Human Anatomy and Physiology
Core concepts
Know the organization of the major organ systems and their integration: cardiovascular (cardiac cycle, blood pressure, circulation), respiratory (gas exchange, ventilation), renal (filtration, reabsorption, acid-base balance), digestive, endocrine (hormone feedback loops), nervous (action potentials, synapses), and musculoskeletal systems. Understand homeostasis and negative feedback, and be able to predict how a disturbance in one system affects another.
Traps
Questions often test directionality: blood flows from the right ventricle to the lungs and from the left ventricle to the body, and oxygenated blood returns via the pulmonary veins to the left atrium. Another common trap is confusing the roles of the sympathetic and parasympathetic divisions. Remember that insulin lowers blood glucose while glucagon raises it, and that the kidney regulates both water balance and pH. Do not assume that all hormones act through negative feedback; oxytocin during labor is a classic positive feedback example.
Worked example
If a person hyperventilates, carbon dioxide is exhaled faster, blood CO2 falls, and pH rises, causing respiratory alkalosis. The rule of thumb: CO2 behaves as an acid in the blood, so more ventilation raises pH and less ventilation lowers it.
Study tip
For each system, memorize one input, one output, and one feedback loop; most physiology questions reduce to tracing a signal through that loop.