Endocrine System A transmitter of chemical “messengers”

Consists of : -GLANDS that release “chemical messengers” called HORMONES. Hormones are carried by blood and affect distal target cells.

Hypothalamus - Controls pituitary gland Pituitary gland- regulate other glands Parathyroid glands- regulates level of calcium in blood Thymus- T cell development, immunity Adrenal glands - respond to stress Pineal gland- melatonin for rhythmic activities ( sleep- wake) Thyroid – thyroxine for metabolism Pancreas – insulin for glucose levels Ovary- estrogen for female eggs, sex characteristics; progesterone to prepare uterus for a fertilized egg Testis – testosterone for sperm development and male sex characteristics Glands

Pituitary gland Master gland of body Located in the depression of sphenoid bone Produces many hormones that affect other glands –thyroid stimulating hormone –Somatotropin- growth hormone –Lutenizing (LH)- causes ovulation –ICSH- causes testes to secrete testosterone –Melanocyte stimulating- distribution of melanin in skin –ADH- antidiuretic hormone ( slows down water removal from blood)

Giantism- oversecretion of growth hormone ( GH) before puberty Dwarfism- undersecretion of GH. Cause: tumor, injury, infection, genetics

Produces hormones that control metabolism and calcium in blood. –hyperthyroidism ( when too much thyroxine)- results in weight loss, increased blood pressure, elevated body temp. –hypothyroidism ( too little thyroxine)- results in low metabolic rates, low body temp, lack of energy, weight gain. Thyroid Gland Iodine- for normal thyroxine production

Sit on top of kidneys; Help the body prepare for and deal with stress; Has two structural parts: adrenal cortex ( involved in metabolism) and adrenal medulla ( “fight or flight” response); Adrenal Glands

Pancreas -Help break down food -Secrete hormones “insulin” and “ glucagon” ; Both help to keep the levels of glucose in the blood stable. -- When pancreas fail to produce or use insulin, diabetes occurs.

2 Groups of Hormones: STEROID and NONSTEROID They need a specific receptor on a specific cell to do their job

Control of the Endocrine System Regulated by feedback mechanism that function to maintain homeostasis ( increase in substance “ feeds back” to stop the process that produced the substance ) Example: Hypothalamus  TRH  Anterior Pituitary  Thyroid  TSHThyroxine

regulates by means of the Growth Water balance ReproductionMetabolism Calcium and glucose levels Response to stress The Endocrine System Pituitary Ovaries TestesThyroidPancreasAdrenals Parathyroids