BIOL 3402 Lecture Notes - Lecture 2: Thyroid, Electrolyte, Glycogenolysis
Document Summary
Gh has widespread effect on body: cartilage, bone, muscle, fat. Induces liver to produce insulin-like growth factors (igf-1) or somatomedins (igf-2: igf-1 prolongs action of gh, hormone half-life. Time for 50% to be cleared from blood. Increases amino acid uptake into cells, suppresses protein catabolism. Stimulates adipocytes to catabolize fats (protein-sparing effect) Bone growth, thickening, and remodeling influenced, especially during childhood and adolescence. Secretion elevated during the 1st two hours of sleep. Attached to roof of 3rd ventricle beneath posterior end of corpus callosum. Synthesizes melatonin from serotonin during the night: fluctuates seasonally, seasonal affective disorder (sad) Largest, purely endocrine gland: dark, reddish brown due to rich blood supply. Secretes thyroxine (t4) and triiodothyronine (t3) in response to tsh from hypothalamus: raises metabolic rate, o2 consumption, heat production, appetite, gh secretion, alertness, reflex speed. Dual nature: endocrine gland, ganglion of sympathetic nervous system. When stimulated it releases: catecholamines (epinephrine, norepinephrine) Glycogenolysis and gluconeogenesis by liver boosts glucose levels.
