mass transport in animals EQ

Question 1

give the pathway a red blood cell takes when travelling in the human circulatory system from kidney to the lungs.
do not include descriptions of pressure changes in the heart or the role of heart valves in your answer. (3)

Answer 1

1. renal vein;
2. vena cava to right atrium;
3. right ventricle to pulmonary artery;

Question 2

vein;

Answer 2

wide(r) lumen;
OR
thinner wall;

Question 3

tissue fluid is formed from blood at the arteriole end of a capillary bed.
explain how water from tissue fluid is returned to the circulatory system. (4)

Answer 3

1. (plasma) proteins remain;
2. (creates) water potential gradient;
   OR
   reduces water potential (of blood);
3. water moves (to blood) by osmosis;
4. returns (to blood) by lymphatic system;

Question 4

suggest two ways the student could improve the quality of his scientific drawing of the blood vessels in this dissection. (2)

Answer 4

1. only use single lines/do not use sketching (lines)/ensure lines are continuous/connected;
2. add labels/annotations/title;
3. add magnification/scale (bar);
4. draw all parts to same scale/relative size;
5. do not use shading/hatching;

Question 5

describe two precautions the student should take when clearing away after the dissection. (2)

Answer 5

1. carry/wash sharp instruments by holding handle
   OR
   carry/wash sharp instruments by pointing away (from body)/down;
2. disinfect instruments/surfaces;
3. disinfect hands
   OR
   wash hands with soap (and water);
4. put organ/gloves/paper towels in a (separate) bag/bin/tray to dispose;

Question 6

explain how an arteriole can reduce the blood flow into capillaries. (2)

Answer 6

1. muscle contracts;
2. constricts/narrows arteriole/lumen;

Question 7

there is a small increase in pressure and in rate of blood flow in the aorta.
explain how this happens and its importance. (2)

Answer 7

1. elastic recoil (of the aorta wall/tissue);
2. smooths the blood flow
   OR
   maintains rate of blood flow;
   OR
   maintains blood pressure;

Question 8

describe the advantage of the Bohr effect during intense exercise. (2)

Answer 8

1. increases dissociation of oxygen;
2. for aerobic respiration at the tissues/muscles/cells
   OR
   anaerobic respiration delayed at the tissues/ muscles/cells
   OR
   less lactate at the tissues/muscles/cells;