Renal physiology No.1 Flashcards
What hormones do the Kidneys produce ?
- Erythropoietin
- Calcitriol
What is the process in which blood filters into the bowman’s capsule ?
Ultrafiltration.
Ultrafiltration is, simply put, filtration that occurs under pressure. What is responsible for maintaining the pressure in this process?
- The afferent and efferent arterioles.
- The afferent arteriole (proximal glomerulus) dilates, while the efferent arteriole (distal glomerulus) constricts. This creates a pressure gradient throughout the glomerulus, causing filtration under pressure.
What is the Triad of symptoms of nephrotic syndrome?
- Proteinuria
- Hypoalbuminemia
- Oedema
What are the 4 basic steps of the nephron.
1- Filtration
2- Reabsorption
3- Secretion
4 - excretion
Cortical vs Juxtamedullary neprhons
What is the difference ?
Cortical nephrons perform the excretory and regulatory functions of a kidney.
Juxtamedullary nephron is involved in concentrating or diluting urea.
What happens at the proximal convoluted tubule?
Reabsorption
What two cells are present within the collecting duct ?
- Intercalated cells
- Principles cells
What are the layers of the filtration Barrier ?
1- Endothelial cells of glomerular capillaries - This has many perforations called fenestrae which prevents the filtration of RBC.
2—Glomerular basement membrane—This has a glycocalyx consisting of negatively charged ions and, therefore, prevents the filtration of negative ions.
3- Epithelial cells of Bowman’s Capsule (podocytes) - Prevents large molecules such as proteins being filtered out.
What cell prevents the filtration of large molecules such as proteins?
Podocytes
Anything that has a lower molecular mass than what number can pass through the filtration membrane ?
68KD
What can pass through the filtration membrane of the glomerulous during ultrafiltration?
H20
NA
K
CL
Glucose
Urea
Creatinine
What can not pass through the filtration membrane of the golmerulous during ultrafiltration ?
Proteins > 68KDa
Immunoglobulins
Ferritin
Blood cells
What is the force in favour of filtration?
What is its value ?
Glomerular blood hydrostatic pressure (GBHP) 60 mmHg
High due to resistant of afferent arteriole
What are the two forces opposing filtration and what are their values ?
Capsular Hydrostatic Pressure (CHP) - 15mmHg due to accumulated fluid in the capsule.
Blood colloid osmotic pressure (BCOP) - 30 mmHg due to proteins such as albumin and fibrinogen in the plasma.
What is the pressure of the glomerular blood hydrostatic pressure (GBHP) ?
60 mmHg
What is the Capsular Hydrostatic Pressure (CHP)?
15 mmHg
What is the Blood Colloid Osmotic Pressure (BCOP)?
30 mmHg
What are the three main regulatory mechanisms that maintain the GFR ?
1- Autoregulation (myogenic, intra-renal baroreceptors mechanism, and macula denser sense).
2- Neural regulation - -Sympaethic and parasympathetic nervous system, e.g. vasoconstriction or dilation.
3- Hormonal regulation
What are the steps of autoregulation of ultrafiltration ?
- Myogenic - Increase stretch of smooth muscle in afferent arteriole walls - Reflex constrictions of arteriole smooth muscle.
- Intra-renal baroreceptor mechanism
- Macula densa sensor - Renin secretion is inversely proportional to the amount of NA and CL entering the distal renal tubules from the loop of henle.
What part of the nephron is CLOSELY located to the bowman’s capsule?
Distal convoluted tubule
What cells are in the first segment of the DCT and are essential for tubuloglomerular feedback?
Macula densa cells
What cells produce renin ?
Juxtaglomerular cells
What is used to estimate EGFR?
Creatinine clearance
