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Questions and Answers
What is one of the primary functions of the proximal tubule?
What is one of the primary functions of the proximal tubule?
- Regulation of blood pH
- Reabsorption of ions and organic molecules (correct)
- Secretion of waste
- Filtration of blood cells
What characteristic feature does blood flow through the kidney exhibit?
What characteristic feature does blood flow through the kidney exhibit?
- Celiac circulation pattern
- Arterial system
- Countercurrent exchange
- Portal system (correct)
Which structure is included in the renal corpuscle?
Which structure is included in the renal corpuscle?
- Glomerulus (correct)
- Distal tubule
- Vasa recta
- Proximal tubule
What happens to the glomerular filtration rate (GFR) and blood pressure when cysts press on nephrons?
What happens to the glomerular filtration rate (GFR) and blood pressure when cysts press on nephrons?
Which ion is NOT directly regulated by the kidney?
Which ion is NOT directly regulated by the kidney?
Which segment of the nephron is responsible for looping down into the medulla and returning to the cortex?
Which segment of the nephron is responsible for looping down into the medulla and returning to the cortex?
What causes the characteristic yellow color of urine?
What causes the characteristic yellow color of urine?
What is the nature of the filtration process in the kidney?
What is the nature of the filtration process in the kidney?
Which barrier is NOT part of the kidney filtration barrier?
Which barrier is NOT part of the kidney filtration barrier?
Which factor is the force for glomerular filtration?
Which factor is the force for glomerular filtration?
What process involves actively transporting substances from the peritubular capillaries into the tubules?
What process involves actively transporting substances from the peritubular capillaries into the tubules?
Which substances are reabsorbed via symport with sodium?
Which substances are reabsorbed via symport with sodium?
What triggers vasoconstriction in the afferent arterioles when blood flow increases?
What triggers vasoconstriction in the afferent arterioles when blood flow increases?
What is the effect of an obstruction in a glomerulus?
What is the effect of an obstruction in a glomerulus?
What substance can diffuse freely through open leak channels if a concentration gradient is present?
What substance can diffuse freely through open leak channels if a concentration gradient is present?
What is the net glomerular filtration pressure given a glomerular hydraulic pressure of 69 mm Hg and a fluid pressure in the Bowman's capsule of 15 mm Hg with plasma osmotic pressure at 30 mm Hg?
What is the net glomerular filtration pressure given a glomerular hydraulic pressure of 69 mm Hg and a fluid pressure in the Bowman's capsule of 15 mm Hg with plasma osmotic pressure at 30 mm Hg?
In a normal kidney, what condition would increase the glomerular filtration rate (GFR)?
In a normal kidney, what condition would increase the glomerular filtration rate (GFR)?
What role do the macula densa cells play in autoregulation?
What role do the macula densa cells play in autoregulation?
What is the main mechanism described for Na+-dependent transport in renal absorption?
What is the main mechanism described for Na+-dependent transport in renal absorption?
Which part of the nephron is primarily affected first by damage to the renal medulla?
Which part of the nephron is primarily affected first by damage to the renal medulla?
Flashcards
What is the primary function of the kidneys?
What is the primary function of the kidneys?
The process of removing waste products from the blood and producing urine.
How do kidneys contribute to ion balance?
How do kidneys contribute to ion balance?
The kidneys maintain a stable balance of important ions in the body's fluids.
How do kidneys regulate blood osmolarity?
How do kidneys regulate blood osmolarity?
The kidneys regulate the amount of water in the blood, ensuring optimal blood osmolarity.
How do kidneys help regulate extracellular fluid volume?
How do kidneys help regulate extracellular fluid volume?
The kidneys adjust the volume of extracellular fluid, ensuring proper fluid balance within the body.
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What is a glomerulus?
What is a glomerulus?
A network of capillaries within the Bowman's capsule where filtration occurs.
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What drives glomerular filtration?
What drives glomerular filtration?
The primary force driving filtration in the glomerulus is the pressure of blood within the glomerular capillaries.
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What is typically found in the filtrate?
What is typically found in the filtrate?
The fluid that enters the nephron from the glomerulus contains various substances, but blood cells and plasma proteins are usually not filtered.
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What is the function of the proximal tubule?
What is the function of the proximal tubule?
The proximal tubule plays a crucial role in reabsorbing water, ions, and organic molecules from the filtrate back into the bloodstream.
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What is the function of the loop of Henle?
What is the function of the loop of Henle?
The loop of Henle, a hairpin-shaped structure in the nephron, contributes to the concentration of urine by regulating the movement of water and ions.
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What is the function of the distal tubule?
What is the function of the distal tubule?
The distal tubule, located after the loop of Henle, further fine-tunes the composition of urine by reabsorbing or secreting specific substances.
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Tubular Secretion
Tubular Secretion
The movement of substances from the peritubular capillaries into the tubules of the nephron, contributing to urine formation.
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Symport with Sodium
Symport with Sodium
Glucose and amino acids are transported across the epithelial cells of the proximal tubule using a protein that binds both the nutrient and sodium ions, facilitating their movement into the bloodstream.
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Renal Autoregulation
Renal Autoregulation
The kidney's ability to maintain a stable glomerular filtration rate (GFR) despite variations in blood pressure.
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Myogenic Response
Myogenic Response
A mechanism where specialized cells in the kidney detect changes in blood pressure and trigger vasoconstriction of the afferent arteriole to maintain stable filtration.
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Tubuloglomerular Feedback
Tubuloglomerular Feedback
A feedback loop where changes in the concentration of substances in the tubule influence filtration rate by affecting the afferent arteriole.
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Excretion and Plasma Concentration Relation
Excretion and Plasma Concentration Relation
When the concentration of a substance in the blood is higher than in the tubules, more of that substance will be excreted in the urine.
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Renal Medulla Damage
Renal Medulla Damage
The collecting ducts are the first structures to be affected when the renal medulla, the inner part of the kidney, is damaged.
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Obstruction in Glomerulus
Obstruction in Glomerulus
An obstruction in a glomerulus would hinder blood flow into the efferent arteriole, which carries blood away from the glomerulus.
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Stretch Reflex in Afferent Arterioles
Stretch Reflex in Afferent Arterioles
An increase in blood flow through the afferent arterioles triggers a stretch reflex, resulting in vasoconstriction to decrease blood flow and maintain stable filtration.
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Urea Reabsorption
Urea Reabsorption
Urea passively moves from the proximal tubule into the blood by following its concentration gradient.
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Kidney Function and Structure
- Kidneys maintain ion balance, blood pH, osmolarity, and extracellular fluid volume.
- Regulated ions include Na+, HCO3-, K+, and Ca2+.
- Urine's yellow color is from urobilinogen.
- Urine is produced by the kidneys and transported to the bladder via ureters.
- Kidneys lie behind the peritoneal membrane.
- Kidney blood flow includes a unique portal system.
- Structures in kidney blood circulation: renal corpuscle, vasa recta, and glomerulus.
- Renal corpuscle is made of Bowman's capsule and glomerulus.
- Secretion is active and energy-dependent.
- Glomerulus: a capillary "knot" in Bowman's capsule.
- Proximal tubule is closest to the renal corpuscle in the nephron.
- Distal tubule connects to the collecting duct in the nephron.
- Loop of Henle is the hairpin-shaped segment of the nephron.
- Loop of Henle descends into the medulla then returns to the cortex.
- Kidney filtration is relatively nonspecific.
- Filtrate normally contains urobilinogen, potassium, and glucose.
Glomerular Filtration
- Cysts on the kidney can raise nephron pressure, decreasing GFR and increasing blood pressure.
- Approximately 1/5 of plasma volume filters into the nephrons.
- Blood cells and plasma proteins aren't normally filtered.
- Filtration barrier consists of Bowman's capsule epithelium, basal lamina, and glomerular capillary endothelium.
- Glomerular filtration pressure is based on blood pressure in glomerular capillaries.
- The proximal tubule primarily reabsorbs ions, organic molecules, and water.
- Secretion actively transports substances from the peritubular capillaries into proximal and distal tubules.
- Glucose and amino acids are reabsorbed via Na+ symport.
Autoregulation and Feedback
- Autoregulation is a mechanism that maintains a constant GFR.
- Myogenic response: smooth muscle in afferent arterioles constricts in response to stretch.
- Tubuloglomerular feedback: macula densa cells signal the afferent arteriole in response to filtrate concentration.
- Myogenic response is paracrine signaling.
- Substances are excreted when plasma concentration exceeds renal concentration.
- Collecting duct function is affected first by renal medulla damage.
- Glomerulus obstruction affects blood flow into the efferent arteriole.
- Increased afferent arteriole blood flow triggers vasoconstriction.
- Urea is passively absorbed in the proximal tubule.
- Na+-dependent transport often involves apical symport proteins and basolateral facilitated diffusion carriers.
Urea and Filtration Pressure
- Urea diffuses freely through channels as Na+ transport creates a water gradient.
- Glomerular hydraulic pressure (69 mm Hg), Bowman's capsule fluid pressure (15 mm Hg), and plasma osmotic pressure (30 mm Hg) determine net GFR (24 mm Hg).
- Decreasing plasma protein concentration increases GFR.
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