Water and Minerals

Intracellular and Extracellular Electrolytes

Electrolytes are minerals that carry an electric charge and are essential for many physiological processes. 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: Essential for action potentials in neurons.

• Muscle Contraction: Required for contraction and relaxation of muscle fibers.

Relationship Between Electrolyte Concentration, Water Movement, and Cell Result

• Water moves across cell membranes by osmosis in response to electrolyte concentration gradients.

• 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 Percentage of Water in the Body

• Age (infants have higher % water than elderly)

• Gender (males typically have more water due to higher muscle mass)

• Body composition (more muscle = more water; more fat = less water)

Function of Water in the Body and Sweating

• Solvent for biochemical reactions

• Transport of nutrients and waste

• Temperature regulation via sweating and evaporation

• Lubrication and cushioning of joints and organs

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 overheating and dehydration.

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

Thirst Mechanism

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

• Stimulates desire to drink fluids to restore balance.

How to Maintain Normal Blood Pressure Through Diet

• Reduce sodium intake

• Increase potassium, calcium, and magnesium intake

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

High/Low Sodium Foods

• High sodium: Processed foods, canned soups, deli meats, snack foods

• Low sodium: Fresh fruits and vegetables, unprocessed grains, fresh meats

Hypercalcemia Associated Problems

• Kidney stones

• Calcification of soft tissues

• Impaired kidney function

• Confusion, muscle weakness

Vitamins and Minerals

Vitamin and Mineral Deficiencies

• Vitamin D: Rickets (children), osteomalacia (adults)

• Vitamin C: Scurvy (bleeding gums, poor wound healing)

• Iron: Anemia (fatigue, weakness)

• Iodine: Goiter, cretinism

• Calcium: Osteoporosis, tetany

• Magnesium: Muscle cramps, irregular heartbeat

• Phosphorus: Weakness, bone pain

• Potassium: Muscle weakness, arrhythmias

• Chloride: Rare, but can cause metabolic alkalosis

Rich Food Sources

Food Sources of Vitamins/Minerals and Endogenous Synthesis

• Some vitamins can be synthesized in the body:

  • Vitamin D: Synthesized in skin with sunlight exposure

  • Niacin: Synthesized from tryptophan (an amino acid)

  • Vitamin K and biotin: Produced by gut bacteria

Relationship Between Vitamin D and Calcium

• Vitamin D increases intestinal absorption of calcium.

• Deficiency in vitamin D impairs calcium absorption, leading to 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 Processes Order and Timing

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

• Peak bone mass is typically achieved by age 30.

• Order: Bone modeling (growth) → Bone remodeling (maintenance)

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.

• Example: 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, Formation, and Damage

• Free radicals are unstable molecules with unpaired electrons.

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

• Damage DNA, proteins, and cell membranes, contributing to aging and diseases (e.g., cancer, heart disease).

What Can Increase or Decrease Risk for Cancer?

• Increase risk: Smoking, excessive alcohol, high-fat diet, low fruit/vegetable intake, exposure to carcinogens

• Decrease risk: High intake of fruits, vegetables, whole grains, regular physical activity, maintaining healthy weight

Vitamins: Functions and Deficiencies

Vitamin C: Functions and Deficiency Risk

• Functions: Collagen synthesis, antioxidant, enhances iron absorption, immune function

• At risk for deficiency: Smokers, people with limited fruit/vegetable intake, alcoholics

Antioxidant Vitamins

• Vitamin C

• Vitamin E

• Beta-carotene (pro-vitamin A)

Other Key Topics

Leukocytes: Definition and Function

• Leukocytes are white blood cells involved in immune defense.

• They identify and destroy pathogens, and play roles in inflammation and allergic responses.

Energy Drinks

• Contain caffeine, sugar, and other stimulants.

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