Studied by 2 people
What are the two main functions of the circulatory system?
Transport
Defence against disease
What are red blood cells?
Specialsed cells adapted to carry oxygen
What are the adpations for a red blood cell and reasons
NO nucleus- more space for oxygen
Biconcave shape - large surface area to volume ratio - more space for diffusion to take place
Haemoglobin rich in iron- binds oxygen together
What do white blood cells do?
Defend against disease/ illness
What are the two types of white blood cells
Lymphocytes and phagocytes
What do lymphocytes do?
lymphocytes produce antibodies
cause microbes to clump together - they are very specific
What do phagocytes do?
engulf microbes and digest the microbes, this is called phagocytosis
What is plasma?
Liquid part of the blood
Function of plasma
its function is transport of blood cells, food molecules, carbon dioxide, hormones and urea
What is the function of platelets?
Its function is to convert fibrinogen into fibrin in blood clotting- the fibrin forms a mesh to trap the blood and form scabs.
What does double circulation mean?
Blood goes through the heart twice for each circuit of the body.
(Once to be sent to the lungs and then sent to the body)
why do arteries have muscle and elastic fibre
arteries contain muscle which is used for strength as blood pressure is high. elastic fibres that allow arteries to expand recoil as blood pulses through.
what is the function valves
In veins which prevent back flow due to low pressure of blood in vein. This keeps blood flow unidirectional.
why do veins have a larger lumen
To reduce friction (blood cells hitting up against the walls) as they carry blood from under a much low pressure
pulmonary artery and pulmonary veins are exceptions to the general rule regarding arteries
Why is the left side of the atrium more thick than the right
muscular because they need to pump blood round the whole blood
what are the benefits for the heart from regular exercise
Strengthened heart muslce so less chance of heart attack
Increased cardiac output - pumps more blood per minute even when not exercising
(The fitter you are the lower your resting time pulse ,active pulse and the quicker your recovery time
What is recovery time
this is the length of time it takes for someone’s pulse rate to return to normal after exercise
what are Coronary arteries
arteries that deliver oxygenated blood to the heart itself. They start from the aorta . You can see running over the outer surface of the heart.
what causes heart attacks
life style factors such as
excess dietary fat
Smoking
Stress
Lack of exercise
Why does a heart attack happen
build up of cholesterol and other fatty substances causes coronary arteries to narrow
this causes a blockage or blood clot
blood carrying glucose and oxygen cannot pass through the coronary arteries and there is reduced blood flow
Heart muscles stops, the cells die die to no respiration and cannot contact
Leads to heart attack
Why does a stroke happen
blockage to arteries in brain reduces blood flow to the brain
the cells are deprived of O2 and glucose
No respiration
cells die and reduced brain function
what is angioplasty and stents
angioplasty is a medical technique that involves the use of balloon like structures to hold open and widen diseased arteries so that stents (small mesh like structures) and can be inserted into blood vessels to hold them open
what are the drugs for cardiovascular diseases
aspirin and statins
what does aspirin to do
helps to thin the blood and make it less sticky and less likely to clot
most diseases are linked so if you suffer from obesity you are more likely to suffer from cardiovascular disease
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