Body Water Composition and Functions

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Questions and Answers

What prompts the movement of water during osmosis?

Water flows equally in both directions.

Water moves toward areas with higher solute concentration. (correct)

Water moves toward areas with lower solute concentration.

Water moves randomly across a membrane.

How should fluid intake be managed during exercise lasting more than one hour?

Electrolytes alone should be consumed.

No additional fluids are necessary.

Water and a carbohydrate solution should be consumed. (correct)

Only water should be consumed.

What happens to vegetables that are sprinkled with salt?

They absorb more water from the soil.

They retain their moisture and do not change.

They become firmer as water moves into them.

They release water due to osmosis toward the higher salt concentration. (correct)

What is the purpose of consuming electrolytes during intense or prolonged exercise?

To balance the water lost through sweat. Signup and view all the answers

What role does the hypothalamus play in regulating water intake?

It monitors blood concentration of water and solutes. Signup and view all the answers

Which of the following groups should notably increase their water intake?

Athletes exercising in high heat and humidity. Signup and view all the answers

What is the best indicator of dehydration?

Darker urine color. Signup and view all the answers

What triggers the sensation of thirst?

High concentration of solutes in the blood. Signup and view all the answers

Which physiological process is NOT directly involved in regulating fluid intake?

Increased urine output. Signup and view all the answers

Why might infants require more water than adults?

Their cells are increasing in size. Signup and view all the answers

Dehydration can lead to which of the following symptoms?

Dizziness and muscle cramps. Signup and view all the answers

Which dietary factor significantly influences the need for increased water intake?

High protein consumption. Signup and view all the answers

When is dehydration most likely to occur?

Before one feels thirsty. Signup and view all the answers

What is the daily recommended intake of water for females?

2.7 liters. Signup and view all the answers

What can excessive water consumption potentially lead to?

Heart attack or organ failure Signup and view all the answers

Which of the following is primarily involved in maintaining electrolyte balance?

Water intake Signup and view all the answers

Which statement about the pH scale is true?

The pH scale ranges from 0 to 14. Signup and view all the answers

Which ion is considered the main intracellular cation?

Potassium (K+) Signup and view all the answers

What is the result of mixing hydrochloric acid (HCl) and sodium hydroxide (NaOH)?

Sodium chloride and water Signup and view all the answers

What defines an acid in terms of electrolyte behavior?

Releases hydrogen ions Signup and view all the answers

Which statement accurately describes water's role as a solvent?

It enhances the ionization of substances. Signup and view all the answers

What is NOT a significant contributor to electrolyte balance?

Exposure to UV light Signup and view all the answers

What characterizes an electrolyte?

It ionizes in water solution. Signup and view all the answers

Which of the following best describes the term 'solutes'?

Substances that are dissolved in a solution. Signup and view all the answers

What percentage of water is made up of intracellular fluid in the body?

55% Signup and view all the answers

Which group is likely to have a higher water content in their bodies?

Children Signup and view all the answers

Which of the following is NOT a function of water in the body?

Stores excess energy as fat Signup and view all the answers

During which digestive process is most water absorbed?

In the small intestine Signup and view all the answers

Which type of food typically contains a high proportion of water and low kcal content?

Fruits Signup and view all the answers

What is the main consequence of prolonged fecal retention in the large intestine?

Increased water absorption back into the body Signup and view all the answers

Which type of fluid comprises the majority of extracellular fluid?

Interstitial fluid Signup and view all the answers

What characteristic of fats relates to their water content?

Low water content and high kcal Signup and view all the answers

What is the primary role of renin in the body?

To initiate the activation of angiotensinogen Signup and view all the answers

What effect does angiotensin have on the adrenal gland?

It stimulates aldosterone secretion Signup and view all the answers

Under normal conditions, which is the typical range of total water excretion per day?

1450 – 3300 ml Signup and view all the answers

What condition can result from excessive water intake without adequate electrolyte balance?

Water intoxication Signup and view all the answers

What symptom is commonly associated with water intoxication due to decreased electrolytes?

Swelling of cells (edema) Signup and view all the answers

How can a person develop a craving for salt during water intoxication?

Due to low sodium levels in the body Signup and view all the answers

What happened to the man who drank water excessively as reported in the newspaper article?

He exhibited confusion and paranoia Signup and view all the answers

What is the role of aldosterone in the body?

To promote sodium retention and water reabsorption Signup and view all the answers

Which of the following is NOT a common means of water excretion in the body?

Salivary glands Signup and view all the answers

What could happen if pure water is administered to a dehydrated person without electrolytes?

Development of water intoxication Signup and view all the answers

Study Notes

Water Content in the Body

The human body is comprised of 60% water.
Water content varies by age, sex, and lean body mass.
Children and males have a higher proportion of water compared to adults and females.
Muscle tissue contains a higher water percentage (70%) than fat tissue (10%).
Bone density also affects water content, being higher in children and males.

Body Water Distribution

55% of body water is intracellular fluid (inside cells).
45% of body water is extracellular fluid (outside cells).
5% of body water is present in other fluids like bone, gallbladder (bile), glands, and fluids in the spine and digestive system.
Interstitial fluid is a component of extracellular fluid, encompassing lymph and blood plasma.
Blood pressure is the force exerted by blood against blood vessels.

Water in Foods

Foods with high water content have low caloric content.
Foods rich in fat have little water and high caloric density.

Water Functions

Water transports nutrients and waste products throughout the body.
It carries vitamins and minerals.
Water acts as a lubricant and cushion for joints, eyes, and amniotic fluid.
It aids in chewing, tasting, and swallowing (saliva).
Sweating helps regulate body temperature.
Water maintains blood volume (blood is 90% water).
Water is essential for chemical reactions like hydrolysis, condensation, and metabolism.

Water Absorption

Over 80% of ingested water is absorbed in the small intestine.
A small amount is absorbed in the stomach.
Water absorption in the large intestine (LI) increases with longer transit time, causing constipation.
Soluble fiber (e.g., psyllium) absorbs water in the LI, softening stool and reducing constipation.

Water Intake Sources

Water intake from food ranges from 700 to 1000 ml.
Water intake from drinking ranges from 550 to 1900 ml.
Water from metabolism accounts for 200 to 300 ml.
Total daily water intake is approximately 1450 to 3300 ml.
Recommended daily intake (AI) for males is 3.7 liters, and for females is 2.7 liters.

Water Intake Regulation

The hypothalamus, part of the brain, regulates thirst.
The hypothalamus monitors water and solute concentration in the blood.
When blood concentration is high (dehydration), the hypothalamus triggers signals to drink.
The mouth, stomach lining and nerves act as stretch receptors to detect fluid volume, stopping ingestion when sufficient. Thirst lags behind the need for water.
Dehydration is the loss of fluids in the body.

Water Excretion

The kidneys excrete 500 to 1500 ml of water.
Feces remove 100 to 200 ml of water.
Lungs expel 250–400 ml of water.
Skin excretes 600–1200 ml of water.
Total water output approximates daily intake (1450–3300 ml).

Water Balance (non-exercisers)

Daily water intake for a non-exercising individual is approximately 2.625 liters (or 2250ml) with water input (food and beverages) contributing 1,875 ml and metabolism providing the remaining amount
This is balanced by excreting approximately water in the form of urination, perspiration and excretion (feces) with excretion roughly around 2.25 liters.

Water Intoxication

Water intoxication occurs when body water levels become excessively high.
This can happen from drinking large volumes in a short period or administering pure water to dehydrated individuals (without electrolytes).

Water Intoxication Symptoms

Symptoms include cellular swelling (edema), muscle cramps, convulsions, and confusion, due to electrolyte imbalance.

Electrolyte Balance

Electrolytes are substances that ionize in water solutions.
They include sodium, chloride and potassium.
Electrolyte balance occurs when the amounts entering the body match those leaving.
This balance is crucial for maintaining cellular function and body processes.

Types of Electrolytes

Acids release hydrogen ions, based accept them and OH predominates.

pH Scale

The pH scale measures the concentration of hydrogen ions (H+).
The lower the pH, the higher the H+ concentration, indicating acidity.
Blood pH is typically between 7.35 and 7.45

Solutes

Solutes are substances dissolved in a solution.

Important Electrolytes (cont'd)

Sodium (Na+) is the major extracellular cation.
Potassium (K+) is the major intracellular cation.
Chloride (Cl−) is another significant electrolyte.

Osmosis and Cell Hydration

Osmosis is the process where water moves across a membrane from an area of low to high solute concentraction.
Osmosis maintains electrolyte balance in body cells.

Water and Electrolytes for Exercise

For exercise lasting an hour or less, only water is needed.
For exercise greater than an hour, a carbohydrate and electrolyte solution (6-8% CHO) might be needed (important if hot/humid or exercise long duration).
Excessive water consumption can cause water intoxication and heart attack or organ failure.

Bottled Water

Bottled water is water intended for human consumption, put in a sealed container.
It can be taken from natural sources or municipal water supplies.

Additional Notes

Individual needs for water and electrolyte replacement vary based on several factors, such as exercise intensity, duration, environment, health status, medical conditions (e.g., diabetes, kidney disease).
Always consult a medical professional for specific guidance on hydration and electrolyte needs.
Electrolyte supplements are not necessary for average healthy individuals unless exercising heavily and/or intensely.

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Description

Explore the vital role of water in the human body through this quiz. Learn about the percentages of water in different tissues, how distribution varies with age and sex, and the functions of water in bodily processes. Test your understanding of body water distribution and its implications for health.