Transport Systems Flashcards
What are the main features of veins?
- Carry blood towards the heart
- Purply-red and low in oxygen
- No pulse
- Have valves to prevent back-flow of blood
- Thin walls with large lumen
What are the main feature of arteries?
- Carry blood away from the heart to organs
- Stretch as blood flows through them which creates a pulse
- Blood is under high pressure so will spurt out every time the heart beats if the artery is cut
- Thick walls and a thick layer of muscles and elastic fibres surrounding the small lumen
What are the main features of capillaries?
- Network of vessels linking arteries and veins
- Narrow with thin walls to allow substances like oxygen to diffuse easily out of the blood cells and CO2 into blood cells
- Narrow lumen and only a single cell thick
How is a heart attack caused?
When the supply of oxygen to your heart is interrupted
How can coronary arteries that supply blood to the heart muscle narrow?
With age or if fatty deposits build up
How does a stent work?
- A stent is a metal mesh put in place in the artery
- A balloon is inflated to open the blood vessel and the stent keeps it open
- Blood can flow freely
- This can be done without general anaesthetic
- Can be used almost anywhere in the body
- Release drugs to stop blood from clotting
How can a bypass surgery help damaged coronary arteries?
- Blocked arteries replaced with veins from another part of the body
- Used where stents can’t help
- Expensive and requires general anaesthetic
What happens is a valve does not work properly?
- Valves can weaken from the large amount of pressure they experience
- The person can become breathless and will die
How do mechanical valves work?
Mechanical valves are made of titanium and polymers and last for a long time but you have to take medicine for the rest of your life to prevent blood clots
How do biological valves work?
These are based on valves taken from animals and the patient does not need to take any medicine. However, they only last for around 15 years.
Why is a transport system vital in your body?
To supply the needs of your body cells and remove waste material they produce
What does your blood circulation system consist of?
The pipes (blood vessels), the pump (heart), and the liquid (blood)
You have two transport systems, called double circulation. What does each of these do?
- One carries blood from your heart to your lungs and back to allow CO2 to be exchanged with air
- The other carries blood around the rest of the body then back again to the heart
Why is double circulation vital to us?
To maintain our warm-blooded nature and make the system efficient
What is the heart made up of?
2 pumps, heart walls that are entirely made of muscle and which are supplied with oxygen by the coronary arteries. The two sides fill and empty at the same time to give a strong heart beat
Blood coming into the right atrium from the vena cava is deoxygenated
Blood from the pulmonary vein is oxygenated
The atria contract together and force the blood down the ventricles
Valves close to stop the blood flowing backwards out of the heart as the blood is pumped. The ventricles contract and force blood downwards. The deoxygenated blood is forced into the pulmonary artery and the oxygenated blood is sent around the body into the aorta artery
a blood is a tissue that consists of a fluid called plasma. What does this contain?
Red blood cells, white blood cells and platelets as well as dissolved substances suspended in it
What colour is blood plasma?
Yellow. Your blood is red because of the red blood cells
What is the job of your red blood cells?
To pick up oxygen from the lungs and carry it to tissues and cells where it is needed
How are red blood cells adapted to make transport efficient?
- Biconcave disc shape to increase SA over which diffusion can take place
- Lots of haemoglobin (a red pigment that carries oxygen)
- No nucleus so there is more room for haemoglobin
What happens to haemoglobin in a high concentration of oxygen?
e.g. in alveoli, oxygen and haemoglobin react to make bright red oxyhemoglobin
What happens to oxyhemoglobin where concentration of oxygen is lower?
It splits up to form purple-red haemoglobin and oxygen which diffuses into cells where it is needed
What are the features of white blood cells?
- Bigger than red blood cells but fewer of them
* Have a nucleus and fight disease
