28 Questions
What is the normal Glomerular Filtration Rate (GFR) range?
120-125 ml/min
Which cells are involved in the tubuloglomerular feedback mechanism?
Macula densa cells
What is the main mechanism to increase blood pressure?
Renin-Angiotensin-Aldosterone mechanism
What is the function of the myogenic mechanism in the kidney?
Constricts afferent arterioles to restrict blood flow to the glomerulus
Which route is limited by tight junctions in the kidney tubules?
Paracellular route
What is the response of the sympathetic nervous system when extracellular fluid (ECF) is low?
Smooth muscles constrict and afferent arterioles constrict
What is the net filtration pressure (NFP) equation?
Outward pressures - Inward pressures = HPgc - (HPcs + OPgc)
What determines who gets filtered and who doesn’t in the kidneys?
Total plasma volume filtered every 22 minutes
What is the main function of a chemical buffer system?
Resist changes in pH when a strong acid or base is added
Which of the following is a major extracellular fluid (ECF) buffer system?
Bicarbonate
What happens when blood pH rises?
Respiratory rate decreases allowing CO2 to accumulate
How do the kidneys regulate acid-base balance?
Adjusting the amount of bicarbonate in the blood
What is the role of type A intercalated cells in the kidneys?
Secrete large numbers of H+ ions to prevent acidosis
In alkalosis, what do intercalated type B cells in the collecting duct exhibit?
Net HCO3- secretion while reclaiming H+ to acidify the blood
What is the main function of phosphate in the body's buffer systems?
To act as a very effective buffer in urine and intracellular fluid
How does the respiratory center respond to raised H+ levels?
Increase respiration rate to remove more CO2 from the blood
What is the main mechanism for increasing blood pressure in hormonal regulation of GFR?
Renin-Angiotensin-Aldosterone mechanism
What is the function of aldosterone in the kidneys?
Regulates Na+ reabsorption and K+ secretion
What is the role of myogenic regulation in GFR?
Vascular smooth muscle contracts when stretched and relaxes when not stretched, affecting systemic blood pressure
What effect does norepinephrine released by sympathetic nerves have on GFR?
Causes vascular smooth muscle constriction, leading to decreased GFR
How is glucose reabsorbed in the renal tubules?
By secondary active transport, with a transport maximum reflecting the number of transport proteins available
What is the primary function of the Renin-Angiotensin-Aldosterone mechanism?
Increasing blood pressure
What is the role of osmotic forces in the renal tubules?
Regulate water reabsorption
What is the effect of aldosterone on Na+ and K+ reabsorption in the collecting ducts?
Regulates Na+ reabsorption and K+ secretion
How does the kidney contribute to the regulation of blood pressure?
By releasing renin and regulating sodium reabsorption
What is the primary function of the tubuloglomerular feedback mechanism?
Maintaining nearly constant GFR
What is the effect of ADH in the renal tubules?
Regulates water reabsorption
How is the pH of 7 maintained in the body?
Through various homeostatic mechanisms to regulate hydrogen ion concentration
Study Notes
Regulation Mechanisms of Glomerular Filtration Rate (GFR)
- Myogenic regulation: Vascular smooth muscle contracts when stretched and relaxes when not stretched, affecting systemic blood pressure and preventing glomerular blood pressure from reaching damaging levels
- Autoregulation: Kidneys maintain nearly constant GFR despite fluctuations in systemic arterial blood pressure using myogenic and tubuloglomerular feedback
- Neural regulation: Norepinephrine released by sympathetic nerves causes vascular smooth muscle constriction, increasing peripheral resistance and blood pressure, leading to decreased GFR
- Hormonal regulation: Renin-Angiotensin-Aldosterone mechanism is the main mechanism for increasing blood pressure, triggered by low BP causing granular cells to release renin
- Tubules I: Osmotic forces, counter-current exchanger, and ADH regulate water reabsorption in the proximal convoluted tubule and collecting ducts
- Tubules II: Sodium ions are actively transported and handled by the tubules, with aldosterone regulating Na+ and K+ reabsorption in the collecting ducts
- Tubules III: Glucose is reabsorbed by secondary active transport, with a transport maximum reflecting the number of transport proteins available in the renal tubules
- Endocrine function of the kidneys: Renin is released by the kidneys to raise blood pressure, while aldosterone regulates Na+ reabsorption and K+ secretion
- Acid-base balance: The pH of 7 is maintained through various homeostatic mechanisms to regulate hydrogen ion concentration in the body
Test your knowledge of the Regulation Mechanisms of Glomerular Filtration Rate (GFR) with this quiz. Explore the myogenic, autoregulatory, neural, hormonal, and tubular mechanisms involved in maintaining GFR and systemic blood pressure. Delve into the endocrine function of the kidneys and their role in acid-base balance.
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