The Structure & Function of the Heart Flashcards
Name the four chambers of the heart.
- right atrium
- left atrium
- right ventricle
- left ventricle
What does the right side of the heart do?
The right side collects deoxygenated blood from the body and pumps it to the lungs to collect oxygen.
What does the left side of the heart do?
The left side collects oxygenated blood from the lungs and pumps it to the body.
What are the walls of the heart made from?
Cardiac muscle that can contract without causing fatigue.
What happens during atrial diastole?
Deoxygenated blood returning from the body via the vena cava fills the right atrium.
Following atrial diastole, there is ventricular diastole- what happens during this time?
The build up of pressure from the blood flowing into the right atrium (during atrial diastole) forces open the AV valve and blood flows into the right ventricle.
After ventricular diastole, there is atrial systole- what happens during this time?
The right atrium contracts, forcing all the blood into the right ventricle.
What happens once all the blood flows into the right ventricle during atrial systole?
The right ventricle’s muscular walls contract (ventricular systole), closing the AV valve and forcing the blood up through the SL valve and out through the pulmonary artery to the lungs.
What happens to oxygenated blood returning from the lungs?
It enters the heart via the pulmonary vein, filling the left atrium (atrial diastole).
What happens due to the pressure during atrial diastole? (Left side)
The AV valve is forced open and blood flows into the left ventricle. The atrium contracts forcing all the blood into the left ventricle. (Atrial systole)
What happens once the left ventricle is full?
The left ventricle’s walls contract (ventricular diastole), closing the AV valve and forcing the blood up through the SL valve and out through the aorta to the body’s organs.
What is responsible for the heart sounds heard with a stethoscope?
The opening and closing of the AV and SL valves.
What is Cardiac Output?
The volume of blood pumped out by either ventricle (out of the heart) per minute.
What is Stroke Volume?
The volume of blood pumped out by either ventricle during one systole.
How is cardiac output determined?
By heart rate and stroke volume.
CO= HR x SV
What is the Cardiac cycle?
The pattern of contraction (systole) and relaxation (diastole) of the heart muscle in one complete heartbeat.
Where does the heartbeat originate from?
The heart.
Where is the Sino-Atrial Node (SAN) situated?
In the wall of the right atrium.
What is the role of the SAN?
Ensures that both atria contract simultaneously by sending out electrical impulses that are carried through the muscular walls of the atria.
The SAN sets the rate at which cardiac muscle cells contract.
How is the timing of cardiac cells contracting controlled?
By the electrical impulse from the SAN spreading through the atria to the atrio-ventricular node (AVN) and through the ventricles.
The electrical impulses generated in the heart produce currents- how may these be detected?
By 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).
What do sympathetic accelerator nerves do?
Release nor-adrenaline (nor-epinephrine) which increases the heart rate.
What do parasympathetic nerves do?
Release acetylcholine which decreases the heart rate.
What happens to the blood pressure in the aorta during the cardiac cycle?
Blood pressure changes.
How is measurement of blood pressure performed?
Using a sphygmomanometer.
What is the typical blood pressure reading for a young adult?
120/70mmHg
What is Hypertension a major risk for?
Many diseases, including coronary heart disease and strokes.
