B4 Flashcards
what are the main types of blood vessels
veins, arteries and capilaries
what are the features of a red blood cell which helps it deliver oxygen to your cells
has lots of haemoglobin for oxygen to bind to, biconcave shape for a larger surface area, no nucleus for more haemoglobin to fit in the cell,
what is the blood of a healthy person mostly made of (all the main components in blood)
plasma, red blood cells, white blood cells, platelets
what is the role of white blood cells
to fight of harmful organisms
what is the role of plasma
transports undigested food and body waste
what is the role of platelets
fragments of cells which help create blood clots
what is the role of the artery
to carry blood away from the heart
what is the role of the vein
to carry blood to the heart
what is the pressure of the blood carried in the artery
its carried at high pressures so the blood moves fast
what is the pressure of the blood carried by the vein
blood in the vein is carried in low pressure which makes the blood travel slowly
what are the adaptations of the arteries which makes it suitable for carrying blood at high pressures
thick inner and outer walls of muscles with a narrow central tube
what are the adaptations of the veins which makes them suitable for carrying blood at low pressures
they have thin outer and inner walls of muscles with a wide central tube
why is blood in the arteries carried at high pressures but not in the veins
blood in the arteries are carried at high pressures because it’s needed to flow quickly to every parts of the body so that cells don’t die due to lack of oxygen. veins don’t need to carry blood at high pressures because… well you don’t need to know the reason.
why do veins have valves
the role of the valve is to prevent backflow by opening and closing. when valves open the allow blood to enter and o towards the heart but then the close in case the blood starts to flow back the way it came from.
how do valves in a vein work
when blood moves up the vein it pushes the valve causing it to open and so blood is allowed to move past it. however if blood does start to flow backwards it pushes the valve to close.
how does blood move up the vein
there are muscles to the side of the veins which pushes the blood up the vein. think of it as a tube of toothpaste and a rolling pin. the pin pushes the toothpaste out of the tube.