1. ENDOCRINE SYSTEM
FUNCTION

2. TYPES OF GLANDS Endocrine Exocrine
Secrete hormones directly into bloodstream
Ductless
Exocrine
Secrete substance through a duct
Sweat, salivary, lacrimal and pancreas

3. Function of Endocrine System
To secrete hormones
Hormones are chemical messengers that coordinate and direct target cells and organs

4. HORMONE CONTROL
Negative feedback – drop in hormone level triggers a chain reaction
Blood level of hormone falls
Brains gets message and sends out hormone to stimulate gland
Gland secretes more hormone
When blood level of hormone increases, brain hormones stop
Nervous control – in some cases, sympathetic nervous system causes direct release of hormone from gland
Example: when stress causes the adrenal medulla to secrete adrenalin

5. PITUITARY GLAND (Figures 11-3 and 11-4)
The master gland
Anterior pituitary lobe
Growth hormone – GH (somatotropin) responsible for growth and development
Prolactin – develops breast tissue, stimulates production of milk after childbirth
Thyroid-stimulating hormone – TSH – stimulates thyroxine
Adrenocorticotropic hormone – ACTH – stimulates adrenal cortex
Follicle-stimulating hormone – FSH – stimulates growth of graafian follicle and production of estrogen in females, sperm in males
Luteinizing hormone – LH – stimulates ovulation and formation of corpus luteum, which produces progesterone in females
Posterior pituitary lobe
Vasopressin – converts to ADH (antidiuretic hormone) in the bloodstream, acts on kidney to concentrate urine and preserve H2O in the body
Oxytocin – released during childbirth causing contractions of the uterus

6. THYROID and PARATHYROID GLANDS
Main hormone, thyroxine, is controlled by secretion of TSH
Thyroxine controls the rate of metabolism
Calcitonin, another hormone that controls calcium ion concentration in the body, prevents hypercalcemia
Parathyroid glands
Produce parathormone which helps control blood calcium, prevents hypocalcemia
See Figures 11-6 and 11-7 pgs

7. THYMUS Endocrine gland and lymphatic organ
Located behind sternum, above and in front of heart
Begins to disappear at puberty

8. ADRENAL GLANDS
Adrenal cortex secretes corticoids (anti-inflammatory hormones) and sex hormones
Androgens
Male sex hormones
Adrenalin
Hormone from adrenal medulla, powerful cardiac stimulant, “fight or flight” hormone

9. GONADS Estrogen Progesterone Testosterone
Development of female reproductive organs, secondary sex characteristics
Progesterone
Plays a part in the menstrual cycle
Testosterone
Male reproductive organs and secondary sex characteristics

10. PANCREAS and PROSTAGLANDINS
Islets of Langerhans – insulin production
Insulin promotes utilization of glucose by the cells
Prostaglandins
Tissue hormones