67: Renal Glomerular Filtration Flashcards
The kidneys are partially protected by ….
Floating Ribs (False Ribs)
The cortex of the kidney contains:
-Convoluted tubules
– more active processes
– more blood flow (100x medulla)
The homeostatic functions of the kidney.
i. Filters and cleans the blood - eliminates waste products and water and urine production (1 – 1.5 L/day excreted)
ii. Controls blood pH, electrolyte concentrations, and volume status
The endocrine functions of the kidney:
i. Synthesizes erythropoietin to stimulate blood cell production
ii. Converts 25-OH vitamin D into its active form 1,25-dihydroxycholecalciferol by the 1-a-hydroxylase enzyme in the proximal tubule
iii. Secretes renin enzyme into circulation to start the renin-angiotensinaldosterone (RAA) axis to increase blood pressure
What two components determine flux across the glomerulus?
Permeability and Glomerular filtration pressures
Filterability Coefficient (Kf) describes…
Permeability of the renal corpuscle
Normal range: 10-15 mmHg
Starling’s Law: 4 pressures in theory affect fluid movement
- Hydrostatic pressure of capillary (PG)
- Hydrostatic pressure of Bowman’s space (PBS)
- Oncotic pressure of blood (plasma) (piG) 4. (Oncotic pressure of Bowman’s space (piBS))
PGC decreases slightly from afferent to efferent due to ……. along the length of the capillary
Flow resistance
pGC increases from afferent to efferent due to ……..of fluid
Filtration
Rate at which the ultrafiltrate forms in Bowman’s space
Glomerular Filtration Rate (GFR)
Formula of Glomerular Filtration Rate (GFR)
GFR = Kf x ΔP Normal values of GFR = 90 - 140 ml/min
Effect of Constriction of Afferent Arterioles on (Renal plasma Flow) RPF and GFR:
Decreases RPF and GFR
Effect of Constriction of Efferent Arterioles on (Renal plasma Flow) RPF and GFR:
Decreases RPF
Increases GFR
Effect of Dilation of Afferent Arterioles on (Renal plasma Flow) RPF and GFR:
Increases RPF and GFR
Effect of Dilation of Efferent Arterioles on (Renal plasma Flow) RPF and GFR:
Increase RPF
Decrease GFR