Overview
This lecture covers essential medical terminology related to the organization and orientation of the human body, including organ systems, body positions, directional terms, body planes, and cavities.
Levels of Organization
- The body is organized from chemical (atoms, molecules) to cellular, tissue, organ, organ system, and organism levels.
- Atoms combine to form molecules, which are the building blocks of body structures.
- Cells are the smallest functional units, containing organelles and performing life functions.
- Tissues are groups of similar cells working together for a specific function.
- Organs consist of two or more tissue types and perform specific physiological tasks.
- Organ systems are groups of organs collaborating to perform major functions.
Major Organ Systems
- Eleven main organ systems include integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, and reproductive.
- Most organs serve multiple systems, collaborating for overall body function.
Anatomical Position and Body Positions
- Anatomical position: standing upright, feet shoulder-width apart, arms at side, palms facing forward.
- Terminology is based on the body being in anatomical position for accuracy.
- Prone describes lying face down; supine describes lying face up.
Regional and Directional Terms
- Specific terms designate regions (e.g., brachial for upper arm, femoral for thigh).
- Directional terms describe locations: anterior (front), posterior (back), superior (above), inferior (below), medial (toward midline), lateral (away from midline), proximal (closer to trunk), distal (farther from trunk), superficial (closer to surface), deep (further from surface).
Body Planes
- Sagittal plane divides the body into right and left parts (midsagittal is equal, parasagittal is unequal).
- Frontal (coronal) plane divides the body into anterior and posterior parts.
- Transverse plane divides the body into upper (superior) and lower (inferior) parts.
Body Cavities
- Dorsal (posterior) cavity: cranial and spinal cavities, protecting brain and spinal cord.
- Ventral (anterior) cavity: includes thoracic and abdominopelvic cavities, allowing organ movement and expansion.
- Body cavities are lined with membranes and contain/protect vital organs.
Key Terms & Definitions
- Anatomy — study of body structure.
- Physiology — study of body function.
- Homeostasis — maintenance of stable internal conditions.
- Anatomical position — standard reference body pose (standing, palms forward).
- Prone — body lying face down.
- Supine — body lying face up.
- Sagittal plane — divides body into right and left.
- Frontal (coronal) plane — divides body into front and back.
- Transverse plane — divides body into upper and lower halves.
- Dorsal cavity — back body cavity (cranial and spinal).
- Ventral cavity — front body cavity (thoracic, abdominopelvic).
Action Items / Next Steps
- Memorize directional, regional, and positional terms.
- Review images/diagrams of body planes and cavities.
- Watch the Crash Course A&P #1 video for further reinforcement.