Blood Vessels, Blood, Tissue Fluid, and Lymph (OCR A-Level Biology A): Flashcards
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Practise the cards
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Direction of blood flow in arteries
Direction of blood flow in arteries
Away from the heart
Direction of blood flow in veins
Direction of blood flow in veins
Towards the heart
Main function of capillaries
Main function of capillaries
Exchange sites for materials between blood and cells
Thickness of capillary walls
Thickness of capillary walls
One cell thick
Three layers of artery wall
Three layers of artery wall
Tunica intima, tunica media, tunica adventitia
Purpose of valves in veins
Purpose of valves in veins
Ensure one-way flow towards the heart
Function of pre-capillary sphincters
Function of pre-capillary sphincters
Regulate blood entry into capillary beds
Function of red blood cells (erythrocytes)
Function of red blood cells (erythrocytes)
Transport oxygen
Key difference: tissue fluid vs blood
Key difference: tissue fluid vs blood
Lacks larger protein molecules
% of fluid recovered at venous end
% of fluid recovered at venous end
90% (remaining 10% returns via lymphatic system)