2. Integration & Control: The Endocrine System
Chapter 36
Integration & Control: The Endocrine System

3. Endocrine System
Works w/ nervous system to control all functions of the body
Endocrine glands
Ductless
Hormones
Pineal, pituitary, thyroid, pancreas, etc.
Exocrine glands
Ducts
Non-hormones
Salivary, sebaceous, sweat

4. Endocrine System Hormones Chemical signals Carried in bloodstream
Affect cells away from gland
Homeostatic

5. Hormones Positive feedback Negative feedback
Increase in hormone stimulates further secretion
Uterine contractions stimulate oxytocin
Negative feedback
Increase in hormone inhibits further secretion
Thyroid Stimulating Hormone produces T3/T4

6. Hormones Peptide hormones Water soluble Mostly protein
Attach to cell membrane
Trigger secondary messenger within cell
Epinephrine, oxytocin, antidiuretic hormone (ADH), etc.

7. Hormones Steroid hormones Water insoluble Cholesterol-based
Cross into cell
Bind to receptors in cytoplasm or nucleus
Estrogen, testosterone, cortisol, etc.

8. Pituitary Gland “Master Gland”
Associated with & directed by hypothalamus
Posterior & Anterior lobes

9. Pituitary Gland Posterior Lobe Stores secretions from hypothalamus
Oxytocin
Uterine contractions
Milk “let down”
ADH
Conserves water
Kidney tubules reabsorb water

10. Pituitary Gland Anterior Lobe Prolactin Breast development
Stimulates & sustains milk production

11. Pituitary Gland Anterior Lobe Growth Hormone (GH)
Stimulates body cells to grow & divide
Mostly young bones & muscles
Thyroid-Stimulating Hormone (TSH)
Thyroid gland growth
Secretion of thyroid hormones
Adrenocorticotropic Hormone (ACTH)
Adrenal gland growth
Secretion of cortisol from adrenal gland

12. Pituitary Gland Anterior Lobe Luteinizing Hormones
Follicle-Stimulating Hormone (FSH)
Stimulates ovulaton
Stimulates estrogen secretion
Stimulates progesterone secretion (females)
Stimulates egg production (females)
Stimulates testosterone secretion (males)
Stimulates sperm production (males)

13. Pituitary Gland Anterior Lobe Melanocyte-Stimulating Hormone (MSH)
Stimulates melanocytes in skin
Increases during human pregnancy
Increases in amphibians in dark location

14. Pituitary Gland Anterior Lobe Endorphins Natural pain-killers
Sense of well-being
Strenuous exercise, excitement, orgasm
“Runner’s High”

16. Thyroid Gland Regulates speed of all basic cellular processes
Energy burning
Protein synthesis
Thyroxine (T4), Triiodothyronine (T3)
Controls metabolism
Affects growth
Calcitonin
Lowers blood calcium levels
Increases deposit of calcium in bones

17. Parathyroid Gland Calcium metabolism Parathyroid Hormone (PTH)
Breaks down bone to release calcium
Increases intestinal absorption
Increases kidney retention

18. Adrenal Gland Cortex Produces corticosteroids Mineralocorticoids
Aldosterone—controls electrolytes through kidneys
Glucocorticoids
Cortisol—“stress hormone”
Increases blood pressure & blood glucose
Suppresses immune system
Andgrogens
Testosterone
Cause masculine traits

19. Adrenal Gland Medulla Hormones released under stress
Increases heart rate, blood pressure, and blood sugar
Hormones released under stress
Increases sympathetic effects
Controlled by sympathetic nervous system
Norepinephrine
20% of medullary hormones
Epinephrine
Maintains blood pressure
80% of medullary hormones

20. Thymus Gland Large in infant Increases until puberty
Shrinks until adulthood
Thymosin
Normal development of immune system

21. Pineal Gland Melatonin Regulates biological clock
Regulates sleep cycle
“Lower” vertebrates, cells resemble photoreceptor cells of eye
May be triggered by light

22. Pancreas Endocrine & exocrine Digestive enzymes Glucagon Insulin
Breaks down glycogen to glucose
Frees stored glycogen in liver
Insulin
Lowers blood glucose
Increases uptake of glucose into body cells

23. Ovaries Estrogen Progesterone Female sexual characteristics
Sperm maturation & libido in males
Progesterone
Prepares uterus for egg implantation
Regulates menstrual cycle

24. Testes Testosterone Male sexual characteristics Sexual behaviors
“Male” behaviors
Aggression
Territoriality

25. Other organs Kidneys Skin Skeletal muscle Adipose (fat)
Erythropoietin—stimulates red blood cell production
Skin
Calcidiol—inactive form of vitamin D
Skeletal muscle
Thrombopoietin—stimulates platelet formation
Adipose (fat)
Leptin—decrease appetite, increase metabolism

26. Hormonal Imbalances Hypersecretion of GH Gigantism—in children
Acromegaly—in adults

27. Hormonal Imbalances Hyposecretion of GH
Pituitary dwarfism—children, slow bone growth

28. Hormonal Imbalances Hypothyroidism Goiter Fatigue
Thin, brittle hair & nails
Weight gain
Poor muscle tone
Goiter
Inflammation of thyroid gland
Can be due to iodine deficiency

29. Hormonal Imbalances Hyperthyroidism Weight loss Ravenous appetite
Irritability, anxiety
Fatigue
Hyperactivity
Graves’ disease
Protrusion of eyes
Edema (fluid accumulation)
Thickening of skin
Goiter

30. Hormonal Imbalances Diabetes insipidus Diabetes mellitus
Deficiency of ADH
Increased urine output
Chronic dehydration risk
Diabetes mellitus
Deficiency of insulin
High blood glucose levels
Type I—usually before age 20, pancreas cells stop producing, autoimmune
Type II—usually after age 40, insulin levels normal, cells don’t respond to it

31. Hormonal Imbalance Addison’s disease Cushing’s disease
Adrenal gland produces insufficient glucocorticoids
Low blood pressure
Darkening of skin
Vomiting, diarrhea
Mood, personality changes
Cushing’s disease
Overproduction of glucocorticoids
Weight gain
Thin skin, often stretched
Muscle weakness
Hirsuitism (horses & humans)
Hyperglycemia