18 Questions
Which of the following is the most important factor that determines the blood flow in a vessel?
The pressure gradient between the beginning and end of the vessel
Which of the following is the primary mechanism of metabolic autoregulation of blood flow?
Autoregulation of the arteriolar diameter
How does an increase in hematocrit affect blood viscosity and blood flow?
Increases viscosity, decreases flow
Which of the following vasoactive substances is most likely to cause vasodilation of the arterioles?
Nitric oxide
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
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
What is the main site of peripheral resistance in the circulatory system?
Arterioles
How does increased diameter of blood vessels affect resistance in the circulatory system?
Decreases resistance
What type of blood flow helps eliminate energy losses in the circulatory system?
Laminar flow
In cases of mild narrowing due to atherosclerosis, what happens to blood flow?
Decreases significantly
How do small changes in arteriolar diameter affect blood flow in the body?
Lead to major changes in flow
Which factor has a less significant effect on blood viscosity compared to hematocrit?
Concentration of plasma proteins
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
Which of the following is the main site of action for the vasodilator substance generated in response to increased shear stress?
Large diameter arterioles
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
Which of the following vasoactive substances is the most potent vasoconstrictor?
Endothelin-1
What is the balance between Thromboxane A2 and Prostacyclin (PGI2) important for?
Maintaining a localized clot without excessive extension, which maintains blood flow
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
Test your knowledge on the effects of decreased hematocrit, concentration of plasma proteins, and vessel diameter on blood viscosity and arterial blood pressure in cases of hemorrhage. Learn about the impact of vasodilation and vasoconstriction on blood flow.
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