Mod 2- Water

Question 1

What percentage of total body weight is water in adults?

Answer 1

60% of total body weight is water.

Question 2

Do children have a higher or lower percentage of water in their bodies compared to adults?

Answer 2

Children have a higher percentage of water in their bodies.

Question 3

Why are infants more prone to dehydration than adults?

Answer 3

Infants have less body fat, lower body weight, and more water in their bodies (over 73%), making them more likely to become dehydrated.

Question 4

What percentage of an infant’s body is water?

Answer 4

Over 73% of an infant’s body is water.

Question 5

What must water intake equal in order to maintain homeostasis?

Answer 5

Water intake from liquids, food, and metabolism must equal water losses from the kidneys, skin, lungs, and faeces.

Question 6

What role does water play as a transport medium in the body?

Answer 6

It carries nutrients to cells and removes waste products from the body.

Question 7

How does water function as a solvent in the body?

Answer 7

It helps dissolve minerals, vitamins, proteins, and sugars so the body can use them.

Question 8

What is water’s metabolic role in the body?

Answer 8

It is involved in chemical reactions like condensation (joining molecules) and hydrolysis (breaking molecules apart).

Question 9

How does water provide lubrication and cushioning in the body?

Answer 9

It protects and cushions joints, eyes, the spinal cord, and the baby during pregnancy (amniotic fluid).

Question 10

How does water help regulate body temperature?

Answer 10

It controls temperature through sweating—heat is lost when sweat evaporates.

Question 11

What is the ideal body temperature that water helps maintain?

Answer 11

37.5°C.

Question 12

How does water help maintain blood volume?

Answer 12

It keeps the right amount of blood in the body to support healthy blood pressure.

Question 13

Where is the majority of the body’s water found?

Answer 13

Inside the cells (intracellular fluid).

Question 14

What percentage of the body’s water is intracellular fluid?

Answer 14

More than two-thirds (over 60%).

Question 15

What is extracellular fluid?

Answer 15

Fluid found outside the cells.

Question 16

What are the two main types of extracellular fluid?

Answer 16

Interstitial fluid (between cells) and intravascular fluid (inside blood vessels, e.g. blood plasma).

Question 17

What part of the brain controls the body’s water balance?

Answer 17

The hypothalamus.

Question 18

What triggers the sensation of thirst?

Answer 18

Low water levels detected by the mouth, hypothalamus, and nerves.

Question 19

What happens when you don’t drink enough water?

Answer 19

Your blood becomes more concentrated and your mouth feels dry, triggering the hypothalamus to make you feel thirsty.

Question 20

What is the first sign of dehydration?

Answer 20

Thirst.

Question 21

Why are older adults at greater risk of dehydration?

Answer 21

They may lose the ability to feel thirst.

Question 22

What are symptoms of worsening dehydration?

Answer 22

Weakness, tiredness, and confusion (delirium).

Question 23

What symptoms occur with a 1–2% loss of body water?

Answer 23

Thirst, fatigue, weakness, vague discomfort, and loss of appetite.

Question 24

What symptoms occur with a 3–4% loss of body water?

Answer 24

Impaired physical performance, dry mouth, reduced urine output, flushed skin, impatience, and apathy.

Question 25

What symptoms occur with a 5–6% loss of body water?

Answer 25

Difficulty concentrating, headache, irritability, sleepiness, poor temperature regulation, and increased breathing rate.

Question 26

What symptoms occur with a 7–10% loss of body water?

Answer 26

Dizziness, muscle spasms, loss of balance, delirium, exhaustion, and possible collapse.

Question 27

What factors affect daily water needs?

Answer 27

Physical activity, temperature, diet, and humidity.

Question 28

Why is it difficult to set one fixed water intake recommendation for everyone?

Answer 28

Because water needs vary based on activity level, climate, and other personal factors.

Question 29

What is the NRV Adequate Intake (AI) for total daily water for men?

Answer 29

3.4 litres per day.

Question 30

What is the NRV Adequate Intake (AI) for total daily water for women?

Answer 30

2.8 litres per day.

Question 31

Who may need more water than the NRV AI?

Answer 31

People who are more active or live in hot or humid climates.

Question 32

What does pale straw yellow urine usually indicate?

Answer 32

That you are well hydrated.

Question 33

What percentage of our total water intake comes from drinks and fluids?

Answer 33

About 80%.

Question 34

What percentage of our total water intake comes from food?

Answer 34

About 20%.

Question 35

What is included in total water intake?

Answer 35

Plain water and water from other drinks like milk or juice.

Question 36

Do tea and coffee contribute to hydration?

Answer 36

Yes, they do, even though they contain caffeine with a mild diuretic effect.

Question 37

How does caffeine affect water loss?

Answer 37

1 mg of caffeine causes approximately 1.1 mL of water loss.

Question 38

What is the net water gain from a 250 mL coffee with 80 mg of caffeine?

Answer 38

About 162 mL (250 mL - 88 mL water loss).

Question 39

What happens to regular caffeine drinkers in terms of water balance?

Answer 39

Their bodies adapt to the mild water loss caused by caffeine.

Question 40

What triggers the body's water balance response?

Answer 40

A drop in blood volume and low blood pressure.

Question 41

What does the hypothalamus detect to help control water balance?

Answer 41

High salt levels in the blood.

Question 42

What hormone does the pituitary gland release in response to signals from the hypothalamus?

Answer 42

ADH (antidiuretic hormone).

Question 43

What does ADH do in the kidneys?

Answer 43

It tells the kidneys to reabsorb water, raising blood volume.

Question 44

Besides acting on the kidneys, what else does ADH do?

Answer 44

It activates the thirst response to encourage fluid intake.

Question 45

What enzyme do the kidneys release during low blood volume or pressure?

Answer 45

Renin.

Question 46

What does renin lead to the release of?

Answer 46

Aldosterone from the adrenal glands.

Question 47

What does aldosterone do in the kidneys?

Answer 47

It tells the kidneys to reabsorb sodium, and water follows, helping restore blood volume and pressure.

Question 48

What is water intoxication and how common is it?

Answer 48

A rare condition caused by excessive water intake or kidney problems reducing urine output.

Question 49

What happens when too much water dilutes the extracellular fluid?

Answer 49

Water moves into cells, causing them to swell and upsetting the water-sodium balance.

Question 50

What serious symptoms can water intoxication cause?

Answer 50

Confusion, seizures (convulsions), and in severe cases, death.

Question 51

How much water intake in a few hours can cause hyponatraemia?

Answer 51

More than 4 litres, especially if already well-hydrated.

Question 52

What is the recommended fluid intake limit during heavy sweating or endurance events?

Answer 52

1–1.5 litres per hour to avoid overhydration.