A 25 year old man is paicipating in a clinical study to determine the cardiovascular response to physical exercise. Basal measurements are Respiratory rate:15,Blood pressure: 120/80,Cardiac output: 5L,Hea rate:50/min.What is his stroke volume during resting conditions (in mL/min)?

**Core Concept**
Cardiac output (CO) is the volume of blood the heart pumps per minute. It is a critical determinant of cardiac function and can be calculated using the formula: CO = Heart Rate (HR) x Stroke Volume (SV). Understanding the relationship between these two parameters is essential in assessing cardiac performance.

**Why the Correct Answer is Right**
To determine stroke volume, we can rearrange the formula CO = HR x SV to solve for SV. Given that the basal measurements are HR = 50/min and CO = 5 L/min, we can substitute these values into the formula: SV = CO / HR. Converting CO from liters per minute to milliliters per minute (1 L = 1000 mL), we get CO = 5000 mL/min. Now, we can calculate SV: SV = 5000 mL/min / 50/min = 100 mL/beat. Therefore, the stroke volume during resting conditions is 100 mL/beat.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided.
* **Option B:** This option is not provided.
* **Option C:** This option is not provided.
* **Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
The Frank-Starling mechanism describes the relationship between stroke volume and ventricular preload. An increase in ventricular preload (e.g., due to exercise or fluid overload) leads to an increase in stroke volume, up to a point where the heart becomes overloaded and efficiency decreases. Understanding this concept is crucial in managing patients with heart failure or cardiac dysfunction.

**Correct Answer: D. 100 mL/beat.**

✓ Correct Answer: C. 100