and Correct Answers. 100% Correct.
2024/2025.
What is the main function of parathyroid hormone?
increase plasma [Ca]
How does PTH function?
transfer Ca from bone fluid --> plasma, increase osteoclast activity, increase kidney resorption,
activate vitamin D
What is the main function of. calcitonin?
decrease plasma [Ca]
where is calcitonin produced?
C cells of thyroid gland
how does calcitonin function?
inhibit osteoclast activity, decrease transfer of Ca from bone fluid to plasma
How does vitamin D function in calcium regulation?
it increases Ca and PO4 absorption by the small intestines.
what is another word for vitamin D?
cholecalciferol
How is vitamin D activated?
activated by the liver and kidney after sun light exposure. Kidney is activated by decreased [Ca] and
[PO4]
what is hyperparathyroidism?
XS PTH, causes osteoporosis and kidney stones
what does vitamin D defictency cause>
rickets in kids, osteomalacia in adults. causes soft and deformed bones
what is parturient paresis?
milk fever, caused by constant elevated Ca2+ in plasma in dairy cattle
what kind of heart do reptiles have?
3 chambered heart
what kind of heart do crocodiles have?
, 4 chambered heart with 2 aortas
How do mammalian and bird fetal hearts bypass the lungs until they are fully formed/
the foramen oval connects the two atria; the ductus arterioles connects the pulmonary artery and
aorta.
are arteries elastic?
yes. they change radius to conduct blood pressure and resistance.
what conducts blood flow during ventricular diastole?
arterial recoil due the the elasticity.
what is the MAP
93mmHg in arteries; 37mmHg at capillary entrance.
what are arteries and arterioles innervated by?
sympathetic neurons, can both constrict and dilate.
what is the most powerful vasoconstrictor?
angiotensin II
what does catecholamine activation of A1-adrenergic receptors cause?
vasoconstriction
what does Epi activation of B2-adrenergic receptors cause?
vasodilation
Which arteries do not constrict?
brain and lung
what is active hyperemia?
increased blood flow due to local metabolic changes
what does histamine do to blood flow>
increases permeability of blood vessels and dilates vessels.q
What do precapillary sphincters do?
control the number of capillaries open for blood flow
what controls the rate of flow in capillaries?
arteriole constriction and dilation.
what is bulk flow>
the movement of a fluid driven by pressure between plasma and ISF (hydrostatic and colloid
osmotic)
Pc