Question

question 7
1 pts
a graphic record of the hearts electrical activity is a(n)
ecg.
eeg.
cat scan.
mri.
question 8
1 pts
after blood leaves the lungs and returns to the heart, it enters the
right atrium.
left atrium.
right ventricle.
left ventricle.
question 9
1 pts
the normal cardiac impulse that initiates mechanical contraction of the heart arises in the
av node.
av bundle.
purkinje fibers.
sa node.

Explanation:

Question 7

• ECG (Electrocardiogram) is specifically for recording the heart's electrical activity.
• EEG (Electroencephalogram) records brain electrical activity.
• CAT scan (Computerized Axial Tomography) and MRI (Magnetic Resonance Imaging) are imaging techniques for anatomical structures, not electrical activity.

• After blood is oxygenated in the lungs (pulmonary circulation), it returns to the heart via the pulmonary veins and enters the left atrium.
• The right atrium receives de - oxygenated blood from the body.
• The right ventricle pumps de - oxygenated blood to the lungs.
• The left ventricle pumps oxygenated blood to the body.

• The SA (Sino - atrial) node is the natural pacemaker of the heart. It initiates the electrical impulses that lead to the mechanical contraction of the heart.
• The AV (Atrio - ventricular) node receives impulses from the SA node and delays them slightly.
• The AV bundle (Bundle of His) and Purkinje fibers conduct the impulses further for ventricular contraction.

Answer:

ECG

Question 8