Chapter 17- Endocrine system

study of structure and function of the endocrine glands and the diagnosis and treatment of disorders of the endocrine system

chemical messenger secreted by cells of an endocrine tissue/gland into the interstitial fluid that diffuses to the blood capillaries, is transported into the bloodstream to specific “target” cells, where it binds to a specific receptor and has an effect on that cell’s physiological activity

pituitary, thyroid, parathyroid, adrenal and pineal glands

hypothalamus, thymus, pancreas, ovaries, testes, kidneys, digestive tract, heart, adipose tissue and placenta

A tropic hormone is a hormone that tells another gland to make and release its own hormones. Think of it like a messenger or a boss that gives instructions to other glands in your body. So, tropic hormones don’t directly do the job themselves—they signal other glands to get the job done!

gland= directly produces hormone (pituitary) endocrine tissue= some capacity to produce hormone but has other functions (hypothalamus)

-chemical composition of the ECF -metabolism and energy balance -biological clock -contraction of smooth and cardiac muscle -some immune system functions

-regulate many aspects of physiology -control growth and development -regulate the reproductive organs

N= neurotransmitters E= hormones

N= close to release site (synapse) E= far away from release site (anywhere)

N= few cell types, neurons, muscle, glands E= any body cells

N= milliseconds E= seconds to days

N= shorter (msec) E= longer (sec to days

-sits within the sella turcica and sphenoid bone -attached to the hypothalamus via the infundibulum -under control of the hypothalamus -largest portion

-gonadotropin-releasing hormone -thyrotropin-releasing hormone -corticotropin-releasing hormone -prolactin-releasing hormone -somatostatin/prolactin-inhibiting hormone -growth hormone-releasing hormone

-oxytocin -antidiuretic hormone -produced by neurons in the hypothalamus, stored on posterior, controlled release from neural response

Grows upwards from primitive pharynx during embryological development, larger portion of pituitary gland

• Grows downwards from the brain; composed of nervous tissue • Stores hormones made by the neurons in hypothalamus

Prolactin (PRL) Thyroid stimulating hormone (TSH) Luteinizing hormone (LH) Follicle-stimulating hormone (FSH) Growth hormone (GH) Adrenocorticotrophic hormone (ACTH) Melanocyte-stimulating hormone (MSH)

1) Protein synthesis - Tissue repair 2) Lipid metabolism - Provides energy via fatty acids + glycerol - Spares protein 3) Carbohydrate metabolism - Stimulates glucose production by liver 4) Electrolyte balance - Promotes Na+, K+, Cl- retention by kidneys, increases Ca2+ absorption by small intestines

-travel freely through blood stream -no transport proteins -catecholamines -peptide hormones -majority of hormones

-need a transport protein to travel -thyroid hormones -Eicosanoids -steroid hormones

is both water soluble and lipid soluble -melatonin is derivative of tryptophan