Textbook Question
Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
a. Potassium ions are responsible for the repolarization phase of the action potential.
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Ch. 25 Fluid, Electrolyte, and Acid-Base Homeostasis
Amerman3rd EditionHuman Anatomy & PhysiologyISBN: 9780138247201, 9780138247928, 9780138201814
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Table of contents
- Ch. 1 Introduction to Anatomy and Physiology24
- Ch. 2 The Chemistry of Life37
- Ch. 3 The Cell54
- Ch. 4 Histology46
- Ch. 5 The Integumentary System30
- Ch. 6 Bones and Bone Tissue36
- Ch. 7 The Skeletal System40
- Ch. 8 Articulations19
- Ch. 9 The Muscular System35
- Ch. 10 Muscle Tissue and Physiology29
- Ch. 11 Introduction to the Nervous System and Nervous Tissue28
- Ch. 12 The Central Nervous System41
- Ch. 13 The Peripheral Nervous System41
- Ch. 14 The Autonomic Nervous System and Homeostasis31
- Ch. 15 The Special Senses39
- Ch. 16 The Endocrine System42
- Ch. 17 The Cardiovascular System I: The Heart28
- Ch. 18 The Cardiovascular System II: The Blood Vessels43
- Ch. 19 Blood32
- Ch. 20 The Lymphatic System and Immunity41
- Ch. 21 The Respiratory System27
- Ch. 22 The Digestive System27
- Ch. 23 Metabolism and Nutrition7
- Ch. 24 The Urinary System39
- Ch. 25 Fluid, Electrolyte, and Acid-Base Homeostasis39
- Ch. 26 The Reproductive System10
- Ch. 27 Development and Heredity5
Amerman3rd EditionHuman Anatomy & PhysiologyISBN: 9780138247201, 9780138247928, 9780138201814Not the one you use?Change textbook
Chapter 25, Problem 9
Which of the following effects tend to be caused by hypernatremia?
a. Inhibition of ADH secretion
b. Cellular crenation
c. Cellular swelling
d. Increased urine production
Verified step by step guidance1
Understand the term 'hypernatremia': Hypernatremia refers to an elevated concentration of sodium (Na⁺) in the blood, typically above 145 mEq/L. This condition often results from dehydration, excessive sodium intake, or loss of water relative to sodium.
Review the physiological effects of hypernatremia: High sodium levels in the extracellular fluid (ECF) create a hypertonic environment, which can cause water to move out of cells by osmosis, leading to cellular shrinkage (crenation).
Analyze the role of ADH (antidiuretic hormone): ADH is secreted to conserve water in the body. Hypernatremia typically stimulates ADH secretion to promote water reabsorption in the kidneys, counteracting the high sodium concentration. Therefore, inhibition of ADH secretion is unlikely.
Evaluate the options: Cellular swelling (option c) occurs in hypotonic conditions, not hypertonic conditions like hypernatremia. Increased urine production (option d) is also unlikely, as the body would aim to conserve water in response to hypernatremia.
Conclude the most likely effect: Cellular crenation (option b) is the most plausible effect of hypernatremia, as water moves out of cells into the hypertonic extracellular environment, causing the cells to shrink.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Hypernatremia
Hypernatremia is a condition characterized by an elevated concentration of sodium in the blood, typically above 145 mEq/L. It often results from dehydration, excessive sodium intake, or impaired kidney function. Understanding hypernatremia is crucial as it can lead to various physiological effects, particularly on fluid balance and cellular function.
Osmosis and Cellular Effects
Osmosis is the movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. In the context of hypernatremia, the high sodium levels in the extracellular fluid can cause water to move out of cells, leading to cellular crenation (shrinking). This concept is essential for understanding the physiological consequences of hypernatremia on cell health.
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Antidiuretic Hormone (ADH)
Antidiuretic hormone (ADH), also known as vasopressin, regulates water balance in the body by promoting water reabsorption in the kidneys. In cases of hypernatremia, the body may initially respond by inhibiting ADH secretion to reduce water retention, which can lead to increased urine production. Understanding the role of ADH is vital for grasping how the body attempts to correct imbalances in sodium and water.
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Related Practice
Textbook Question
Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
c. Hyperkalemia tends to decrease the resting membrane potential and hyperpolarize excitable cells.
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Textbook Question
Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
e. Dehydration is characterized by a decreased volume and increased osmolarity of the ECF.
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Textbook Question
Which of the following statements best describes the principle of mass balance?
a. The amount of a variable that is gained by the body through ingestion equals the amount that is lost from the body.
b. The body maintains a stable mass at all times.
c. The amount of each variable brought into the body must be balanced by all other variables.
d. The amount of a variable ingested is regulated by a positive feedback loop.
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Textbook Question
Which of the following is false with respect to sodium ions in human physiology?
a. Sodium ions are the most abundant extracellular cation.
b. Sodium ions are an important osmotic particle in the ECF.
c. The entry of sodium ions into a cell causes depolarization.
d. Sodium ions are more concentrated in the cytosol than in the ECF.
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Textbook Question
Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
b. Insulin, aldosterone, and epinephrine stimulate the uptake of potassium ions into cells.
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