Overview

While anatomy studies the structure (what it looks like), physiology studies the function (how it works). It explains how bodies survive, grow, and reproduce.

Core Idea

Homeostasis: The ability of an organism to maintain a stable internal environment despite changes in the external environment (e.g., keeping body temperature at 37°C).

Formal Definition (if applicable)

Negative Feedback Loop: A regulatory mechanism in which a stimulus causes an opposite output in order to maintain an ideal level of whatever is being regulated.

Intuition

Your body is like a high-tech building with climate control. If it gets too hot, the AC (sweating) kicks in. If it gets too cold, the heater (shivering) turns on. Physiology explains the wiring of these systems.

Examples

  • Action Potential: The electrical signal that travels down a nerve.
  • Gas Exchange: How lungs take in oxygen and release carbon dioxide.
  • Digestion: Breaking down food into nutrients the body can use.

Common Misconceptions

  • “We only use 10% of our brains.” (We use all of it, just not all at once.)
  • “Muscle turns into fat.” (They are different tissues; one cannot turn into the other.)
  • Anatomy: The study of structure.
  • Pathophysiology: The study of disordered physiological processes (disease).
  • Endocrinology: The study of hormones.

Applications

  • Medicine: Diagnosing and treating illness (when physiology goes wrong).
  • Sports Science: Optimizing human performance.
  • Pharmacology: Understanding how drugs affect body functions.

Criticism / Limitations

Physiology often relies on animal models, which may not always perfectly predict human responses. It also struggles to explain the “mind-body” connection (consciousness).

Further Reading

  • Guyton and Hall, Textbook of Medical Physiology
  • Boron and Boulpaep, Medical Physiology