Water and Electrolytes

Intracellular and Extracellular Electrolytes

Electrolytes are minerals that carry an electric charge when dissolved in water. They are essential for many physiological processes, including fluid balance, nerve transmission, and muscle contraction.

• Intracellular Electrolytes: The primary electrolytes inside cells are potassium (K+) and phosphate (PO43-).

• Extracellular Electrolytes: The main electrolytes outside cells are sodium (Na+) and chloride (Cl-).

• Function: Electrolytes help regulate water movement between compartments by osmosis.

• Example: High sodium concentration outside the cell draws water out, potentially causing cell shrinkage.

Major Functions of Electrolytes

• Maintain fluid balance across cell membranes

• Transmit nerve impulses

• Support muscle contraction

• Regulate blood pressure

Relationship Between Electrolyte Concentration, Water Movement, and Cell Result

• Water moves from areas of low solute concentration to high solute concentration (osmosis).

• If extracellular fluid is hypertonic (higher solute concentration), water leaves the cell, causing it to shrink.

• If extracellular fluid is hypotonic, water enters the cell, causing it to swell or burst.

Factors Affecting Percentage of Water in the Body

• Age: Infants have higher water content than adults.

• Gender: Males typically have more body water due to higher muscle mass.

• Body composition: More muscle increases water content; more fat decreases it.

Function of Water in the Body and Sweating

• Solvent for biochemical reactions

• Transport of nutrients and waste

• Regulation of body temperature (sweating dissipates heat)

• Lubrication and cushioning of joints

Definition and Differences: 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 during exercise.

• Heat Exhaustion: Heavy sweating, weakness, and rapid pulse from excessive heat and dehydration.

• Heat Stroke: Life-threatening condition where body temperature rises above 40°C (104°F), causing confusion, organ failure, or death.

Thirst Mechanism

• Regulated by the hypothalamus in response to increased blood osmolality or decreased blood volume.

• Stimulates the desire to drink fluids to restore balance.

Maintaining Normal Blood Pressure Through Diet

• Reduce sodium intake

• Increase potassium, calcium, and magnesium intake

• Follow the DASH diet (Dietary Approaches to Stop Hypertension)

Vitamins and Minerals

Vitamin and Mineral Deficiencies

• Calcium: Deficiency can cause osteoporosis and muscle spasms.

• Magnesium: Deficiency may lead to muscle cramps, mental disorders, and osteoporosis.

• Chloride: Rarely deficient, but can cause metabolic alkalosis.

• Phosphorus: Deficiency is rare; can cause bone pain and muscle weakness.

• Potassium: Deficiency (hypokalemia) can cause muscle weakness, arrhythmias.

• Beta-carotene: Precursor to vitamin A; deficiency can cause vision problems.

• Vitamin E: Deficiency can cause nerve and muscle damage.

Rich Food Sources

Food Sources of Vitamins/Minerals and Endogenous Synthesis

• Some vitamins can be synthesized in the body, such as vitamin D (from sunlight) and niacin (from tryptophan).

• Most minerals must be obtained from the diet.

Relationship Between Vitamin D and Calcium

• Vitamin D enhances intestinal absorption of calcium.

• Deficiency in vitamin D can lead to poor calcium absorption and bone disorders.

Hypercalcemia Associated Problems

• Excess calcium in the blood can cause kidney stones, bone pain, and impaired absorption of other minerals.

Osteoblasts vs Osteoclasts

• Osteoblasts: Cells that build new bone tissue.

• Osteoclasts: Cells that break down bone tissue.

• Bone remodeling is a balance between these two cell types.

Bone Development Processes Order and Timing

• Bone development (ossification) begins in the embryo and continues through adolescence.

• Peak bone mass is typically reached in early adulthood.

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 for vitamin A).

Heme vs Non-Heme Sources of Iron

Antioxidants and Free Radicals

Antioxidants and Their Role Against Free Radicals

• Antioxidants neutralize free radicals, preventing cellular damage.

• Key antioxidant vitamins: Vitamin C, Vitamin E, beta-carotene.

• Minerals with antioxidant roles: Selenium, manganese.

Free Radicals: Risk Factors, Issues, Formation, and Damage

• Free radicals are unstable molecules with unpaired electrons.

• Formed during normal metabolism, exposure to pollution, radiation, or smoking.

• Can damage DNA, proteins, and cell membranes, contributing to aging and diseases like cancer.

What Can Increase or Decrease Risk for Cancer?

• Increase risk: Smoking, excessive alcohol, processed meats, low fruit/vegetable intake, obesity.

• Decrease risk: High intake of fruits, vegetables, whole grains, regular physical activity.

Other Key Topics

Leukocytes: Definition and Function

• Leukocytes are white blood cells involved in immune defense.

• They identify and destroy pathogens and foreign substances.

Vitamin C: Functions and Deficiency Risk

• Functions: Collagen synthesis, antioxidant, enhances iron absorption, immune support.

• At risk for deficiency: Smokers, people with limited fruit/vegetable intake, certain medical conditions.

High/Low Sodium Foods

• High sodium: Processed foods, canned soups, salted snacks, fast food.

• Low sodium: Fresh fruits and vegetables, unprocessed grains, unsalted nuts.

Energy Drinks

• Contain caffeine, sugar, and other stimulants.

• May cause dehydration, increased heart rate, and sleep disturbances if consumed in excess.

Summary Table: Major Electrolytes and Their Functions

Formulas and Equations

• Osmosis: Water movement across a semipermeable membrane from low to high solute concentration.

• Blood Pressure Equation:

• Body Water Percentage:

Additional info: Some explanations and tables were expanded for clarity and completeness based on standard nutrition curriculum.