Flashcards in Renal and Acid/Base Physiology - Theoretical Questions Deck (119)
How is the Flow/Mass ratio of the Kidney in comparison with the Brain or Heart? Bigger/Smaller? Why?
Kidney: ~600 ml/min /200 g (one kidney)
Brain - ~700 ml/min /1500 g
Heart - ~200 ml/min / 400g
It's about 5 times larger in the Kidney - For Filtration.
Pathway of the Renal Blood Flow:
Renal Artery-Segmental arteries-Interlobular Arteries-Arcuate arteries-Intralobular arteries-Afferent Arterioles-Glomerular Capillaries-Efferent Arterioles-Peritubular/Vasa Recta - Venules...
What is the most Effective Starling Force in the Renal Corpuscle?
Glomerular Capillary Hydrostatic Pressure.
Higher than in Systemic Capillaries.
What is the Starling Force in the Renal Corpuscle that changes the most while blood circulates there?
Glomerular Capillary Oncotic Pressure rises.
No protein filtration in Renal Corpuscle.
How does the regulation of renal circulation Protects glomerular capillaries?
Constriction of Afferent arterioles by Bayliss effect prevents them from receiving hydrostatic pressure which is too High
How does the regulation of renal circulation help balance out the flow between the different Renal Corpuscles capillaries?
Macula densa of DCT senses elevations in NaCl, releases Adenosine to Afferent Arterioles SMCs- constrict to limit filtration and allow flow to other Corpuscles.
How does the regulation of renal circulation help conserve Sodium and Water?
Glomerular Cell Cascade (JG Cells):
Macula densa of DCT senses decrease in NaCl,
releases Adenosine to JG cell which Releases Renin and Activate the Renin-Angiotensin-Aldosterone System.
How Angiotensin acts on the Afferent and Efferent Arterioles when in High / Low concentrations?
High Angiotensin-II: Constricts both Afferent and Efferent, GFR is Lower.
Low Angiotensin-II: Constricts Efferent, GFR is Higher.
What are the two main factors that support the High GFR and FF possible in the Renal Circulation?
1)Glomerular Capillary Pressure is Twice as High
2)Filtration Coefficient is 100 times higher - High Surface area and Permeability.
What are the Layers of the Renal Corpuscle Filtration Barrier?
1 - Fenestrated Endothelium (Negatively charged)
2 - Basement Membrane (Pouros + Negatively charged)
3 - Podocytes Layer (Negatively charged+Filtration Slits)
Defenition of Renal Clearance:
Renal Clearance: Volume of plasma per unit time from which all the given substance have been removed by the kidneys and Excreted in urine. Cx (ml/min)
How many Nephrons are in each kidney?
About a Million
What will happen with Albumin as it goes through the Renal Circulation?
Albumin is not filtered at all.
Large size and negative charge prevent it from passing the Filtration barrier.
What will happen with Glucose as it goes through the Renal Circulation? In DM?
Filtered but completely reabsorbed to Peritubular cap.
Glucosuria is common in DM - saturated transporters.
What will happen with PAH as it goes through the Renal Circulation?
Filtered and also Secreted by Peritubular capillaries.
We can say that 90% of PAH is excreted and doesnt get to the Renal veins (normally neglected).
What can we measure thanks to the unique excretion process done by PAH?
RPF will be equal to the clearance of PAH (Cpah).
What medicine goes in the same route as PAH? Why?
Antibiotics for Urinary tract infection.
To reach the urinary tract.
What will happen with Inulin as it goes through the Renal Circulation? What can we measure from that?
Inulin is Filtered and Not Secreted/Absorbed.
Clearance of Inulin will be equal to GFR.
What will happen with Creatinine as it goes through the Renal Circulation? How is different from Inulin?
Creatinine is Filtered and Not Secreted/Absorbed.
Since Creatinine is an Endogenous molecule it will form at a specific metabolic rate that could damage GFR measurements.
GFR Regulation by Sympathetic nervous system:
Norepinephrine will bind to Alpha-1 receptors of Afferent arterioles (Mostly) and cause decrease in GFR.
GFR Regulation by Atrial natriuretic peptide :
ANP dilates Afferent arterioles (lightly constricts effernts), Causes an increase in GFR.
GFR Regulation by Prostaglandins:
Prostaglandins dilate Afferent arterioles causes an increase in GFR.
GFR Regulation by Dopamine:
Dopamine dilates Afferent arterioles causes an increase in GFR.
What are the main functions of the Early Proximal Convoluted Tubule?
Early Proximal Convoluted Tubule : Reabsorption of 20% of Na allows for cotransport with Glucose (SGLT2), AA, Pi, Lactate and Citrate. Cl goes Paracellularly. Aq1 and 2.
Bicarbonate formed by CA reaction goes with Na.
what is the cause for Cl to be Reabsorbed paracellularly in the Late Proximal Convoluted Tubule?
What will this cause in response?
After the absorption of Na in the Early convoluted tubule the Cl amount that stayed in the filtrate causes elevation of Negative charge that will drive it to follow Na.
Then, again Na, Ca and K will follow for the same reason.
Late Proximal Convoluted Tubule -Job in Acid/Base regulation:
has a Na/H Exchanger - lowers blood pH.
Late Proximal Convoluted Tubule - Examples for gets secreted?
PAH, NE, Epi and Oxaloacetate
(and H with H/Na Exchanger)
Action of Acetazolamide:
Inhibition of Carbonic Anhydrase (CA) therefore NaHCO3 will not be transported later to peritubular capillaries.
How much of Na is Reabsorbed in the Proximal Convoluted Tubule? Which transporters are carrying glucose in each surface and each part of it?
Early - SGLT2, Late - SGLT1, both on Apical surfaces.
Glut1 and Glut2 on the Basal surfaces for both.