Question

Which blood vessel is best suited for exchange of gases and nutrients with the surrounding tissue? a. artery c. capillary b. vein d. arteriole

Short answer

c. capillary

Step-by-step solution

Understand the Function of Each Blood Vessel

Arteries carry blood away from the heart under high pressure and are not suitable for exchanging gases and nutrients. Veins carry blood back to the heart and also aren't suitable for this exchange due to their larger diameter and thinner walls.

Assess the Characteristics of Capillaries

Capillaries are small, thin-walled blood vessels that allow for the exchange of gases (like oxygen and carbon dioxide), nutrients, and waste products with surrounding tissue. Their thin walls and extensive network make them well-suited for this function.

Evaluate the Role of Arterioles

Arterioles are small branches of arteries that lead to capillaries. While they play a role in blood flow regulation, they are not the primary sites for gas and nutrient exchange.

Identify the Correct Option

Based on the understanding of the functions and structures of these blood vessels, capillaries are best suited for the exchange of gases and nutrients with surrounding tissue.

Key concepts

capillaries

Capillaries are the smallest and thinnest of all blood vessels in the circulatory system. Their primary role is to facilitate the exchange of gases, nutrients, and waste products between the blood and surrounding tissues. Capillaries connect arterioles (small branches of arteries) to venules (small branches of veins).

The walls of capillaries are just one cell thick, allowing for easy and efficient diffusion of substances.
This thinness ensures minimal barrier to the exchange process, making capillaries ideal for this purpose.
Additionally, the extensive network of capillaries increases the surface area available for exchange, which enhances the overall efficiency of nutrient and gas transfer.

• Thin-walled structure
• Extensive network
• Efficient exchange of substances

gas exchange

Gas exchange is a critical function that occurs primarily in the capillaries. This process involves the movement of oxygen from the blood into tissues and carbon dioxide from the tissues into the blood.

Oxygen carried in the red blood cells diffuses through the thin capillary walls into the surrounding tissues where it is used for cellular respiration. Conversely, carbon dioxide, a waste product of respiration, diffuses from the tissues into the blood to be transported to the lungs for exhalation.
This bidirectional exchange ensures that the body's cells have a constant supply of oxygen for energy production and a means to remove metabolic waste products.

• Oxygen diffusion
• Carbon dioxide removal
• Cellular respiration support

nutrient exchange

Nutrient exchange, like gas exchange, occurs predominantly in the capillaries. Nutrients such as glucose, amino acids, and fatty acids are transported in the blood to the body's tissues.

These nutrients pass through the thin walls of the capillaries and enter the cells where they are used for energy production, growth, and repair. At the same time, waste products from cellular metabolism, such as urea and lactic acid, diffuse back into the blood to be processed and excreted by the kidneys.

• Transport of essential nutrients
• Removal of waste products
• Cellular maintenance

This exchange is tightly regulated to ensure that cells have all they need to function optimally while preventing the accumulation of harmful substances.

circulatory system

The circulatory system is responsible for transporting blood throughout the body. It comprises the heart, blood vessels (arteries, veins, and capillaries), and blood.

Arteries carry oxygen-rich blood away from the heart to the tissues, while veins return oxygen-poor blood back to the heart. The heart pumps the blood, ensuring continuous flow and adequate circulation. Capillaries bridge the transition between arteries and veins, facilitating the exchange of gases, nutrients, and waste products.

• Heart and blood vessels
• Oxygen transport
• Waste removal

Collectively, the circulatory system enables life by ensuring every cell receives the oxygen and nutrients it needs while removing metabolic waste products efficiently.