ANS 230: Water

Why is water classified as a 'non-caloric' essential nutrient?

It provides no calories or energy to the body.

How does the quantity of water required by animals compare to other nutrients?

It is required in larger quantities than any other nutrient.

Why is water often categorized separately from other macronutrients like carbohydrates or fats?

It serves as the medium for nutrient use rather than a fuel source itself.

Does water contain carbon in its chemical structure?

No, water lacks carbon.

Which element in a water molecule is more electronegative, causing it to pull shared electrons closer?

Oxygen

What type of partial charge is found on the oxygen atom of a water molecule?

A partial negative charge delta-.

What type of partial charge is found on the hydrogen atoms of a water molecule?

Partial positive charges (delta+).

What geometric shape characterizes a water molecule, contributing to its overall polarity?

A bent shape.

Water is considered the 'universal solvent' because it dissolves salts and _____ organic molecules.

hydrophilic

Name two types of organic molecules that are readily dissolved by water.

Sugars and amino acids.

What is the definition of 'high specific heat' in the context of water?

The requirement of a large amount of energy to raise the temperature of water by one degree.

How does water's high specific heat benefit cellular metabolism?

It helps regulate and keep the heat generated by metabolism low.

What is 'heat of vaporization' regarding water?

The large amount of energy required to convert water from a liquid to a gas.

By what process does the evaporation of sweat remove excess body heat?

Evaporative cooling.

Which type of intermolecular force is responsible for the cohesive properties of water?

Hydrogen bonds.

What is 'surface tension' in water?

The tendency of the liquid's surface to resist rupture when under tension or stress.

Property: Adhesive properties of water

Definition: The ability of water to stick to substances other than itself.

Why is adequate water volume necessary for nutrient concentration maintenance?

To keep nutrients like amino acids, glucose, and fatty acids within physiological ranges in intra- and extracellular spaces.

What is 'osmo-equilibrium' in animals?

The maintenance of salt and water balance.

What is the approximate water content of the fat-free body in various animal species?

$\sim 72-75\%$

According to the lecture text, intracellular fluid accounts for approximately what percentage of body weight?

50%

According to the lecture text, extracellular fluid accounts for approximately what percentage of body weight?

$\sim 20\%$

Which sub-compartment of extracellular fluid makes up about 15% of body weight?

Interstitial fluid.

Which sub-compartment of extracellular fluid makes up about $5\%$ of body weight?

Plasma.

How does understanding fluid compartments assist in medical diagnosis?

It helps identify imbalances in diseases like kidney failure, heart failure, and dehydration.

In clinical management, why is knowledge of water compartments essential for IV fluid administration?

It determines correct dosages and allows for targeting specific compartments for drug delivery.

What are 'aquaporins'?

Specialized proteins that facilitate the movement of water across cell membranes.

Which two organs are primarily responsible for the absorption of dietary water?

The Small Intestine (SI) and Large Intestine (LI).

How does lipid diffusion of water across a membrane compare to pore-mediated flow?

Lipid diffusion is slow and temperature-sensitive, while pore-mediated flow is rapid and temperature-insensitive.

Which desert animal is capable of drinking through its skin via capillary action?

The Thorny Devil.

How do desert rodents typically obtain water without frequent drinking?

They rely on metabolic water.

What water management challenge is specific to marine animals?

Managing high salt intake from their environment.

Which animal group requires high water volumes specifically to maintain nutrient physiological ranges and milk production?

Livestock (Cattle/Goats).

What is the typical water requirement for a lactating dairy cow weighing 500 kg?

90 L/day (or 0.18 L/kg Body Weight).

What is the typical water requirement for a 2 kg poultry hen?

0.5 L/day (or 0.25 L/kg Body Weight).

What is the average water content range in grains?

$9-30\%$

Approximately how much water is contained in hay?

$< 5\%$

What is the typical water content range for silage?

65-75

What is the water content of pasture forage?

$> 90\%$

How much metabolic water is produced from the oxidation of $100$ g of fat?

$\sim 110$ g

How much metabolic water is produced from the oxidation of $100$ g of carbohydrates?

$\sim 55$ g

How much metabolic water is produced from the oxidation of $100$ g of protein?

$\sim 42$ g

Urine typically accounts for what percentage of total water loss in animals?

75% to 85%

Name three substances that, when increased in the body, lead to higher water loss via urination.

Glucose, ketones, and urea.

How does the presence of undigested feed affect water loss?

It increases fecal water loss.

Which animal species is noted for having high evaporative water loss through sweat?

Horses.

Which two animals are described as having poorly developed sweat glands?

Chickens and Dogs.

How does ambient temperature affect water loss in animals?

Higher ambient temperatures result in greater water loss.

What is the approximate water turnover time in ruminants?

7 days.

Why do nonruminants have a more rapid water turnover compared to ruminants?

They have less water in the gastrointestinal tract (GIT).

How much body water loss can a camel tolerate?

30

What is unique about a camel's red blood cells (RBCs)?

They are elliptical in shape.

Approximately how much water can a camel drink in $13$ minutes?

$30$ gallons.

What is 'adaptive heterothermy' as seen in camels?

A mechanism where body temperature varies to conserve water by reducing the need for evaporative cooling.

How does a camel minimize water loss through excretion?

By having low urine output ($0.5-1$ l/d) and low fecal water content.