lecture 32 - glomerular function Flashcards
Is filtration relatively selective or unselective at the golmerulus?
Unselective
What 3 factors determine glomerular filtration?
Renal blood flow, filtration barrier, driving forces
What proportion of cardiac output goes to renal blood flow?
20%
What are the 4 forces/pressures driving or opposing glomerular filtration?
Glomerular hydrostatic pressure (GHP), blood colloid osmotic pressure (BCOP), Capsular hydrostatic pressure (CsHP) and Capsular colloid osmotic pressure (CsHOP)
What relative pressures favour filtration in the glomerulus (positive or negative)?
Positive pressures
What relative pressures oppose filtration in the glomerulus (positive or negative)?
negative pressures
What are the 2 types of pressures that favour or oppose glomerular filtration?
Hydrostatic pressure, colloid osmotic pressure
What is hydrostatic pressure?
Pressure due to the volume of fluid in a space
What is colloid osmotic pressure?
Osmotic pressure due to protein in a fluid
What are the positive pressures that favour filtration in the glomerulus?
Glomerular hydrostatic pressure
What are the negative pressures that oppose filtration in the glomerulus?
Blood colloid osmotic pressure and capsular hydrostatic pressure
What is the source of glomerular hydrostatic pressure?
Blood pressure - blood in glomerular capillaries tries to force water into the capsular space
What is the source of the blood colloid osmotic pressure?
Protein, specifically albumin, in the blood tries to pull fluid from the capsular space into the glomerular capillary
What is the source of the capsular hydrostatic pressure?
Pressure of filtrate and fluid already present in the capsular fluid opposes filtration
Why is the value of the capsular colloid osmotic pressure 0mmHg?
Because no protein in the the capsular space as it is too big to be filtered