Question

1. What type of blood vessels have the slowest velocity of blood flow?

   	a.	arteries
   	b.	arterioles
   	c.	veins
   	d.	capillaries

2. What would be the consequences if we were to reverse the direction of water flow over the gills of a fish, moving water inward from the side of the fish, past the gills, then out of the mouth? This reversal of water flow would ________.

   	a.	reduce the efficiency of gas exchange
   	b.	change the exchange of gases in the body from carbon dioxide out and oxygen in, to carbon dioxide in and oxygen out
   	c.	increase the efficiency of gas exchange
   	d.	result in no effect/differences in gas exchange

3. QUESTION 58

4. Which of the following gives the correct sequence of the regions of the nephron with respect to fluid flow ?

   	a.	distal tubule -> ascending Loop of Henle -> descending Loop of Henle -> proximal tubule -> collecting duct
   	b.	ascending Loop of Henle ->descending Loop of Henle -> proximal tubule -> distal tubule -> collecting duct
   	c.	proximal tubule -> ascending limb of Henle -> descending limb of Henle -> distal tubule -> collecting duct
   	d.	proximal tubule -> descending Loop of Henle -> ascending Loop of Henle -> distal tubule -> collecting duct

Answer 1

As the total cross-sectional area of the vessels increases, the velocity of flow decreases. Blood flow is slowest in the capillaries, which allows time for exchange of gases and nutrients.

Option C

The arrangement of water flowing past the gills in the opposite direction to the blood (called countercurrent flow) means that they can extract oxygen at 3 times the rate a human can. ... This way, the blood is absorbing more and more oxygen as it moves along.

Question-58

Right option is D