3.2 transport in animals Flashcards
what are the main factors which affect the need for a transport system
-size
-SA:V ratio
-level of metabolic activity
what are the features of a good transport system
- a fluid or medium to carry nutrients, oxygen and wastes around the body (blood)
-a pump to create pressure that will push fluid around the body
-exchange surfaces that enable substances to enter blood and leave it again
-tubes or vessels to carry the blood
-two circuits ( one to pick up oxygen and one to deliver it to tissues)
describe single and double circulatory systems
single- heart, gills, body, heart
double- heart, body, heart, lungs, heart
advantages of single circulation
less complex
doesn’t require complex organs
disadvantages of single circulation
can only carry blood at a low pressure
slow movement of blood
activity level of the animal tends to be low
advantages of double circulation
the heart can increase pressure so blood flows to the body quicker
can carry blood at high pressure
the heart can pump blood further around the body
identify the 5 types of blood vessel
arteries
arterioles (oxygenated blood from heart to body cells)
capillaries
venules
veins (deoxygenated blood from from Body cells to heart)
describe the types of blood vessels
arteries lead into arterioles then into capillaries where gas exchange occurs the into venules, into veins and back into the heart
what is the structure or arteries and veins
lumen
endothelium
elastic fibres
smooth muscle
collagen fibres
structure of the capillary
lumen
endothelium
describe arteries
carry blood away from heart(oxygenated)
blood is at high pressure
artery wall is thick
lumen is small
does not contain valves
describe how the components of arteries contribute to their use
elastic fibres- provide flexibilty
smooth muscle-contracts and relaxes changing size of lumen
collagen- provides structural support to maintain shape and volume
describe veins
carry blood back to heart (deoxygenated)
blood is at low pressure
walls are thin as do not need to stretch or recoil
lumen is large to ease flow of blood
contain valves to prevent back flow of blood as it is at a low pressure
describe capillaries
very thin walls
exchange materials between blood and tissue fluid
lumen very narrow
walls of flattened endothelial cells
walls are leaky
identify the 3 fluid types
blood
tissue fluid
lymph