Blood Viscosity and Hemorrhage Quiz

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Which of the following is the most important factor that determines the blood flow in a vessel?

The viscosity of the blood
The cardiac output of the left ventricle
The pressure gradient between the beginning and end of the vessel (correct)
The length of the vessel

Which of the following is the primary mechanism of metabolic autoregulation of blood flow?

Increased blood viscosity
Autoregulation of the arteriolar diameter (correct)
Increased cardiac output
Vasodilation of the venules

How does an increase in hematocrit affect blood viscosity and blood flow?

Decreases viscosity, increases flow
Has no effect on viscosity or flow
Increases viscosity, increases flow
Increases viscosity, decreases flow (correct)

Which of the following vasoactive substances is most likely to cause vasodilation of the arterioles?

Nitric oxide (B) Signup and view all the answers

What is the relationship between the radius of a vessel and its resistance to blood flow?

Resistance is inversely proportional to the fourth power of the radius (D) Signup and view all the answers

Which of the following is the most important mechanism by which the body can autoregulate blood flow to meet the metabolic needs of a tissue?

Dilating the arterioles (D) Signup and view all the answers

What is the main site of peripheral resistance in the circulatory system?

Arterioles (A) Signup and view all the answers

How does increased diameter of blood vessels affect resistance in the circulatory system?

Decreases resistance (B) Signup and view all the answers

What type of blood flow helps eliminate energy losses in the circulatory system?

Laminar flow (B) Signup and view all the answers

In cases of mild narrowing due to atherosclerosis, what happens to blood flow?

Decreases significantly (A) Signup and view all the answers

How do small changes in arteriolar diameter affect blood flow in the body?

Lead to major changes in flow (C) Signup and view all the answers

Which factor has a less significant effect on blood viscosity compared to hematocrit?

Concentration of plasma proteins (B) Signup and view all the answers

Which of the following is the most important trigger for the continuous generation of a vasodilator substance?

Increased shear stress on the blood vessel wall (D) Signup and view all the answers

Which of the following is the main site of action for the vasodilator substance generated in response to increased shear stress?

Large diameter arterioles (B) Signup and view all the answers

How do vasodilator drugs (e.g., Nitrovasodilators) affect the heart?

They decrease the venous return and preload, and decrease the arterial blood pressure and afterload (C) Signup and view all the answers

Which of the following vasoactive substances is the most potent vasoconstrictor?

Endothelin-1 (A) Signup and view all the answers

What is the balance between Thromboxane A2 and Prostacyclin (PGI2) important for?

Maintaining a localized clot without excessive extension, which maintains blood flow (C) Signup and view all the answers

How does autoregulation of blood flow to some tissues work?

The blood flow is adjusted to match the metabolic activities of the tissue, and remains constant despite changes in arterial blood pressure (A) Signup and view all the answers