The endocrine system consists of glands that release hormones to regulate bodily functions. Hormones travel through the bloodstream to target organs and cells. Hormone release is controlled through negative feedback mechanisms where rising hormone levels inhibit further release. The pituitary gland regulates growth and milk production and stimulates other glands. The thyroid and parathyroid glands control calcium and metabolic rates while the adrenals produce stress hormones and regulate minerals. The pancreas regulates blood sugar through insulin and glucagon and the pineal establishes circadian rhythms.

1. Human Endocrine
System

2. Endocrine Overview
 Hormones- chemical
messengers travel
through body
 Target cell or organ-
organ or cells that a
hormone affects

3. Control of Hormone Release
 Negative feedback mechanism- hormone
release is triggered by stimulus, rising levels
of hormone inhibit further release
 Endocrine stimuli-
 Hormonal- hormones stimulate the release of
others
 Humoral- blood stimulates release of hormones
 Neural- nerves stimulate hormone release

4. Anterior Pituitary Gland
 Growth Hormone (GH)- affects growth of
skeletal muscles and bones
 Prolactin (PRL)- stimulates milk production
after pregnancy
 Gonadotropic- regulates hormone activity of
sex organs
 Also effects adrenal cortex and thyroid
hormone release

5. Posterior Pituitary
 Oxytocin- helps during
pregnancy
 Antidiuretic hormone
(ADH)- inhibits urine
production
 Alcohol inhibits ADH
causing increased output
of urine

6. Thyroid Gland
 Thyroid hormone
 Controls the rate at
which glucose is
“burned”
 Calcitonin
 Decreases calcium
levels in blood deposits
on bone

7. Parathyroid Gland
 Parathyroidhormone
(PTH)- regulates
Ca2+ in blood
 If Ca2+ level drops
bones is broken down

8. Adrenal Gland
 Adrenal Cortex
 Releases hormones that
regulate mineral content in
blood
 Adrenal Medulla
 Produces epinephrine and
norepinephrine
 Helps with stressful situations

9. Pancreas
 Insulin- increases
glucose uptake into cells
and stores in liver
 Glucagon- stimulates
breakdown of glucose
stores in the liver

10. Pineal Gland
 Melatonin
 Establishes body’s day/ night cycle

11. Thymus
 Thymosin
 “Programs” T cells

12. Gonads
 Androgens (male)- sperm formation,
development of male char
 Estrogens (female)- development of female
char