Exam7 Chs 31-32 Endocrine Control & Disorders

• controls rate of enzymatic rxns • controls transport of ions or molecules across cell membranes • controls gene expression and synthesis of proteins

• chemical messengers • initiate pre-programmed responses in target cells • “on” switch that tells cell to carry out response

• released by gland/cell • circulated in bloodstream • reach target cell • specific action

• must bind w/receptors on target cells • surface or intracellular • type specific to hormone

milliseconds to days

• cells the hormones will be acting upon - specificity of signaling can be controlled if only some cells can respond to a particular hormone

• # of receptors - affinity of receptors

internal secretion of hormones directly into bloodstream to reach distant target cells

• targets nearby cells (para = near) - growth factor, clotting factor, retinoic acid, neurotransmitters

• local chemical signal that acts on the cell that secreted it (auto = self) • estrogen can be released by ovary and fxn as a hormone or act locally via paracrine signaling to stimulate oogenesis • testosterone can be released by testes and fxn as hormone or act locally via paracrine signaling to stimulate spermatogenesis

• amino acid compounds • do not dissolve in lipids • hard to get into the cell, easy to get out of the cell • Amines, Proteins, Glycoproteins, Peptides, Prostaglandins

• derived from amino acid Tyrosine Dopamine, Epinephrine, Norephinephrine

• made up of long chains of amino acids - GH, PTH, Prolactin

• proteins joined to carbohydrates - FSH, LH, TSH

• short chains of amino acids - ADH, Oxytocin, TRH, Somatostatin, GnRH

fatty acids produced in a wide variety of cells

• lipid based • derived from cholesterol • dissolve in lipids • easy to get into the cell, hard to get out of the cell • estrogen, progesterone, testosterone, aldosterone, cortisol, androgens (DHEA)

• endocrine gland secretes nonsteroid hormone • body fluid carries hormone to target cell • hormone combines w/receptor site on membrane of target cell, activating G protein (messenger) • G protein activates adenylate cyclase • adenylate cyclase fxns to turn ATP into cAMP • cAMP activates protein kinases that change the metabolic processes in the cell which causes the hormone’s effects

• endocrine gland secretes steroid hormone to be carried by blood to target cell • steroid hormone diffuses thru target cell membrane and into cytoplasm or nucleus b/c soluble in lipids, no need for messenger • hormone combines w/receptor molecule in cytoplasm/nucleus • hormone-receptor complex binds to DNA & promotes transcription of messenger RNA • mRNA enters cytoplasm & directs protein synthesis • synthesized proteins produce hormone’s effects

controls hormones and trophic hormones

on or in the cell

• altering existing proteins - making new proteins

• amount of active hormone available to cell - # and activity of target cell receptors

cell makes more hormone receptors