Overview
This lecture covers anatomical terminology, body directional terms, body planes and sections, major body cavities, and the membranes lining these cavities, all foundational for studying human anatomy.
Homeostasis & Feedback
- Homeostasis maintains stable internal conditions necessary for life.
- Negative feedback returns a value to a set point, stabilizing the system (e.g., body temperature).
- Positive feedback amplifies a change and occurs in rare events (e.g., childbirth, blood clotting).
Anatomical Position & Directional Terms
- Anatomical position: standing upright, facing forward, arms at sides, palms, and toes facing forward.
- Anatomical left/right refers to the subject's own left/right, not the observer’s.
- Directional terms are always used assuming anatomical position.
Pairs of Directional Terms
- Superior: toward the head; Inferior: away from the head.
- Anterior (ventral): toward the front; Posterior (dorsal): toward the back.
- Medial: toward the midline; Lateral: away from the midline; Intermediate: between medial and lateral.
- Proximal: closer to limb attachment; Distal: farther from limb attachment (limbs only).
- Superficial: toward the body surface; Deep: away from the body surface.
Body Planes & Sections
- Sagittal plane divides body into left and right; midsagittal is equal halves, parasagittal is uneven.
- Frontal (coronal) plane divides body into front (anterior) and back (posterior).
- Transverse (cross-section) plane divides body into upper (superior) and lower (inferior) parts.
Anatomical Terminology
- Anatomical terms often indicate location (e.g., axillary = armpit, patella = kneecap).
- Focus on terms used in today’s lab and practice worksheet; more will be learned throughout the semester.
Body Cavities
- Dorsal (posterior) body cavity contains cranial (brain) and vertebral (spinal cord) cavities.
- Ventral (anterior) body cavity includes thoracic (chest, divided into pleural, mediastinum, pericardial) and abdominopelvic cavities (abdominal and pelvic).
- Diaphragm separates thoracic and abdominopelvic cavities.
Abdominopelvic Regions & Quadrants
- Nine regions: umbilical (center), epigastric (above), hypogastric (below), right/left hypochondriac, right/left lumbar, right/left iliac.
- Four quadrants: upper/lower left and right.
Serous Membranes
- Serous membranes line cavities and organs, reducing friction via serous fluid.
- Visceral layer contacts organs; parietal layer lines cavity walls.
- Named pericardium (heart), pleura (lungs), peritoneum (abdominal organs).
Additional Cavities
- Oral (mouth), nasal, orbital (eyes), middle ear, and synovial (joint) cavities.
Key Terms & Definitions
- Homeostasis — stable internal environment.
- Negative Feedback — mechanism restoring a system to its set point.
- Positive Feedback — mechanism amplifying changes, rare in the body.
- Anatomical Position — standard body orientation for reference.
- Directional Terms — words describing locations in the body (e.g., superior/inferior).
- Serous Membrane — double membrane lining body cavities and organs.
- Pericardium — serous membrane around the heart.
- Pleura — serous membrane around the lungs.
- Peritoneum — serous membrane around abdominal organs.
Action Items / Next Steps
- Practice using directional terms and anatomical terminology during lab activities.
- Focus on the anatomical terms present in the lab and practice worksheet.
- Review diagrams of body cavities, planes, and abdominopelvic regions/quadrants.