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Difficulty: MediumExcretion and Excretory Organs

Match each mammalian nephron region on the left with its primary physiological function during urine formation on the right.

  • GlomerulusUltrafiltration of blood plasma under high hydrostatic pressure
  • Proximal convoluted tubuleSelective reabsorption of glucose, amino acids, and the bulk of filtrate water
  • Loop of HenleEstablishment of an osmotic medullary gradient for urine concentration
  • Distal convoluted tubuleHormone-regulated reabsorption of sodium and selective tubular secretion of potassium and hydrogen ions

Answer

Glomerulus matches with Ultrafiltration under high hydrostatic pressure; Proximal convoluted tubule matches with Selective reabsorption of glucose, amino acids, and bulk filtrate water; Loop of Henle matches with Establishment of an osmotic medullary gradient; Distal convoluted tubule matches with Hormone-regulated reabsorption of sodium and selective tubular secretion.
Each nephron section performs a distinct step in urine formation: the glomerulus filters blood plasma under pressure; the proximal convoluted tubule reabsorbs vital solutes like glucose; the Loop of Henle generates the medullary osmotic gradient; and the distal convoluted tubule carries out selective secretion and hormone-controlled electrolyte tuning.

Step-by-Step Solution

1
Identify the primary function of the renal corpuscle/glomerulus
High blood pressure forces water and dissolved solutes out of capillaries into Bowman's capsule (ultrafiltration).
Afferent arteriole diameter is larger than efferent arteriole diameter, creating hydrostatic filtration pressure.
2
Determine the main process occurring in the proximal convoluted tubule
Obligatory reabsorption of 100% glucose, amino acids, and ~65-70% of salts and water occurs here.
Epithelial lining has a microvillar brush border that maximizes surface area for active transport.
3
Identify the role of the hair-pin shaped Loop of Henle
Creates a hyperosmolal gradient in the renal medulla via countercurrent multiplication.
Descending limb is permeable to water, while ascending limb actively pumps out sodium and chloride ions.
4
Determine the functional role of the distal convoluted tubule
Fine-tunes electrolyte balance via active secretion of ions (K+K^+, H+H^+) and aldosterone-stimulated Na+Na^+ absorption.
Target region for hormonal regulation to maintain systemic pH and blood volume balance.

Key Concept

Nephron functional anatomy and urine formation processes
Estimated Time:1m 15s
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Topics

Excretion and Excretory Organs

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