Biology B2 - Cardiovascular Disease (Artificial Hearts, B & M Valves, Artificial Blood)

What can an artificial heart do?

pump blood around the body

what do doctors usually do if a patient has heart failure?

perform a heart transplant using organ donors

However In what cases would a doctor use an artificial heart?

if organ donors aren't available right away

or they're not the best option for that patient

what are artficial hearts?

mechanical devices that pump blood for someone who's haert as failed

are articficial hearts tempoarary?

yes they are a normally temporary fix to keep the person alive until a matching donor comes along or to let the person recover by allwing the heart to res & heal

In some cases they're used a permaneant fix, why?

reduces the need for a donor heart

main advantage of an artificial heart?

They're less likely to be rejected by the body's immune system than a donor heart.

why is this?

because they are made from metal or plastics so the body doesn't recognise them as foreign and attack as it would with living tissue

what are the disadvantages of an artificial heart

surgery can lead to bleeding and infection

-they dont' work as well as a healthy natural one - parts could wear out or the electrical motor could fail

-blood doesn't flow through as smoothly - can cause blood clots and lead to strokes

-patient has too take drugs to thin their blood to make sure this doesn't happen

-this can cause problems with bleeding if they get hurt

What can faulty heart valves be replaced with?

Biological or mechanical valves

How can the valves in the heart be damaged or weakened?

by heart attacks, infection or old age

what can this damage do?

cause the valve tissue to stiffen, so it won't open properly or

valve may become leaky, allowing blood to flow in both directions rather than just forward

What does this mean?

blood won't circulate as effectively as normal

severe valve damage can be treated by...

replacing the valve

where can replacement valves be taken from?

-Humans or other mammals eg humans or other mammals : (biological valves) or

-Man-made : mechanical valves

What can artificial blood do?

keep you alive in an emergency

What happens when someone loses a lot of blood?

their heart can still pump the remaining red blood cells around (get oxygen to their organs) as long as the volume of blood can be topped up

What is artificial blood

Artificial blood is a blood substitute

State one example of a blood substitute and explain it

saline - used to replace the lost volume of blood - it's safe if no air bubbles get into the blood and can keep people alive even if they lose 2/3 of their red blood cells

-this may give the patient enough time to produce new blood cells

-if not they will need a blood transfusion