Topic 1.1- test continued

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  • Created by: Hannah
  • Created on: 25-03-13 11:32
What makes both arteries and veins strong and durable?
The walls of both vessels contain collagen, a tough fibrous protein
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What is the benefit of containing elastic fibres?
It allows them to stretch and recoil
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what is the benefit of them having smooth muscle cells?
it allows them to constrict and dilate
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What are the key differences between veins and arteries?
Arteries have narrow lumen; veins have wide lumen. arteries have thicker walls; veins have thinner walls. arteries have more collagen, elastic fibres and smooth muscle; veins have less collagen, elastic fibres and smooth muscles.veins- valve.
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How blood moves through the vessels: fill in blanks. Every time the heart contracts (systole) blood is forced into .... and their elastic walls stretch to accomodate the blood. during .... (relaxation of the heart),
arteries, diastole
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(continued) the elasticity of the artery walls causes them to recoil behind the blood helping to ....... ... ... .....
Push the blood forward
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Cont: the blood moves along the artery as each section in series stretches and recoils in this way.by the time the blood reaches the smaller arteries and capillaries there is a steady flow of blood. in t' capillaries this allowsxchange btween blood+?
the surrounding cells through the one cell thick capillary walls.
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(cont)What does the network of capillaries that lies close to every cell ensure?
there is rapid diffusion between the blood and surrounding cells.
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The heart has a .... direct effect on the flow of blood through the veins. in veins, blood flow is assisted by the .... of skeletal muscles during movement of limbs and breathing.
Less
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Low pressure in the ... (chest cavity) when breathing in also helps draw blood back into the heart from the veins.
Thorax
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How is backflow prevented from occuring?
By valves within the veins. the steady flow without pulses of blood means that the blood is under low pressure in veins.
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How is the heart supplied with blood?
through two vessels called the coronary arteries.
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How the heart works: the chambers of the heart alternatively contract and relax in a rhythmic cycle. what is contraction and relaxation known as?
Contraction- systole relax- diastole
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Define: cardiac cycle
One complete sequence of filling and pumping blood.
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During systole, cardiac muscle .... and the heart pumps blood out through the .... and ..... ....
Systole, aorta, pulmonary arteries.
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During ....., cardiac muscle ..... and the heart fills with blood.
diastole, relaxes
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The cardiac cycle can be simplified into three phases; what?
Atrial systole, ventricular systole and diastole.
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What happens during Atrial systole?
Blood returns to the heart due to the action of skeletal and gaseous exchange (breathing) muscles as you move and breathe. blood under low pressure flows into the left and right atria from the pulmonary veins and vena cava.
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(cont)
as the atria fill, the pressure against the atriventricular valves pushes them open and blood begins to leak into the ventricles. the atria walls contract, forcing more blood into the ventricles.
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What happens during ventricular systole?
the ventricles contract from the base of the heart upwards,^ the pressure in the ventricles. this pushes blood up nd out through the arteries.the pressure of blood against atrioventricular valves closes thm nd prevents blood flowing backwards2 atria
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What happens during diastole?
The atria and ventricles relax.elastic recoil of the relaxing heart walls lowers pressure in the atria and ventricles.blood under high pressure in arteries is drawn back towards the ventricles, closing the semilunar valves and preventing further....
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(continued)
... backflow. the coronary arteries fill during diastole. low pressure in the atria helps draw blood into the heart from the veins.
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ATHEROSCLEROSIS: what is it?
Its the disease process that leads to coronary heart disease and strokes.
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What can occur during atherosclerosis?
fatty deposits can either block an artery directly or increase the chances of being blocked by a blood clot (thrombosis).
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What can happen if the blood supply is blocked?
the affected cells can become permanently damaged. in the arteries supplying the brain it results in a stroke..the supply of blood ot the brain is restricted or blocked, causing damage or death to cells in the brain.
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Atherosclerosis can be triggered by a number of factors. whatever the trigger,what is the couorse of events that follow in atherosclerosis?
The endothelium, a delicate layer of cells lining the inside of the artery, seperating the blood that flows along the artery from the muscular wall becomes damaged for some reason. for instance could be as a result of high blood pressure, which ..
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(cont)
... puts extra strain on the layer of cells. 2)once the lining of the artery is breached there is an inflammatory response. white blood cells leave the blood vessel and move into the artery wall. these cells accumulate chemicals from the blood...
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(cont)
.. particularly cholesterol. a deposit builds up called an atheroma.3) calcium salts and fibrous tissue also build up at the site, resulting in a hard swelling called a plaque on the inner wall of the artery. the build up of fibrous tissue means ..
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(cont)
the artery loses some elasticity, in other words it hardens. 4)plaques cause the artery to narrow. this makes it more difficult for the heart to pump blood around the body and can lead to a rise in blood pressure.
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A dangerous positive feedback begins to build up- what is the meaning of this in terms of atherosclerosis?
plaques lead to a raised blood pressure and raised blood pressure makes it more likely that further plaques will form.
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Why does the blood clot in arteries?. fill in blanks: when blood vessel walls are damaged or blood flows very slowly, a blood clot is much more likely to form. when ...., a type of blood cell without a nucleus come into contact with the damaged ...
platelets
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... vessel wall they change from ...... ..... to spheres with long thin projections. their cell surfaces change ,c ausing them to stick to exposed collagen in the wall and to each other to form a temporary .... ....
flattened discs, platelet plug
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How are clots formed?
The direct contact of blood with collagen within the damaged artery wall also triggers a complex series of chemical changes in the blood. a cascade of changes results in the soluble plasma protein called prothrombin being converted to thrombin...
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(cont)
...thrombin is an enzyme that catalyses the conversion of another soluble plasma protein, fibrinogen, into long insoluble strands of the protein fibrin. these fibrin strands form tangled mesh that traps blood cells 2 form clot.
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Why do only arteries get atherosclerosis?
The fast- flowing blood in arteries is under high pressure so there is significant chance of damage to walls. the low pressure in the veins means that ther is less risk of damage to the walls.
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The consequences of atherosclerosis in regards to coronary heart disease?what happens due to the narrowing of coronary arteries?
It limits the amount of oxygen- rich blood reaching the heart muscle. the result may be a chest pain called angina.Because the heart muscle lacks oxygen it is forced to respire anaerobically. it is thought this results in chemical changes.
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(cont)What is released when a fatty plaque in the coronary arteries ruptures and what does it lead to?
Cholesterol and it leads to rapid clot formation.the blood supply to the heart may be blocked completely. the heart muscle supplied by these arteries doesnt receive any blood so is said to be ischaemic (without blood)...
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(cont)
.. if they affected muscle cells are starved of oxygen for long they will be permanantly damaged. this= heart attack.
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The consequences of atherosclerosis in regards to a stroke?
if supply of blood to the brain is only briefly interrupted a mini stroke may occur. a mini- stroke has all the symptoms of a full stroke but the effects only last for a short period and full recovery can happen quite quickly.
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Card 2

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What is the benefit of containing elastic fibres?

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It allows them to stretch and recoil

Card 3

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what is the benefit of them having smooth muscle cells?

Back

Preview of the front of card 3

Card 4

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What are the key differences between veins and arteries?

Back

Preview of the front of card 4

Card 5

Front

How blood moves through the vessels: fill in blanks. Every time the heart contracts (systole) blood is forced into .... and their elastic walls stretch to accomodate the blood. during .... (relaxation of the heart),

Back

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