The Heart Flashcards
closed circulatory system
blood is pumped around the body and is always contained within a network of blood vessels
open circulatory system
blood is inside the body cavity and bathes the organs
what are the right atrium and right ventricle separated by
atrioventricular (AV) valve known as the tricuspid valve
what is the left atrium and left ventricle separated by
another AV known as the bicuspid valve
what is the right ventricle and the pulmonary artery separated by
by a semilunar (SL) valve known as the pulmonary valve
what is the left ventricle and aorta separated by
SL valve known as the aortic valve
when does the valve open
pressure of blood behind them is greater than the pressure in front of them
when does the valve close
pressure of blood in front of them is greater than the pressure behind them
what does valve tendon / cords do
prevent the valve from flipping inside out
left ventricle
thicker muscle than on right ventricle because it has to pump blood all around body
ventricles
thicker than atria as it has to pump blood out of the heart
atrioventricular valve
prevent back flow of blood from ventricles into atria
semilunar valve
prevent back flow from aorta or pulmonary artery into ventricles
what is the vena cava
brings blood from the body
what is the pulmonary vein
brings blood from the lungs
what is the pulmonary artery
takes blood to the lungs
what is the aorta
takes blood to the body
what are coronary arteries
The muscle of the heart itself is supplied with blood by a series of blood vessels. wrapped around heart
what is septum
prevents oxygenated and deoxygenated blood from mixing
what is atrial systole
when the walls of the atria contract so atrial volume decreases and pressure increases
pressure in atria rises above than in ventricles, forcing the AV to open. blood forced onto ventricles
ventricles diastole
ventricular systole
walls of ventricles contract
ventricular volume decreases, pressure increases
pressure in ventricles rises above that in aorta and pulmonary artery forcing the semilunar valves open so blood is forced into arteries.
at the same time atria relaxing. atrial diastole.
cardiac diastole
atria and ventricles relax and pressure in chambers decrease causing semilunar valves to close
Explain point A of cardiac cycle graph
The atrium has filled with blood
Pressure is higher in the atrium than in the ventricle, so the AV valve is open
What happens between point A and B
Left atrium contracts, causing an increase in atrial pressure and forcing blood into the left ventricle
Ventricular pressure increases slightly
Pressure is higher in the atrium than in the ventricle, so the AV valve is open
Explain point B
Left ventricle contracts causing the ventricular pressure to increase
Pressure in the left atrium drops as the muscle relaxes
AV valve shuts
What happens at point C
The ventricle continues to contract
Pressure in the left ventricle exceeds that in the aorta so aortic valve opens
What happens at point D
Left ventricle has been emptied of blood
Muscles in the walls of the left ventricle relax and pressure falls below that in the newly filed aorta so aortic valve closes
What happens at point D
Left ventricle has been emptied of blood
Muscles in the walls of the left ventricle relax and pressure falls below that in the newly filed aorta so aortic valve closes
What happens at point D and E
ventricles relax and ventricular pressure continues to decrease
blood flowing into atrium from pulmonary vein causing increase in pressure
What happens at point E
The relaxed left atrium fills with blood, causing the pressure in the atrium to exceed and the AV valve opens
