2.5 Flashcards
(15 cards)
what happens to the blood gas it moves away from the heart
blood pressure decreases
what do all blood vessels have
a lumen
an endothelial lining
what do arteries do
• carry blood away from heart
• carry blood at high pressure
• stretch and recoil
• contract and dilate
describe arteries
• narrow lumen
• thick smooth muscle with elastic fibres
• elastic fibres ( connective tissue)
what do veins do
• carry blood back to heart
• thin walls
• carry blood at low pressure
describe veins
• wide lumen
• valves
• thin muscle tissue
• connective tissue ( elastic fibres)
what do capillaries do
• where all exchange between tissue occurs
• one cell thick
what is pressure filtration
when blood traveling at a high pressure from the arteries towards the capillaries, it occurs resulting h in plasma passing through capillary wall into tissue fluid surrounding the cell
what is the difference between tissue fluid and plasma
tissue fluid does not have plasma proteins
what does tissue fluid do
supplies cells with glucose, oxygen and other substances and collects waste from cells
what happens to tissue fluid after pressure filtration
most returns to the blood
what happens to excess tissue fluid
lynsohstic vessels absorb it and return it as lymph to the circulatory system
what does vasoconstriction do
reduce blood flow
what does vasodilation do
increase blood flow
