36 Questions
What is the standard range for glomerular filtration rate (GFR) for males?
95–145 ml/min
Which substance has the highest sieving coefficient based on the provided data?
Inulin
What is the retention capacity of the glomerulus for albumin?
0.001
Which substance with a molecular weight greater than 10000 Da is least hindered when passing through the membrane?
Albumin
What is the ratio of concentration in filtrate to concentration in plasma for glucose based on the sieving coefficient?
14.6
What is the approximate glomerular filtration rate (GFR) in liters per day?
180 l/day
Which structure actively squeezes blood from the glomerulus into the Bowman-capsule?
Proximal tubule
What is the primary composition of the primary urine in the nephron?
Glucose, urea, and salts
Where does the passive backflow of 80% of the primary urinary water occur?
Descending tubule
Which part of the nephron is responsible for active transport of salts and nutrients in the water-impermeable distal tubule?
Proximal tubule
What is the formula for calculating glomerular filtration rate (GFR) using creatinine clearance?
GFR = (Urine creatinine concentration x Urine flow rate) / Plasma creatinine concentration
In the context of kidney parameters, what does RBF stand for?
Renal Blood Flow
Which of the following conditions could lead to pre-renal kidney failure?
Thrombus blocking a blood vessel
What is the normal glomerular filtration rate (GFR) in healthy individuals?
125 ml/min
What does FECr = 100% indicate in the context of GFR estimation using creatinine?
No reabsorption or secretion of creatinine
What is the standard Glomerular Filtration Rate (GFR) for males?
95-145 ml/min
How is the Sieving coefficient (S) defined?
Ratio of concentration in filtrate to concentration in plasma
What does a Fractional Excretion (FE) of 0 indicate?
Complete reabsorption in tubule
What is the Renal Blood Flow (RBF) a measure of?
Blood flow through the kidneys
What is the approximate plasma flow through the kidneys (RPF)?
~550 ml/min
What is the typical blood flow rate in hemodialysis?
200 - 300 ml/min
What is the purpose of ultrafiltration in hemodialysis?
To excrete water from the patient
What is the maximum transmembrane pressure (TMP) in hemodiafiltration?
300 mmHg
What does the term 'diffusive transport' refer to in the context of hemodialysis?
Movement of water-soluble toxins through the dialyzer membrane
What is the typical filtration rate in hemodiafiltration based on body weight?
25 ml / kg h
What does the sieving coefficient (S) measure?
Ratio of concentration in filtrate to concentration in plasma
What does the term 'fractional excretion (FE)' represent?
Percentage of a substance's matter flow in the final urine compared to the matter flow in the primary urine
What does clearance (C) measure according to the given information?
Plasma volume-flow that is completely cleared
In the context of kidney parameters, what does GFR stand for?
Glomerular filtration rate
What is a clinical indicator for acute kidney failure based on the information provided?
FENa = 1%
What is the approximate range of priming volume for the fibers used in ultrafiltration?
60 – 120 ml
Which type of dialyzer membrane is more permeable to medium-sized molecules?
High-Flux
What is the molecular weight cut-off (MWCO) based on the provided information?
Molecular weight where 90% are retained
What does the sieving coefficient measure for dialyzer membranes?
% of substances passing through the membrane
Which parameter determines the selectivity of a dialyzer membrane?
$90$% retention (S = $10$%) of vital proteins and molecules
What is the trade-off associated with High-Flux dialyzers compared to Low-Flux dialyzers?
$20$% retention of vital proteins and molecules
Study Notes
Glomerular Filtration Rate (GFR)
- Standard GFR for males: 130 mL/min
- Approximate GFR in liters per day: 180 L/day
- Normal GFR in healthy individuals: 130 mL/min
Sieving Coefficient and Fractional Excretion
- Sieving coefficient (S) measures the ability of a substance to pass through a membrane
- Formula for S: S = (concentration in filtrate) / (concentration in plasma)
- Substance with the highest sieving coefficient: glucose (S ≈ 1)
- Fractional excretion (FE) represents the percentage of the filtered load that is excreted in the urine
- FE = 100% indicates that the entire filtered load is excreted in the urine
Nephron and Glomerulus
- Retention capacity of the glomerulus for albumin: 99%
- Structure that actively squeezes blood from the glomerulus into the Bowman-capsule: mesangial cells
- Primary composition of the primary urine in the nephron: water, ions, glucose, and other small molecules
- Location of passive backflow of 80% of the primary urinary water: proximal convoluted tubule
- Part of the nephron responsible for active transport of salts and nutrients in the water-impermeable distal tubule: distal tubule
Kidney Parameters
- RBF stands for Renal Blood Flow
- Formula for calculating GFR using creatinine clearance: GFR = (urine creatinine) / (plasma creatinine) x (urine flow rate)
- GFR stands for Glomerular Filtration Rate
Hemodialysis
- Typical blood flow rate in hemodialysis: 200-400 mL/min
- Purpose of ultrafiltration in hemodialysis: remove excess water and solutes from the blood
- Typical filtration rate in hemodiafiltration based on body weight: 20-30 mL/kg/h
- Maximum transmembrane pressure (TMP) in hemodiafiltration: 500 mmHg
- Diffusive transport refers to the movement of solutes across a membrane down their concentration gradient
- Trade-off associated with High-Flux dialyzers compared to Low-Flux dialyzers: higher removal of larger molecules but also higher removal of beneficial nutrients
Dialyzer Membranes
- Molecular weight cut-off (MWCO) based on the provided information: 10,000-50,000 Da
- Sieving coefficient measures the ability of a substance to pass through a dialyzer membrane
- Parameter that determines the selectivity of a dialyzer membrane: molecular weight cut-off (MWCO)
- High-Flux dialyzers are more permeable to medium-sized molecules
Test your knowledge of the components and processes involved in a hemodialysis setup, including measurement devices, artificial organs, patient parameters, and dialysis principles.
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