Water, Electrolytes, and Major Minerals

These flashcards review body water compartments, fluid regulation, dehydration stages, water functions, and the major minerals—sodium, chloride, potassium, calcium, phosphorus, magnesium, and sulfur—including their locations, functions, deficiency symptoms, and food sources.

What proportion of total body water is found inside versus outside cells?

About two-thirds is intracellular fluid and one-third is extracellular fluid.

What are the two main components of extracellular fluid?

Interstitial fluid that surrounds cells and intravascular fluid (plasma) within blood vessels.

What condition is characterized by water accumulating in the wrong place, such as interstitial spaces?

Edema.

Why does excessive sodium intake cause water retention and possibly swelling?

Water follows electrolytes; extra sodium pulls water into blood and tissues, increasing volume, pressure, and edema.

What principle explains why fluid shifts occur when electrolyte concentrations change?

Water follows electrolytes.

What signal prompts you to begin drinking water?

Thirst, triggered by the hypothalamus and sensations such as a dry mouth.

Which feedback mechanism tells you to stop drinking when you have had enough water?

Stretch receptors in the stomach send satiety signals via the hypothalamus.

What are the early signs of dehydration?

Fatigue and thirst.

What symptoms appear as dehydration becomes moderate to severe?

Dry mouth, light skin, headache, exhaustion, delirium.

What can untreated severe dehydration ultimately lead to?

Death.

What is the Adequate Intake (AI) for daily water consumption for adults?

Approximately 2–3 liters per day.

How does sweating help regulate body temperature?

Water evaporates from the skin as sweat, removing heat and cooling the body.

Give two examples of water’s role in transport within the body.

Carries nutrients and oxygen to cells and removes waste products.

Name three functions of water in digestion and excretion.

Assists in breaking down food, aids nutrient absorption, and removes waste via urine, feces, and sweat.

Which body structures are lubricated by water?

Joints, tissues, and mucous membranes.

Where is sodium primarily located in the body’s fluid compartments?

Outside the cells (extracellular fluid).

List two major functions of sodium.

Maintains fluid and electrolyte balance; assists nerve impulse transmission and muscle contraction.

What are the symptoms of sodium deficiency (hyponatremia) caused by excessive losses?

Headache, confusion, stupor, seizures, and coma.

Identify two common dietary sources of sodium.

Table salt or soy sauce and processed foods.

Where is chloride mainly found and what critical role does it play in the stomach?

Outside cells; it is part of hydrochloric acid needed for digestion.

Where is potassium predominantly located in the body?

Inside the cells (intracellular fluid).

Give two key functions of potassium.

Maintains fluid and electrolyte balance; supports nerve impulses and muscle contractions.

What are common symptoms of potassium deficiency?

Irregular heartbeat, muscular weakness, and glucose intolerance.

List several potassium-rich foods.

Whole foods such as meats, milk, fruits, vegetables, grains, and legumes.

What is the most abundant mineral in the human body?

Calcium.

Name two physiological processes that depend on adequate calcium.

Mineralization of bones and teeth; muscle contraction and relaxation (also nerve function, blood clotting, blood pressure regulation).

What adult disease results from long-term calcium deficiency?

Osteoporosis (bone loss).

Give three dietary sources of calcium.

Milk and milk products, small fish with edible bones, and calcium-set tofu or leafy greens like bok choy and kale.

Which mineral works alongside calcium in bone mineralization and energy transfer?

Phosphorus.

Provide two functions of phosphorus besides bone formation.

Component of genetic material and phospholipids; part of ATP energy transfer and acid-base buffering.

Name two phosphorus-rich food groups.

Protein-rich foods such as meats, fish, poultry, eggs, milk, legumes, and nuts.

State two roles of magnesium in the body.

Contributes to bone mineralization and participates in energy metabolism and muscle contraction.

What symptoms are associated with magnesium deficiency?

Muscle cramps, tetany, and seizures.

Identify three good dietary sources of magnesium.

Nuts, legumes, and green leafy vegetables (also some fish).

How does sulfur help stabilize protein structure?

By forming disulfide bridges between amino acids.

Name two vitamins or hormones that contain sulfur.

The vitamins biotin and thiamin, and the hormone insulin.

Why is a specific dietary deficiency of sulfur unlikely?

Adequate protein intake supplies sufficient sulfur, so protein deficiency would occur first.

List several foods that provide sulfur.

Protein-rich foods such as meat, fish, poultry, eggs, milk, legumes, and nuts.