12 Questions
What percentage of total cardiac output is the renal blood flow under normal resting conditions?
20%
Which type of transport mechanism is responsible for the reabsorption of glucose in the kidneys?
Facilitated diffusion
What is the primary function of the glomerular capillary?
Filtration of blood
What is the term for the amount of substance that is completely removed from the blood by the kidneys?
Clearance
Which of the following arteries is an end artery that supplies blood to the glomerular capillary?
Afferent arteriole
What is the relationship between GFR and clearance?
GFR is directly proportional to clearance
What is the primary function of the glomerular membrane during filtration?
To block the passage of cells and proteins
Which of the following is NOT a determinant of the filtration rate in the glomerulus?
Blood pH levels
What is the primary function of the afferent and efferent arterioles in the glomerulus?
To facilitate the autoregulation of GFR
What is the normal rate of glomerular filtration under normal circumstances?
125 ml/minute
Which of the following is NOT a physiological process that helps maintain a constant GFR?
Parasympathetic nervous system regulation
What is the primary force that drives the movement of fluid out of the glomerulus and into the Bowman's space?
Hydrostatic pressure
Study Notes
Renal Blood Flow (RBF) and Glomerular Filtration Rate (GFR)
- RBF is 20% of total cardiac output under normal resting conditions
- Blood enters the kidney through renal arteries, dividing into segmental, interlobar, arcuate, and interlobular arteries, and finally, the afferent arteriole
- Blood exits the glomerular capillary through the efferent arteriole
Filtration
- Glomerular filtration is the most important function of the kidney
- Plasma passively filtrates across the glomerular membrane, forming the ultrafiltrate
- All blood contents, except cells and proteins, are filtered through this process
Regulation of Glomerular Filtration
- Filtration rate is determined by Starling forces, including hydraulic and oncotic pressure differences between the glomerular capillary and the Bowman space
- Alterations in GFR can occur with changes in Starling forces
- Oncotic pressure is primarily determined by plasma proteins, mainly albumin
- Hydraulic pressure, or hydrostatic pressure, forces blood components out of the glomerulus and into the Bowman space
Regulation of GFR
- GFR is tightly maintained at a relatively constant level of 125 ml/minute through two physiological processes:
- Autoregulation: fast, myogenic response
- Tubulo-glomerular feedback: slow response
This quiz assesses learners' understanding of renal physiology, focusing on glomerular filtration, tubular reabsorption, and secretion, as well as the transport mechanisms for organic substances. It covers the role of active transport and co-transport in tubular reabsorption and secretion.
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