Item 3 Label the structural features of arteries, veins, and capillaries. Part A Drag the appropriate labels to their respective targets. Collagen fibers Artery Endothelium • Previous F3 F5 er 19 Mastering Homework – Attempt 1 3 of 17 Collagen fibers Artery Endothelium Basement membrane Vasa vasorum Lumen Endothelial cells Capillary network Next revious 2U Submitting an external tool Available after Sep 20 at 11:59pm
The Correct Answer and Explanation is:
To correctly label the structural features of arteries, veins, and capillaries, you should understand the composition and function of each blood vessel type. Based on standard anatomy and physiology resources, here’s how the labels match each structure:
Correct Labels for Structural Features:
Artery:
- Collagen fibers – outermost layer providing strength
- Vasa vasorum – small blood vessels that supply the walls of large arteries
- Lumen – central blood-containing space
- Endothelial cells – innermost lining of the artery
- Basement membrane – supports the endothelial cells
Vein:
- Collagen fibers – outer support
- Vasa vasorum – present in large veins like in arteries
- Lumen – larger than in arteries to hold more blood
- Endothelial cells – same as arteries, forming the inner lining
- Basement membrane – also present, though less robust than in arteries
Capillary:
- Endothelial cells – the only structural layer in capillaries
- Basement membrane – supports endothelial cells
- Capillary network – refers to the interconnected web of capillaries
Explanation (300+ words):
Blood vessels are categorized into three main types: arteries, veins, and capillaries, each designed to support a specific function in the circulatory system. Understanding their structures is critical to recognizing their roles in maintaining blood flow and tissue perfusion.
Arteries carry blood away from the heart and must withstand high pressure. Their walls are thick and consist of three main layers: the tunica externa (which includes collagen fibers for strength), tunica media (smooth muscle and elastic tissue), and tunica intima (which includes the endothelial cells and basement membrane). Larger arteries, like the aorta, have vasa vasorum, small vessels that nourish the outer wall of the artery. The lumen is relatively narrow compared to veins, maintaining pressure as blood travels to organs.
Veins, which return blood to the heart, operate under lower pressure and have thinner walls with larger lumens. This allows them to act as blood reservoirs. Like arteries, veins also contain collagen fibers, endothelial cells, and a basement membrane, but they have less elastic tissue and smooth muscle. Vasa vasorum are also present in large veins, helping to nourish their walls.
Capillaries are the smallest and thinnest vessels, designed for the exchange of gases, nutrients, and wastes between blood and tissues. They are composed of only a single layer of endothelial cells and a basement membrane, which allows for rapid diffusion. These form capillary networks, which are dense webs of capillaries connecting arterioles and venules, ensuring close contact with tissues.
Understanding these structural differences helps in grasping how blood pressure is regulated and how oxygen and nutrients are delivered efficiently throughout the body. Each vessel’s anatomy is perfectly suited to its physiological function.