The Circulatory System Flashcards
How does the heart pump blood around the body?
It’s contracts
Why do we have a double circulatory system?
One pumps deoxygenated blood to the lungs to take in oxygen and the other pumps oxygenated blood around the body to give up its oxygen to the body cells
How many chambers does the heart have?
4
Name the 4 chambers of the heart
Right atrium, right ventricle, left atrium and left ventricle
Where does the blood which flows into the atriums come from?
The vena cava or the pulmonary vein
When the atriums contract, where does the blood go?
Into the ventricles
When the ventricles contract, where does the blood go?
The pulmonary vein or the aorta and out of the heart
What does the blood flow to the organs through?
Arteries
What does the blood flow through when it returns to the heart?
Veins
How many types of blood vessels are there?
3
What is the function of an artery?
To carry blood away from the heart
What is the function of a capillary?
They’re involved in the exchange of materials at the tissues
What is the function of a vein?
To carry blood to the heart
How is an artery adapted?
The walls are strong and elastic to withstand pressure and they have layers of muscles to keeps them strong with elastic fibres to allow them to stretch and spring back
How is a capillary adapted?
They’re really small so they can get to every cell, they have permeable walls do diffusion can happen and they are only one cells thick so this increases the rate of diffusion
How is a vein adapted?
Less thick walls because not as much pressure and valves to help keep the blood flow in the right direction
What are the 4 main things in the blood?
Red blood cells, white blood cells, platelets and plasma
What do red blood cells do and why are the good at this?
The carry oxygen - they have a doughnut shape giving them a large surface area for absorbing more oxygen, they don’t have a nuclear do more space for oxygen and they carry haemoglobin
What is haemoglobin?
A red pigment which combines with oxygen in the lungs to make oxyhemoglobin and in body tissues the oxyhemoglobin splits up into haemoglobin and oxygen into release oxygen into the cells
What do white blood cells do and why are the good at this?
Defend against disease - they change shape to engulf microorganism and produce antibodies and antitoxins
What do platelets do and why are the good at this?
Help blood clot - they are small fragments of cells which help the blood to clot at wounds
What does plasma do and why are they good at this?
Carries everything in the blood - carries red and white blood cells, platelets, nutrients, carbon dioxide, urea, hormones, antitoxins and antibodies
What is coronary heart disease?
A disease where the arteries that supply blood to your heart get blocked by fatty deposits which makes the arteries narrow and restricts blood flow which can result in a heart attack
What can you do to resolve this?
Insert stents into the arteries
What do stents do?
Keep the arteries open do blood can pass through
What are the advantages of stents?
They lower the risk of a heart attack
What are the disadvantages of stents?
Over time the artery can narrow again which makes the stent irritate the artery so scar tissues grows, and the patient has to take drugs to stop blood clots
What is artificial blood?
A blood substitute which is normally a salt solution (saline) which is used to replace blood which has been lost and help keep people alive and allow them to replace their red blood cells
What are the advantages of an artificial heart?
Less likely to be rejected by body’s immune system and reduces need for heart donors
What are the disadvantages of an artificial heart?
Surgery to fit it can cause bleeding and infection, artificial hearts don’t work as well as natural ones, it can fail, blood doesn’t flow as smoothly so can lead to strokes and patient had to take blood thinking drugs
