Physiology Quiz: Muscles and Nervous System

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What type of cell is responsible for producing the myelin sheath?

Schwann cell (correct)
Muscle cell
Mitochondria
Axoplasm

What is a characteristic of the action potential of skeletal muscle?

It spreads inwards to all parts of the muscle (correct)
It is longer than the action potential of cardiac muscle
It is not essential for muscle contraction
It has a prolonged plateau phase

What is required for contraction in smooth muscle?

Monoamine oxidase
K+
Acetylcholine
Calmodulin (correct)

What is the role of tropomyosin in skeletal muscle?

Covering up the actin binding sites of myosin at rest (C) Signup and view all the answers

How does neostigmine improve muscular weakness?

It blocks the action of acetylcholine esterase (C) Signup and view all the answers

How many oxygen molecules are carried by one Hb molecule?

4 (B) Signup and view all the answers

What is the characteristic of the S.A node that makes it the pacemaker of the heart?

Its natural leakiness to Na+ (A) Signup and view all the answers

What is the duration of the absolute refractory period in the heart?

It lasts till cardiac contraction (D) Signup and view all the answers

During which phase of the cardiac cycle does the first heart sound occur?

Isovolumetric contraction (D) Signup and view all the answers

Which of the following vessels does not have sympathetic control?

Cerebral vessels (B) Signup and view all the answers

What is the main component of the blood-brain barrier?

Astrocytes (A) Signup and view all the answers

What is the effect of stimulating the sympathetic nerves on the heart?

It produces a positive bathmotropic effect (B) Signup and view all the answers

What is the primary cause of CO2 bubbles formation?

Due to increase in barometric pressure (A) Signup and view all the answers

What is the normal value of FEV1 in an adult?

80% (B) Signup and view all the answers

Which gas is most important in maintaining alveolar ventilation?

Carbon dioxide (B) Signup and view all the answers

What is the primary indication for hyperbaric oxygen therapy?

Gas gangrene (D) Signup and view all the answers

What is the effect of high altitude on alveolar PO2 and PCO2?

Decrease in PO2, decrease in PCO2 (B) Signup and view all the answers

What is the primary function of surfactant in the lungs?

To reduce surface tension (A) Signup and view all the answers

Where is a diastolic murmur typically loudest?

Apex of the heart (C) Signup and view all the answers

What causes the 's' wave in ECG to be below the isoelectric line?

Change in direction of the impulse when the ventricles are getting depolarized (D) Signup and view all the answers

Which of the following is least likely to cause hypertension?

Chronically increased secretion of thyroid gland (A) Signup and view all the answers

What happens to lymph flow from the foot when an individual rises from the supine to standing position?

It increases (B) Signup and view all the answers

What determines the pressure in the radial artery?

The rate of discharge in sympathetic nerve fibers to the arm (C) Signup and view all the answers

Why is the 'T' wave in ECG above the isoelectric line?

Change in the direction of repolarization from the wave of depolarization (D) Signup and view all the answers

What is the effect of negative G on the eye?

Temporary blinding with redout (A) Signup and view all the answers

What happens to airway resistance in asthama?

It increases (B) Signup and view all the answers

What is the effect of decreased PCO2, decreased H+, and increased PO2 on breathing?

Hypoventilation (A) Signup and view all the answers