30 Questions
What percentage of cardiac output is blood flow through the kidneys in an average 70 kg male?
25%
What is the approximate weight of the kidneys in a 70 kg male, compared to total body weight?
0.4%
What is the primary factor that contributes to the high blood flow through the kidneys?
Importance of the kidneys in filtering waste
What is the term for the regulation of renal blood flow, maintaining a constant flow despite changes in blood pressure?
Autoregulation
What is the name of the equation used to calculate renal plasma flow and renal blood flow?
Not specified in the text
What is the author of the physiology textbook that provided the figure illustrating renal blood flow?
L.S. Costanzo
What is the primary function of the 'myogenic mechanism' in renal autoregulation?
To respond to changes in arterial pressure via smooth muscle contraction
What is the name of the structure responsible for sensing [NaCl] levels in tubular fluid in the 'tubuloglomerular feedback' mechanism?
Macula densa
Over what range of arterial blood pressure (ABP) is autoregulation of renal blood flow (RBF) and glomerular filtration rate (GFR) maintained?
90-180 mm Hg
What is the term used to describe the phenomenon of maintaining relatively constant renal blood flow (RBF) and glomerular filtration rate (GFR) despite changes in arterial pressure?
Autoregulation
What is the primary function of the afferent arteriole in autoregulation of renal blood flow (RBF) and glomerular filtration rate (GFR)?
To regulate the tone of the afferent arteriole in response to changes in arterial pressure
What is the equation that describes the relationship between renal blood flow (RBF) and the arteriolar resistance?
RBF = ΔP / R
What is the principle used to measure true renal plasma flow (RPF)?
The Fick principle applied to the kidney
What is the formula to calculate renal plasma flow (RPF) using PAH?
RPF = [U] PAH x V / ([RA] PAH - [RV] PAH)
Why is PAH ideal for measuring renal plasma flow (RPF)?
Because PAH is neither used nor produced by the kidney and has a high clearance rate
What is the significance of [RV] PAH being nearly zero?
It indicates that the kidneys remove most of PAH from renal arterial blood by filtration and secretion
What is the unit of measurement for urinary flow rate (V)?
ml/min
What is the relationship between the amount of PAH entering the kidney and the amount of PAH leaving the kidney?
The amount of PAH entering the kidney is equal to the amount of PAH leaving the kidney
What is one of the primary functions of the renal blood flow in terms of urine production?
To concentrate and dilute urine
What is the formula for blood flow through any organ?
Q = ΔP / R
What is the unit of measurement for the pressure difference in the formula for renal blood flow?
millimeters of mercury (mmHg)
What is the term for the opposition to blood flow through a vessel?
Resistance
What is the term for the blood vessels that play a crucial role in regulating renal blood flow?
Afferent and efferent arterioles
What is the approximate value of the pressure difference between the renal artery and renal vein?
3 - 4 mmHg
What is the formula to calculate Renal Blood Flow (RBF) from Renal Plasma Flow (RPF) and haematocrit?
RBF = RPF × (1 - Hct)
What is the unit of measurement for Renal Blood Flow (RBF) and Renal Plasma Flow (RPF)?
ml/min
What is the value of haematocrit (Hct) in the given example?
0.45
What is the clearance of PAH in the given example?
600 ml/min
What is the value of Renal Blood Flow (RBF) in the given example?
1091 ml/min
What is the concentration of PAH in urine in the given example?
600 mg/dl
This quiz covers the physiology of the kidney, including its functions and processes. Test your knowledge of renal physiology based on lectures by Dr. J. Mohan. References include Costanzo, Koeppen, and Hall.
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