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