32 Questions
What is the driving force for blood flow?
The pressure difference between the two ends of the vessel
According to the Poiseuille equation, which factor has the greatest effect on vascular resistance?
Radius of the blood vessel
What is the relationship between vascular resistance and blood flow?
Decreasing resistance increases flow
What is the direction of blood flow determined by?
The pressure gradient from high to low pressure
What is the major mechanism for changing blood flow in the cardiovascular system?
Changing the radius of the blood vessels
What is the average pressure in the aorta?
around 100 mmHg
What is the primary function of veins in the circulatory system?
To transport deoxygenated blood from tissues back to the heart
Which factor is directly proportional to the resistance to blood flow?
All of the above
Which of the following statements about vein compliance is correct?
Vein compliance is higher than artery compliance
What happens to blood distribution when veins constrict?
Blood shifts from veins to arteries
If the radius of a blood vessel decreases by half, how does the resistance change?
It increases by a factor of 16
What is the relationship between the arrangement of blood vessels and the total resistance to blood flow?
Vessels arranged in parallel offer less resistance than vessels arranged in series
What is the purpose of valves in veins?
To prevent backflow of blood
What is the formula for calculating the resistance to blood flow?
$R = 8\eta l/\pi r^4$
Which factor contributes to the large blood storage capacity of the venous system?
Large cross-sectional area of veins
How does the velocity of blood flow in veins compare to arteries?
Velocity is lower in veins than arteries
What is the purpose of the parallel arrangement of blood vessels in the systemic circulation?
To distribute the blood flow to different organs simultaneously
What is the relationship between cardiac output, blood pressure, and total peripheral resistance?
Cardiac output is directly proportional to blood pressure and inversely proportional to total peripheral resistance
What happens to the velocity of blood flow as the systemic arteries branch into smaller vessels?
It decreases
Which of the following statements is true regarding the cross-sectional area of blood vessels?
The cross-sectional area is larger for capillaries than for arteries.
What happens to the velocity of blood flow as it moves from arterioles to capillaries?
It decreases
How does the velocity of blood flow relate to the total cross-sectional area of blood vessels?
They are inversely proportional
What is the purpose of the slower blood flow velocity in capillaries?
To allow more time for nutrient exchange
Which of the following statements is correct about the relationship between blood flow and cross-sectional area?
Blood flow varies inversely with cross-sectional area.
What is the primary function of the systemic circulation?
To carry oxygenated blood away from the heart
Which artery has the highest compliance in the systemic circulation?
Aorta
What is the primary function of arterioles in the circulatory system?
Control blood flow into capillaries
Which receptor is predominant in arterioles of most visceral organs?
Alpha 1 adrenergic receptor
What is the primary endogenous agonist at beta 2 adrenergic receptors in arterioles?
Epinephrine
How do lipid-soluble substances cross the capillary wall?
By dissolving in and diffusing across the endothelial membrane
What is the role of venules in the circulatory system?
Collect blood from capillaries and coalesce into veins
Where is vascular resistance highest in the circulatory system?
Arterioles
physio 1
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