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 27

Textbook Question

Dan has been lost in the desert for 2 days with very little water. As a result of this exposure, you would expect to observe which of the following?
(a) Increased ADH levels
(b) Decreased blood osmolarity
(c) Normal urine production
(d) Increased blood volume
(e) Cells enlarged with fluid

Verified step by step guidance

Understand the physiological context: Dan has been in the desert for 2 days with very little water, which means his body is likely experiencing dehydration. Dehydration triggers specific responses in the body to conserve water and maintain homeostasis.

Review the role of antidiuretic hormone (ADH): ADH is released by the posterior pituitary gland in response to increased blood osmolarity (concentration of solutes in the blood). Its primary function is to promote water reabsorption in the kidneys, reducing urine output and helping to restore fluid balance.

Analyze blood osmolarity: Dehydration leads to a decrease in water content in the blood, which increases blood osmolarity. This triggers the release of ADH to counteract the imbalance. Therefore, decreased blood osmolarity (option b) would not be expected in this scenario.

Evaluate urine production: Normal urine production (option c) is unlikely during dehydration because the kidneys will conserve water under the influence of ADH, leading to reduced urine output.

Assess blood volume and cell size: Dehydration typically results in decreased blood volume (not increased, as in option d) due to fluid loss. Additionally, cells shrink rather than enlarge (option e) because water moves out of the cells into the extracellular space to balance osmolarity.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Antidiuretic Hormone (ADH)

Antidiuretic Hormone (ADH), also known as vasopressin, is a hormone produced by the hypothalamus and released by the posterior pituitary gland. It plays a crucial role in regulating water balance in the body by promoting water reabsorption in the kidneys. In situations of dehydration, such as being lost in the desert, ADH levels increase to conserve water, leading to concentrated urine and reduced urine output.

Blood Osmolarity

Blood osmolarity refers to the concentration of solutes in the blood, which affects the movement of water between compartments in the body. When a person is dehydrated, the osmolarity of the blood increases due to a higher concentration of solutes, such as sodium. This increase triggers the release of ADH to help retain water and restore balance, making it unlikely for blood osmolarity to decrease in this scenario.

Urine Production

Urine production is the process by which the kidneys filter blood to remove waste and excess substances, resulting in urine. In conditions of dehydration, the body aims to conserve water, leading to decreased urine output. This is a physiological response to maintain fluid balance, and thus, one would expect urine production to be lower rather than normal in Dan's situation after two days without adequate water.

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Textbook Question

Drinking a solution hypotonic to the ECF causes the ECF to:

(a) Increase in volume and become hypertonic to the ICF

(b) Decrease in volume and become hypertonic to the ICF

(d) Increase in volume and become hypotonic to the ICF

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Textbook Question

What are fluid shifts? What is their function, and what factors can cause them?

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Textbook Question

Osmoreceptors in the hypothalamus monitor the osmotic concentration of the ECF and secrete _______ in response to higher osmotic concentrations.

(a) BNP

(b) ANP

(d) ADH

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Textbook Question

Identify four hormones that mediate major physiological adjustments affecting fluid and electrolyte balance. What are the primary effects of each hormone?

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Textbook Question

Yuka is dehydrated, so her physician prescribes intravenous fluids. The attending nurse becomes distracted and erroneously gives Yuka a hypertonic glucose solution instead of normal saline. What effect will this mistake have on Yuka’s plasma ADH levels and urine volume?

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Textbook Question

Effects of aldosterone include:

a. Increase in sodium ion excretion

b. Increase in water retention

c. Increase in potassium ion concentration in the urine

d. Higher blood pressure

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Textbook Question

Low blood pressure detected by the cells in the green box directly stimulates the release of:

a. Aldosterone

b. Renin