& x20; Pushing fluid out of the blood stream determining overall fluid movement across the capillary wall, is… - RUHS, Jaipur, M.Sc Nursing Entrance Exam-2018

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2018

Applied Physiology

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2018

Explanation

Hydrostatic pressure is the force exerted by the blood against the capillary walls, acting as a 'pushing' force.
This pressure is the primary driver of filtration, the process where fluid moves from the capillaries into the interstitial space.
It is highest at the arterial end of the capillary, promoting the delivery of nutrients and oxygen to tissues.
The balance between hydrostatic pressure and osmotic pressure (Starling's forces) determines the net direction of fluid movement across the capillary.

Option B: Osmotic pressure is a 'pulling' force, not a 'pushing' force. It draws fluid back into the capillaries.
Option C: Diffusion describes the movement of solutes (particles) down their concentration gradient, not the bulk movement of fluid driven by pressure.
Option D: Vasoconstriction is the narrowing of blood vessels. It is a mechanism that can alter blood pressure, but it is not the force itself that pushes fluid out.

Clinical Relevance

Nursing practice connection: Knowing Capillary Fluid Dynamics and Starling's Forces helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Understanding hydrostatic pressure is crucial for explaining edema. Conditions like heart failure increase venous pressure, which raises capillary hydrostatic pressure, forcing excess fluid into the interstitial tissues.
In liver disease, the production of albumin can decrease, lowering the colloid osmotic pressure. This imbalance means the hydrostatic 'push' is less opposed, leading to fluid accumulation (ascites).
A nurse monitors for edema by assessing for swelling, particularly in dependent areas like the legs and ankles, which is a direct clinical sign of altered capillary fluid dynamics.

How to Approach the Question

First, identify the key action in the question: 'Pushing fluid out of the blood stream'.
Next, analyze the options in the context of fluid dynamics at the capillary level.
Recall the two main forces governing capillary exchange: hydrostatic pressure ('push') and osmotic pressure ('pull').
Match the action 'pushing out' with the correct physiological term, which is hydrostatic pressure.
Differentiate this from osmotic pressure, which pulls fluid in, and from diffusion, which moves solutes, not bulk fluid.
Eliminate vasoconstriction as it is a process of vessel narrowing, not a direct force of fluid movement.

Concept Tested & Keywords

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