IPHY 2420 Exam 2

Minimize contact with water

Water soluble vitamins, Vitamin Bs, C

Reduce Heat

Vitamins B1, B2, C

Limit Light

Vitamin B2

Avoid air

Vitamins B, C, A, E, K

Ban basics

Vitamins B1, B2, C, K

Preserve vitamin content in food

Use minimal water and cooking time, store in airtight opaque containers, and avoid alkaline ingredients.

What are the two main fluid compartments of the body?

Intracellular (ICF) and extracellular (ECF) fluids.

Intracellular fluid (ICF) compartment

inside cells (~2/3 of total body fluid).

Extracellular fluid (ECF) Compartment

outside cells (~1/3), includes interstitial fluid + plasma.

Differences in body fluid content

Males vs. females: Males usually have higher fluid % due to more lean muscle.

Young vs. old: Younger individuals have higher fluid content; older adults lower (more fat, less muscle).

Lean vs. adipose: Muscle tissue has higher water content; fat has lower.

Extracellular Fluid

Contains mainly sodium (Na⁺) and chloride (Cl⁻).

Intracellular Fluid

Contains mainly potassium (K⁺) and phosphorus (as phosphate, PO₄³⁻).

Functions of body fluids

1. Dissolve and transport substances: water dissolves ions, amino acids, glucose, vitamins, minerals, etc.

2. Maintain blood volume: more fluid = higher blood pressure; less fluid = lower blood pressure.

3. Maintain body temperature: water's high heat capacity helps regulate internal temperature; sweating cools the body through evaporative cooling.

4. Protect and lubricate tissues: fluids cushion the brain, spinal cord, joints, lungs, GI tract, and developing fetus.

What property of water helps regulate temperature?

High Heat Capacity

Osmosis

The passive movement of water across a semi-permeable membrane from an area of low solute concentration to high solute concentration. It requires no energy and is crucial for maintaining cellular fluid balance and homeostasis.

Electrolyte Function

Fluid balance, nerve impulses, muscle contraction, and acid-base balance.

Fluid Balance is Disrupted

Loss of fluids from diarrhea, vomiting, or excessive sweating disrupts electrolyte levels. This can change electrical signals through the heart, leading to irregular heartbeats and, in severe cases, death

Fluid balance regulated

The hypothalamus regulates thirst. Stimuli include: increased solute concentration in blood, decreased blood volume or blood pressure, and dry mouth/throat. However, thirst does not always ensure enough fluid intake, which can lead to imbalance.

Main sources of water gain

beverages, food (fruits, vegetables, meats), and metabolic water (byproduct of chemical reactions, ~10-14% of needs).

Main source of water loss

Urine, feces, sweat, evaporation, and exhalation.

Recommended water intake for males and females

Males: ~3.7 L/day (15.5 cups, 3.0 L as beverages). Females: ~2.7 L/day (11.5 cups, 2.2 L as beverages). General rule: 1.0-1.5 mL of water per kcal expended.

hyponatremia

Abnormally low blood sodium concentration, usually caused by drinking too much water without sodium replacement. It makes extracellular fluid hypotonic, causing water to enter cells by osmosis. This leads to cell swelling, especially in brain cells (cerebral edema), which can result in confusion, seizures, coma, or death.

Water the kidneys excrete per hour

Maximum of ~0.8-1.0 liters (27-33 ounces) of water per hour. If intake exceeds this, water intoxication and hyponatremia can occur.

Functions of sodium

Helps maintain fluid and electrolyte balance, regulates blood pressure and pH, transmits nerve impulses, and assists in nutrient transport (like glucose into cells).

AI and UL for sodium

Adequate Intake (AI): 1500 mg/day (~3/4 teaspoon salt). Tolerable Upper Intake Level (UL): less than 2300 mg/day.

Average sodium intake in the U.S.

Most Americans consume about 3400 mg/day, mainly from processed and restaurant foods (over 70% of total intake).

Too much sodium

Can cause hypertension, fluid retention, edema, and hypernatremia (excess sodium in blood).

Too little sodium

Can result from prolonged sweating, vomiting, or diarrhea. Symptoms include dizziness, fatigue, nausea, muscle cramps, and in athletes, exercise-associated hyponatremia.

Functions of potassium

Maintains fluid and electrolyte balance, pH balance, nerve transmission, and muscle contraction. It also helps lower blood pressure by counteracting sodium's effects.

Recommended potassium intake

Males: 3400 mg/day; Females: 2600 mg/day. Potassium is mainly found in unprocessed foods such as fruits, vegetables, and whole grains.

Too much potassium

Hyperkalemia: high potassium in blood, often seen in kidney disease. It disrupts heart rhythm and can cause cardiac arrest. At-risk individuals should avoid salt substitutes (KCl).

Too little potassium

Hypokalemia: low blood potassium, caused by kidney disease, diabetic acidosis, diuretics, dehydration, or laxative/alcohol abuse. Symptoms include confusion, appetite loss, muscle weakness, and heart arrhythmias.

Functions of chloride

Chloride maintains fluid balance and is a component of stomach acid (HCl), essential for digestion.

Functions of phosphorus

Phosphorus is required for fluid balance and plays a critical role in bone formation (85% is stored in bones). It is abundant in protein-rich foods such as meat, milk, and eggs. Animal sources are better absorbed than plant sources.

Signs of mild vs severe dehydration

Mild: thirst, dry mouth, reduced urine output, darker urine, headache, cramps. Severe: no urination, very dark urine, dry skin, confusion, dizziness, rapid heart rate, sunken eyes, shock, unconsciousness.

Three types of heat illness

1. Heat cramps (muscle spasms due to fluid/electrolyte imbalance).

2. Heat exhaustion (weakness, nausea, heavy sweating, dizziness).

3. Heatstroke (life-threatening failure of heat regulation, high body temp, confusion, dry hot skin).

Heat cramps treatment

Stop activity, rest, cool down, and hydrate with fluids/electrolytes. Persistent cramps may indicate a more serious condition.

Heat exhaustion

Symptoms: thirst, weakness, vomiting, dizziness, cool skin, heavy sweating, elevated pulse. Treatment: rest, rapid cooling, and fluid replacement (sports drinks).

Heatstroke

Symptoms: very high body temp (>105°F), rapid pulse, weakness, confusion/disorientation, hot dry skin. Treatment: emergency cooling, hydration, and immediate medical attention (life-threatening).

Heat Acclimatization

Adaptation to heat over 1-2 weeks. Leads to improved hydration behavior, increased blood volume, salt/water retention, and more efficient sweating (earlier, greater, and across more body surface). This reduces risk of heat illness. BP stays the same.

Heat Cramp

Muscle pain or spasm due largely to the loss of salt from the body from sweating during intense activity in the heat, or inadequate intake of salt.

What is water intoxication? What is the medical term for it (related to sodium levels in the blood)?

It is the disruption of brain function caused by drinking too much water

The medical term is hyponatremia (low blood sodium concentration).

What would happen to cells in the body as a result of "water intoxication"? What factors contributed to the condition of the radio station contestant?

With hyponatremia, extracellular fluid becomes hypotonic relative to cells.

Water moves into cells by osmosis → cells swell.

Key contributing factors:

She drank almost two gallons (~256 oz) in ~3 hours (~85 oz/hour).

She was not allowed to urinate or vomit, so her kidneys couldn't help regulate fluid balance.

Sodium concentration in her blood became dangerously diluted.

What type of cell are we especially concerned about during water intoxication? What is excess fluid accumulation in these cells called?

Most concerning are neurons (brain cells), since the brain is enclosed in the rigid skull.

Excess fluid accumulation in these cells = cerebral edema (swelling of the brain).

Hydrocephalus: accumulation of the fluids in the cell

This can cause headache, confusion, seizures, coma, and even death.

If the contestant had been allowed to urinate, would her kidneys have been able to keep up with her consuming ~85 oz/hour? How much fluid can the kidneys excrete per hour?

Kidneys can excrete max ~0.8-1.0 L/hour (≈27-33 oz/hour) under ideal conditions.

She was drinking ~85 oz/hour, well above this limit.

So even if allowed to urinate, her kidneys would not have kept up, and water intoxication would still have developed.

If the contestant had gone to the hospital, how could her condition have been treated?

Treatment would focus on restoring sodium balance and reducing brain swelling:

Careful administration of hypertonic saline (3% NaCl) IV to raise sodium levels.

Diuretics to promote water excretion.

In severe cases, medications to reduce intracranial pressure.

Given the above information and information presented in the article, what might Clay be experiencing and what contributed to it?

Clay likely developed exercise-associated hyponatremia (EAH).

Contributing factors:

Marathon in rising heat (more sweating → sodium loss).

He drank large amounts of plain water at every aid station → diluted sodium further.

Symptoms (nausea, cloudy thinking, muscle cramps) are classic for hyponatremia.

What could Clay have done to avoid having to drop out of the race?

To prevent hyponatremia:

Alternate water with electrolyte-containing sports drinks to replace sodium.

Drink to thirst cues rather than forcing fluids at every stop.

Monitor signs of overhydration (bloating, nausea).

Athlete or not, what water consumption pattern is most likely to cause water intoxication (hyponatremia)?

Drinking very large amounts of water in a short time without allowing for urination or sodium replacement.

Example: >3-4 L in just a few hours (such as during contests, hazing rituals, or endurance events).

Pattern = rapid, excessive water intake + impaired sodium balance/excretion.

Three subatomic particles of an atom

Electrons (negative charge, orbit nucleus), Protons (positive charge, in nucleus), Neutrons (neutral charge, in nucleus).

Oxidation

loss of electrons. From the atoms of one molecule. Paired reactions with reduction in metabolism.

Reduction

Gain of electrons. To the atoms of another molecule. Paired reactions with Oxidation in metabolism.

Free radicals

Unstable atoms or molecules with unpaired electrons. They are highly reactive and steal electrons from stable atoms, creating more free radicals.

Free radicals formation

Formed during normal metabolic reactions, immune responses, and from external sources such as tobacco smoke, radiation, UV light, and pollution.

Damages free radicals cause(Oxidative stress)

They damage cell membranes, proteins, LDL cholesterol (leading to plaque buildup), and DNA. This can cause disease development.

Diseases are linked to oxidative stress

Arthritis, cancer, COPD, cataracts, Alzheimer's, Parkinson's, cardiovascular disease, type 2 diabetes.

Antioxidants fight free radicals

Antioxidants donate electrons to stabilize free radicals without becoming unstable themselves. They include vitamins (C, E), minerals (selenium, Copper, Iron Manganese, Zinc), and phytochemicals (beta-carotene).

Three Antioxidant Enzyme System Defenses

Convert free radicals into less harmful substances

Break down oxidized fatty acids (e.g., hydrogen peroxide → water)

Repair oxidized molecules and recycle oxidized antioxidants

Vitamin C and Vitamin E recycled in oxidative repair

Vitamin E donates an electron to neutralize free radicals, becoming oxidized.

Vitamin C donates an electron to regenerate Vitamin E back to its active form.

Oxidized Vitamin C is then restored by glutathione and other reducing agents.

This antioxidant network allows continuous protection against oxidative damage.

Main function of Vitamin E

Vitamin E (fat-soluble tocopherols) protects polyunsaturated fatty acids (PUFAs) and LDLs from oxidation, stabilizes cell membranes, and donates electrons to neutralize free radicals.

Food sources of Vitamin E

Vegetable oils, nuts, seeds, wheat germ, soybeans. Poor sources: animal and dairy products.

Too much or too little Vitamin E

Excess: can increase risk of heart failure and interfere with anticoagulant medications (warfarin, aspirin). Deficiency: uncommon

Functions of Vitamin C

Antioxidant, collagen synthesis (important for bone, teeth, skin, blood vessels), immune protection (WBCs), important in wound healing, regenerates Vitamin E, enhances iron absorption.

Recommended intake of Vitamin C

Men: 90 mg/day, Women: 75 mg/day, Smokers: +35 mg/day. UL: 2000 mg/day.

Sources of Vitamin C

Fresh fruits and vegetables. Example: citrus, bell peppers, strawberries, broccoli.

Too much vitamin C

Excess: nausea, diarrhea, kidney stones, iron toxicity in hemochromatosis

Too little Vitamin C

Deficiency: scurvy (bleeding gums, poor wound healing, anemia, depression).

Functions of Selenium

Trace mineral. Needed for production of thyroid hormone thyroxine. Antioxidant: part of glutathione peroxidase enzyme system that neutralizes peroxides.

Food Sources of Selenium

Brazil nuts (very high), meats, seafood. Levels vary depending on soil content.

Beta-carotene

A phytochemical carotenoid (plant pigment: red, orange, yellow, green). It is a provitamin that can be converted into Vitamin A (retinol).

Functions of beta-carotene

Weak antioxidant. Protects cell membranes and LDLs. Enhances immune system, protects skin from UV damage, supports eye health.

Too much beta-carotene

Not toxic, but skin may turn yellow/orange (carotenosis). Harmless and reversible. No deficiency symptoms because it is not essential.

Food sources of beta-carotene

Carrots, sweet potatoes, pumpkin, spinach, kale, mangoes, apricots, broccoli.

Functions of Vitamin A

Fat-soluble vitamin stored in liver and adipose tissue. Roles: cell differentiation, reproduction, bone growth, vision (part of rhodopsin in rods react to changes in light brightness, iodopsin in cones allow different colors to be seen).

Too much Vitamin A

Toxic in high doses from supplements or animal liver. Can cause birth defects, liver damage, blindness. Example: polar bear liver contains lethal amounts.

What happens with too little Vitamin A

Night blindness (early sign), xerophthalmia (irreversible blindness).

Cancer and its risk rates

Cancer is uncontrolled cell division due to DNA mutations. Lifetime risk: males ~50%, females ~33%. One-third of deaths linked to nutrition/lifestyle.

Three stages of carcinogenesis

1. Initiation: DNA damage by carcinogen. Can dorm for years

2. Promotion: mutated cell divides, oncogenes activated, tumor suppressors inactivated.

3. Progression: uncontrolled growth, tumor formation, metastasis.

Nutrition factors increase cancer risk

Obesity, red/processed meats, charred foods (PAHs, HCAs), nitrates (nitrosamines), high salt, high calcium (>1500 mg/day), alcohol, low physical activity, beta-carotene supplements in smokers.

Nutrition factors decrease cancer risk

Fruits/vegetables, carotenoids, tomato products (lycopene), allium vegetables (onion, garlic), Vitamin C, folate, fiber, milk/calcium, omega-3 fatty acids, soy (before adulthood).

How does obesity increase cancer risk

Increases inflammation, insulin resistance, hormone changes, and decreases survival after cancer diagnosis. Obesity in adolescence increases adult cancer risk.

Benefit of eating the rainbow

Different colored fruits/vegetables contain different phytochemicals: red (lycopene), purple (anthocyanins), orange (beta-carotene), yellow-green (lutein, zeaxanthin), green (sulforaphanes), white-green (allyl sulfides).

Side effects of cancer treatment

Surgery, radiation, chemotherapy can damage healthy cells, leading to hair loss, nausea, appetite loss, dry mouth, sore throat, dental issues, diarrhea, constipation, fatigue, depression.

How can cancer treatment side effects be managed nutritionally

Eat several small high-calorie, high-protein meals/snacks. Use calorie-dense foods (butter, cream, cheese, eggs, meat, legumes). Drink shakes or supplements. Eat favorite foods anytime. Separate fluids from meals. Exercise lightly to increase appetite.

Nutrients are important for bone health

Calcium, Vitamin D, Vitamin K2, Magnesium, Phosphorus, Copper, Protein, Vitamin C, and Fluoride.

Main functions of bone

Provides structure and support, protects organs, allows movement, stores minerals like calcium, phosphorus and Fluoride, and houses bone marrow for blood cell production.

Components of bone

35% organic material (mainly collagen for flexibility) and 65% mineral (calcium and phosphate for strength).

Two types of bone tissue

Cortical bone (dense outer shell, 80% of skeleton, many small bones) and trabecular bone (spongy inner lattice, 20%, site of rapid turnover, supports cortical bone).

Bone Development

bone growth, bone modeling, bone remodeling

Bone Growth

Determines bone size

Begins in the womb

Continues into early adulthood

Bone Modeling

Determines bone shape

Begins in the womb

Continues into early adulthood

Bone Remodeling

Occurs during adulthood

Maintains bone density

Replaces old bone w/new bone to maintain mineral balance

Involves resorption and formation

Bone remodeling

The lifelong process of bone renewal involving resorption (osteoclasts break down bone) and formation (osteoblasts build new bone).

Osteoclasts

Bone break down cells and release calcium

Osteoblasts

New bone build cells by laying down collagen and minerals.

Resorption

Bone surface broken down by osteoclasts

Osteoclasts erode bone to:

Release calcium & minerals into blood

Repair bone or provide minerals for other sites

Formation

New bone created by osteoblasts

Osteoblasts produce collagen matrix

Hydroxyapatite (Ca & P) deposits around collagen fibers

Peak bone density occur

Around age 30; after that, bone resorption exceeds formation, leading to gradual bone loss. Female loss more due to menopause.

bone density measure

By DEXA (dual-energy X-ray absorptiometry). A T-score compares bone density to a healthy 30-year-old.

The closer to 0 (or higher) your T-score is, the better your bone density.

Osteoporosis

A disease of low bone mass and deterioration of bone tissue, leading to increased fracture risk, especially in spine and hip. fragile bones, fractures, kyphosis. Typically no symptoms early on