Circulatory System Quiz

Which type of blood vessel is the smallest in the circulatory system?

• Arteries

• Veins

• Capillaries

• Arterioles

Answer explanation

Capillaries are the smallest blood vessels in the circulatory system, allowing for the exchange of oxygen, carbon dioxide, and nutrients between blood and tissues. They are narrower than arteries, veins, and arterioles.

How many layers or tunics do arteries have?

• 2 layers

• 3 layers

• 4 layers

• 5 layers

Answer explanation

Arteries have 3 layers: the tunica intima (inner), tunica media (middle), and tunica externa (outer). This structure allows them to handle high pressure and maintain elasticity, making '3 layers' the correct answer.

What happens to capillary networks in tissues with higher metabolic rates?

• They become less dense

• They remain unchanged

• They become denser

• They disappear

Answer explanation

Tissues with higher metabolic rates require more oxygen and nutrients, leading to an increase in capillary density to enhance blood flow and support metabolic demands. Therefore, they become denser.

What is the capillary pattern in tissues with lower metabolic rates?

• Dense networks

• Few capillaries

• Direct connections only

• No capillaries

Answer explanation

Tissues with lower metabolic rates require less oxygen and nutrients, resulting in fewer capillaries. This is why the correct answer is 'Few capillaries', as dense networks are typically found in more metabolically active tissues.

What forces molecules through the membrane during filtration?

• Osmotic pressure

• Hydrostatic pressure

• Atmospheric pressure

• Diffusion pressure

Answer explanation

Hydrostatic pressure is the force that drives molecules through the membrane during filtration. It pushes fluid and solutes from an area of higher pressure to an area of lower pressure, facilitating the filtration process.

From where is the pressure derived during filtration in capillaries?

• Arterial contraction

• Ventricular contraction

• Capillary contraction

• Venous contraction

Answer explanation

The pressure during filtration in capillaries is primarily derived from ventricular contraction, which pumps blood into the arteries, creating the necessary pressure for filtration.

What creates osmotic pressure inside capillaries?

• Lipid-soluble substances

• Water-soluble substances

• Impermant solute such as plasma proteins

• Carbohydrates

Answer explanation

Osmotic pressure in capillaries is primarily created by impermeant solutes like plasma proteins. These proteins cannot easily cross the capillary walls, leading to a concentration gradient that draws water into the capillaries.

Which method of exchange involves hydrostatic pressure?

• Diffusion

• Filtration

• Osmosis

• Active transport

Answer explanation

Filtration is the method of exchange that involves hydrostatic pressure, as it relies on pressure differences to move fluid and solutes through a membrane, unlike diffusion, osmosis, or active transport.

Under what condition do veins carry blood?

• High pressure

• Medium pressure

• Low pressure

• No pressure

Answer explanation

Veins carry blood under low pressure, as they return deoxygenated blood to the heart. Unlike arteries, which operate under high pressure from the heart's pumping, veins rely on muscle contractions and one-way valves to facilitate blood flow.

Which vessels transport blood from capillaries to veins?

• Arteries

• Arterioles

• Venules

• Capillaries

Answer explanation

Venules are small blood vessels that collect blood from capillaries and transport it to veins. They play a crucial role in the circulatory system by ensuring the flow of blood back to the heart.