- Heart and ECG
Which factors are important when trying to obtain an accurate ECG recording?
1. The electrodes should be in their correct positions. 2. The electrodes should adhere properly to the skin.
What is the correct order for the flow of blood entering the heart from the systemic circulation through the venae cavae?
1. right atrium 2. right ventricle 3. pulmonary trunk 4. left atrium 5. pulmonary veins 6. left ventricle
How are the sounds of a heartbeat created?
By heart valves closing
In an ECG, the _____ wave is associated with atrial depolarization.
P wave
Which ECG component corresponds to the depolarization of the atria?
P wave.
The first heart sound, "lubb" is heard when the AV valves close, and this is
QRS complex.
Which ECG component reflects depolarization of the ventricles?
QRS complex.
The ____ _____ can be determined by counting the number of QRS complexes on the EG during one minute.
cardiac rate
The time from ventricular depolarization to the end of ventricular repolarization corresponds to which ECG component?
S-T segment.
In an ECG, the ____ wave is associated with ventricular repolarization.
T wave
Which ECG component corresponds to the repolarization of the ventricular fibers?
T wave
The first heart sound, "lubb", is associated with the closing of which valves?
The atrioventricular (AV) valves.
At which point on an ECG is the second heart sound, "dupp," heard?
The end of the T wave.
The second heart sound, "dupp", is associated with the closing of which valves?
The semilunar valves.
What is the function of the four heart valves?
They allow the blood to flow in only one direction through the heart.
True or False: The QRS complex on an ECG reflects ventricular depolarization.
True
True or False: The ventricles contract during the first heart sound.
True
The AV valves are closing during ventricular
contraction (systole)
The _____ is a straight line used as a point of departure for the electrical activity recorded in an ECG.
baseline
When the heart contracts, this is due to an electrical change called ___?
depolarization
What does an ECG measure?
electrical impulses.
The electrical activity that occurs in the heart when it contracts and relaxes can be recorded, and is called an
electrocardiogram
The second heart sound, "dupp" is heard when the semilunar valves close, and this is related to the ___ on an ECG.
end of the T wave.
Atria completely fill with blood during which period
from the end of the second heart sound to the beginning of the first heart sound.
If you record an ECG on a test subject that has just exercised, it will show an increase in what ___?
heart rate.
A turbulent noise, created by the backflow of blood as a heart valve closes, is called a _____.
murmur
An interval of an ECG is
one or more waves and a straight line
A cardiac cycle is:
one set of atrial contractions followed by one set of ventricular contractions.
The semilunar valves are closing during ventricular
relaxation (diastole)
The time period when the heart is contracting is called ____?
systole.
The P-Q interval of an ECG corresponds to the time for a cardiac impulse to travel from:
the SA node through the AV node.
The P-Q (or P-R) interval is the time it takes for what?
the electrical impulse to spread through the atria.
Which heart sound is shorter and crisper?
the first heart sound.
Which ventricle pumps blood through the pulmonary artery to the lungs?
the right ventricle
The ventricles relax during ___.
the second heart sound.
The S-T segment of an ECG is the time for:
ventricles to contract
What are the top chambers of the heart called?
Atria
At which point on an ECG is the first heart sound"lubb", heard?
During the QRS complex
___ impulses stimulate cardiac muscle to contract.
Electrical
Blood leaves the ventricles during which period?
From the end of the first heart sound to the beginning of the second heart sound,.
Which atrium receives freshly oxygenated blood from the lungs
Left atrium
How many cardiac cycles occur from the beginning of one heart beat to the beginning of the next?
One
A segment of an ECG is:
a straight line between two waves.
The heart contract because of
an electrical impulse.
The electrical impulse is delays in the AV node before propagating to the bundle of His. During this delay the ____ contract.
atria