Key Area 6- Structure and Function of the Heart Flashcards
What are the four chambers of the heart?
. Right atrium
. Right ventricle
. Left atrium
. Left ventricle
What are the four vessels of the heart?
. Vena cava
. Pulmonary artery
. Pulmonary vein
. Aorta
What are the four valves of the heart?
. Right atrio-ventricular valves
. Right semi-lunar valves
. Left atrio-ventricular valves
. Left semi-lunar valves
What is the pathway of blood through the heart?
. Vena cava (blood returning from the body)
. Right atrium
. Right atrio-ventricular valves
. Right ventricle
. Right semi-lunar valves
. Pulmonary artery
. LUNGS ( site of gas exchange)
. Pulmonary vein
. Left atrium
. Left atrio-ventricular valve
. Left ventricle
. Left semi-lunar valve
. Aorta
. Blood to the body
Why the wall of the left ventricle thicker than the wall of the right ventricle?
Because the left ventricle has to pump blood to the whole body, whereas the right ventricle only has to pump blood to the lungs
What do AV valves prevent?
They prevent the back flow of blood from ventricles to atria
What do SL valves?
They prevent the back flow of blood into the ventricles from the pulmonary and aorta arteries
What is a systole?
The SL valves open during ventricular allowing blood into the arteries
What is a diastole?
The SL valves close when arterial pressure exceeds ventricular pressure, and the muscle relaxes
What is the formula for cardiac output?
Cardiac output (CO) = Heart Rate (HR) x Stroke Volume (SV)
What is heart rate (Pulse)?
The number of heartbeats that occurs per minute
What is stroke volume?
The volume of blood expelled by each ventricle on contraction. (The stronger the contraction, the greater the stroke volume)
What is cardiac output?
The volume of blood pumped out of a ventricle per minute (It can be determined by heart rate and stroke volume hence formula)
What is the cardiac cycle?
The pattern of contraction (systole) and relaxation (diastole) shown by the heart during one complete heartbeat
What is the average cardiac cycle?
0.8 seconds, which is based on a heart rate of 75 beats per minute
What happens during diastole?
. The blood returning to the atria flows into the ventricle and is under high pressure in the arteries
. This causes the SL valves to close, preventing the back flow of blood
. Pressure in the atria and ventricles is lowered by the relaxation of the cardiac muscles
. The coronary arteries fill during diastole
What happens during artrial systole?
. It transfers the remainder of the blood through the AV valves to the ventricles
. Blood under low pressure flows into the atria from the pulmonary veins and vena cava
. As the atria fill, the pressure of blood against the AV valves pushes them open therefore blood leaks into ventricles
.The atria walls contract, forcing blood into ventricles
.The SL valves remain closed
What happens during ventricular systole?
. It closes the AV valves and pumps the blood out through the SL valves to the aorta and pulmonary artery
. The ventricles contract from the bottom of the heart upwards, increasing the pressure in the ventricles
. Blood is pushed through the arteries
. The pressure of the blood against the AV valves closes them, preventing back flow
What is responsible for the heart sounds heard with a stethoscope?
The opening and closing of the AV and SL valves
What brings about the sequence of events that occurs during each heartbeat?
The activities of sino-atrial node (SAN)/ pacemaker and the conducting system of the heart