Renal Tubular Functions, Urine Concentration and Dilution is part of the Renal Physiology section of Physiology. Practise 50 exam-style MCQs for NEET PG, FMGE, INI-CET and NEET SS, each with the correct answer and a detailed explanation.
Collecting duct principal and intercalated cells, the thick ascending limb as diluting segment, aquaporin failure in nephrogenic diabetes insipidus and medullary hyperosmolarity drive these Renal Tubular Functions, Urine Concentration and Dilution MCQs — high-yield NEET PG revision.
Normal range of urine osmolality is 50-1400 mOsm/L Reference: Ganong, 25th edition page no.686
Colleting duct is made up of two types of cell: principal cells (P cells) and intercalated cells (I cells) Reference: Ganong, 25th edition page no.672
PCT reabsorbs 67% of Nacl, water, K+ & filtered urea. 70% of calcium, 100% of glucose & amino acids, 80% of phosphate & bicarbonate. Sodium reabsorption is mainly due to Na+ - H+ antiport Another major transport protein for sodium is SGLT2. Other important sodium transporters in PCT are Na/Pi cotransporter, Na amino acid cotransporter & Na/lactate CT cotransporter. Na+-H+ antiporter is the main determinant of Na & H20 reabsorption in PCT. Na & H+ exchange is linked directly to reabsorption of HCO3- through Na+ Hco3- cotransporter at basal membrane Key Takeaway: The first part of the PCT contains Na+/K+ ATPase, Na+-glucose co-transporter (SGLT2), and Na+-H+ antiporter (NHE3), all playing crucial roles in sodium and solute reabsorption.
normal or elevated levels of ADH are present but the renal tubular segments cannot respond appropriately. This condition is referred to as nephrogenic diabetes insipidus because the abnormality resides in the kidneys. This abnormality can be due to failure of the countercurrent mechanism to form a hyperosmotic renal medullary interstitium or failure of the distal and collecting tubules and collecting ducts to respond to ADH (due to impaired function/defect in aquaporin-2 receptor or V2 receptor. In either case, large volumes of dilute urine are formed, which causes dehydration unless fluid intake is increased by the same amount as urine volume is increased.
Sodium ions are most important as far as medullary hyperosmolarity is concerned Reference: Ganong, 25th edition page no.685
Thick ascending loop of Henle - "the diluting segment" Thick ascending loop of Henle is permeable to solutes and impermeable to water Sodium, chloride and potassium moves out of the thick ascending limb through Na-K-2Cl cotransporter Because of selective movement of solutes leaving water inside fluid inside thick ascending limb becomes hypotonic to plasma Reference: Ganong,'s Review of Medical Physiology, 25th edition., ch-37, page no 684
The fluid in the descending limb of the loop of Henle becomes hypertonic because it is permeable to water It is this hypertonic fluid going to reach ascending limb of the loop of Henle Reference: Ganong, 25th edition page no.681
50% of medullary hyperosmolarity is due to urea Reference: Ganong, 25th edition page no.686
Collecting duct principal and intercalated cells, the thick ascending limb as diluting segment, aquaporin failure in nephrogenic diabetes insipidus and medullary hyperosmolarity drive these Renal Tubular Functions, Urine Concentration and Dilution MCQs — high-yield NEET PG revision.
MedLadder includes 50 curated MCQs for Renal Tubular Functions, Urine Concentration and Dilution under Physiology (Renal Physiology), covering NEET PG, FMGE, INI-CET and NEET SS preparation.
