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

22. 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

23. Slide 9.36
Hormones of the OvariesHormones of the Ovaries
• Estrogens
• Produced by Graafian follicles or the placenta
• Targets:
• Gonadal tissue
• Female reproductive organs

24. 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

25. 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

26. 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

27. 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

28. Slide 9.39
Other Hormone-Producing TissuesOther Hormone-Producing Tissues
and Organsand Organs
• Parts of the small intestine
• Parts of the stomach
• Kidneys
• Heart
• Many other areas have scattered
endocrine cells

29. 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

30. Slide 9.41
Developmental Aspects of theDevelopmental 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