Orientation and Organization of the Human Body (Anatomy & Physiology)

Anatomy and Physiology

  • Anatomy: study of the structure and shape of the body and its parts; relationships among parts.
  • Physiology: study of how the parts function; the workings of the body.
  • Core idea: structure determines function; form dictates what parts can do.

Interrelationship of Structure and Function

  • Anatomy and physiology are inseparable; understanding both explains how organs and systems interact to sustain life.

Levels of Structural Organization

  • Six levels: 6
    • Chemical level: atoms form molecules.
    • Cellular level: cells are the basic unit of life.
    • Tissue level: tissues are groups of similar cells.
    • Organ level: organs are structures composed of two or more tissue types performing a specific function.
    • Organ system level: organ systems are groups of organs working together.
    • Organismal level: the organism as a whole, the sum of all levels.
  • There are 11 organ systems in the human body.

From Atoms to Organisms

  • Atoms combine to form molecules.
  • Molecules form cells.
  • Cells form tissues.
  • Tissues form organs.
  • Organs form organ systems.
  • Organ systems form the organism (the human body).

The Organ Systems Overview

  • Integumentary System: external covering of the body (skin, hair, nails); protects, cushions, vitamin D synthesis, temperature regulation; sensory receptors.
  • Skeletal System: bones and joints; supports and protects organs; framework for muscles; stores minerals; blood cell formation.
  • Muscular System: enables movement and locomotion; maintains posture; generates heat.
  • Nervous System: fast-acting control system; brain, spinal cord, nerves; senses changes; transmits nerve impulses; responds to stimuli.
  • Endocrine System: glands secrete hormones that regulate growth, reproduction, and metabolism; slower, widespread effects.
  • Cardiovascular System: heart and blood vessels; circulates blood to transport oxygen, nutrients, wastes; maintains BP.
  • Lymphatic System: returns leaked fluid to the blood; lymph nodes and lymphoid organs; involved in immunity.
  • Respiratory System: supplies oxygen and removes carbon dioxide; includes airways and lungs; gas exchange in alveoli.
  • Digestive System: tube running mouth to anus; breaks down food; absorbs nutrients; delivers them to the blood.
  • Urinary System: kidneys, ureters, bladder, urethra; removes wastes; regulates water and electrolyte balance.
  • Reproductive System: organs that produce gametes and hormones; enables reproduction.