Blood vessels and tissue fluidAQA A-Level Biology: Flashcards

Exam questions on Blood vessels and tissue fluid

1. A student examined transverse sections of an artery and of the vein running alongside it in a mammal, using a light microscope. The artery had a thicker wall and a narrower lumen than the vein.
   Explain how the structure of a vein is adapted to its function.2 marks
2. During exercise, blood flow to the skeletal muscles increases while blood flow to the digestive system decreases. This is controlled by the arterioles that supply the capillary beds in these organs.
   Blood flows more slowly in the capillaries than in the arterioles. Explain why this is an advantage.2 marks
3. In a capillary in the leg of a healthy person, the hydrostatic pressure of the blood is 4.0 kPa at the arteriolar end and falls to 2.0 kPa at the venous end. The plasma proteins exert an opposing force of 3.3 kPa throughout the capillary, which draws water back into the blood by osmosis. A patient with severe liver disease makes too little albumin, a plasma protein, and has swollen ankles caused by excess tissue fluid.
   Use the data to explain the movement of fluid at the arteriolar end and at the venous end of the capillary in a healthy person.3 marks