Ch. 25 Fluid, Electrolyte, and Acid-Base Homeostasis

Amerman3rd EditionHuman Anatomy & PhysiologyISBN: 9780138247201, 9780138247928, 9780138201814Not the one you use?Change textbook

Amerman 3rd Edition

Ch. 25 Fluid, Electrolyte, and Acid-Base Homeostasis

Problem L3.2

Chapter 25, Problem L3.2

What do you think has happened to Elise's ECF volume and osmolarity over the past 3 days? Will this lead to a change in the volume of water in the cytosol of her cells? Explain.

Verified step by step guidance

Understand the context: ECF (extracellular fluid) volume and osmolarity are influenced by factors such as fluid intake, fluid loss, and solute concentration. Cytosol volume (intracellular fluid) is affected by osmotic gradients between the ECF and ICF (intracellular fluid).

Analyze the changes in ECF volume: If Elise has experienced dehydration (e.g., due to insufficient fluid intake or excessive fluid loss), her ECF volume would decrease. Conversely, overhydration would increase ECF volume.

Analyze the changes in ECF osmolarity: Dehydration typically increases ECF osmolarity due to a higher concentration of solutes (e.g., sodium ions) relative to water. Overhydration would decrease ECF osmolarity as water dilutes the solutes.

Determine the osmotic effect on the cytosol: If ECF osmolarity increases (hypertonic ECF), water will move out of the cytosol (ICF) into the ECF, causing cells to shrink. If ECF osmolarity decreases (hypotonic ECF), water will move into the cytosol, causing cells to swell.

Conclude the relationship: Based on the changes in ECF volume and osmolarity, predict whether water movement will occur between the ECF and ICF. This movement is driven by osmosis to restore osmotic balance, directly impacting the cytosol volume in Elise's cells.

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.

Extracellular Fluid (ECF) Volume

Extracellular fluid volume refers to the total volume of fluid outside of cells, which includes interstitial fluid and plasma. Changes in ECF volume can significantly affect cellular function, as it influences the osmotic balance and the distribution of nutrients and waste products. An increase or decrease in ECF volume can result from various factors, including fluid intake, loss, or shifts due to pathological conditions.

Osmolarity

Osmolarity is a measure of the concentration of solutes in a solution, expressed as osmoles of solute per liter of solution. It plays a crucial role in determining the movement of water across cell membranes through osmosis. Changes in osmolarity can lead to shifts in water between the ECF and intracellular fluid, affecting cell volume and function.

Cellular Osmoregulation

Cellular osmoregulation is the process by which cells maintain their internal environment, particularly the balance of water and solutes. This involves mechanisms that adjust the volume of water in the cytosol in response to changes in ECF volume and osmolarity. If ECF osmolarity increases, water may move out of cells, leading to cell shrinkage, while a decrease can cause cells to swell.

Recommended video:

07:16

Osmoregulation and Nitrogenous Waste

Related Practice

Textbook Question

As a percentage of body weight, the total body water tends to be higher in ________ and lower in ________ .

a. infants; men

b. women; men

c. men; infants

d. infants; women

views

Textbook Question

A laboratory printout of arterial blood gases indicates that a patient has an increased Pco₂ , decreased pH, and normal bicarbonate ion concentration. Is this patient in acidosis or alkalosis? Is the pH disturbance respiratory or metabolic in nature? Explain your reasoning. How long do you think the patient has had this pH disturbance? (Hint: Look at the bicarbonate ion concentration. What system controls the concentration of bicarbonate ions, and how quickly does it compensate for pH disturbances?)

views

Textbook Question

A cell in a/an ________ fluid will lose water, and a cell in a/an ________ fluid will gain water.

views

Textbook Question

Ms. Johanssen is a patient in the hospital. The nurse examines her laboratory reports and notices that she has developed hyperkalemia and acidosis over the past several days. On closer examination of her medical chart, the nurse also sees that her physician recently doubled her dose of spironolactone, an aldosterone-blocking diuretic. How does this explain her laboratory findings?

views

Textbook Question

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

a. The thirst mechanism is mediated by osmoreceptors located in the cerebral cortex.

views

Textbook Question

What happens to the concentration of sodium ions in the ECF if you consume a large amount of salt without consuming any water? How will this affect the osmotic pressure of the ECF? Why could this lead to an elevation in blood pressure?

views