Mass Transport-A level revision

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The hydrostatic pressure falls from the arterial end of the capillary to the venule end of the capillary, explain why? ( 1 mark)
Loss of water/Loss of fluid
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High blood pressure leads to an accumulation of tissue fluid. Explain how? (3 marks)
1.High blood pressure=high hydrostatic pressure. 2. Increases outward pressure from arterial end of capillary. 3. so more tissue fluid is formed.
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The water potential of the blood plasma is more negative at the venule end of the capillary than at the arterial end of the capillary. Explain why? (3 marks)
1. Water has left the capillary. 2.Proteins in blood too large to leave the capillary. 3. Increasing concentration of blood proteins.
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The haemoglobin in one organism may have a different chemical structure from the haemoglobin in another organism. Explain how? (1 mark)
Different primary structure/amino acids
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Describe the Bohr effect?
1. When cells respire they produce carbon dioxide, which raises the pCO2. 2. This increases the rate of oxygen unloading so the dissociation curve shifts right. The saturation of blood with oxygen is lower for a given pO2.
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Describe Ultrafiltration (Tissue Fluid)?
-Higher hydrostatic pressure in blood than tissue fluid due to heart pumping, elastic recoil and blood entering narrower tube. -Forces small molecules through capillary walls + into tissue fluid. -Large molecules stay in plasma.
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Describe Reabsorption (tissue fluid)?
-Lower hydrostatic pressure in blood than tissue fluid due to ultrafiltration and blood entering wider tube. -Ultrafiltration slows down. -Proteins left in blood create more negative water potential in blood than tissue fluid.
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Describe the rest of Reabsorption (tissue fluid)/
Water moves from tissue fluid into blood by osmosis. -Small molecules into blood through diffusion.
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Describe formation of lymph (tissue fluid)?
-Tissue fluid that does not enter the blood enters the lymph capillary. -This makes the fluid lymph. -lymph vessels return lymph to blood via ducts near the heart.
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What is the function of the coronary arteries?
Carry oxygen to heart muscle
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Describe the cohesion-tension theory (movement of water across the leaf)?
1.Water evaporates from the leaves at the top of the xylem. 2. This creates tension, which pulls more water into the leaf. 3. Water molecules are cohesive so when some are pulled into the leaf others follow. 4. Water enters the stem through the roots
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Describe the formation of tissue fluid?
1. At the start of the capillary bed, nearest the arteries the hydrostatic pressure inside the capillaries is greater than the hydrostatic pressure in the tissue fluid. 2. This difference in hydrostatic pressure means an outward pressure forces fluid
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Continued?
Out of the capillaries and into spaces around cells forming tissue fluid. 3. As fluid leaves, the hydrostatic pressure reduces in the capillaries- so the hydrostatic pressure is much lower at the venule end of the capillary bed.
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Continued?
4. Due to the fluid loss, and an increasing concentration of plasma proteins, the water potential at the venule end of the capillary bed is lower than the water potential in the tissue fluid.
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Step 5?
5. This means that some water re-enters the capillaries from the tissue fluid at the venule end by osmosis.
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What is tissue fluid?
Tissue fluid is the fluid that surrounds cells in tissues. It is made from small molecules that leave the blood plasma e.g. oxygen, water and nutrients.
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High absorption of salt from the diet can result in a higher than normal concentration of salt in the blood plasma entering capillaries. This can lead to a build-up of tissue fluid. Explain how?
1. Higher salt results in lower water potential of tissue fluid. 2. so less water returns to capillary by osmosis at the venule end.
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Other cards in this set

Card 2

Front

High blood pressure leads to an accumulation of tissue fluid. Explain how? (3 marks)

Back

1.High blood pressure=high hydrostatic pressure. 2. Increases outward pressure from arterial end of capillary. 3. so more tissue fluid is formed.

Card 3

Front

The water potential of the blood plasma is more negative at the venule end of the capillary than at the arterial end of the capillary. Explain why? (3 marks)

Back

Preview of the front of card 3

Card 4

Front

The haemoglobin in one organism may have a different chemical structure from the haemoglobin in another organism. Explain how? (1 mark)

Back

Preview of the front of card 4

Card 5

Front

Describe the Bohr effect?

Back

Preview of the front of card 5
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