Mass Transport- Animals

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Give 3 structural features of an artery
Small lumen, thick muscle layer, thick elastic layer
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Give 2 structural features of a vein
Large lumen, thin muscle layer
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Why do arteries have thick elastic and muscle tissue?
To withstand high pressure, even out pressure fluctuations and so they can stretch and recoil
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Which blood vessels contain valves?
Veins
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Why do arteries have high pressure?
They need to pump blood away from the heart to all the organs
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Give 3 features of capillaries which help them carry out their function
Wall is only 1 cell thick, they are numerous and highly branched, smooth lining, flattened epithelial cells, large surface area
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How does being numerous and highly branched help capillaries?
They are close to all cells, decreasing the diffusion distance
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How does having a wall 1 cell thick help capillaries?
They have a short diffusion pathway
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How does having a narrow diameter help capillaries?
Red blood cells can only just fit through, slowing them down to give more time for diffusion
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Why are capillaries leaky?
Phagocytic white blood cells can escape to fight infection
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Why do capillaries have a smooth lining?
To reduce friction for more rapid diffusion
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What happens near the arteriole end of a capillary?
The hydrostatic pressure is higher than the water potential effect so fluid is forced out
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What happens near the venuole end of a capillary?
Water potential effect is higher than the hydrostatic pressure so water is reabsorbed into the capillary by osmosis
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In which direction does blood flow in the capillary?
From the arteriole end to the venule end (high hydrostatic pressure to low hydrostatic pressure)
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What does tissue fluid contain?
Carbon dioxide and waste materials
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The cardiac muscle is myogenic. What does this mean?
It does not need an impulse to contract
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What valve is found between the left atrium and left ventricle?
Left atrioventricular valve (bicuspid)
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What valve is found between the right atrium and right ventricle?
Right atrioventricular valve (tricuspid)
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Where is the aorta and what is its function?
Connected to the left ventricle and transports oxygenated blood to all parts of the body except the lungs
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What blood vessel is connected to the right atrium and what is its function?
The vena cava, to bring deoxygenated blood back from the tissues of the body except lungs
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Where is the pulmonary artery and what is its function?
Connected to the right ventricle and carries deoxygenated blood away from the heart to the lungs
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What blood vessel is connected to the left atrium and what is its function?
The pulmonary vein, to bring oxygenated blood back to the heart from the lungs
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Why is the wall of the left ventricle much thicker than the right ventricle?
It has to pump blood to the whole body
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Name 3 risk factors associated with cardiovascular disease
Smoking, high blood pressure, high blood cholesterol, diet
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What happens in atrial systole?
The atria contract and atrioventricular valves open
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What happens in ventricular systole? (after atrial systole)
The ventricles contract, increasing ventricular pressure and causing the atrioventricular valves to close, so the pressure rises further. When the pressure is higher than that in the aorta and pulmonary artery, blood is forced into these vessels
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What happens in diastole? (after ventricular systole)
Blood returns to the atria from the pulmonary vein and vena cava. The atria and ventricles relax
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Where does loading of oxygen occur in a human?
In the lungs
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Where does unloading of oxygen occur?
Respiring cells and tissues
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Give the equation for oxygen loading
Hb + 4O2 -------> HbO8
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What type of structure does haemoglobin have?
Quaternary- It is made up of 2 alpha and 2 beta polypeptides. Each molecule has 4 haem groups, each able to carry 1 oxygen molecule
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What is partial pressure?
The pressure exerted by one gas in a mixture of gases
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What goes on each of the axis in an oxygen dissociation curve?
y-axis: % saturation of haemoglobin with oxygen, x-axis: ppO2/kPa
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What does a standard oxygen dissociation curve suggest about loading and unloading of oxygen?
Haemoglobin is better at loading oxygen at high O2 partial pressures and better at unloading O2 at low partial pressures
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Why is an oxygen dissociation curve s-shaped?
The first O2 which binds to the haemoglobin changes its shape making it easier for the second and third O2 molecules to bind, causing the gradient to become steeper. However, the curve flattens as binding for the fourth O2 is more difficult.
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Describe Bohr Shift of oxygen dissociation curves
The dissociation curve moves to the right at higher ppCO2 as CO2 reduces affinity of haemoglobin for oxygen so more O2 is unloaded to meet increased respiration rate
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What is myoglobin?
An oxygen store in muscles and it allows aerobic respiration to continue at low O2 partial pressures. It only unloads oxygen at very low O2 partial pressures so it has a very high affinity for O2
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Other cards in this set

Card 2

Front

Give 2 structural features of a vein

Back

Large lumen, thin muscle layer

Card 3

Front

Why do arteries have thick elastic and muscle tissue?

Back

Preview of the front of card 3

Card 4

Front

Which blood vessels contain valves?

Back

Preview of the front of card 4

Card 5

Front

Why do arteries have high pressure?

Back

Preview of the front of card 5
View more cards

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