Blood Vessels and Circulatory Systems Revision Carousel Flashcards
Describe 3 structural layers of an artery.
-Thin layer of elastic tissues allowing for stretch can recoil
-Thick layer of smooth muscle
-Thick layer of elastic tissues providing strength to withstand high pressure
Describe how capillaries are adapted for exchange.
-Narrow Lumen so oxygen transfer is better
-Walls have a single layer of endothelial cells reducing diffusion distance
-Walls are permeable allowing plasma and substances to leave blood
What is the inner tissue lining of a blood vessel called? What is its role?
Endothelium which reduces friction with the flowing blood
Describe how veins are adapted to carry blood back to heart.
-Wide lumen to ease blood flow
-Thin layer of elastic as no need to stretch and recoil
-Valves to prevent backflow of blood
State 2 disadvantages of open circulatory systems.
-BP is low and slow blood flow
-Circulation is therefore affected by body movements
Describe what is meant by the term open circulation.
Blood is not always held in vessels but it circulated throughout the body cavity and tissues and cells directly bathe in blood
Describe 3 disadvantages of single circulatory systems as seen in fish
-BP drops as it passes through gill capillaries
-Limited delivery of O2 and nutrients to respiring tissues
-Blood flows slowly through as its under low pressure
Explain why fish don’t need as much energy as mammals.
As they are not as metabolically active as mammals as they don’t maintain their body temperature (thermo-regulation)
State 3 advantages of closed circulation over open circulation
-Blood travels at higher pressure so flow is faster
-O2/nutrients and CO2 is removed quicker
-Transport is independent of body movements
What is the role of arterioles?
Takes blood away from artery to capillary
-have a layer of smooth muscle which contracts restricting and slowing blood flow
Describe the function of a venule.
Takes blood from capillaries to veins
