Anatomy and Physiology
Anatomy and Physiology in the RRB Staff Nurse paper tests structure–function links and the normal values that make abnormal findings meaningful. Questions are usually applied: which organ produces a hormone, which vessel carries oxygenated blood, what happens when a value moves outside range.
Cell, tissue and homeostasis
The cell membrane is selectively permeable; mitochondria produce ATP; the nucleus holds DNA. Homeostasis keeps pH at 7.35–7.45, core temperature near 37 °C and fasting blood glucose around 70–110 mg/dL. Negative feedback reverses change; positive feedback amplifies it, as in labour contractions and clotting.
Systems to know cold
- Respiratory: alveoli exchange gases; surfactant reduces surface tension; the right lung has three lobes, the left two.
- Cardiovascular: cardiac output = heart rate × stroke volume, normally about 5 L/min; the pulmonary artery carries deoxygenated blood.
- Renal: the nephron filters plasma; the kidney secretes erythropoietin and renin and activates vitamin D.
- Endocrine: insulin lowers glucose and glucagon raises it; parathyroid hormone raises serum calcium; the thyroid needs iodine.
- Skeletal: 206 bones in the adult; red marrow forms blood cells.
Worked example
Heart rate 70/min, stroke volume 70 mL. Cardiac output = 70 × 70 = 4900 mL/min, about 4.9 L/min. If stroke volume falls to 50 mL while rate stays 70, output falls to 3500 mL/min; a compensatory rise in rate to 100 restores 5000 mL/min.
Traps
The pulmonary artery is the exception: it carries deoxygenated blood to the lungs, while the aorta carries oxygenated blood. Do not confuse the kidney (erythropoietin) with the liver (albumin, clotting factors). Normal pH is 7.35–7.45, not 7.0.