EXPH 387 Final Exam - Questions with Verified Answers Endocrine system and nervous system regulates all of Homeostasis Avg size of endocrine system
... [Show More] 0.5kg Endocrine organs consist of glands, hormones, and target/receptor organs Glands are classified as either endocrine or exocrine Endocrine system has what kind of glands? Ductless Characteristics of Endocrine system -ductless glands -secrete substances into extracellular spaces -diffuses into bloodstream for transport to target tissues in the body 2 chemical categories of hormones -steroid-derived hormones -amine or polypeptide hormones Steroid-derived hormones not soluble in blood plasma; synthesized from cholesterol via adrenal cortex and gonads; receptors are usually found within the cell Steroid-derived are ______ but _____ hydrophobic but lipophilic Amine or polypeptide hormones soluble in blood plasma; located on the cell membrane of target tissues Polypeptide are _____ but _____ hydrophilic but lipophobic Major function of hormones -modifying rate of intracellular protein synthesis via DNA stimulation -changing rate of enzyme activity -altering plasma membrane transport via 2nd messenger -inducing secretory activity What is the first step in initiating hormonal action? hormone-receptor binding Up-regulation target cells form more receptors in response to increasing hormone levels Down-regulation loss of receptor which prevents target cells from overresponding to persistently high hormone levels Cyclic AMP critical 2nd messenger to all protein hormones Protein hormones initially bind to their cellular receptors where in the plasma membrane All protein hormones secrete in a pulsatile manner Endocrine glands are stimulated by -hormonal stimulation -humeral stimulation -neural stimulation Hormonal stimulation many hormones influence the secretion of other hormones (tropic hormone) Humeral stimulation changing levels of certain ions, and nutrients in blood, bile, and other body fluids Neural stimulation hormone release is affected by neural activity (SNS releases epinephrine & norepinephrine during stress) Pituitary gland master gland Anterior pituitary hormones -growth hormones -ACTH -TSH -prolactin -FSH -LH Anterior pituitary is controlled by Hypothalamus Growth hormone exerts physiologic activity by 1. promoting cell division and proliferation 2. increasing protein synthesis 3. decreasing CHO breakdown and increase in the mobilization of lipids for energy GH is stimulated by fasting, starvation, increased blood amino acid levels, and stress (trauma, excitement, emotional, & HEAVY EXERCISE) GH is dependent on exercise intensity and duration Thyroid-stimulation hormone (thyrotropin) controls amount of hormone secretion by the thyroid gland What is the effect of TSH and exercise? increase in TSH does not occur consistently in response to exercise ACTH (corticotropin) regulates output of hormones secreted by the adrenal cortex in a manner similar to TSH ACTH acts directly to -enhance fatty acid mobilization from adipose tissue -increases glucogenesis -stimulate protein catabolism ACTH concentrations may increase proportionally with exercise intensity and duration Prolactin supports milk secretion from mammary glands Prolactin & exercise increases at high exercise intensities and recovers toward baseline within 45 mins Follicle-stimulating hormone initiates growth in the ovaries and stimulates them to secrete estrogen and helps aid sperm development Luteinizing hormone causing estrogen secretion and rupture of follicle and stimulates testes to secrete testosterone [Show Less]