Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

26. Fluid and Electrolyte Balance, Acid Base Balance

Fluid Balance

Anatomy & Physiology

26. Fluid and Electrolyte Balance, Acid Base Balance

Fluid Balance

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Problem L3.2

Textbook Question

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.

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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.