Chapter 9: Fluid and Electrolyte Balance
Student Learning Outcomes
1. List and explain the functions of water in the body.
2. Describe the control mechanisms that regulate water intake and output.
3. Identify recommended intakes and sources of water.
4. Describe the health consequences of dehydration.
5. List four minerals that function as electrolytes.
6. Describe how electrolytes control fluid balance, acid-base balance, and nerve impulse
transmission.
7. List dietary sources and daily requirements of the electrolyte minerals.
8. Outline dietary modifications and other lifestyle strategies to lower blood pressure.
Fact Check: Is it healthy to drink a gallon of water per day?
One gallon of water per day is significantly more than the Adequate Intake (AI) of water for
adults.
For most people, one gallon of water consumed throughout the day is not enough to be
dangerous, but it will certainly increase your urine production!
Section 9.1 Concepts: Water: Essential to Human Life
1. Why is it significant that water is the universal solvent?
2. Describe how water regulates body temperature.
3. Provide two examples of water’s role as a lubricant.
Water Is Essential to Human Life
H2O= 2 molecules of Hydrogen + 1 Oxygen
Every cell, tissue, and organ contains some water
Comprises 50% to 70% of human body
Water is often called the universal solvent because so many different solutes can be dissolved
in it
● This property of water makes it:
○ An ideal transport vehicle for nutrients and wastes
○ A medium for many chemical reactions of human metabolism
Water Percentages in Body Components
Muscle: 73% water
Adipose Tissue: 10% to 20% water
Bone: Approximately 20% water
Human Body: 50% to 70% water
As body fat content increases
● % of lean tissue decreases and total body water decreases
Extremely lean athletes: 70% body water
Water Is the Universal Solvent
Universal solvent
, ● Dissolves substances in the body
Water transports nutrients and wastes.
Primary component of blood and lymph
Primary medium for chemical reactions
● Result in metabolic water
Water Transports Nutrients and Wastes
Majority of the nutrients we consume-carbohydrates, proteins, minerals, and many vitamins-are
water soluble.
Lipids are not soluble in water.
● Surrounded by a layer of phospolipids and protein
● Dispersed throughout the water-based environment within cells and around tissues
Nutrient metabolism generates some waste products, most of which are dissolved in water and
exit the body as urine.
● Metabolic water (one cup or more per day) contributes to the maintenance of fluid
balance in the body
Protein Breakdown:
● Nitrogen: Part of protein that cannot be used for energy-has to be excreted as urea.
● Excess protein intake requires increase in water intake
Sodium:
Excess sodium consumption leads to increased sodium excretion in urine.
Urine output
● (1 to 2L per day)
Depends on intake of fluid, protein, and sodium
Water Contributes to Body Temperature Regulation
Body holds head efficiently
50% to 70% water
Requires a lot of energy to change body temperature
Macronutrients:
Energy released
60% becomes heat
40% is used by cells
When overheated:
● Body secreates fluid: perspiration
● Evaporates through skin pores
● Heat energy is released
● Body is cooled
● 1L of evaporated perspiration equals 600 kcal of lost heat
Water Moistens, Lubricates, and Cushions
Saliva
● Helps food pass from esophagus to stomach
Mucus
Student Learning Outcomes
1. List and explain the functions of water in the body.
2. Describe the control mechanisms that regulate water intake and output.
3. Identify recommended intakes and sources of water.
4. Describe the health consequences of dehydration.
5. List four minerals that function as electrolytes.
6. Describe how electrolytes control fluid balance, acid-base balance, and nerve impulse
transmission.
7. List dietary sources and daily requirements of the electrolyte minerals.
8. Outline dietary modifications and other lifestyle strategies to lower blood pressure.
Fact Check: Is it healthy to drink a gallon of water per day?
One gallon of water per day is significantly more than the Adequate Intake (AI) of water for
adults.
For most people, one gallon of water consumed throughout the day is not enough to be
dangerous, but it will certainly increase your urine production!
Section 9.1 Concepts: Water: Essential to Human Life
1. Why is it significant that water is the universal solvent?
2. Describe how water regulates body temperature.
3. Provide two examples of water’s role as a lubricant.
Water Is Essential to Human Life
H2O= 2 molecules of Hydrogen + 1 Oxygen
Every cell, tissue, and organ contains some water
Comprises 50% to 70% of human body
Water is often called the universal solvent because so many different solutes can be dissolved
in it
● This property of water makes it:
○ An ideal transport vehicle for nutrients and wastes
○ A medium for many chemical reactions of human metabolism
Water Percentages in Body Components
Muscle: 73% water
Adipose Tissue: 10% to 20% water
Bone: Approximately 20% water
Human Body: 50% to 70% water
As body fat content increases
● % of lean tissue decreases and total body water decreases
Extremely lean athletes: 70% body water
Water Is the Universal Solvent
Universal solvent
, ● Dissolves substances in the body
Water transports nutrients and wastes.
Primary component of blood and lymph
Primary medium for chemical reactions
● Result in metabolic water
Water Transports Nutrients and Wastes
Majority of the nutrients we consume-carbohydrates, proteins, minerals, and many vitamins-are
water soluble.
Lipids are not soluble in water.
● Surrounded by a layer of phospolipids and protein
● Dispersed throughout the water-based environment within cells and around tissues
Nutrient metabolism generates some waste products, most of which are dissolved in water and
exit the body as urine.
● Metabolic water (one cup or more per day) contributes to the maintenance of fluid
balance in the body
Protein Breakdown:
● Nitrogen: Part of protein that cannot be used for energy-has to be excreted as urea.
● Excess protein intake requires increase in water intake
Sodium:
Excess sodium consumption leads to increased sodium excretion in urine.
Urine output
● (1 to 2L per day)
Depends on intake of fluid, protein, and sodium
Water Contributes to Body Temperature Regulation
Body holds head efficiently
50% to 70% water
Requires a lot of energy to change body temperature
Macronutrients:
Energy released
60% becomes heat
40% is used by cells
When overheated:
● Body secreates fluid: perspiration
● Evaporates through skin pores
● Heat energy is released
● Body is cooled
● 1L of evaporated perspiration equals 600 kcal of lost heat
Water Moistens, Lubricates, and Cushions
Saliva
● Helps food pass from esophagus to stomach
Mucus
