A. BLOOD VESSELS
Muscle and
elastic tissue
Connective tissue
(outer layer)
Endothelium
(inner lining)
Lumen
(hole)
(hole)
ARTERY VEIN CAPILLARY
ARTERY VEIN CAPILLARY
Function Carries blood away from the Carries blood Connects arteries and
heart back to the heart veins for exchange
Thick layer of muscle and Thin layer of Very thin.
Wall thickness elastic tissue muscle and One cell thick for fast
elastic tissue diffusion across it.
Lumen size Small Large Very small
Blood flow High pressure Low pressure Very low pressure
Contains valves No Yes No
• Thick collagen outer wall • Pocket valves • Thin walls for a
withstands high blood prevent blood shorter diffusion
How structure is pressure falling distance
related to backwards
function • Thick layer of muscle due to the low • Permeable walls for
tissue constricts or dilates pressure and faster diffusion
to withstand the high gravity
blood pressure •. Close to cells for a
• Wide lumen shorter diffusion
• Thick layer of elastic tissue offers less distance
stretches to accommodate resistance to
surge in blood flow and blood flow • Small diameter so
recoils to smooth out the can fit in small
blood flow spaces for faster
diffusion
• Small lumen maintains
high blood pressure • Many tiny
capillaries create a
• Smooth lumen to reduce large surface area
friction so blood flow has for faster diffusion
less resistance
, B. ARTERIOLES AND VENULES
Vein Artery
Venule Arteriole
(Small vein) (small artery)
Capillary
ARTERIOLES VENULES
(Small arteries) (Small veins)
Connect arteries to capillaries Connect capillaries to veins
Contain smooth muscle than can
contract and relax Ensures that blood containing waste is taken
This changes the diameter of the arteriole away from organs by veins
This allows it to control the blood flow to
different organs
Muscle and
elastic tissue
Connective tissue
(outer layer)
Endothelium
(inner lining)
Lumen
(hole)
(hole)
ARTERY VEIN CAPILLARY
ARTERY VEIN CAPILLARY
Function Carries blood away from the Carries blood Connects arteries and
heart back to the heart veins for exchange
Thick layer of muscle and Thin layer of Very thin.
Wall thickness elastic tissue muscle and One cell thick for fast
elastic tissue diffusion across it.
Lumen size Small Large Very small
Blood flow High pressure Low pressure Very low pressure
Contains valves No Yes No
• Thick collagen outer wall • Pocket valves • Thin walls for a
withstands high blood prevent blood shorter diffusion
How structure is pressure falling distance
related to backwards
function • Thick layer of muscle due to the low • Permeable walls for
tissue constricts or dilates pressure and faster diffusion
to withstand the high gravity
blood pressure •. Close to cells for a
• Wide lumen shorter diffusion
• Thick layer of elastic tissue offers less distance
stretches to accommodate resistance to
surge in blood flow and blood flow • Small diameter so
recoils to smooth out the can fit in small
blood flow spaces for faster
diffusion
• Small lumen maintains
high blood pressure • Many tiny
capillaries create a
• Smooth lumen to reduce large surface area
friction so blood flow has for faster diffusion
less resistance
, B. ARTERIOLES AND VENULES
Vein Artery
Venule Arteriole
(Small vein) (small artery)
Capillary
ARTERIOLES VENULES
(Small arteries) (Small veins)
Connect arteries to capillaries Connect capillaries to veins
Contain smooth muscle than can
contract and relax Ensures that blood containing waste is taken
This changes the diameter of the arteriole away from organs by veins
This allows it to control the blood flow to
different organs
