What must occur in order for muscle contraction?
Calcium must bind troponin so that tropomyosin can move and myosin can bind actin in order to cause a power stroke, and therefore muscle contraction
What happens is the difference between the descending and ascending loop of henle?
The ascending limb is impermeable to water but is permeable to ions, whereas the descending limb is permeable to water and impermeable to ions
What is that largest vein in the human body?
The inferior vena cava