Homeostatic Systems

Question 1

Calcium levels

Answer 1

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

Question 2

T3 & T4 levels

Answer 2

Low T3 & T4 or low body temperature - hypothalamus releases TRH - pituitary releases TSH - Thyroid gland releases T3 & T4

Question 3

Blood sugar levels

Answer 3

High - insulin from pancreas - cellular uptake of glucose - liber converts glucose to glycogen
Low - glucagon from pancreas - break down glycogen to form glucose

Question 4

Body Temperature

Answer 4

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