Introduction to Anatomy and Physiology

Key Concepts

• Anatomy: Study of the structure and relationships between body parts.
• Physiology: Science of how body parts function together and keep the body alive.

Interesting Facts About the Human Body

• Intestines length: ~3-story building if stretched out.
• Lifetime saliva production: Enough to fill more than one swimming pool.
• Dead skin cell loss: About 50 kilograms over a lifetime, feeding colonies of dust mites.

Importance of Anatomy and Physiology

• Understanding processes like illness, recovery, eating, sleeping, thinking, etc.
• Comprehending the cause of death, disease, and recovery mechanisms.

Historical Context

• Ancient Practices: Galen used pigs for vivisections; Da Vinci conducted human dissections secretly.
• 17th-18th Century: Anatomists allowed regulated human dissections, becoming public events attended by famous artists.
• 1832 Anatomy Act (Britain): Provided corpses from executed murderers for medical study; modern use of voluntarily donated bodies.

Complementarity of Structure and Function

• Form determines function (e.g., heart valves, bones).
• Applies at all levels of body organization: from cells to tissues to organs to systems.

Levels of Organization

1. Atoms and Molecules: Basic chemical level.
2. Cells: Smallest units of living things (e.g., red blood cells, motor neurons).
3. Tissues: Groups of similar cells (e.g., muscles, connective tissues).
4. Organs: Combinations of tissues performing specific functions (e.g., heart, liver).
5. Organ Systems: Groups of organs working together (e.g., digestive system).
6. Organism: Complete living entities (e.g., humans, dogs).

Homeostasis

• Maintaining stable internal conditions despite external changes.
• Vital for survival; imbalance leads to death (e.g., through organ failure, suffocation, dehydration).

Anatomical Language

• Directional Terms: Precise language for medical communication.
  • Anterior (front) vs. Posterior (back)
  • Superior (top) vs. Inferior (bottom)
  • Medial (toward midline) vs. Lateral (away from midline)
  • Proximal (closer to trunk) vs. Distal (farther from trunk)

Planes of the Body

• Sagittal Plane: Divides body into left and right parts.
• Parasagittal Plane: Parallel to sagittal but offset.
• Coronal (Frontal) Plane: Splits body into front and back parts.
• Transverse (Horizontal) Plane: Divides body into top and bottom parts.

Practical Application

• Using anatomical language to locate specific body parts (e.g., surgeon locating a toothpick in the esophagus).

Conclusion

• Anatomy studies the structure, while physiology studies the function of body parts.
• Central principles include the complementarity of structure and function, organizational hierarchy, and homeostasis.
• Directional terms are crucial for accurate medical communication.