Renal Physiology: Nephron Structure and Function

Questions and Answers

What is the primary function of the proximal tubule in the nephron?

Reabsorption of glucose and salts (correct)

Concentration of urine

Secretion of hydrogen ions

Filtration of blood plasma

Which structure is located in the cortex of the kidney?

Proximal tubule (correct)

Distal tubule (correct)

Collecting duct

Medulla

In which part of the nephron does the secretion of hydrogen ions primarily occur?

Loop of Henle

Distal tubule (correct)

Bowman's capsule

Proximal tubule

What is the role of glomeruli in kidney function?

Filtration of blood to form urine Signup and view all the answers

Which ion is primarily involved in the secretion process occurring in the distal tubule?

Hydrogen Signup and view all the answers

Salts are primarily reabsorbed in which section of the nephron?

Proximal tubule Signup and view all the answers

What is the primary function of the nephron in the kidney?

To act as the major functional unit for filtration of blood Signup and view all the answers

Which of the following substances is NOT typically included in the glomerular filtrate?

Red blood cells Signup and view all the answers

What does the nephron filter on average per minute?

120 ml Signup and view all the answers

Which component of the nephron is responsible for filtration of plasma?

Glomerulus Signup and view all the answers

Which statement is true regarding the selectivity of the nephron's filtration process?

It selectively filters substances of less than 70,000 MW. Signup and view all the answers

How many nephrons does an average human kidney contain?

1 million Signup and view all the answers

What substances comprise the glomerular filtrate?

Water, glucose, electrolytes, amino acids, and urea Signup and view all the answers

Which of the following best describes the loop of Henle?

A segment that plays a critical role in the concentration of urine Signup and view all the answers

What is the primary function of the proximal tubule in relation to sodium?

Reabsorbs sodium ions and bicarbonate while secreting drugs Signup and view all the answers

Which of the following correctly describes the role of the descending loop of Henle?

Reabsorbs water but not solutes Signup and view all the answers

What is the threshold level for glucose reabsorption in the proximal tubule?

160-180 mg/di Signup and view all the answers

What is the main function of the distal and collecting tubules?

Reabsorbs sodium and secretes potassium ions Signup and view all the answers

What condition is indicated by polyuria?

Excessive production of urine over 2500 ml/day Signup and view all the answers

During which phase does the ascending loop of Henle reabsorb solutes without reabsorbing any water?

Upward phase of the loop Signup and view all the answers

Which substances are primarily reabsorbed by the proximal tubule?

Sodium, bicarbonate, and amino acids Signup and view all the answers

What effect do diuretics have on urine volume?

Inhibit sodium reabsorption to increase urine output Signup and view all the answers

Study Notes

Renal Physiology

Nephron is the major functional unit of the kidney, with approximately 1 million nephrons per kidney.
Composed of glomerulus and renal tubules, and acts as a non-selective filter for plasma substances under 70,000 MW.
Glomerular filtrate includes water, glucose, electrolytes, amino acids, urea, uric acid, creatinine, and ammonia.
Filters approximately 120 ml/min, which is about one-fifth of renal plasma.

Nephron Structure and Function

Glomerulus: A coil of capillary vessels where filtration occurs.
Proximal Tubule:
- Reabsorbs water, sodium chloride, bicarbonate, potassium, calcium, amino acids, phosphates, protein, and glucose.
- Glucose threshold for reabsorption is 160-180 mg/dL.
- Secretes sulfates, glucuronides, hydrogen ions, and drugs.
Loop of Henle:
- Descending limb: Reabsorbs water; solutes are not reabsorbed.
- Ascending limb: Reabsorbs solutes (sodium, chloride, calcium, magnesium); water is not reabsorbed.
Distal and Collecting Tubules:
- Reabsorbs sodium and secretes potassium, ammonia, and hydrogen ions, with potassium ions exchanged for sodium ions.

Urine Volume

Normal Volume: Average of 1200-1500 ml/day.
Polyuria: Exceeds 2500 ml/day; can be caused by diabetes insipidus, diabetes mellitus, use of diuretics, caffeine, alcohol, or excessive water intake.
Oliguria: Defined but specific causes not provided in the text.

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Description

This quiz explores the fundamentals of renal physiology, focusing on the nephron as the kidney's major functional unit. It covers the structure and functions of the glomerulus, proximal tubule, and loop of Henle, as well as their roles in filtration and reabsorption processes. Test your understanding of kidney function and the importance of these structures.