Capillary Fluid Exchange and Hemorrhage Response

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What is the primary force that tends to force fluid outward through the capillary membrane?

Capillary plasma colloid osmotic pressure

Interstitial fluid colloid osmotic pressure

Interstitial fluid hydrostatic pressure

Capillary hydrostatic pressure (correct)

When does the interstitial fluid hydrostatic pressure tend to force fluid outward through the capillary membrane?

When it is 5 mm Hg or lower

When it is 20 mm Hg or higher

When it is positive

When it is negative (correct)

What is the role of capillary plasma colloid osmotic pressure in fluid movement through capillary membranes?

Tends to cause osmosis of fluid outward

Has no influence on fluid movement

Tends to force fluid inward (correct)

Neutralizes the other forces

What happens if the net filtration pressure is positive?

There will be a net fluid filtration across the capillaries (C) Signup and view all the answers

What is the main consequence of decreased baroreceptor input to the brain?

Increased sympathetic nervous system activation (D) Signup and view all the answers

Which of the following Starling forces leads to osmosis of fluid inward through the capillary membrane?

Capillary plasma colloid osmotic pressure (B) Signup and view all the answers

Which region of the circulation is particularly affected by sympathetic vasoconstriction during hemorrhage?

All of the above (D) Signup and view all the answers

When will there be a net fluid absorption from the interstitial spaces into the capillaries based on Starling forces?

When the sum of forces is negative (A) Signup and view all the answers

Which force primarily drives fluid filtration across the capillary vessel wall?

Blood pressure in the capillaries (A) Signup and view all the answers

What is the purpose of the sympathetically mediated venoconstriction during hemorrhage?

To limit the fall in preload on the right side of the heart (B) Signup and view all the answers

What is the role of starling forces in fluid movement across the capillary wall?

Regulate osmotic gradient between blood and tissue (C) Signup and view all the answers

At what level of blood loss does the sympathetic activation become succeeded by inhibition of sympathetic outflow and progression to circulatory shock?

About 25-35% blood volume loss (C) Signup and view all the answers

How does the brain and coronary circulations respond to sympathetic vasoconstriction during hemorrhage?

They are relatively preserved (B) Signup and view all the answers

In which region of the capillary do forces favoring filtration dominate?

Arterial end (D) Signup and view all the answers

What is the main effect of decreased baroreceptor input on the parasympathetic nerve supply to the heart?

Decreased parasympathetic activity (B) Signup and view all the answers

How does blood loss affect arterial blood pressure?

Decreases arterial blood pressure (B) Signup and view all the answers

What is the purpose of compensatory responses triggered by CVS reflexes after blood loss?

Restore arterial blood pressure (C) Signup and view all the answers

Which organ plays a crucial role in the long-term restoration of blood volume following hemorrhage?

Kidney (B) Signup and view all the answers

What is the function of the precapillary sphincter?

Regulates the blood flow into the capillary (D) Signup and view all the answers

What causes the intermittent periods of capillary blood flow known as vasomotion?

Contractions of metarterioles and precapillary sphincters (D) Signup and view all the answers

What plays a crucial role in determining the degree of opening and closing of metarterioles and precapillary sphincters?

Concentration of oxygen (C) Signup and view all the answers

What does capillary tone refer to?

Percentage of partially and totally closed capillaries at a specific time (C) Signup and view all the answers

How does the local tissue affect the function of metarterioles and precapillary sphincters?

By changing nutrient concentrations (A) Signup and view all the answers

What happens to capillary blood flow when tissue oxygen usage is high and oxygen concentration decreases?

Intermittent periods of capillary blood flow occur more often (B) Signup and view all the answers

What is the expected mean arterial blood pressure range after a 15 – 20% hemorrhage?

80– 90 mm Hg (C) Signup and view all the answers

How does decreased blood volume affect right atrial pressure and cardiac output?

Decreases right atrial pressure and increases cardiac output (D) Signup and view all the answers

What happens to mean arterial pressure when there is a 20% reduction in blood volume?

Decreases (D) Signup and view all the answers

What is the consequence of a blood volume loss of 30 – 40% on mean arterial blood pressure?

Reduction to 50 – 70 mm Hg (C) Signup and view all the answers

Which regulatory mechanism plays a role in restoring blood pressure after hemorrhage?

Carotid sinus baroreceptor reflex (D) Signup and view all the answers

What is the expected cardiac output after a 20% reduction in blood volume?

$3 L/min$ (B) Signup and view all the answers