09) Transport in animals Flashcards
1.1. Describe the circulatory system
System of blood vessels with a pump and valves to ensure one-way flow of blood that transport and exchange materials
Blood: liquid flowing around system carrying materials to cells
Vessels: include arteries and veins to contain the blood
Valves: ensure one-way flow of blood
Sites of exchange: where materials needed by cells and waste can be exchanged between capillaries and tissues
1.2. Describe the single circulation of a fish
blood passes through heart once per circulation
blood moves in the correct direction because the heart pumps continuously
the heart receives deoxygenated blood into the atrium and pumps it through the ventricle to continue to the gills
blood is oxygenated as it passes through gill capillaries. the walls are so thin that carbon dioxide can be released from the blood and accepted into the blood before the blood moves onwards through the vessels
oxygenated blood supplies cells with oxygen as it flows through arteries into capillaries where exchange of materials occur
blood flow rate and blood pressure fall when blood leaves the gills. it’s fine for fish but not sufficient for mammals’ kidney function
1.3. Describe the double circulation of a mammal
Blood passes through heart twice per circulation
Pulmonary circulation: deoxygenated blood flows from heart to lungs, oxygenated blood returns to heart from lungs
Systematic circulation: oxygenated blood flows from heart through rest of body (excluding lungs) then deoxygenated blood flows back to heart
Animals with double circulation have more than two chambers in their heart
blood pressure can be higher because blood is pressurised twice per cycle around the whole body
blood pressure and flow rate is reduced as it passes through the lungs so if the blood doesn’t return to the heart it would continue to the tissues at a lower blood pressure and flow rate
some mammals are very large so sufficient blood pressure is higher because it needs enough force to send the blood around the distance of the body
animals’ blood needs to be supplied quicker because their metabolic rates are higher
animals need to maintain higher body temperatures, which requires sufficient blood flow
a double pump or four-chamber heart allows the separation of oxygenated and deoxygenated blood
1.4. Explain the advantages of a double circulation
Blood pressure and flow rate to the tissues is increased. delivers greater blood flow
heart pumps oxygenated blood returned to it from the lungs and pressure is reduced when blood passes through the lungs
would pass through the body much more slowly if it wasn’t returned
animals with double circulatory systems are very big, must travel greater distance and sufficient blood pressure is higher
usually have high metabolic rates, need blood supplied to their tissues quicker so it isn’t all used up
need to maintain higher temperatures, so need a higher blood flow to maintain it
