Physiology Review Slides Lec. 16 Flashcards
Macula Densa
- Located in the DISTAL Tubule
- Positioned near the Glomerulus
Components of the Filtration Barrier
3 Total
- Podocytes
- Endothelium
- Basement Membrane
“PEB”
Basement Membrane of the Filtration Barrier
- STRONG Neg charge
How are Afferent Arterioles protected against the effects of Angiotensin II?
- The release of PROSTAGLANDINS and NO
- Vasodilators
The Basement membrane in the Glomerulus is composed of what?
- Composed of Collagen and Proteoglycan fibers
What is the GFR
- 125ml/min
- 180L/day
What has the greatest effect on Increasing GFR?
Glomerular Hydrostatic Pressure
What is the major storage site of Renin
JG cells
JG cells
Juxtaglomerular Cells
- Cells outside the Glomerulus on the AFFERENT side
- Major Storage Site of RENIN
Endothelin
Released by DAMAGED vascular endothelial cells of the KIDNEYS
Endothelium of glomerular capillaries
- With Fenestrations (Pores)
- Negative charge
Decreasing GFR on Renal Autoregualtion
- Slow flow rate in Loop of Henle
- INCREASE in reabsorption of Na+ and Cl- in the ASCENDING Limb
- DECREASE of sodium chloride at the MACULA DENSA
Even though Albumin is smaller that the Filtration pores, why does it NOT filter through?
- Albumin is Negatively Charged
- The Filtration Barrier is Also Negative
- They repel
Decrease in [NaCL] on Renal Autoregulation
- Signal from the Macula Densa
- Decrease Resistance in the AFFERENTArterioles (More blood flow)
- INCREASE Renin from JG cells
- INCREASE Angiotensin II
- INCREASE EFFERENT Arterioles resistance (Increase GFR)
Podocytes
- Found in the Glomerulus
- Have Interdigitating “FINGER-LIKE” extensions
- Negative Charge
Angiotensin II
- Constricts EFFERENT Arterioles
(Has little to know effect on AFFERENT Arterioles) - Formed in situations associates w/ blood volume depletion
Minimal Change Nephropathy Disease
- Loss of NEGATIVE Charges on the BASEMENT Membrane
- Presence of Albumin in the Urine
Fxn of the Macula Densa
Q- Senses how much SODIUM is in the Glomerulus
- Decreases Afferent Resistance (More blood flow in Glomerulus)
- Stimulates JG cells to secrete renin
