CBET Anatomy and Physiology Basics 5

Question 1

During inspiration, the diaphragm contracts and moves inferiorly, causing intrathoracic pressure to:

Accepted Answer

Decrease, drawing air into the lungs

Answer

Diaphragm contraction increases thoracic volume, which decreases intrathoracic (pleural) pressure below atmospheric, causing air to flow in.

Question 2

Which ion is primarily responsible for the depolarization phase of a cardiac action potential?

Accepted Answer

Sodium (Na⁺) influx

Answer

Rapid Na⁺ influx through fast voltage-gated sodium channels causes the sharp depolarization (phase 0) of the cardiac action potential.

Question 3

A ventilator-dependent patient has a tidal volume of 500 mL and a respiratory rate of 12 breaths/min. What is the minute ventilation?

Accepted Answer

6,000 mL/min

Answer

Minute ventilation = tidal volume × respiratory rate = 500 mL × 12 breaths/min = 6,000 mL/min (6 L/min).

Question 4

The sinoatrial (SA) node is located in which chamber of the heart?

Accepted Answer

Right atrium

Answer

The SA node is embedded in the wall of the right atrium near the junction with the superior vena cava and serves as the heart's primary pacemaker.

Question 5

Which blood vessel carries oxygenated blood from the lungs back to the heart?

Accepted Answer

Pulmonary vein

Answer

The pulmonary veins (four total) carry oxygen-rich blood from the lungs to the left atrium, making them unique among veins.

CBET - Certified Biomedical Equipment Technician Practice Test