Flashcards in The Heart as a Pump Deck (122)
Where does the heart pump blood to?
Exchange vessels in the lungs, and then through resistance vessels to the exchange vessels in the tissue
Via what does blood return to the heart?
What do resistance vessels do?
Restrict blood flow, to drive supply to the hard to perfuse areas of the body
What do the capacitance vessels enable?
The system to vary the amount of blood pumped around the body
What do the capacitance vessels act as?
A storage facility
Why is the storage facility of capacitance vessels important?
Means that different amounts of blood can be in the circulation, so supply can change to meet demand
What would happen if the circulatory system was just a simple system with pumps and pipes?
It wouldn’t work very well as the blood would go to the easiest places to perfuse
How do the resistance vessels prevent blood just going to the places that are easiest to perfuse?
They stop blood going to some areas, so the blood has to go elsewhere
Which of the circulations is high pressure?
Which of the circulations is low pressure?
What must be true of the outputs of the left and right sides?
They must be equal over time
What do the atria act as?
‘Priming pumps’ for the ventricles
What is meant by the atria acting as priming pumps?
They fill with blood so they can fill the ventricles
What does the right side of the heart do?
Pumps deoxygenated blood from the right ventricle through the pulmonary artery to the lungs for oxygenation
What is between the right ventricle and the pulmonary artery?
The pulmonary valve
How does blood in the lungs return to the heart?
Through the pulmonary vein into the left atrium
What is between the left atrium and left ventricle?
The mitral valve (also known as the bicuspid valve)
What does the left ventricle do?
Pumps oxygenated blood to the body through the aorta
What is between the left ventricle and the aorta?
The aortic valve
How does blood from tissues return to the heart?
Through the superior and inferior vena cava into the right atrium
What is between the right atrium and right ventricle?
The tricuspid valve
What is the typical pressure in the left atrium?
What is the typical pressure in the left ventricle?
120mmHg systole / 10mmHg diastole
What is the typical pressure in the aorta?
120mmHg systole / 80mmHg diastole
What is the typical pressure in the right atrium?
What is the typical pressure in the right ventricle?
25mmHg systole / 4mmHg diastole
What is the typical pressure in the pulmonary artery?
25mmHg systole / 10mmHg diastole
What is systole?
Contraction and ejection of the blood from the ventricles
What is diastole?
Relaxation and filling of the ventricles