alleryStart learning →Why is mannitol given after a head injury?
AIt blocks sodium recovery in the distal tubule
BIt replaces the plasma proteins lost in injury
CIt draws water off osmotically to cut swelling
DIt raises renal blood flow by dilating vessels
Answer & Solution
Correct answer: C. It draws water off osmotically to cut swelling
1. Mannitol is an indigestible sugar and acts as an osmotic diuretic.
2. Osmotic diuretics promote water loss by osmosis rather than by blocking a transporter.
3. That osmotic pull is used to reduce brain swelling after head injury.
4. Unrecovered glucose in poorly controlled diabetes acts as a powerful osmotic diuretic in exactly the same way.
_Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 25 "The Urinary System", section 25.9 Regulation of Fluid Volume and Composition_
Keep practising The Urinary System
Browse all The Urinary System questions for NEET PG, or explore more Physiology topics.
Related questions
How many times over is the entire blood volume filtered through the kidneys in a day?What proportion of hospitalised patients does acute kidney injury affect?What happens to the bladder in late pregnancy?What is sodium's place in determining plasma osmolarity?What is a diuretic?If no further water reabsorption happened beyond the distal tubule, roughly how much urineWhen the kidney deaminates glutamine, what does the body gain and what does it lose?Which statement describes simple diffusion in the nephron?