Textbook Question
Sylvia is suffering from severe edema in her arms and legs. Her physician prescribes a diuretic (a substance that increases the volume of urine produced). Why might this help alleviate Sylvia’s problem?
1
views
Ch. 26 The Urinary System
Martini, Nath, Bartholomew12th EditionFundamentals of Anatomy and PhysiologyISBN: 9780137854011
Not the one you use?Change textbookSelect a different textbook
Table of contents
- Ch. 1 An Introduction to Anatomy and Physiology25
- Ch. 2 The Chemical Level of Organization34
- Ch. 3 The Cellular Level of Organization29
- Ch. 4 The Tissue Level of Organization24
- Ch. 5 The Integumentary System17
- Ch. 6 Bones and Bone Structure33
- Ch. 7 The Axial Skeleton11
- Ch. 8 The Appendicular Skeleton17
- Ch. 9 Joints13
- Ch. 10 Muscle Tissue12
- Ch. 11 The Muscular System28
- Ch. 12 Nervous Tissue18
- Ch. 13 The Spinal Cord, Spinal Nerves, and Spinal Reflexes22
- Ch. 14 The Brain and Cranial Nerves20
- Ch. 15 Sensory Pathways and the Somatic Nervous System17
- Ch. 16 The Autonomic Nervous System and Higher-Order Functions30
- Ch. 17 The Special Senses15
- Ch. 18 The Endocrine System21
- Ch. 19 Blood31
- Ch. 20 The Heart31
- Ch. 21 Blood Vessels and Circulation26
- Ch. 22 The Lymphatic System and Immunity25
- Ch. 23 The Respiratory System4
- Ch. 24 The Digestive System18
- Ch. 26 The Urinary System31
- Ch. 27 Fluids & Electrolytes30
- Ch. 28 The Reproductive System12
- Ch. 29 Development and Inheritance17
Martini, Nath, Bartholomew12th EditionFundamentals of Anatomy and PhysiologyISBN: 9780137854011Not the one you use?Change textbook
Chapter 25, Problem 30
Mannitol is a sugar that is filtered, but not reabsorbed, by the kidneys. What effect would drinking a solution of mannitol have on the volume of urine produced?
Verified step by step guidance1
Understand the role of mannitol in the kidneys: Mannitol is filtered by the glomerulus but is not reabsorbed in the renal tubules, meaning it remains in the tubular fluid.
Recall that substances remaining in the tubular fluid increase its osmolarity, which affects water reabsorption by osmosis.
Since mannitol stays in the tubules, it creates an osmotic gradient that prevents water from being reabsorbed back into the bloodstream, leading to more water remaining in the urine.
This osmotic effect causes an increase in urine volume, a process known as osmotic diuresis.
Therefore, drinking a mannitol solution would increase the volume of urine produced by reducing water reabsorption in the kidneys.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Glomerular Filtration
Glomerular filtration is the process by which blood plasma is filtered through the glomeruli in the kidneys, allowing water and small molecules like mannitol to pass into the renal tubules while retaining larger molecules and cells in the bloodstream.
Recommended video:
3:15
Glomerular Filtration Rate
Tubular Reabsorption
Tubular reabsorption is the process where substances filtered into the renal tubules are selectively reabsorbed back into the bloodstream. Since mannitol is not reabsorbed, it remains in the tubules, affecting water movement.
Recommended video:
4:06Introduction to Tubular Reabsorption
Osmotic Diuresis
Osmotic diuresis occurs when non-reabsorbed solutes like mannitol increase the osmolarity of the tubular fluid, preventing water reabsorption and leading to increased urine volume as water follows the solute into the urine.
Recommended video:
1:01Renal Physiology Step 2: Tubular Reabsorption Example 3
Related Practice
Textbook Question
The drug Diamox is sometimes used to treat mountain sickness. Diamox inhibits the action of carbonic anhydrase in the proximal convoluted tubule. Polyuria (excessive urine production resulting in frequent urination) is a side effect associated with the medication. Why does polyuria occur?
1
views
Textbook Question
David’s grandfather suffers from hypertension. His doctor tells him that part of his problem stems from renal arteriosclerosis. Why would this cause hypertension?
1
views
Textbook Question
In response to excess water in the body,
(a) Antidiuretic hormone is secreted by the anterior lobe of the pituitary gland.
(b) The active transport mechanisms in the ascending thick limb of the nephron loop cease functioning.
(c) The permeability of the distal convoluted tubules and collecting ducts to water is decreased.
(d) The permeability of the ascending limb of the nephron loop is increased.
(e) The glomerular filtration rate is reduced.
1
views