The structure and function of arteries capillaries and veins Flashcards
What’s the function of arteries
carry blood away from the heart
What does an artery consist of
an outer layer of connective tissue, smooth muscle and the endothelium lining the central lumen
what does the arteries outer layer have
connective tissue containing elastic fibres
What does the middle layer fo arteries contain
smooth muscle with more elastic fibres
What do the elastci walls of the arteries do
stretch and recoil to accomodate the surge of blood
What supplies oxygenated blood to heart muscle
coronary artery
what can the smooth muscle in the walls fo arteries do
can contract causing vasoconstriction or relax causing vasodilation to control blood flow
What do capillaries consist of
the endothelium lining in the lumen
Whats the function of capillaries
allow gass xchange of substances with tissues
describe the capillaries walls
very thin to allow efficient exchange of materials
Whats the function of veins
carry blood back to the heart
What does the outer layer of veins consist of
connective tissue containing elastic fibres
What does the middle layer fo veins consist of
smooth muscle with mroe elastic fibres
What do veins have
an endothelium lining the central lumen
Whats the function of valves
prevent the backflow of blood
What pressure does blood in the veins move at
low pressue
why is the layer of smooth muscle thinner in veins than in arteries
because blood flows at low pressue
Why do capillaries have a very narrow diameter
allows them to run close to every cell of the body
What does pressure filtration do
forces plasma to pass through capillary walls into the tissue fluid surrounding the cells
tissue fluid and blood plasma are similar in composition with the exception of
plasma proteins which are too large to be filtered through the capillary walls
Whats the function fo lymphatic vessels
absorb excess tissue fluid and return it as lympth to the circulatory system
What is it knwon as when the fluid is absorbed by lymphatic vessels
Lymph
Whats the function of tissue fluid
supplies cells with glucose oxygen and other substances