Organization of the Human Body

Organization of the Human Body

• Anatomy is the study of the structure and shape of the body and its parts.
• Physiology is the study of how the body and its parts work or function.
• Levels of organization: Chemical, Cellular, Tissue, Organ, System, Organismal

Levels of Organization and Body Systems

• Chemical Level: Atoms (e.g., C, H, O, N, P) combine to form molecules (e.g., DNA).
• Cellular Level: Cells are the basic structural and functional units of life.
• Tissue Level: Groups of similar cells working together to perform a specific function form tissues.
• Organ Level: Different tissues combine to form organs which have specific functions.
• System Level: Related organs working together to perform an overall function.
• Organismal Level: The entire organism, resulting from all of the other levels functioning together.

Life Processes

• Metabolism: The sum of all chemical processes in the body.
• Responsiveness: The body's ability to detect and respond to changes in its internal or external environment.
• Movement: Includes motion of the whole body, individual organs, single cells, and organelles.
• Growth: Increase in body size.
• Differentiation: Unspecialized cells become specialized cells.
• Reproduction: Formation of new cells or a new individual.

Survival Needs

• Water: Essential for metabolic reactions, maintaining body temperature, and appropriate atmospheric pressure.

Homeostasis

• Homeostasis is the maintenance of a stable internal environment despite changes inside or outside the body.
• It's a dynamic state of equilibrium.
• Maintaining homeostasis is essential for normal body function and life.

Feedback Systems

• A negative feedback system works to maintain dynamic equilibrium in an organism by returning conditions to normal.
• A positive feedback system reinforces a change in the body.

Anatomical Terms - The Language of Anatomy

• Anatomical terms are used to avoid ambiguity and facilitate communication regarding locations, directions, regions, and structures that may be used in research or studies.

Anatomical Terms - Directional Terms

• Directional terms are used to describe the relationship between body structures. Key examples: Superior, Inferior, Anterior, Posterior, Medial, Lateral, etc.

Anatomical Terms - Body Planes and Sections

• Body planes and sections are imaginary lines used to divide the body (or an organ) into different perspectives.

Body Cavities

• Cranial cavity contains the brain in the skull.
• Vertebral canal contains the spinal cord.
• Thoracic cavity contains the heart, lungs, and other organs.
• Abdominopelvic cavity contains the abdominal and pelvic cavities with significant organs like the digestive system.

Abdominopelvic Regions

• Multiple subdivisions exist to identify regional locations.

Quadrants of the Abdominopelvic Cavity

• Further subdivisions used to distinguish areas for diagnosis and surgical reference.