What is the main function of the counter-current mechanism in the kidney?

• Filtration

• Excretion of urea

• Formation of concentrated urine

• Buffer regulation

Which part of nephron is responsible for creating the medullary gradient?

• Proximal tubule

• Distal tubule

• Loop of Henle

• Collecting duct

Which hormone plays a key role in water reabsorption in the collecting duct?

• Aldosterone

• Renin

• ADH

• Erythropoietin

Which of the following is NOT a function of the kidney?

• Erythropoietin secretion

• Filtration of blood

• Vitamin D synthesis

• Insulin secretion

What is the full form of JGA?

• Juxtaglomerular artery

• Juxtaglomerular apparatus

• Juxtamedullary apparatus

• Jugular glandular apparatus

Which cells secrete renin in the JG apparatus?

• Mesangial cells

• Macula densa

• Juxtaglomerular cells

• Podocytes

Macula densa senses the concentration of?

• Urea

• Potassium

• Sodium chloride

• Creatinine

Which part of nephron contains the macula densa?

• Proximal tubule

• Distal tubule

• Thick ascending limb

• Loop of Henle

What is the main difference between cortical and juxtamedullary nephrons?

• Length of loop of Henle

• Number of nephrons

• Glomerular location

• Size of glomerulus

Juxtamedullary nephrons are primarily responsible for?

• Filtration

• Acid-base balance

• Urine dilution

• Concentrated urine formation