Physiology and Health: The Structure and Function of the Heart Flashcards
The heart has four chambers and works as a double pump, what are the four chambers?
Right atrium, right ventricle, left atrium and left ventricle
What does the right side of the heart do?
Collects deoxygenated blood from the body and pumps it to the lungs to collect oxygen
What does the left side of the heart do?
Collects oxygenated blood from the lungs and pumps it to the body
The volume of blood pumped through each ventricle per minute is called the cardiac output, what is the equation for cardiac output?
Cardiac output = Heart rate x Stroke volume: CO = HR x SV
What do the left and right ventricles do?
Pump the same volume of blood through the aorta and pulmonary artery
What is the cardiac cycle?
The pattern of contraction (systole) and relaxation (diastole) of the heart muscle in one complete heartbeat
What happens during diastole?
Blood returning to the atria flows into the ventricles
Atrial systole does what?
Transfers the remainder of the blood through the atrio-ventricular (AV) valves to the ventricles
What happens during ventricular systole?
It closes the AV valves and pumps the blood out through the semi-lunar valves to the aorta and pulmonary artery
What happens in diastole?
The higher pressure in the arteries closes the SL valves
Deoxygenated blood returning from the body via the vena cava does what?
Fills the right atrium (during atrial systole)
The build-up of pressure during atrial diastole does what?
Forces open the AV valve and blood flows into the right ventricle during ventricular diastole
The right atrium contracts, doing what?
Forcing all the blood into the right ventricle (atrial systole)
Once full, the right ventricle’s muscular walls contract (ventricular systole), doing what?
Closing the AV valve and forcing the blood up through the semi-lunar valve and out through the pulmonary artery to the lungs
Oxygenated blood returning from the lungs via the pulmonary vein does what?
Fills the left atrium (during atrial diastole)
The build-up of pressure during atrial diastole does what?
Forces open the AV valve and blood flows into the left ventricle. The atrium contracts forcing all the blood into the ventricle (atrial systole)
Once full, the left ventricle’s muscular walls contract (ventricular systole), doing what?
Closing the AV valve and forcing the blood up through the SL valve and out through the aorta to the body’s organs
The opening and closing of the AV and SL valves are responsible for what?
The heart sounds heard with a stethoscope
Where does the heartbeat originate?
In the heart itself
The auto-rhythmic cells of the sino-atrial node (SAN) or pacemaker, located in the wall of the right atrium, does what?
Set the rate at which the heart contracts
The timing of cardiac muscle cell contraction is controlled by what?
Impulses from the SAN spreading through the atria causing atrial systole
The impulses then travel to the atrio-ventricular node (AVN), located in the centre of the heart and then what happens?
Impulses from the AVN travel down fibres in the centre wall of the heart and then up through the walls of the ventricles, causing ventricular systole
Impulses in the heart generate currents that can be detected by what?
An electrocardiogram (ECG)
What does the medulla in the brain do?
Regulates the rate of the SAN through the antagonistic action of the autonomic nervous system (ANS)
A sympathetic (accelerator) nerve releases noradrenaline which does what?
Decreases the heart rate
When does blood pressure increase and decrease?
Increases during ventricular systole.
Decreases during diastole.
Measurement of blood pressure is performed using what?
A sphygmomanometer
What does an inflatable cuff do?
Stops blood flow in the artery and deflates gradually
The blood starts to flow (detected by a pulse) when?
At systolic pressure
The blood flows freely through the artery (and a pulse is not detected) when?
At diastolic pressure
What is the typical blood pressure reading for a young adult?
120/80 mmHg
Hypertension (high blood pressure) is a major risk factor for many diseases and conditions, what is an example of one of these?
Coronary heart disease (CHD)
