1. Endocrine System
Unit 6

2. Endocrine System Regulates: Controls growth & development
…coordinates and controls the activities of the body
Regulates:
extracellular fluid
metabolism
biological clock
contraction of cardiac & smooth muscle
glandular secretion
some immune functions
Controls growth & development
Regulates reproductive system

3. Endocrine System vs. Nervous System
hormones
far from site of release
cells throughout body
seconds - hours - days
long duration
Nervous System
neurotransmitters
close to release site
muscles, glands, neurons
milliseconds
brief duration

4. Hormones and Glands
Hormones: Chemical substances that are produced in one part of the body and transported by the blood to influence activities in another part of the body

5. Endocrine vs. Exocrine Endocrine Exocrine hormones into blood
pituitary, thyroid, parathyroid. adrenal, pineal
secondary function
hypothalamus, thymus, pancreas, testes, ovaries, kidneys, stomach, GI, skin, heart, & placenta
Exocrine
ducts
cavity/surface
sweat, oil, mucous, digestive glands

6. Hormone Activity and Cellular Response
A given hormone affects only target cells
Hormone receptors develop as a cell differentiates
Different cells may respond in different ways to the same hormone
Some hormones are present much of the time, while others appear only sporadically
The amount of a circulating hormone is usually governed by negative-feedback control
Hormones are usually broken down rapidly
A hormone can increase the rate at which other substances enter or leave the target cell
A hormone can stimulate a target cell to synthesize enzymes, proteins, or other substances
A hormone can prompt the target cell’s machinery to activate or suppress existing cellular enzymes

7. Hormone Chemistry
Steroid hormones – fat-soluble molecules (made from cholesterol)
Sex hormones groups: estrogens, androgens and progesterones.
Males and females make all three, just in different amounts.
Steroids pass into a cell's nucleus, bind to specific receptors and genes and trigger the cell to make proteins.
Steroid hormones must attach to transport proteins synthesized by liver
improve transport by making them water-soluble
Amino acid derivatives – water-soluble molecules derived from amino acids
Epinephrine, insulin, growth hormone.
These hormones are stored in endocrine cells until needed.
They act by binding to protein receptors on the outside surface of the cell. The binding alerts a second messenger molecule inside the cell that activates enzymes and other cellular proteins or influences gene expression.
Regulate such processes as metabolism, lactation, growth and reproduction.
Amino Acid hormones circulate in ‘free’ form in blood

8. Steroid Hormone Action
Amino Acid Hormone Action

9. Hormonal Interactions
Permissive effect
a second hormone, strengthens the effects of the first
ex. thyroid strengthens epinephrine’s effect upon lipolysis
Synergistic effect
two hormones acting together for greater effect
ex. estrogen & LH are both needed for oocyte production
Antagonistic effects
two hormones with opposite effects
ex. insulin promotes glycogen formation & glucagon stimulates glycogen breakdown

10. Control of Hormone Secretion
Regulated by signals from nervous system, chemical changes in the blood or by other hormones
Negative feedback control (most common)
decrease/increase in blood level is reversed
Positive feedback control
the change produced by the hormone causes more hormone to be released
Disorders involve either hyposecretion or hypersecretion of a hormone

11. Endocrine Gland Stimuli
How are endocrine glands stimulated?
Hormonal - where a hormone stimulates the gland to release its hormone
tropic hormone - a hormone that stimulates a gland to release another hormone
-tropin a suffix often used on tropic hormones
2. Humoral - where the gland monitors the conditions it is going to control
3. Neural - where a nerve impulse stimulates the gland to release its hormone

12. Hypothalamus & Pituitary Gland

13. Hypothalamus Oxytocin Antidiuretic hormone (ADH) Releasing hormones
Inhibiting hormones

14. Anterior Pituitary Growth hormone (GH)
Thyroid stimulating hormone (TSH)
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Prolactin (PRL)
Adrenocorticotropin hormone (ACTH)
Melanocyte-stimulating hormone (MSH)

15. Anterior Pituitary Hormones

16. Posterior pituitary

17. Posterior pituitary

18. Posterior Pituitary Hormones
Oxytocin during Labor
Stimulation of uterus by baby
Hormone release from posterior pituitary
Uterine smooth muscle contracts until birth of baby
Baby pushed into cervix, increase hormone release
More muscle contraction occurs
When baby is born, positive feedback ceases
ADH

19. Thyroid Gland

20. Actions of Thyroid Hormones

21. Control of T3 & T4 Secretion

22. Parathyroid Gland

23. Regulation of Calcium Blood Levels

24. Actions of Parathyroid Hormones

25. Adrenal Gland

26. Adrenal Gland Cortex Medulla mineralocorticoids Aldosterone
increase reabsorption of Na+ with Cl- (and H2O)
promotes excretion of K+ and H+
glucocorticoids
cortisol
corticosterone
cortisone
androgens
dehydroepiandrosterone (DHEA)
Medulla
receive innervation from sympathetic nervous system
release epinephrine and norepinephrine in response to stress
Produces rapid, drastic effects involving several targets (fight or flight response).

27. Regulation of Aldosterone

28. Glucocorticoids Cortisol 95% of glucocorticoid activity
protein catabolism
glucose formation
stimulate lipolysis
resistance to stress
anti-inflammatory effects
depression of immune responses

29. Summary of Adrenal Gland Hormones

30. Stress Response

31. Pancreas

32. Functions of Pancreas Exocrine function - Acini -
- cells clusters that produce digestive enzymes
Endocrine function
- Islets of Langerhans
- clusters of hormone secreting cells

33. Regulation of Glucagon & Insulin Secretion

34. Pancreatic Islet Hormones

35. Pineal Gland

36. Other Hormones

37. Pituitary Gland Disorders
Pituitary dwarfism
- hyposecretion of hGH
Giantism
- hypersecretion of hGH (childhood)
Acromegaly
- hypersecretion of hGH (adult)

38. Thyroid Gland Disorders
Congenital hypothyroidism
- hyposecretion of thyroid hormone
Myxedema
- hypothyroidism during adult years
Grave’s disease
- hyperthyroidism
- exophthalmos (edema behind eyes)
Goiter
- enlarged thyroid

39. Thyroid Hormone Disorders
Hyperthyroidism - excessive secretion high basal metabolism (Grave’s disease), high temperature, sweating, weight loss, irritability, high bp
Hypothyroidism - deficiency (cretinism) weight gain, lethargy, intolerance to cold, simple goiter

40. Adrenal Gland Disorders
Cushing’s Syndrome
- hypersecretion of cortisol
Addison’s Disease
- hyposecretion of glucocorticoids and aldosterone

41. Diabetes Mellitus & Hyperinsulinism
Type I
- insulin-dependent diabetes mellitus (IDDM)
Type II
- non-insulin-dependent diabetes mellitus (NIDDM)