transport in humans Flashcards
what are the main functions of the blood?
- transport substances round the body
- part of the immune system (defends against disease)
- distributes heat round the body
- forms scab to stop bleeding out and infection
what are the 4 components of the blood?
- red blood cells
- platelets
- white blood cells
- plasma
what percentage of the blood is plasma?
55%
what percentage of the blood is white blood cells and platelets?
> 1%
what percentage of the blood is red blood cells?
45%
which cells are involved with blood clotting?
- platelets
- clotting factors
- blood cells
- fibrin
how do platelets help when you get cut?
they stick together to form a temporary clot
what are platelets?
bits of cell broken of larger cells
what shape is a red blood cell and why?
biconcave disk to increase surface area to volume ratio
why don’t red blood cells have a nucleus?
so there is more room for oxygen
what does carbon monoxide do?
binds to haemoglobin replacing the oxygen
what does a phagocyte do?
engulf the bacteria and digest it
what do lymphocytes do?
recognise the microbe, produces antibodies these fit the antigens these antigens are then either digested, die or break open
what are memory cells?
they stay in the blood long after the pathogen has been destroyed so that if the same pathogen returns they will recognise it and will respond faster and produce higher quantity’s of antibodies
where do arteries go?
away from the heart