Water, Electrolytes, Vitamins, Minerals, and Antioxidants: Exam 3 Study Guide

Study Guide - Smart Notes

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Water and Electrolytes

Intracellular and Extracellular Electrolytes

Electrolytes are minerals that carry an electric charge when dissolved in water. They are distributed in the body's fluid compartments:

Intracellular electrolytes: Predominantly potassium (K+) and phosphate (PO43-).
Extracellular electrolytes: Mainly sodium (Na+) and chloride (Cl-).

Electrolytes help regulate fluid balance, nerve transmission, and muscle contraction.

Major Functions of Electrolytes

Fluid balance: Maintain osmotic pressure and water distribution between compartments.
Nerve impulse transmission: Sodium and potassium gradients are essential for action potentials.
Muscle contraction: Calcium, sodium, and potassium are involved in muscle function.

Relationship Between Electrolyte Concentration, Water Movement, and Cell Result

Water moves across cell membranes by osmosis in response to electrolyte concentration differences.
If extracellular fluid is hypertonic (higher solute concentration), water leaves the cell, causing it to shrink.
If extracellular fluid is hypotonic (lower solute concentration), water enters the cell, causing it to swell or burst.

Factors Affecting Body Water Percentage

Age (decreases with age)
Gender (males usually have higher percentage due to more muscle mass)
Body composition (more muscle = more water; more fat = less water)

Functions of Water in the Body

Solvent for biochemical reactions
Transport of nutrients and waste
Temperature regulation (sweating)
Lubrication and cushioning of joints

Dehydration, Heat Stroke, Heat Cramps, Heat Exhaustion

Dehydration: Excessive loss of body water, leading to impaired function.
Heat cramps: Muscle spasms due to loss of electrolytes and fluids.
Heat exhaustion: Heavy sweating, weakness, rapid pulse; body overheats but can still cool itself.
Heat stroke: Life-threatening; body temperature rises above 40°C (104°F), sweating stops, confusion, possible unconsciousness.

Thirst Mechanism

Regulated by the hypothalamus in response to increased blood osmolality or decreased blood volume.
Stimulates desire to drink before dehydration becomes severe.

Vitamins and Minerals

Vitamin and Mineral Deficiencies

Vitamin D: Deficiency leads to rickets in children, osteomalacia in adults.
Calcium: Deficiency causes osteoporosis, muscle spasms.
Iron: Deficiency causes anemia, fatigue.
Vitamin C: Deficiency causes scurvy (bleeding gums, poor wound healing).
Iodine: Deficiency causes goiter, hypothyroidism.
Magnesium: Deficiency can cause muscle cramps, seizures.
Phosphorus: Deficiency is rare but can cause bone pain, muscle weakness.
Potassium: Deficiency (hypokalemia) can cause muscle weakness, arrhythmias.
Chloride: Deficiency is rare but can cause metabolic alkalosis.

Rich Food Sources

Calcium: Dairy products, leafy greens, fortified foods.
Magnesium: Nuts, whole grains, leafy green vegetables.
Chloride: Table salt (NaCl), processed foods.
Phosphorus: Meat, dairy, nuts, legumes.
Potassium: Bananas, potatoes, oranges, beans.
Beta-carotene: Carrots, sweet potatoes, spinach.
Vitamin E: Vegetable oils, nuts, seeds.

Food Sources and Synthesis in the Body

Some vitamins (e.g., vitamin D) can be synthesized in the body with sunlight exposure.
Vitamin K and biotin can be produced by gut bacteria.
Most vitamins and minerals must be obtained from the diet.

Relationship Between Vitamin D and Calcium

Vitamin D increases intestinal absorption of calcium.
Deficiency in vitamin D impairs calcium absorption, increasing risk of bone disorders.

Osteoblasts vs Osteoclasts

Osteoblasts: Cells that build bone by depositing minerals.
Osteoclasts: Cells that break down bone, releasing minerals into the blood.

Bone Development Process and Timing

Bone development (ossification) begins in the embryo and continues through adolescence.
Peak bone mass is typically achieved by age 30.
Process: Bone formation (osteoblasts) → Bone resorption (osteoclasts) → Bone remodeling.

Hypercalcemia Associated Problems

Excess calcium in the blood can cause kidney stones, calcification of soft tissues, impaired kidney function, and abnormal heart rhythms.

Heme vs Non-Heme Iron Sources

Heme iron: Found in animal products (meat, poultry, fish); better absorbed.
Non-heme iron: Found in plant foods (beans, lentils, spinach); less efficiently absorbed.

Leukocytes: Definition and Function

Leukocytes are white blood cells involved in immune defense against pathogens.

Neural Tube Defect

Birth defects of the brain, spine, or spinal cord due to incomplete closure of the neural tube.
Folic acid deficiency during pregnancy increases risk.

Pro-vitamin

A substance that can be converted into a vitamin in the body (e.g., beta-carotene is a pro-vitamin A).

Antioxidants and Free Radicals

Antioxidants and Their Role

Antioxidants neutralize free radicals, preventing cellular damage.
Key antioxidant vitamins: Vitamin C, Vitamin E, beta-carotene.

Free Radicals: Formation, Risks, and Damage

Free radicals are unstable molecules with unpaired electrons, formed during normal metabolism or exposure to toxins (e.g., smoking, pollution).
They can damage DNA, proteins, and cell membranes, contributing to aging and diseases like cancer.
Risk factors: Smoking, pollution, radiation, inflammation.

Antioxidant Vitamins

Vitamin C: Water-soluble, protects against oxidative damage in aqueous environments.
Vitamin E: Fat-soluble, protects cell membranes from lipid peroxidation.
Beta-carotene: Precursor to vitamin A, neutralizes singlet oxygen.

Vitamin C Functions and Deficiency Risk

Collagen synthesis, immune function, antioxidant activity, enhances iron absorption.
At risk: Smokers, people with limited fruit/vegetable intake, alcoholics.

What Increases or Decreases Cancer Risk?

Increases risk: Smoking, high red/processed meat intake, low fruit/vegetable intake, obesity, alcohol, certain infections.
Decreases risk: High intake of fruits, vegetables, whole grains, regular physical activity, maintaining healthy weight.

Table: Major Minerals, Functions, Deficiency, and Food Sources

Mineral	Major Functions	Deficiency Symptoms	Rich Food Sources
Calcium	Bone/teeth health, muscle contraction, nerve signaling	Osteoporosis, muscle spasms	Dairy, leafy greens, fortified foods
Magnesium	Enzyme function, muscle/nerve function, bone health	Muscle cramps, seizures	Nuts, whole grains, leafy greens
Phosphorus	Bone/teeth health, energy metabolism	Bone pain, muscle weakness	Meat, dairy, nuts, legumes
Potassium	Fluid balance, nerve/muscle function	Muscle weakness, arrhythmias	Bananas, potatoes, beans
Chloride	Fluid balance, stomach acid (HCl) production	Metabolic alkalosis (rare)	Table salt, processed foods

Key Definitions

Pro-vitamin: A substance that can be converted into a vitamin in the body.
Dehydration: Excessive loss of body water.
Osteoblasts: Bone-forming cells.
Osteoclasts: Bone-resorbing cells.
Leukocytes: White blood cells involved in immune defense.

Formulas and Equations

Osmosis: Water moves from low solute concentration to high solute concentration across a semipermeable membrane.
Blood Pressure Equation:

Body Water Percentage (approximate):

Additional info: Some explanations and examples have been expanded for clarity and completeness based on standard nutrition curriculum.