transport in humans Flashcards
what is the 2 main function of blood
to transport substances around the body and
to protect our body from infections
blood is made out of 4 components. what are they?
red blood cells
white blood cells
platelets
plasma
the function of red blood cells
transports oxygen throughout the body
the function of white blood cells
ingests and destroys foreign particles through phagocytosis (the process of engulfing foreign substance)
the function of platelets
prevent excessive blood loos through blood clotting
the function of plasma
transport various substances around the body
such as blood cells, ions, soluble food substances, hormones, dissolved carbon dioxide, vitamins, urea etc etc
allow diffusion and exchange of substance
describe blood clotting
damaged blood vessels activates platelets
then they convert plasma protein fibrinogen to fibrin
fibrin strands from a mesh of fibres arnd the platelet plug and traps blood cells to form a clot
the circulatory system consists of…
the heart and blood vessels
the heart is a muscular pump that…
circulates blood throughout the body
what are the 3 main types of blood vessels
arteries, veins and capillaries
the wall thickness of arteries
thick wall, muscular elastic tissue
the wall thickness of veins
thin & less elastic tissue
the wall thickness of capillaries
one-cell thick
the function of valves
prevent back flow of blood
are there valves in the arteries
absent
are there valves in the vein
present