1. Homeostasis Aldosterone Thymus Gland Hyperglycemia
Chapter 12 Key Terms
Hormones Melatonin
Homeostasis Aldosterone
Thymus Gland Hyperglycemia
Hypophysis Hypothalamus
Infundibulum Acidosis
Adrenal Gland Alpha Cells
Beta Cells Chief Cells
Insulin Androgens
Ovaries Testes

2. Chapter 12: Endocrine system
ANATOMY & PHYSIOLOGY
Chapter 12: Endocrine system

3. Introduction Purpose Works closely with the nervous system
Homeostasis: maintaining the body’s internal environment within certain narrow ranges
Involves growth, maturation, metabolism, and reproduction
Works closely with the nervous system
Hypothalamus sends chemical signals (neurotransmitters) to the endocrine system
Endocrine Glands
Ductless glands that secrete hormones directly into bloodstream

4. Hormones Negative feedback loop 3 chemical categories
Mechanism by which hormones function
3 chemical categories
Modified amino acids
Protein hormones
Steroid hormones

5. Hypothalamus Controls the pituitary gland Infundibulum
Funnel shaped extension from hypothalamus to pituitary gland
Produces chemical signals
Releasing hormones
Releasing inhibitory hormones

6. Endocrine Glands Pituitary Gland (A) Thyroid Gland (B)
Parathyroid Gland
Adrenal Gland (C)
Testes (D)
Ovaries (E)
Pancreas (F)
Thymus Gland (G)
Pineal Gland (H)

7. Pituitary Gland
Also known as the Hypophysis, and also the “Master Gland”
Divided into two lobes
Anterior Pituitary Gland
Posterior Pituitary Gland

8. Anterior Pituitary Gland
Growth Hormone (GH)
Stimulates cell growth and division
Stimulates bone and muscle growth
Pituitary Dwarfism: result of too little GH
Gigantism: result of too much GH
Thyroid Stimulating Hormone (TSH)
Stimulates thyroid to release its hormone

9. Anterior Pituitary Gland
Adrenocorticotropic Hormone (ACTH)
Stimulates adrenal cortex to secrete its hormone (Cortisol)
Helps reduce inflammation
Melanocyte-stimulating Hormone (MSH)
Stimulates production of melanin in the skin
Follicle-stimulating Hormone (FSH)
Stimulates the production of sperm in males
Stimulates development of follicles in ovaries

10. Anterior Pituitary Gland
Luteinizing Hormone (LH)
Stimulates production of progesterone and ovulation in ovary
Stimulates production of testosterone in males
Lactogenic Hormone (LTH)
AKA Prolactin
Stimulates milk production in a pregnant female
May cause decrease in male sex hormones

11. Posterior Pituitary Gland
Antidiuretic Hormone (ADH)
AKA Vasopressin
Maintains body’s water balance by promoting water reabsorption in the kidneys
Oxytocin
Stimulates contraction of smooth muscles in the uterus
Sometimes given to help induce labor if the uterus does not contract sufficiently on its own during childbirth

12. Thyroid Gland
Consists of two lobes connected by a smaller band called the isthmus
Stimulated by TSH from the Pituitary Gland
Requires Iodine to function properly
Iodine deficiency causes goiters
Releases T3 and T4
Contain 3 and 4 Iodine atoms
Regulate metabolism of carbs, fats, proteins for proper growth and development

13. Thyroid Gland Calcitonin Hypothyroidism Hyperthyroidism
Lowers calcium and phosphate concentrations in the blood
Inhibits release of ions from bones, and increases excretion of ions by the kidneys
Hypothyroidism
Low levels of thyroid hormones
Cretinism
Hyperthyroidism
Too much secretion of thyroid hormones

14. Parathyroid Gland 4 small glands on posterior surface of thyroid gland
Made of chief cells and oxyphil cells
Releases Parathyroid Hormone (PTH)
Raises blood calcium levels by causing bone matrix to break down, releasing calcium and phosphate ions into bloodstream

15. Adrenal Gland Located on top of the kidneys Adrenal Medulla
Epinephrine (adrenaline) and Norepinephrine (noradrenaline)
Released as a response to signals of the autonomic nervous system
Fight or flight hormones
Causes a breakdown of glycogen to glucose
Stimulates release of fatty acids from fat cells

16. Adrenal Cortex Aldosterone Cortisol (Hydrocortisone) Cortisone
Regulates Na reabsorption and K excretion by kidneys
Released by outer layer of cortex
Cortisol (Hydrocortisone)
Helps maintain blood glucose levels between meals
Synthesizes glucose from amino acids
Cortisone
Steroid often give as medication to reduce inflammation

17. Adrenal Cortex Androgens Addison’s disease Cushing’s syndrome
Promotes development of male characteristics
Addison’s disease
Not enough hormones secreted by adrenal cortex
Causes change of electrolyte balance in blood
Cushing’s syndrome
Blood glucose concentrations remains high, causing puffy skin and obesity because of excess tissue fluid

18. Pancreas Part of digestive and endocrine systems Alpha Cells
Secretes Glucagon
Raises blood sugar level
Beta Cells
Secretes Insulin
Lowers blood sugar level

19. Diabetes Mellitus Deficiency in insulin production Type 1 Type 2
Previously called juvenile diabetes
Body does not produce insulin
5% of diabetics
Type 2
Body does not use insulin properly (insulin resistance)
Previously called adult onset diabetes
Balanced diet, exercise, proper body weight

20. Testes and Ovaries Ovaries Testes
Releases estrogen and progesterone
Promote development of female characteristics
Control menstrual cycle
Testes
Releases testosterone
Promotes development of male reproductive structures and male characteristics
Both controlled by LH and LTH from Pituitary gland

21. Thymus Gland Located in the mediastinum
Helps in development of the immune system
Thymosin
Promotes production of T lymphocytes

22. Pineal Gland Melatonin Serotonin
Secreted directly into cerebrospinal fluid
Inhibits secretion of LH and LTH
Regulates circadian rhythms (feeling of tired and onset of sleep)
Bright light inhibits secretion of melatonin
Serotonin
Acts as neurotransmitter and vasoconstrictor
Stimulates smooth muscle contractions