In humans , deoxygenated blood flows from:

Options

A. Left auricle to left ventricle during auricular systole
B. Right auricule to right ventricle during atrial systole
C. Right ventricle to aorta during ventricular systole
D. Pulmonary vein to left auricle during auricular systole

Answer

To solve the question "In humans, deoxygenated blood flows from:", we need to understand the flow of blood through the human heart and the circulatory system. Here’s a step-by-step breakdown:

### Step 1: Understand the Heart's Structure
The human heart consists of four chambers:
- Right Atrium (RA)
- Right Ventricle (RV)
- Left Atrium (LA)
- Left Ventricle (LV)

### Step 2: Identify the Flow of Blood
1. **Oxygenated Blood Flow**: Blood returns from the lungs, rich in oxygen, via the pulmonary veins to the left atrium. From the left atrium, it flows into the left ventricle and is pumped to the body through the aorta.
2. **Deoxygenated Blood Flow**: Blood that has delivered oxygen to the body returns to the heart as deoxygenated blood. This blood enters the right atrium from the body through the superior and inferior vena cavae.

### Step 3: Focus on Deoxygenated Blood
- Deoxygenated blood flows from the right atrium to the right ventricle during atrial systole (the contraction of the atria).
- From the right ventricle, during ventricular systole (the contraction of the ventricles), the deoxygenated blood is pumped to the lungs via the pulmonary arteries for oxygenation.

### Step 4: Analyze the Options
1. **Left Auricle to Left Ventricle**: This is incorrect as this pathway carries oxygenated blood.
2. **Right Auricle to Right Ventricle**: This is correct as it describes the flow of deoxygenated blood.
3. **Right Ventricle to Aorta**: This is incorrect for deoxygenated blood; this occurs during ventricular systole but carries oxygenated blood to the body.
4. **Pulmonary Vein to Left Auricle**: This is incorrect as it carries oxygenated blood from the lungs to the left atrium.

### Conclusion
The correct answer is that deoxygenated blood flows from the **Right Auricle to Right Ventricle**.

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