To Evaluate Cardiac Function, Scientists and Physicians Measure Both the Pressure

question 31

Multiple Choice

To evaluate cardiac function, scientists and physicians measure both the pressure and the volume inside the heart. When both pressure and volume data are plotted on the same graph, the resulting graph is called a pressure-volume loop. To create a pressure-volume loop, a catheter (a thin tube) is inserted into the vessels of the heart, and measurements of both left ventricular pressure and left ventricular volume are taken. The data are plotted on a graph, and cardiac function can then be evaluated from the distribution of the data and the shape of the loop.
The following figure shows a typical left ventricle pressure-volume loop for a healthy young adult. The cardiac cycle proceeds counterclockwise. Each complete turn around the loop (for example, starting at point A and ending back at point A) represents one complete cardiac cycle.

-How much blood is ejected from the left ventricle during one contraction?

• A) 35 mL
• B) 65 mL
• C) 70 mL
• D) 135 mL

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Definitions:

Chest Tube

A medical device inserted into the pleural space of the chest to remove air, fluid, or pus, thereby facilitating lung expansion.

Purse-String Suture

A circular stitch used in surgical procedures to close wounds, openings or secure tubing in place.

Occlusive Dressing

refers to a type of wound covering that is completely sealed around the edges, designed to retain moisture and promote healing by creating a controlled environment.

Non-Rebreather Mask

A device used in medical emergencies to deliver high concentrations of oxygen to patients who are breathing inadequately.