BJC Health Science cheat sheet

Health is a state of complete physical, mental, and social well-being, not merely the absence of disease (WHO definition).

The health triangle has three sides - physical, mental/emotional, and social - and imbalance on one side affects the other two.

Wellness is the active, ongoing process of making choices toward a higher level of functioning; it is a continuum, not a fixed state.

The wellness continuum runs from premature death at one end through disability, average wellness, and optimal wellness at the other.

Risk factors are behaviors or conditions that increase the chance of disease or injury; protective factors reduce that chance.

The leading actual causes of death in developed nations are largely behavioral: tobacco use, poor diet and inactivity, and alcohol misuse.

Heredity, environment, and available health care are non-modifiable or external influences; lifestyle choices are the factor an individual controls directly.

Life expectancy is the average number of years a person is expected to live; quality of life measures how well those years are lived.

Levels of organization, in order: cell → tissue → organ → organ system → organism.

Skeletal system: about 206 bones in an adult; functions are support, protection, movement, mineral storage, and blood cell production in marrow.

Muscular system: skeletal (voluntary, striated), smooth (involuntary, in organs), and cardiac (involuntary, striated, in the heart) muscle types.

Digestive tract order: mouth → esophagus → stomach → small intestine → large intestine; most nutrient absorption occurs in the small intestine.

Circulatory system: the heart has four chambers; arteries carry blood away from the heart, veins carry it back, and capillaries permit exchange.

Respiratory system: gas exchange occurs in the alveoli; oxygen enters the blood and carbon dioxide is removed there.

Nervous system: the neuron is the functional unit; the brain and spinal cord form the central nervous system, nerves form the peripheral.

Endocrine glands release hormones into the bloodstream; insulin from the pancreas lowers blood glucose, glucagon raises it.

Urinary system: the kidneys filter blood, producing urine; they regulate water balance, electrolyte levels, and blood pressure.

Communicable diseases spread through contact, airborne droplets, vectors, food and water, or blood; non-communicable diseases do not spread between people.

Pathogen categories include bacteria, viruses, fungi, protozoa, and parasites; antibiotics act on bacteria, not on viruses.

The chain of infection has six links - pathogen, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host - and breaking any link stops spread.

Primary prevention acts before disease occurs (immunization, hand hygiene); secondary prevention is early detection (screening); tertiary prevention limits disability.

Herd immunity protects unvaccinated individuals when a high proportion of a population is immune, reducing pathogen transmission.

Incidence counts new cases in a period; prevalence counts all existing cases at a point in time.

Standard precautions such as hand washing and glove use apply to all body fluids regardless of a known diagnosis.

Vector control targets organisms such as mosquitoes and ticks that transmit pathogens between hosts.

Six nutrient classes: carbohydrates, proteins, fats, vitamins, minerals, and water; water is the most essential for life.

Carbohydrates and fats are primary energy sources; protein supplies about 4 kcal per gram, as do carbohydrates, while fats supply about 9 kcal per gram.

Amino acids are the building blocks of protein; nine are essential and must come from the diet.

Vitamins are micronutrients needed in small amounts; fat-soluble vitamins (A, D, E, K) are stored in body fat, water-soluble ones are not.

MyPlate groups foods into fruits, vegetables, grains, protein foods, and dairy, with vegetables and grains making up the largest share.

The FITT principle describes exercise prescription: Frequency, Intensity, Time, and Type.

Aerobic activity trains the heart and lungs; resistance training builds muscular strength and endurance; stretching improves flexibility.

Body mass index is weight in kilograms divided by height in meters squared (kg/m²); it is a screening tool, not a diagnosis.

Dehydration impairs performance and thermoregulation; fluid needs rise with heat, humidity, and exercise duration.

Mental health includes emotional, psychological, and social well-being and affects how a person thinks, feels, and acts.

The five general adaptation syndrome stages described by Selye are alarm, resistance, and exhaustion - three stages, with the alarm stage triggering the fight-or-flight response.

Defense mechanisms such as denial, rationalization, and projection are unconscious strategies that reduce anxiety in the short term.

Maslow's hierarchy orders needs from physiological, safety, belonging, esteem, to self-actualization.

Depression is characterized by persistent sadness, loss of interest, and changes in sleep or appetite lasting two weeks or more.

Warning signs of suicide risk include withdrawal, giving away possessions, and talking about being a burden; asking directly does not increase risk.

Stigma is a mark of disgrace that discourages people from seeking treatment; reducing stigma improves help-seeking behavior.

Grief follows recognizable stages that vary by individual; there is no fixed timetable, and reactions may recur.

The emergency action steps are Check, Call, Care: check the scene and the person, call emergency services, then give care.

Adult CPR: compressions at a rate of 100–120 per minute, at least 2 inches deep, with a compression-to-ventilation ratio of 30:2.

For a choking adult who can cough, encourage coughing; for a conscious person who cannot breathe, give back blows and abdominal thrusts.

Severe bleeding is controlled with direct pressure; a tourniquet is used only when direct pressure fails on a limb.

For burns, cool with running water; do not apply ice or pop blisters.

For suspected poisoning, call a poison control center and do not induce vomiting unless instructed.

The RICE method for soft-tissue injury is Rest, Ice, Compression, Elevation.

An AED analyzes the heart rhythm and delivers a shock for ventricular fibrillation; it should be used as soon as it is available.

Fire safety: stay low under smoke, test doors for heat, and never re-enter a burning building.

Autonomy respects a patient's right to make decisions; beneficence means acting for the patient's good; nonmaleficence means doing no harm.

Informed consent requires that the patient understand the procedure, its risks, and alternatives, and consent voluntarily.

Confidentiality is a legal and ethical duty; protected health information may be shared only for treatment, payment, or operations under privacy law.

Scope of practice defines the tasks a health professional is legally permitted to perform; exceeding it is a violation.

The health care team hierarchy includes physicians, nurses, allied health professionals, and technicians, each with defined responsibilities.

Professional credentials include licensure (legal permission to practice), certification (verified competence), and registration (listing on an official roster).

A living will and health care proxy are advance directives that state wishes or name a decision-maker if a patient cannot speak.

Mandatory reporting laws require health workers to report suspected abuse, neglect, or certain communicable diseases to authorities.