BPK 105 Study Guide - Final Guide: Capillary Pressure, Colloid, Blood Pressure
27 Apr 2018
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Module 12 - Review Questions - Part 2
3. Illustrate and describe the pressures that influence filtration pressure at the bowmans
capsule. [5 marks]
- Filtration pressure allows for filtrate to form. Filtration pressure is a pressure gradient and
its calculation involves the subtraction of the forces that move fluid into the glomerular
capillary from the Bowman capsule from the forces that move fluid into the Bowman
capsule from the glomerular capillary (glomerular capillary pressure - capsular pressure -
colloid osmotic pressure = filtration pressure).
- The blood pressure that is in the glomerular capillary is called glomerular capillary
pressure. Glomerular capillary pressure is a significant force that moves fluid into the
Bowman capsule from the glomerular capillary via the filtration membrane (into the
Bowman capsule from the blood).
- Capsular pressure and colloid osmotic pressure are significant forces that go against the
pressure that causes the fluid to move into the Bowman capsule’s lumen (into the blood
from the Bowman capsule).
- While the capsular pressure results from the pressure due to the filtrate that is located
inside the Bowman capsule, the colloid osmotic pressure results from the pressure due
to filtrate that is located in the glomerular capillary. Colloid osmotic pressure results from
blood protein pressure uses osmosis to move fluid.
- The majority of plasma membranes are unable to go through the filtration membrane and
so, establishes a pressure - called an osmotic pressure - in which the movement from
the Bowman capsule into the glomerular capillary preferred. Because the combination of
the colloid osmotic pressure and the capsular pressure are smaller than the glomerular
capillary pressure, the filtration fluid causes fluid to move into the Bowman capsule from
the glomerulus.
- The filtration pressure does not vary very much in most cases, but urine volume and
filtrate volume both lower with the decrease of filtration pressure. Conversely, urine
volume and filtrate volume both rise with a rise in filtration pressure.
- Blood pressure in the glomerular capillaries also impacts filtration pressure. Typically,
the blood pressure in the majority of capillaries is lower than in the glomerular capillaries.
- When the blood pressure in the glomerular capillaries decreases, so does the filtration
pressure. When the blood pressure in the glomerular capillaries increases, so does the
filtration pressure.
- With a higher concentration in proteins in the blood, more water moves into the
glomerular capillaries by osmosis; this lowers filtration pressure. When the concentration
in blood protein lowers, so does the filtration pressure, because this prevents water from
going into the glomerular capillaries by osmosis. (Van Putte et al., 507).
Document Summary
Module 12 - review questions - part 2: illustrate and describe the pressures that influence filtration pressure at the bowmans capsule. The blood pressure that is in the glomerular capillary is called glomerular capillary pressure. Glomerular capillary pressure is a significant force that moves fluid into the. Bowman capsule from the glomerular capillary via the filtration membrane (into the. Capsular pressure and colloid osmotic pressure are significant forces that go against the pressure that causes the fluid to move into the bowman capsule s lumen (into the blood from the bowman capsule). While the capsular pressure results from the pressure due to the filtrate that is located inside the bowman capsule, the colloid osmotic pressure results from the pressure due to filtrate that is located in the glomerular capillary. Colloid osmotic pressure results from blood protein pressure uses osmosis to move fluid.
