1. Exocrine vs. endocrine glands
Exocrine glands secrete their products into ducts that carry these products to other organs or outside the body
Endocrine glands secrete their products directly into the bloodstream
Hormones are chemical signals that promote communication between cells, body parts, and even individuals

2. Major glands of the endocrine system
15.1 Hypothalamus and pituitary gland
Major glands of the endocrine system
Hypothalamus
Posterior pituitary gland
Anterior pituitary gland
Thyroid gland
Parathyroid glands
Adrenal Cortex
Adrenal Medulla
Pancreas
Testes
Ovaries
Thymus gland
Pineal gland
Kidneys
Adipose Tissue

3. 15.1 Endocrine glands Hypothalamus Pituitary Gland Posterior pituitary
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Hypothalamus
Pituitary Gland
Posterior pituitary
Anterior pituitary
Parathyroids
parathyroid glands
(posterior surface of thyroid)
Thymus
Thyroid
Pancreas
Adrenal Gland
Adrenal cortex
Gonads
Testes
Ovaries
testis
(male)
ovary (female)

4. 15.2 Hypothalamus and pituitary gland
Regulates internal environment through the autonomic nervous system
Helps control heartbeat
Helps control breathing rate
Helps control body temperature
Helps control water balance
Controls glandular secretions
Secretes ADH and Oxytocin

5. 2. Posterior pituitary gland
15.2 Hypothalamus and pituitary gland
2. Posterior pituitary gland
Stores antidiuretic hormone (ADH) and oxytocin that are produced by the hypothalamus
ADH: regulates water balance by reabsorbing water into the bloodstream
Oxytocin: causes uterine contractions during childbirth and allows milk to be released during nursing

6. 3. Anterior pituitary gland
15.2 Hypothalamus and pituitary gland
3. Anterior pituitary gland
Controlled by hypothalamic-releasing and hypothalamic-inhibiting hormones
Hormones produced by the anterior pituitary:
Thyroid-stimulating hormone (TSH): stimulates the thyroid to produce thyroid hormones
Adrenocorticotropic hormone (ACTH): stimulates the adrenal cortex to produce cortisol
Gonadotropic hormones: stimulate gonads to produce sex cells and hormones
Prolactin (PRL): stimulates mammary glands to develop and produce milk only after childbirth
Melanocyte-stimulating hormone (MSH): causes skin cells to produce melanin
Growth hormone (GH): promotes skeletal and muscular growth

7. The hypothalamus and pituitary
15.2 Hypothalamus and pituitary gland
The hypothalamus and pituitary
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hypothalamus
Neurosecretory cells produce
hypothalamic-releasing and
hypothalamic-inhibiting hormones.
2. These hormones are secreted into
a portal system.
Neurosecretory cells produce
ADH and oxytocin.
optic
chiasm
3. Each type of hypothalamic
hormone either stimulates or
inhibits production and secretion
of an anterior pituitary hormone.
2. These hormones move down
axons to axon terminals.
portal system
4. The anterior pituitary secretes
its hormones into the bloodstream,
which delivers them to specific
cells, tissues, and glands.
3. When appropriate, ADH and
oxytocin are secreted from axon
terminals into the bloodstream.
Thyroid:
thyroid-stimulating
hormone (TSH)
Adrenal cortex:
adrenocorticotropic
hormone (ACTH)
Posterior pituitary
Anterior pituitary
Kidney tubules:
antidiuretic
hormone (ADH)
Smooth muscle
in uterus:
oxytocin
Mammary glands:
oxytocin
Mammary glands:
prolactin (PRL)
Bones, tissues:
growth hormone
(GH)
Ovaries, testes:
gonadotropic
hormones (FSH, LH)

8. What happens when the body produces too much or too little GH?
15.2 Hypothalamus and pituitary gland
What happens when the body produces too much or too little GH?
Pituitary dwarfism – too little GH is produced during childhood that results in small stature
Giantism – too much GH is produced during childhood that results in poor health
Acromegaly – overproduction of GH as an adult that results in larger than normal feet, hands, and face

9. What happens when GH is produced in improper results during childhood?
15.2 Hypothalamus and pituitary gland
What happens when GH is produced in improper results during childhood?

10. What happens when GH is produced in high amounts during adulthood?
15.2 Hypothalamus and pituitary gland
What happens when GH is produced in high amounts during adulthood?
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Age 9
Age 16
Age 33
Age 52
(all): From Clinical Pathological Conference, “Acromegaly, Diabetes, Hypermetabolism, Proteinura and Heart Failure,” American Journal of Medicine 20 (1956) 133, with permission from Excerpta Medica, Inc.

11. 4. Thyroid gland A large gland located below the larynx
15.3 Thyroid and parathyroid glands
4. Thyroid gland
A large gland located below the larynx
Iodine is needed in the diet to allow the thyroid gland to produce its hormones
It produces:
Thyroid hormone (TH): regulates metabolism
Calcitonin: helps lower blood Ca2+ levels by stimulating the deposition of calcium in the bones

12. Thyroid abnormalities
15.3 Thyroid and parathyroid glands
Thyroid abnormalities
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affected eye
a. Simple goiter
b. Congenital hypothyroidism
c. Exophthalmic goiter
a: © Bruce Coleman, Inc./Alamy; b: © Medical-on- Line/Alamy; c: © Dr. P. Marazzi/Photo Researchers,Inc.

13. 15.3 Thyroid and parathyroid glands
Small glands embedded in the surface of the thyroid gland
Produces parathyroid hormone (PTH):
causes blood Ca2+ level to increase by promoting osteoclast activity
Promotes reabsorption of Ca2+ by the kidneys

14. 15.3 Thyroid and parathyroid glands

15. 6. Adrenal glands Glands that sit on top of the kidneys
Produces: hormones that allow a short-term response to stress (“fight or flight” response)
Epinephrine (adrenaline)
Produces hormones that provide a long-term response to stress
Glucocorticoids:
regulate carbohydrate, protein, and fat metabolism
Suppress the body’s inflammatory response
e.g., cortisol and cortisone

16. 7. Pancreas Fish-shaped organ behind the stomach
Composed of 2 tissues:
Exocrine: produces and secretes digestive juices
Endocrine (islets of Langerhans): produces and secretes hormones
Insulin – secreted when blood glucose is high and stimulates uptake of glucose by cells (muscle and liver)
Glucagon – secreted when blood glucose is low and stimulates the breakdown of glycogen in the liver

17. 15.5 Pancreas

18. 8. Testes Gonads found in males Produce androgens (e.g., testosterone)
15.6 Other endocrine glands
8. Testes
Gonads found in males
Produce androgens (e.g., testosterone)
Stimulates growth of the penis and testes
Responsible for 2 male sex characteristics such as facial, underarm, and pubic hair
Prompts the larynx and vocal cords to enlarge resulting in a lower voice
Promotes muscular strength

19. 9. Ovaries Gonads found in females Produce estrogen and progesterone
15.6 Other endocrine glands
9. Ovaries
Gonads found in females
Produce estrogen and progesterone
Stimulates growth of the vagina and uterus
Responsible for secondary sex characteristics such as female body hair, fat distribution, and breast development
Responsible for egg maturation
Regulates the uterine cycle

20. Hormones produced by the testes and ovaries
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Stimulates the male
secondary sex
characteristics and
maturation of sperm
Stimulates the female
secondary sex
characteristics and
maturation of eggs
hypothalamus
anterior
pituitary
testosterone
FSH, LH
FSH, LH
estrogen and
progesterone
testis
ovary

21. 10. Thymus gland Lies beneath the sternum
15.6 Other endocrine glands
10. Thymus gland
Lies beneath the sternum
This gland is largest and most active during childhood
T lymphocytes mature here
Secretes hormones called thymosins that aid in differentiation of lymphocytes

22. © The McGraw-Hill Companies, Inc./Evelyn Jo Johnson, photographer
15.6 Other endocrine glands
11. Pineal gland
Located in the brain
Secretes melatonin that regulates the sleep/wake cycle (circadian rhythm)
May also regulate sexual development
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a. Experimental
b. Winter
6 P.M.
6 A.M.
c. Summer
© The McGraw-Hill Companies, Inc./Evelyn Jo Johnson, photographer