Major Themes of Anatomy & Physiology – Quick Review

Anatomy vs Physiology

  • Anatomy: study of structure & form.
  • Physiology: study of function.
  • Principle: form equals function—structure determines capability.

Characteristics of Life

  • Organization: higher order than non-living matter.
  • Cellular composition: one or more cells; cell = basic structural/functional unit.
  • Metabolism: total chemistry of the body; anabolism + catabolism.
  • Responsiveness: detect & respond to stimuli.
  • Generative properties: reproduction, development, growth, repair.
  • Homeostasis: keep internal conditions stable.
  • Evolution: populations undergo genetic change over time.

Homeostasis & Feedback

  • Maintains variables near a set point via feedback loops.
  • Negative feedback: response negates initial change.
    • Receptor → Integrating center → Effector sequence restores balance.

Negative Feedback Example – Body Temperature

  • Heat gain: skin vessel constriction + shivering when below 37∘C37^\circ C.
  • Heat loss: skin vessel dilation + sweating when above 37∘C37^\circ C.

Positive Feedback & Rapid Change

  • Self-amplifying loop; output intensifies stimulus.
  • Produces swift events: childbirth, blood clotting, nerve signal propagation.
  • Potentially harmful if unchecked (e.g., runaway fever).

Disease

  • Results when homeostatic mechanisms fail; internal balance lost.

Renal Physiology – Nephron & Diuretics (Key Points)

  • PCT: bulk reabsorption; osmotic agents act here.
  • Loop of Henle:
    • Descending limb reabsorbs H2OH_2O.
    • Ascending limb reabsorbs NaClNaCl; loop diuretics inhibit.
  • DCT: fine-tunes Na+Na^{+} & Ca2+Ca^{2+}; thiazides act.
  • Collecting duct: regulated by aldosterone (Na+/K+Na^{+}/K^{+}) & ADH (H2OH_2O); K-sparing diuretics affect.

Auditory System Overview

  • External ear: collects sound.
  • Middle ear: conducts vibrations.
  • Inner ear (cochlea): converts mechanical waves to neural impulses.
  • Auditory nerve → brain centers for binaural processing.