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
what are the functions of blood
transport
defence
thermoregulation
maintaining PH of body fluids
what does blood contain
erythrocytes (red blood cells)
platelets (fragments of large megakaryocytic involved in blood clotting)
leucocytes (white blood cells)
plasma
structure of erythrocytes
very small
haemoglobin is very close to the plasma membrane- oxygen is loaded and unloaded very quickly in and out of the cell
capillaries are only 1 cell wide so only one erythrocyte can go through at a time
describe plasma proteins and blood pressure
-about 8% of blood plasma consists of plasma proteins of which held may be albumins
-balance between hydrostatic pressure of blood and osmotic pressure is important in the formation of tissue fluid
what does tissue fluid do
allows the body to easily and quickly move dissolved molecules into the body cell and take away waste materials
describe hydrostatic pressure in blood
it is high inside capillaries, forcing blood plasma out the capillaries through the endothelium and onto the bodies cells
describe oncotic pressure
the removal of blood plasma which causes there to. be a decrease in the water potential of blood as a result water moves back in the capillaries through osmosis
describe formation of tissue fluid
High hydrostatic pressure exists at the arterial end of the capillary. The hydrostatic pressure inside the capillary is higher than the hydrostatic pressure in the tissue fluid.
This difference in pressure forces water and other small molecules out of the capillary, forming tissue fluid. Proteins and cells stay inside the capillary because they’re too large to leave.
The hydrostatic pressure in the capillary reduces as water leaves the capillary.
describe how tissue fluid returns to the blood
Water potential at the venule end of the capillary is lower than that of the tissue fluid. This is due to the loss of fluid from the capillary and an increasing concentration of proteins and cells that don’t leave the capillary.
Some of the tissue fluid re-enters the capillary from the venule end via osmosis. The tissue fluid loses most of its oxygen and other nutrients to the cells but has gained carbon dioxide and waste materials.
Excess tissue fluid is drained into the lymphatic system and then back into the circulatory system.
what does the lymphatic system consist of
lymphatic capillaries
lymph nodes
describe the features of blood plasma
high hydrostatic pressure
more negative oncotic pressure
red blood cells, neuropils, lymphocytes
plasma proteins
transported in lipoproteins
describe the features of tissue fluid
low hydrostatic pressure
less negative oncotic pressure
some neutrophils
few proteins
few fats
describe the features of lymph
low hydrostatic pressure
less negative oncotic pressure
lymphocytes
few proteins
more fats especially near the digestive system
describe the movement of fluids in blood
hydrostatic pressure tends to push fluid out into the tissues
oncotic pressure tends to pull water back into the blood
describe the movement of fluids in tissue fluid
hydrostatic pressure tends to push fluid into the capillaries
oncotic pressure pulls water into into the tissue fluid
