Glomerular Filtration Flashcards
What is the function of Granular Cells? Cells of the Macula Densa?
Granular cells —> Renin Release
Macular Densa —> Sensing flow of filtrate
What do the sympathetic nerves in the glomerulus project to?
Smooth muscle cells and granular cells of afferent arterioles
What are the three layers of glomerular capillaries?
- Fenestrated Endothelium
- Negatively charged Basement membrane
- Podocytes
What are the factors which determine filter ability?
- Molecular weight
2. Molecular charge (Negative charge)
What impedes the filtration of albumins?
Negative charge of basement membrane of glomerulus
What is the exception for proteins in the urine?
Tam-Horsfall protein - function unclear maybe kidney stone prevention
What is Profound proteinura, and what is it’s major effect on the body?
3 g/day
Can lead to low plasma protein concentration and a decrease in plasma osmotic pressure —> Edema
Describe Nephrotic Syndrome
- Periorbital Edema
- Decrease in plasma albumin
- Overall increase in swelling/edema
What is glomerulonephritis?
Autoimmune
Antigen-Antibody complex attack wall of capillaries and cause inflammation
Hematura, Other blood cells in urine and glomerulus; Mesangial cell contraction and proliferation
Can lead to Renal insufficiency, Oliguria, or Anuria
Describe minimal change disease
Proteinurea
- Podocytes damaged and/or negative basement membrane diminished
- Typically affect children
- Diffuse loss of podocytes foot processes; No capillary damage detected from microscope
***Treat with Steroids
How does Chronic kidney disease develop?
Antigens —> Inflammation —> Mesangial proliferation —> Decreased GFR
How does Diabetic nephropathy differ in appearance to other?
Begins with an increase in GFR and decreases after Mesangial proliferation?
What is GFR and what is the normal value?
Volume of filtrate per unit time in nephron from plasma.
100 ml/min
What are the forces which underlie filtration? How is Net Filtration Pressure calculated?
(Beginning Of arterioles)
Out of Cappilary:
Hydrostatic pressure (PH) - 45 mmHg
Into capillary:
Hydrostatic Pressure (PBS) - 10 mmHg
Osmotic pressure (PO) - 25
NFR = PH - PBS - PO
How is GFR calculated?
GFR = NFP X Kf
Kf = Filtration coefficient which is 100X greater then in systemic capillaries
How does NFP change as you continue along the Glomerular capillary?
NFP Decreases
As fluid moves out, Osmotic pressure increases
How dose Hydrostatic pressure change GFR?
Afferent Vasoconstriction:
- INC Resistance
- Decrease in RBF
- DEC Hydrostatic pressure in Capillary —> DEC GFR
Efferent Vasoconstriction:
- INC Hydrostatic Pressure
- INC GFR
How does ANP affect GFR?
- DEC Afferent resistance
- INC Efferent resistance
- INC NFP —> INC GFR*
What is responsible for increased GFR in initial stages of diabetes?
Increased glomerular hypertension
What is the treatment for Diabetic nephropathy and how does it work?
Cilazapril —> Dilation Of efferent arterioles —> Reduced glomerular hypertension —> Reduced GFR and Proteinura
How does Contritcion of Ureters Decrease GFR?
- INC in PBS (opposing force in NFP)
- Net decrease in GFR
How does the kidney autoregulate during intense physical exercise?
- Afferent arteriole Contraction plays major role
- Changes in vascular resistance results in constant RBF and GFR
How is RPF calculated?
RPF = RBF X (1-Ht)
How is GFR related to RPF?
GFR = Filtration fraction (FF) X RPF
