11. Basic physiological processes of the kidney: filtration, reabsorption, secretion, excretion Flashcards
Filtration: what is it determined by
The rate of filtration is determined by the effective filtration pressure (EFP) and the permeability of the barriers.
Filtration: Capillary filtration coefficient: degree of ultrafiltration taking place in the
renal glomerulus
degree of ultrafiltration taking place in the
renal glomerulus is a hundred times higher than in
any other capillary areas.
Filtration: Capillary filtration coefficient: most important factor
is the lamina densa of the basal membrane. It is negatively charged, and accordingly it strongly reflects the proteins.
Filtration: Capillary filtration coefficient: regulation of size of filtrating surface
The size of the filtrating surface is presumably regulated by the mesangial cells containing myogen elements.
Filtration: Effective filtration pressure: eqauation:
EFP = GP – (CP + GCP)
Filtration: Effective filtration pressure: explain equation
Components of EFP:
▪ Hydrostatic pressure of the glomerulus (GP)
▪ Bowman-sheath’s pressure (CP)
▪ Colloid-osmotic pressure of the plasma (GCP) EFP = GP – (CP + GCP)
Filtration: Effective filtration pressure: extent of ultrafiltration depends on what
The extent of Ultrafiltration depends on the pressure gradient, which actually prevails on both sides of the interface.
Reabsorption: what are the 2 main pathways
Two main pathways for the reabsorption of the
ultrafiltrate: paracellular and transcellular.
Secretion: how does it occur
From the plasma leaving the glomerulus through the efferent arteriole further substances can get into the tubular lumen at the site of the peritubular capillaries.
Excretion: how is urine formed
As a result of the filtration, reabsorption and secretion by the end of the tubular system the secondary filtrate of urine is formed
Excretion: rate of excretion
Rate of excretion = the urine or selected material excreted.
