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Biology & Health Literacy
KNOWLEDGE
YOUR BODY IS A BIOLOGICAL SYSTEM: It follows rules. Understanding those rules helps you stay healthy, treat problems, and avoid making things worse.
Goal: Know enough to make informed decisions about health and recognize when professional help is needed.
How the Body Works
Major Systems Overview
| System | Function | Key Organs |
|---|
| Circulatory | Transports blood, oxygen, nutrients | Heart, blood vessels |
| Respiratory | Gas exchange (oxygen in, CO2 out) | Lungs, diaphragm |
| Digestive | Breaks down food, absorbs nutrients | Stomach, intestines, liver |
| Nervous | Controls body, processes information | Brain, spinal cord, nerves |
| Immune | Fights infection and disease | White blood cells, lymph nodes |
| Musculoskeletal | Movement, structure | Muscles, bones, joints |
| Endocrine | Hormones, metabolism | Pancreas, thyroid, adrenal glands |
| Urinary | Filters blood, removes waste | Kidneys, bladder |
Vital Signs
Key indicators of body function. Know what's normal:
| Sign | Normal Adult | Concerning |
|---|
| Heart rate | 60-100 bpm | <50 or >120 at rest |
| Blood pressure | 90/60 to 120/80 | >140/90 or <90/60 |
| Temperature | 97-99°F (36.1-37.2°C) | >103°F (39.4°C) |
| Respiration | 12-20 breaths/min | <10 or >24 |
| Oxygen saturation | 95-100% | <92% |
Normal varies by individual. Athletes may have lower heart rate. Know YOUR normal.
How Disease Works
Types of Pathogens
| Type | Examples | Treatment |
|---|
| Bacteria | Strep, E. coli, Salmonella | Antibiotics |
| Viruses | Flu, cold, COVID, norovirus | Supportive care, antivirals (some) |
| Fungi | Athlete's foot, ringworm, yeast | Antifungals |
| Parasites | Giardia, ticks, lice, worms | Antiparasitics |
Antibiotics don't work on viruses. Taking antibiotics for a cold is useless and harmful (resistance).
Infection Transmission
- Contact: Touching infected person or surface
- Droplet: Cough/sneeze travels short distance (3-6 feet)
- Airborne: Suspended in air, travels farther (measles, TB)
- Fecal-oral: Contaminated food/water, poor hygiene
- Blood: Needles, transfusions, mother to child
- Vector: Mosquitoes, ticks, fleas
Infection Prevention
- Hand washing: 20 seconds with soap. Most effective prevention.
- Sanitation: Clean surfaces, proper food handling
- Isolation: Sick people stay home, avoid contact
- Vaccination: Prevents many serious diseases
- Safe water/food: Treat water, cook food thoroughly
Common Health Issues
Fever
- What it is: Body's immune response. Not inherently dangerous.
- When to treat: Discomfort, over 103°F in adults
- When to worry: Over 104°F, stiff neck, confusion, won't wake, rash
- Treatment: Rest, fluids, acetaminophen or ibuprofen. Lukewarm bath if very high.
Fever helps fight infection. Treating mild fever may prolong illness. Focus on comfort.
Dehydration
- Signs: Thirst, dark urine, dry mouth, dizziness, confusion
- Severe signs: No urine for 8+ hours, rapid heartbeat, fainting
- Treatment: Oral rehydration (water + salt + sugar), or ORS packets
- Prevention: Drink before thirsty, more in heat/activity/illness
DIY oral rehydration: 1 liter water + 6 tsp sugar + ½ tsp salt. Add potassium (banana, orange juice) if available.
Wound Infection
- Signs: Increasing pain, redness spreading, warmth, pus, red streaks
- Treatment: Clean with clean water, remove debris, keep covered
- When to worry: Red streaks toward heart, fever, won't heal
- Prevention: Clean all wounds, remove debris, keep covered
Food Poisoning
- Cause: Bacteria or toxins in food. Onset hours to days after eating.
- Symptoms: Nausea, vomiting, diarrhea, cramps, fever
- Treatment: Hydration (most important), rest, let it pass
- When to seek help: Blood in stool, severe dehydration, high fever, lasting >3 days
Medication Basics
Common OTC Medications
| Drug | Uses | Notes |
|---|
| Acetaminophen (Tylenol) | Pain, fever | Liver damage in overdose. No anti-inflammatory. |
| Ibuprofen (Advil) | Pain, fever, inflammation | Take with food. Avoid with kidney issues. |
| Aspirin | Pain, fever, heart attack prevention | Don't give to children (Reye's syndrome). |
| Diphenhydramine (Benadryl) | Allergies, sleep | Drowsy. Don't drive. |
| Loperamide (Imodium) | Diarrhea | Don't use for infectious diarrhea (traps bacteria). |
| Antacids | Heartburn | Calcium/magnesium/aluminum varieties. |
Medication Safety
- Dosing: Follow instructions exactly. More is not better.
- Interactions: Some drugs don't mix. Check before combining.
- Expiration: Most drugs lose potency but don't become dangerous (few exceptions).
- Storage: Cool, dry place. Bathroom is often too humid.
- Keep list: All medications you take. Show to any doctor.
Acetaminophen overdose is the #1 cause of acute liver failure. Many cold medicines contain it. Don't double up.
Nutrition Basics
Essential Nutrients
| Nutrient | Purpose | Sources |
|---|
| Protein | Build/repair tissue | Meat, eggs, beans, nuts |
| Carbohydrates | Energy | Grains, fruits, vegetables |
| Fats | Energy, cell function | Oils, nuts, animal fats |
| Vitamin C | Immune, tissue repair | Citrus, peppers, berries |
| Vitamin D | Bone health, immune | Sunlight, fish, fortified foods |
| Iron | Blood oxygen transport | Red meat, beans, leafy greens |
| Calcium | Bones, muscle function | Dairy, leafy greens, fortified foods |
Scurvy and Deficiency Diseases
When certain nutrients are missing long-term:
- Scurvy (Vitamin C): Bleeding gums, loose teeth, bruising, fatigue
- Rickets (Vitamin D/Calcium): Soft bones, deformities in children
- Anemia (Iron): Fatigue, weakness, pale skin, shortness of breath
- Beri-beri (Thiamine/B1): Nerve damage, heart failure
These seem rare but appear in prolonged crises with limited diet. Diverse food prevents them.
Checklists
Know Your Numbers
- [ ] Your normal resting heart rate
- [ ] Your normal blood pressure
- [ ] Your normal temperature
- [ ] Your blood type (if known)
- [ ] Allergies (medications, foods, environmental)
- [ ] Current medications and doses
Health Knowledge to Learn
- [ ] How to take vital signs
- [ ] Signs of infection vs healing
- [ ] When to seek professional help
- [ ] Basic first aid (separate section)
- [ ] How diseases spread
- [ ] How to stay hydrated
Scenario Drills
Drill: Recognize Emergency Signs
Which of these need immediate emergency care?
- Fever of 101°F in adult
- Confusion and stiff neck with fever
- Vomiting for 2 hours
- Difficulty breathing, blue lips
- Small cut on finger
- Chest pain radiating to arm
Answers: Confusion + stiff neck, difficulty breathing + blue lips, chest pain to arm = emergencies. Others need monitoring but not necessarily emergency.
Drill: Hydration Assessment
Person has been vomiting for 6 hours. Urine is dark yellow. Mouth is dry. Alert but tired.
- Degree of dehydration: Moderate
- Action: Oral rehydration solution, small sips frequently
- Monitor for: No urine for 8+ hours, confusion, fainting = severe, needs IV
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