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The blood flows strictly by a fixed rout...

The blood flows strictly by a fixed route through blood vessels, the arteries and veins. Basically, each artery and vein consists of three layers. Which of the following layer consists of smooth muscles elastic fibres?

A

Outer layer, tunica externa

B

Middle layer, tunica intima

C

Inner layer, tunica intima

D

Tunica media

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding which layer of arteries and veins consists of smooth muscles and elastic fibers, we can follow these steps: ### Step-by-Step Solution: 1. **Understand the Structure of Blood Vessels**: Blood vessels, including arteries and veins, are composed of three main layers: the tunica externa (or adventitia), tunica media, and tunica intima. 2. **Identify the Layers**: - **Tunica Externa**: This is the outermost layer, primarily made of connective tissue and is relatively thin. It provides structural support and protection to the blood vessel. - **Tunica Media**: This is the middle layer and is typically the thickest layer in arteries. It consists mainly of smooth muscle and elastic fibers, allowing the vessel to withstand and regulate blood pressure. - **Tunica Intima**: This is the innermost layer, which is thin and consists of endothelial cells that line the lumen of the blood vessel. 3. **Focus on the Question**: The question specifically asks which layer contains smooth muscles and elastic fibers. 4. **Analyze the Options**: - The tunica externa does not contain significant smooth muscle or elastic fibers. - The tunica intima is primarily composed of endothelial cells and does not have smooth muscle or elastic fibers. - The tunica media is known for its rich composition of smooth muscle and elastic fibers, which are crucial for maintaining blood pressure and allowing for the elasticity required during the pulsatile flow of blood. 5. **Conclusion**: Based on the analysis, the layer that consists of smooth muscles and elastic fibers is the **tunica media**. ### Final Answer: The layer that consists of smooth muscles and elastic fibers is the **tunica media**.
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