Which of the following factor(s) increase blood pressure ?
A. Increase of cardiac output
B. Constriction of blood vessel
C. Activation of parasympathetic nerve
D. Increase of blood volume

Options

A. A, B, D are correct
B. B, C, D are correct
C. A, C, D are correct
D. All are correct

Answer

To determine which factors increase blood pressure, let's analyze each option step by step:

### Step 1: Analyze Cardiac Output
- **Definition**: Cardiac output refers to the amount of blood the heart pumps in a minute. It is calculated as the product of stroke volume (the amount of blood pumped with each heartbeat) and heart rate (the number of heartbeats per minute).
- **Effect on Blood Pressure**: An increase in cardiac output leads to more blood being pumped into the arteries, which raises blood pressure.
- **Conclusion**: **Option A (Increase of cardiac output)** increases blood pressure.

### Step 2: Analyze Blood Vessel Constriction
- **Definition**: Blood vessel constriction refers to the narrowing of blood vessels, which decreases the diameter of the vessel (lumen).
- **Effect on Blood Pressure**: When blood vessels constrict, the resistance to blood flow increases, causing blood pressure to rise.
- **Conclusion**: **Option B (Constriction of blood vessel)** increases blood pressure.

### Step 3: Analyze Activation of Parasympathetic Nerve
- **Definition**: The parasympathetic nervous system is part of the autonomic nervous system that conserves energy and slows down the heart rate.
- **Effect on Blood Pressure**: Activation of the parasympathetic nervous system generally leads to a decrease in heart rate and can lower blood pressure.
- **Conclusion**: **Option C (Activation of parasympathetic nerve)** does not increase blood pressure.

### Step 4: Analyze Increase of Blood Volume
- **Definition**: Blood volume refers to the total amount of blood circulating within the body.
- **Effect on Blood Pressure**: An increase in blood volume means there is more fluid in the circulatory system, which can elevate blood pressure due to the increased volume exerting more pressure against the vessel walls.
- **Conclusion**: **Option D (Increase of blood volume)** increases blood pressure.

### Final Conclusion
Based on the analysis:
- **Correct Options**: A (Increase of cardiac output), B (Constriction of blood vessel), and D (Increase of blood volume) all increase blood pressure.
- **Incorrect Option**: C (Activation of parasympathetic nerve) does not increase blood pressure.

### Summary of Correct Answers:
- A, B, D are the factors that increase blood pressure.

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