Running Repairs Flashcards
(39 cards)
Human foetuses have a hole in the heart between the atria
How does oxygen reach the foetus
Placenta passes oxygen from mothers bloodstream by diffusion so blood by-passes the lungs
If atrioventricular and semi-lunar valves become weak or damaged faulty valves can occur
What happens with faulty valves and how can it be solved
Faulty valves allow blood to flow backwards, reducing blood pressure
Faulty valves can be replaced by artificial valves
Advantages of heart pacemaker and valves over a transplant
Less risk of rejection
Less traumatic operation
Disadvantages of heart pacemaker and valves over a transplant
Parts may need replacing after a few years
What happens if cholesterol plaques build up in the arteries
Leads to blockages
deprives cells of oxygen so they die, causing heart attack and coronary heart disease
Bypass surgery
Uses blood vessels from leg to replace damaged coronary arteries
to restore blood flow to heart muscle
Heart-assist devices
Pumps that reduce work of heart muscles while they recover after heart attack
Explain how the blood clots after damage to blood vessels
Why does blood clot
Platelets exposed to air
Causes series of chemical reactions to occur leading to formation of mesh of fibrin (protein) fibres called a clot
Prevents excess blood loss and entry of pathogens
What vitamin is needed for normal blood clotting
Vitamin K
What vitamin promotes healthy blood clotting
Vitamin C in green vegetables and fruit
What slows blood clotting
Not drugs
Cranberries and alcohol
Thrombosis
When blood clots abnormally inside undamaged blood vessels and blocks them partially or completely
What can thrombosis lead to
Heart attack or stroke
What drugs interfere with clotting process and can treat thrombosis
Anticoagulants
Warfarin, heparin and aspirin
What are the four different blood groups
A, B, AB, O
What other markers may be found on surface of red blood cells
(For two other different blood groups)
Rhesus protein
If you have it you are rhesus positive Rh+
If you dont you are rhesus negative Rh-
What marker proteins found on red blood cell surface makes them clump
Agglutinins
Someone with A-agglutinins is in group A
Someone with B-agglutinins is in group B
Someone with A-agglutinins and B-agglutinins is in group AB
Someone with no agglutinins is in group O
Why is it important that donated blood is matched carefully
The body produces antibodies when it detects foreign agglutinins
The blood would all clot
What blood groups can A accept from
It has Anti- B antibody in circulation
A or O
What blood groups can B accept from
It has Anti-A antibody in circulation
B or O
What blood groups can AB accept from
It has no antibodies in circulation
A, B, AB, O
What blood groups can O accept from
It has Anti-A and Anti-B antibody in circulation
O
Why must all organisms carry out gas exchange
To obtain oxygen in order to release energy from food by aerobic respiration
How do some small organisms get oxygen without lungs or gills
Diffusion in moist permeable skin (worm)
