Question

1. In an EKG pattern, the P wave is caused by;

1. Repolarization of ventricular nerves
2. Repolarization of atrial nerves
3. Depolarization of atrial nerves
4. Depolarization of ventricular nerves

2. The pacemaker of the heart is the:

1. Purkinje fibers
2. AV node
3. SA node
4. AV bundle

3. Which of the following waves of an EKG is correct?

1. P wave-depolarization of atria
2. QRS wave-repolarization of ventricles
3. T wave-depolarization of ventricles
4. QRS wave-depolarization of atria

4. Which of following is correctly matched?

1. Tricuspid valve- permits blood flow from right to left atrium
2. Pulmonary valve- permits blood flow from left ventricle to aorta
3. Mitral valve- permits blood flow from left atrium to left ventricle
4. Aortic valve- permits blood flow from right ventricle to pulmonary artery

5. Once cells of SA node reach threshold:

1. An action potential is triggered
2. Heart attack occurs
3. Heart rate increases
4. Blood pressure increases

6. If two white sheep, where white gene is dominant, produces an offspring that is a black sheep, the white sheep is:

1. Homozygous dominant
2. Heterozygous dominant
3. Heterozygous recessive
4. Homozygous recessive

Answer 1

1)

C) Depolarization of atrial nerves.

• The P wave indicate atrial depolarizartion.
• P wave occur when SA node ( sino atrial node ) , creates an action potential that depolarizes atria.
• Normal PR interval is 0.6 - 1.2 second.
• Option D is incorrect because ,ventricular depolarization is marked by QRS complex.
• option A is incorrect because ventricular repolarization is marked by T wave.
• Option B is incorrect ,because Repolarization of atrial nerves is not denoted by P wave.

2)

c) SA node

• Sino atrial node is a small specialized cells in the top of the right atrium.
• It produces electrical impulses which causes heart beat.
• It produce action potential at a range of 100-120 / minute and can control heart, hence it is called pacemaker of heart.
• Option B is incorrect because AV node is known as pace setter of heart.
• Option D is incorrect because AV bundle , is the fibre that connect SA node and AV node.
• Option A is incorrect because purkinje fiber are networks of fibers that receive conductive signals originating at the atrioventricular node (AVN).

3)

a) P wave-depolarization of atria

• P wave represents atrial depolarization ,which is due to atrial contraction or atrial systole.
• option B and D is wrong because ventricular depolarization is marked by QRS complex and not ventricular repolarization or depolarization of atria
• Option C is wrong because ventricular repolarization is marked by T wave and not depolarization of ventricle.

4)

c) Mitral valve- permits blood flow from left atrium to left ventricle

• Mitral valve is also known as bicuspid valve , which transmit blood from left atrium to left ventricle.
• Tricuspid valve transmit blood from right atrium to right ventricle.
• Option B is wrong because aortic valve permits blood flow from left ventricle to aorta.
• Option D is wrong because pulmonary valve permits blood flow from right ventricle to pulmonary artery.
• Option A os wrong , because there is no valve between left and right atrium in normal adults.