1. Endocrine System Overview
Anatomy & Physiology

2. Endocrine System Overview
Endocrine system works with nervous system to coordinate activities of body cells
Endocrine glands- ductless; make hormones
Hormones influence metabolic activities
Exocrine glands- external secretions onto surface or other organ; sweat, mammary, lacrimal, salivary glands

3. Endocrine System Overview (continued)
Hormones: chemicals released into blood to regulate metabolic functions of body cells
Hormones can be circulating or local

4. Circulating Hormones:
Main Types of Hormones
Circulating Hormones:
Amino acid based: most common
Steroids: made from cholesterol
Local Hormones
Autocrines: affect cells that secrete them
Paracrines: affect local and other cells

5. Control of Hormone Release
Typically regulated by negative feedback system; receptors (upregulated or down)
3 Stimuli that Release Hormones
Neural: nerve fibers stimulate hormone release
Fight-or-flight
Hormonal: release in response to hormones made by other endocrine organs
Chain of command (pg. 271)
Humoral: secrete in response to changing levels of nutrients in blood
glucagon

6. Major Endocrine Organs
Pituitary gland- “Vice president”; secretes 6 hormones from anterior; 2 posterior
Includes: Growth Hormone (GH), PRO, ACTH, TSH, FSH, LH; posterior: ADH and oxytocin
Thyroid gland- butterfly shaped; in neck
Thyroid hormone (TH)- body’s major metabolic hormone
Calcitonin- regulates blood levels of calcium

8. Major Endocrine Organs (continued)
Parathyroid gland- found behind thyroid;
Secretes parathyroid hormone (PTH)
Important in controlling blood Ca+ levels
Adrenal gland- pyramid shaped; top of kidneys
A. cortex-makes corticosteroids including gonadocorticoids (sex hormones)
Androgens: testosterone and estrogens
A. Medulla: epinephrine & norepinephrine
Pancreas- endocrine/exocrine gland
insulin and glucagon
Regulate blood sugar

9. Major Endocrine Organs (continued)
Gonads(Ovaries or Testes- sex hormones
Female: estrogens and progesterones
Male: testosterone
Pineal gland- pine cone-shaped; secretes melatonin (regulates sleep cycles)
Thymus- beneath sternum; shrinks from child to adulthood.
Makes peptide hormones; T lymphocytes

11. Other Hormone-Producing Structures
GI tract, placenta, kidneys, skin, and adipose tissue can produce hormones
Adipose & fatty tissue- leptin & prostaglandins
Kidneys- erythropoietin (EPO)