1. Chapter 16: The Endocrine System

2. Objectives Define the terms endocrine and exocrine.
Describe the physiology of hormones including the different types and the mechanisms of their actions.
Compare endocrine and neural controls of physiology.

3. Functions System of glands and cells
make hormones
Alters metabolic activities of many tissues and organs simultaneously
Regulates long-term processes:
growth
development
reproduction

4. What is a Hormone?
A chemical messenger that is produced at one site and carried by the blood to its site of action (target cells)

5. Mechanism of Hormone Action
Hormones produce one or more of the following cellular changes:
alter plasma membrane permeability
stimulate protein synthesis
activate or deactivate enzyme systems
induce secretory activity
stimulate mitosis

6. Homeostasis Homeostasis How we maintain homeostasis
maintaining internal balance in the body
organism must keep internal conditions stable even if environment changes
also called “dynamic equilibrium”
How we maintain homeostasis
nervous system
endocrine system

7. What is the functional significance of the differences between the two systems?
Endocrine System
Nervous System
Chemical signals control body functions
Is unable to handle split-second responses
Nerve signals control body functions
Handles crisis management

8. Endocrine vs. Exocrine Endocrine Glands Exocrine Glands
Glandular secretory cells that release their secretions directly into the blood stream
The glands are called ductless
Secrete their products onto epithelial surfaces-
(skin or mucosa)
The glands that have ducts

9. Glands Hypothalamus Pituitary Thyroid Parathyroid Adrenal Pineal
Pancreas
Thymus
Gonads

11. Hypothalamus

12. Hypothalamus Links the nervous system to the endocrine system
Controls:
body temperature
hunger
thirst
fatigue
sleep
circadian cycles

13. Controlling Body Temperature
nerve signals
brain
sweat
dilates surface blood vessels
high
body temperature
low
constricts surface blood vessels
shiver
brain
nerve signals

14. Pituitary Gland Functions: Hormone: Location:
stimulates the elongation of bones in the body
“master gland” since it regulates endocrine functions
Hormone:
growth hormone
Location:
base of the brain, below hypothalamus

15. Pituitary Gland

17. Pituitary Gland Hormones

18. Pituitary Gland Hormones

19. Pituitary Dwarfism

20. Gigantism

21. Andre the Giant
At 7'4" and 500 pounds, Andre the Giant could have been famous for his size alone. His drive, talent and ambition, however, proved to be as big as Andre himself, and the wrestler became legendary for his achievements in and out of the ring.

22. Acromegaly Occurs in adults Bones of hands face and feet are enlarged
Due to the release of growth hormone in adults

25. Thyroid Gland Functions: Location: controls metabolism
regulates tissue growth
maintains blood pressure
glucose oxidation
makes proteins
Location:
by the Adams apple
largest gland in the body

26. Thyroid Gland

27. Goiter Not enough iodine in the diet (iodine deficiency)
Causes swelling of the thyroid gland

28. Goiter

30. Graves Disease Overactive thyroid
Excessive amounts of thyroid hormones are produced
Inflammation of the eye muscles by attacking autoantibodies

31. Parathyroid Glands 4 Functions: Hormone: Location:
breaks down bone to regulate blood calcium
Hormone:
secretes parathormone
Location:
embedded in the thyroid

33. Adrenal Glands Functions: Secretion: Location: raises heart rate
increases breathing
increases blood sugar level
dilates blood vessels
Secretion:
adrenaline
Location:
on top of the two kidneys

34. Pineal Gland Function: Secretion: Location:
modulates the wake/sleep patterns
modulates photoperiodic (seasonal) functions
Secretion:
melatonin
Location:
near the center of the brain

36. Pancreas Functions: Secretions: Location: controls blood sugar
breaks down carbohydrates, proteins, and fats
Secretions:
insulin
glucagon
hormones that control the
blood sugar in the body
Location:
behind the stomach
side of the small intestine

37. Pancreas Secretions Insulin Glucagon allows glucose to enter cells
LOWERS blood glucose levels
Glucagon
stimulates liver to make glucose
RAISES blood glucose levels

38. Islets of Langerhans Two cell types: Alpha () cells produces glucagon
Beta () cells produce insulin

39. Diabetes
Under-secretion of insulin
High blood sugar

40. Regulation of Blood Sugar
insulin
body cells take up sugar from blood
liver stores sugar
reduces appetite
pancreas
liver
high
blood sugar level
(90mg/100ml)
low
liver releases sugar
triggers hunger
pancreas
liver
glucagon

41. Thymus Function: Secretion: Location: controls the immune system
development of T-lymphocytes
Secretion:
Thymosin
Location:
thorax
anterior mediastinum

42. Ovaries Two main hormones: Estrogen
create female secondary sex characteristics
Progesterone
thickens the uterus lining every month

43. Testes One main hormone: Testosterone (an androgen)
affects the secondary sex characteristics in men

44. Hirsutism
Caused by an increase in testosterone secretion

45. Aging Causes few functional changes Decline in concentration of:
growth hormone
reproductive hormones