Homeostatic Systems Flashcards
Calcium levels
Low - Parathyroid gland secretes PTH - osteoclasts break down bown, renal reabsorption, Vit D synthesis causes increased intestinal absorption
High - Calcitonin from thyroid - osteoclast activity halted, kidney reabsorption stops
T3 & T4 levels
Low T3 & T4 or low body temperature - hypothalamus releases TRH - pituitary releases TSH - Thyroid gland releases T3 & T4
Blood sugar levels
High - insulin from pancreas - cellular uptake of glucose - liber converts glucose to glycogen
Low - glucagon from pancreas - break down glycogen to form glucose
Body Temperature
High - hypothalamus heat-loss centre activated - capillaries near skin dilate & sweat glands release sweat
Low- activates heat-promoting centre of hypothalamus - skin blood vessels contract - blood travels through deeper tissue - skeletal muscles shiver