Trasport in animals spec

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  • Created by: rachel
  • Created on: 15-03-13 07:50
Explain the need for transport systems in multicellular animals in terms of size.
Once an animal has several layers of cells any oxygen or nutrients diffusing in from the outside will be used up by the other layers of the cells & the cells deeper in the body will not get any oxygen or nutrients.
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Explain the need for transport systems in multicellular animals in terms of level of activity.
If an animal is very active, then it will need a good supply of nutrients & oxygen to supply the energy for movement.
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Explain the need for transport systems in multicellular animals in terms of surface area:volume ratio.
To allow animals to grow to large size, needs range of tissues & structural support to give body strength. Volume increases as body gets thicker but surface area doesn't increase as much. The sa:v of a large animal is relatively small - not enough sa
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Explain the meaning of the term 'single circulatory system' with reference to the circulatory systems of fish or mammals.
A circulation in which the blood flows through the heart once during each circulation of the body. e.g. a fish.
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Explain the meaning of the term 'double circulatory system' with reference to the circulatory systems of fish or mammals.
A circulation in which the blood flows through the heart twice during each complete circulation of the body. e.g. mammals.
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Explain the meaning of the term 'open circulatory system' with reference to the circulatory systems of insects & fish.
The blood is not always in vessels (blood bathes) e.g. insects.
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Explain the meaning of the term 'closed circulatory system' with reference to the circulatory systems of insects & fish.
The blood is always in vessels e.g. fish.
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Give the advantages of a closed circulatory system.
- possible to maintain a high blood pressure. - increased rate of flow & so delivery of substances. - flow can be diverted & directed.
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Describe the external structure of the mammalian heart.
The largest parts of the heart are the ventricles. Above ventricles is atria which are much smaller. Coronary arteries lie over surface of heart & carry oxygenated blood to heart. At top of heart are the veins that carry blood to heart & arteries.
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Describe the internal structure of the mammalian heart.
Divided into 4 chambers. 2 upper = atria which receive blood from major veins. 2 lower - ventricles separated by septum & separated from atria by AV valves. AV valves attached to tendinous cords. pulmonary artery & aorta have semilunar valves.
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Describe where the oxygenated & deoxygenated blood flows to and from.
deoxygenated blood flows from body to right atrium from vena cava. Oxygenated blood from lungs goes to left atrium.
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What do AV valves do?
Av valves prevent blood from flowing backwards.
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What do tendinous cords do?
Prevent he valves from turning inside out.
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What do semilunar valves do?
Prevent backflow.
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Explain differences in thicknesses of walls of the different chambers of the heart in terms of their functions.
Atria-very thin- --> ventricles. Right ventricle-thicker than atria- --> lungs + blood vessels in lung = v. thin & may burst. Left ventricle-thicker than right - more muscle to create more force-high BP push b. against greater resistance --> body
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Describe the first step of the cardiac cycle, with reference to the action of the valves in the heart.
1. When both the atria & the ventricles are relaxed, blood flows into the atria from the major veins.
16 of 50
Describe the second step of the cardiac cycle, with reference to the action of the valves in the heart.
2. The blood flows through the atrioventricular valves into the ventricles.
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Describe the third step of the cardiac cycle, with reference to the action of the valves in the heart.
3. The atria contract simultaneously, pushing blood into ventricles.
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Describe the fourth step of the cardiac cycle, with reference to the action of the valves in the heart.
4. Blood fills the atrioventricular valve, causing them to snap shut & preventing the blood from flowing back into the ventricles.
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Describe the fifth step of the cardiac cycle, with reference to the action of the valves in the heart.
5. When the pressure in the arteries is higher than the pressure in the ventricles, the semilunar valves shut.
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Describe the sixth step of the cardiac cycle, with reference to the action of the valves in the heart.
6. The walls of the ventricles contract, starting at the bottom.
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Describe the seventh step of the cardiac cycle, with reference to the action of the valves in the heart.
7. When the pressure in the ventricles is higher than the pressure in the arteries, the semilunar valves are pushed open & blood is pushed out of the heart. The contraction only lasts for a short time.
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Describe the eighth step of the cardiac cycle, with reference to the action of the valves in the heart.
8. The ventricles relax.
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Describe the ninth step of the cardiac cycle, with reference to the action of the valves in the heart.
9. When the pressure in the ventricles drops to below that of the atria, the atrioventricular valves open again.
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Describe the tenth step of the cardiac cycle, with reference to the action of the valves in the heart.
10. When the pressure in the ventricles drops to below that of the arteries, the semilunar valves shut again.
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Describe how the heart action is coordinated with reference to the sinoatrial node (SAN), the atrioventricular node (AVN) & the purkyne tissue.
SAN starts excitation wave. Spreads over wall of atria until reaches AVN. atrial systole occurs & this contraction is synchronised. Delay at AVN & then excitation spreads down septum -> bundle of his & purkyne fibres. ventricular systole occurs at ap
26 of 50
Describe the functions of the arteries.
Carry blood at HP (artery wall = able to withstand. Its thick with thick layer of collagen for strength). Endothelium = folded which prevents damage as can stretch under pressure. Must be able to maintain HP. - thick layer elastic tissue & smooth mus
27 of 50
Describe the function of the veins.
Carry blood at LP. Lumen = ease of BF. Walls-thinner layers of collagen, smooth muscle & elastic tissue-no stretch&recoil, no reduced BF. Contain valves- can be flattened as thin. Pressure applied to blood, forcing move in direction dictated by valve
28 of 50
Describe the function of capillaries
Walls consist of single layer of endothelial cells (reduce diffusion distance for exch.) Lumen is same diameter as RBC (7um) - ensures that RBC's are squeezed as they pass along capillaries. Diffusion distance = shorter so more likely to give up O2.
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Describe why the hydrostatic pressure decreases with distance from the heart.
There are more vessels producing a larger total lumen. Theres a reduced distance to blood flow & also loss of plasma from capillaries.
30 of 50
Explain the difference between blood, tissue & lymph in terms of the cells within them.
Blood: Erythrocytes & Leucocytes & platelets. Tissue fluid: Some phagocytic white blood cells. Lymph: lymphocytes.
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Explain the difference between blood, tissue & lymph in terms of the proteins within them.
Blood: hormones & plasma proteins. Tissue fluid: some hormones, proteins secreted by body cells. Lymph: some proteins.
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Explain the difference between blood, tissue & lymph in terms of the fats within them.
Blood: some transported as lipoproteins. Tissue fluid: None. Lymph: more than in blood.
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Explain the difference between blood, tissue & lymph in terms of the glucose within them.
Blood: 80-120mg per 100cm3. Tissue fluid: less. Lymph: less.
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Explain the difference between blood, tissue & lymph in terms of the amino-acids within them.
Blood: more. Tissue fluid: less. Lymph: less.
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Explain the difference between blood, tissue & lymph in terms of the oxygen within them.
Blood: more. Tissue fluid: less. Lymph: less.
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Explain the difference between blood, tissue & lymph in terms of the CO2 within them.
Blood: little. Tissue fluid: more. Lymph: more.
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Describe how tissue fluid is formed from plasma.
At arterial end of cap, blood under HP due to contractions from heart (hydrost. pressure)-Greater than osmotic pressure pulling H2O into cap from tissues. Pushes plasma fluid out cap, leaving lge protein mol behind & leaves through fenestration in ca
38 of 50
Describe a haemoglobin molecule.
Consists of 4 sub-units. Each sub-unit consists of a polypeptide & a haem-group. Haem-group contains 1 iron ion (Fe2+). Because Fe2+ attacks O2 it has affinity for it. A mol of haemoglobin can hold 4 molecules of oxygen (eight atoms).
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Describe the role of haemoglobin in carrying oxygen.
At low OT the H doesn't readily take up O2. When OT rises, diffusion gradient into H mol. steeply rises. Once 1 mol of O2 has associated with haem-group, shape of H mol. slightly changes making it easier for 2nd & 3rd mol to associate.
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What is known as the conformational change?
When a molecule of haemoglobin slightly changes shape to make it easier for the second & third molecules to associate.
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Describe why the curve showing haemoglobin carrying oxygen is sigmoid?
Once Hb mol contains 3 O2 mol it's not as easy for 4th to associate with haem group. This means that its difficult to achieve 100% saturation, even at high O2 pressures. Makes curve level off again making it S shaped.
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Describe the first step in the role of haemoglobin carrying carbon dioxide - (the creation of the product carbonic acid).
As CO2 diffuses into the blood, some enters RBC's & combines with H2O to form carbonic acid, catalysed by carbonic anhydrase. (CO2 + H2O --> H2CO3)
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Describe the second step in the role of haemoglobin carrying carbon dioxide.
This carbonic acid then dissociates to form H+ ions & hydrogen carbonate ions. (H2CO3 --> H+ +HCO3-)
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Describe the third step in the role of haemoglobin carrying carbon dioxide.
The hydrogen carbonate ions diffuse out RBC. Charge in RBS maintained by chloride shift (the movement for chloride ions into the cell).
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Describe the fourth step in the role of haemoglobin carrying carbon dioxide.
H+ ions could cause contents of cell to become v. acidic so haemoglobin acts as buffer.
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Describe the fifth step in the role of haemoglobin carrying carbon dioxide.
The oxyhaemoglobin dissociates & the H+ ions are taken up by the haemoglobin to form haemoglobonic acid.
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Describe & explain the significance of the dissociation curves of adult oxyhaemoglobin at different CO2 levels (the Bohr effect).
Actively respiring tissue produces more CO2 & needs more O2 for aerobic respiration to release energy. Ha.transports CO2; so less Ha. available to combine with O2. Bohr shift causes more O2 released so when more CO2 present curve shifts to right.
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Which curve shifts to the right in the Bohr effect?
The oxyhaemoglobin dissociation curve.
49 of 50
Explain the significance of the different affinities of fetal haemoglobin & adult haemoglobin for oxygen.
Fetal haemoglobin: higher affinity for O2 than adult & takes up O2 in lower partial pressure of O2. Placenta has low partial pressure of O2. At low partial pressure of O2, in the placenta, adult haemoglobin will dissociate.
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Other cards in this set

Card 2

Front

Explain the need for transport systems in multicellular animals in terms of level of activity.

Back

If an animal is very active, then it will need a good supply of nutrients & oxygen to supply the energy for movement.

Card 3

Front

Explain the need for transport systems in multicellular animals in terms of surface area:volume ratio.

Back

Preview of the front of card 3

Card 4

Front

Explain the meaning of the term 'single circulatory system' with reference to the circulatory systems of fish or mammals.

Back

Preview of the front of card 4

Card 5

Front

Explain the meaning of the term 'double circulatory system' with reference to the circulatory systems of fish or mammals.

Back

Preview of the front of card 5
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