Human Endocrine System

Endocrine Overview

Hormones- chemical messengers travel through body

Target cell or organ- organ or cells that a hormone affects

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

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

Posterior Pituitary

Oxytocin- helps during pregnancy

Antidiuretic hormone (ADH)- inhibits urine production Alcohol inhibits ADH

causing increased output of urine

Thyroid Gland

Thyroid hormone Controls the rate at

which glucose is “burned”

Calcitonin Decreases calcium

levels in blood deposits on bone

Parathyroid Gland

Parathyroid hormone (PTH)- regulates Ca2+ in blood If Ca2+ level drops

bones is broken down

Adrenal Gland

Adrenal Cortex Releases hormones that

regulate mineral content in blood

Adrenal Medulla Produces epinephrine and

norepinephrine Helps with stressful situations

Pancreas

Insulin- increases glucose uptake into cells and stores in liver

Glucagon- stimulates breakdown of glucose stores in the liver

Pineal Gland

Melatonin Establishes body’s day/ night cycle

Thymus

Thymosin “Programs” T cells

Gonads

Androgens (male)- sperm formation, development of male char

Estrogens (female)- development of female char