Circulations

What are the two main functions of the circulatory system?

1. Transport

2. 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