chapter 9 - transport in animals Flashcards
*describe what the circulatory system is
a system of blood vessels with a pump and valves to ensure one-way flow of blood.
*describe the single circulation of a fish
- the blood goes through the heart once for each complete circuit.
- it is the simplest circulatory system of all vertebrates.
- the heart consists of 1 atrium and 1 ventricle.
- the ventricle sends blood to the gills, where it is oxygenated, the blood then flows to all parts of the body, and then returns back to the heart.
*describe the double circulation of a mammal
- the blood passes through the heart twice during one complete circuit.
what is the name given to the 2 circulations in double circulation?
- through the lungs: pulmonary circulation
- through the body: systemic circulation
*what are the advantages of double circulation? explain
- blood travelling through the small capillaries in the lungs loses a lot of its pressure.
- blood cannot travel as fast.
- by returning the blood to the heart after going through the lungs its pressure can be raised again before sending it to the body.
*What blood vessels carry blood away from the heart?
arteries
*what blood vessels carry blood towards the heart?
veins
*what name is given to the valves that separate the atrium from the ventricle?
atrioventricular valves
*what name is given to the valves in the pulmonary artery and aorta?
semi-lunar valves
*what name is given to the valve that separates the left atrium from the left ventricle?
bicuspid valve
OR mitral valve
*what name is given to the valve in the pulmonary? artery
pulmonary valve
*what name is given to the valve in the aorta?
aortic valve
*explain the relative thickness of the muscle wall of the left and right ventricles
the left ventricle has a thicker muscle wall than the right ventricle as it has to pump blood at high pressure around the entire body, whereas the right ventricle is pumping blood at lower pressure to only one organ (the lungs).
*explain the relative thickness of the muscle wall of the atria compared to that of the ventricles
the ventricles have thicker muscle walls than the atria as they are pumping blood out of the heart and so need to generate a higher pressure.
*explain the function of the septum
the septum is a wall of muscle that separates the 2 sides of the heart and so prevents mixing of oxygenated and deoxygenated blood.
what side of the heart receives oxygenated blood?
left
from the lungs and pumps it to the body
what side of the heart receives deoxygenated blood?
right
from the body and pumps it to the lungs
*describe the functioning of the heart in terms of the contraction of muscles of the atria and ventricles and the action of valves
1- deoxygenated blood coming from the body flows into the RA via the vena cava.
2-the RA contracts, so blood is pushed through the tricuspid valve into the RV.
3- walls of the RV contract, an blood is pushed into the pulmonary artery through the pulmonary valve.
4- blood travels to the lungs where it is oxygenated.
5- oxygenated blood returns from the lungs into the LA via the pulmonary vein.
6- it passes through the bicuspid valve into the left ventricle.
7- thick muscle wall of the LV contract to push the blood into the aorta through the aortic valve and all the way around the body.
explain why pressure of the blood going to the lungs should be lower
the blood is going directly to capillaries which would burst under high pressure.
low pressure means that the blood flows slower to give time for diffusion of gases to occur.