Human Anatomy, Physiology, and Health
What to know
Major systems and their functions: circulatory (heart, blood vessels, blood transport, gas exchange), respiratory (lungs, alveoli for gas exchange), digestive (breakdown and absorption of nutrients), nervous (signal transmission, brain and spinal cord), endocrine (hormones regulating metabolism and growth), musculoskeletal (support and movement), excretory (kidneys filter blood, regulate water and salts), and immune (defense against pathogens).
Homeostasis maintains stable internal conditions - temperature, pH, blood glucose, water balance - through feedback loops. Negative feedback reverses a change (insulin lowers high blood glucose); positive feedback amplifies one (childbirth contractions). The heart has four chambers; arteries carry blood away from the heart, veins return it, and capillaries exchange materials. Blood carries oxygen via hemoglobin, nutrients, hormones, and wastes. Neurons transmit electrical impulses; synapses use neurotransmitters.
Health topics: pathogens cause infectious disease; the immune system uses antibodies and white blood cells. Vaccines stimulate immunity without causing disease. Nutrition requires balanced macronutrients and micronutrients; exercise and sleep support health. Risk factors for chronic disease include poor diet, inactivity, smoking, and genetics.
Traps
Questions reverse artery and vein direction, treat positive feedback as "good," or confuse the roles of insulin and glucagon. Watch for claims that vaccines cause the disease they prevent.
Rule of thumb and worked example
After a meal, blood glucose rises; the pancreas releases insulin, which signals cells to take up glucose and the liver to store it, lowering blood glucose - negative feedback. Between meals, glucagon raises blood glucose by releasing stored glucose.