During exercise, the blood flow to the active skeletal muscles is ...

[mydiamond]

During exercise, the blood flow to the active skeletal muscles is increased by autoregulation. How does this work? What other controls on blood flow operate?

Question 2

The placenta is a source of all of the following hormones, except
 A) hCG.
  B) relaxin.
  C) placental lactogen.
  D) progesterone.
  E) luteinizing hormone.

[aloop]

Answer to Question 1

When a skeletal muscle becomes more active, it consumes oxygen and nutrients and releases carbon dioxide, waste products, and potassium ions. One effect of reduced oxygen is to cause the smooth muscle cells that block capillary blood flow, the precapillary sphincters, to relax. As these relax, the capillaries open and plasma and red cells can perfuse the active tissue. After recovery from exercise is complete, gases and metabolites return to normal and blood flow returns to its resting value. This local mechanism works along with central control of vasodilation by the sympathetic vasodilator fibers that appear to utilize nitric oxide (NO) as the transmitter substance.

Answer to Question 2

E

[mydiamond]

TYSM

[lkanara2]

Excellent