60 Questions
What is the relationship between HPg (Hydrostatic Pressure in the glomerulus) and NFP (Net Filtration Pressure)?
The relationship is inverse, as an increase in HPg leads to a decrease in NFP.
What are the two main types of controls that regulate the glomerular filtration rate (GFR)?
Intrinsic and extrinsic controls
Which of the following is an example of an intrinsic control mechanism that regulates GFR?
Renal autoregulation
What is the effect of sympathetic division stimulation on the glomerular filtration rate (GFR)?
Sympathetic stimulation decreases GFR.
What is the effect of atrial natriuretic peptide (ANP) on the glomerular filtration rate (GFR)?
ANP increases GFR.
Why is the glomerular filtration rate (GFR) tightly regulated?
To control the amount of substances reabsorbed into the blood and excreted in the urine.
Which process involves the movement of solutes from the blood into the tubular fluid?
Tubular secretion
What is the primary purpose of tubular reabsorption?
To return vital solutes and water to the blood
Which statement is true about the relationship between tubular reabsorption and tubular secretion?
They involve the movement of materials in opposite directions
What is the primary purpose of tubular secretion?
To selectively move materials into the tubules for elimination
Which process is primarily responsible for the formation of urine?
All three processes contribute equally
Which of the following statements is true about the relative amounts of tubular reabsorption and tubular secretion?
There is generally more tubular reabsorption than tubular secretion
What is the main effect of increased sympathetic stimulation on the kidneys?
Decreases blood flow into the glomeruli
What is the main purpose of renal autoregulation?
To produce urine at a constant rate despite fluctuations in systemic blood pressure
What is the purpose of the extrinsic controls on glomerular filtration rate described in the text?
To adjust urine output based on physiological need
What are the two mechanisms by which renal autoregulation functions?
Myogenic response and tubuloglomerular feedback
What is the effect of atrial natriuretic peptide (ANP) stimulation on glomerular filtration rate?
Increases GFR through vasodilation of the afferent arteriole
What is the range of mean arterial pressure (MAP) over which renal autoregulation is effective?
80-180 mm Hg
What is the primary mechanism by which sympathetic stimulation decreases GFR?
Decreased blood flow into the glomeruli due to vasoconstriction of the afferent arteriole
How does the myogenic response contribute to renal autoregulation?
By causing vasoconstriction in response to decreased blood pressure
How does the tubuloglomerular feedback mechanism contribute to renal autoregulation?
By decreasing the filtration surface area in response to increased blood pressure
What is the physiological stimulus that triggers increased sympathetic stimulation of the kidneys?
Exercise or emergency situations
How does the intrinsic and extrinsic control mechanisms of GFR differ?
Intrinsic controls maintain GFR within normal limits, while extrinsic controls change GFR to adjust urine output
What is the purpose of the figures in the text?
To demonstrate the role of the myogenic response and tubuloglomerular feedback in renal autoregulation
What happens to the amount of substances in the tubular fluid when the filtrate amount increases?
They increase
What is the role of macula densa cells in the nephron?
Measure NaCl levels in the tubular fluid
How does an increase in glomerular hydrostatic pressure (HPg) affect substances in the tubular filtrate?
Substances increase
What is the significance of an increase in NFP (Net Filtration Pressure) on substances in the tubular fluid?
More substances remain
How does a decrease in HPg affect substances in the tubular filtrate?
Substances decrease
What is the role of the JG apparatus in monitoring filtrate formation?
Monitor the amount of filtrate formed
What is the effect on the value of NFP if HPg decreases from 65 mm Hg to 55 mm Hg?
The NFP decreases
What role do the macula densa cells play in the regulation of blood pressure in the glomerulus?
Indirectly measure blood pressure in the glomerulus through NaCl levels
How does an increase in glomerular hydrostatic pressure (HPg) affect the rate of reabsorption in the tubules?
Increases the rate of reabsorption
How are NaCl levels in tubular fluid related to glomerular hydrostatic pressure (HPg)?
NaCl levels increase as HPg increases
If the amount of filtrate formed increases, what is the likely effect on NaCl levels in the tubular fluid?
NaCl levels increase
What happens to NFP if glomerular hydrostatic pressure (HPg) and capsular hydrostatic pressure (HPc) both increase by 5 mm Hg each?
NFP increases by 5 mm Hg
What is the effect of sympathetic stimulation on mesangial cells?
Induces contraction
How does atrial natriuretic peptide (ANP) affect the afferent arteriole?
Causes vasodilation
What is the function of angiotensin II in the context of GFR?
Causes a decrease in GFR
How does atrial natriuretic peptide (ANP) impact glomerular filtration rate (GFR)?
Increases GFR
What adjustments allow the body to conserve fluid under conditions of sympathetic activation?
Contraction of mesangial cells and vasoconstriction of afferent arteriole
What triggers the release of atrial natriuretic peptide (ANP) from atrial cardiac muscle cells?
Distension of atrial chambers due to increased blood volume return or blood pressure
What type of proteins are generally not filtered across the filtration membrane?
Negatively charged proteins
Where is the filtrate caught before being funneled into the proximal convoluted tubule?
Renal corpuscle
Which function do mesangial cells perform in the kidney related to filtration membrane?
Phagocytize macromolecules
What happens to substances that are not filtered across the filtration membrane?
They exit through the efferent arteriole
How are substances like antigen-antibody complexes removed from the basement membrane?
By phagocytosis of mesangial cells
What can damage the filtration membrane according to the text?
Certain diseases and heavy metals
Which substances are freely filtered through the glomerular filtration membrane?
Water, glucose, amino acids, and small ions
What happens to substances that are not filtered through the glomerular filtration membrane?
They remain in the blood plasma
What is the primary function of mesangial cells in the glomerulus?
To phagocytize or remove debris from the glomerulus
What is the approximate daily volume of filtrate produced by the kidneys?
180 L
What property of the glomerular filtration membrane prevents large proteins from being filtered?
Both the negative charge and small openings
Which of the following substances would be considered filtered in a limited way by the glomerulus?
Hormones
What is the primary effect of atrial natriuretic peptide (ANP) on the glomerular filtration rate (GFR)?
Increases GFR by relaxing the mesangial cells
What is the primary purpose of the tubuloglomerular feedback mechanism in renal autoregulation?
To maintain GFR within a normal range
According to the information provided, over what range of mean arterial pressure (MAP) is renal autoregulation effective?
80-180 mmHg
What is the primary mechanism by which sympathetic stimulation decreases the glomerular filtration rate (GFR)?
Constriction of the afferent arteriole
What is the main purpose of the extrinsic controls on glomerular filtration rate (GFR) described in the text?
To regulate fluid balance and blood volume
What is the primary mechanism by which renal autoregulation maintains the glomerular filtration rate (GFR) when mean arterial pressure (MAP) decreases?
Vasodilation of the afferent arteriole
Learn about the processes of tubular reabsorption and secretion in the renal system. Understand how vital solutes are reabsorbed while waste products are eliminated through tubular secretion. Figure 24.10 illustrates an overview of these processes.
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