Anatomy and Physiology / Unit 1: Body Organization and Homeostasis
1.4 Body Regions, Planes and Cavities
Notes
Regions are named areas (for example cephalic head, cervical neck, thoracic chest, abdominal, pelvic, brachial arm, femoral thigh).
- Planes are imaginary flat cuts. A sagittal plane divides the body into left and right parts (a midsagittal cut makes equal halves). A frontal (coronal) plane divides it into front (anterior) and back (posterior) parts. A transverse (horizontal) plane divides it into upper (superior) and lower (inferior) parts.
- Dorsal cavity: cranial cavity (brain) and vertebral (spinal) cavity (spinal cord).
- Ventral cavity: thoracic cavity (heart, lungs; the heart sits in the mediastinum) and abdominopelvic cavity (digestive organs, bladder, reproductive organs). The diaphragm separates thoracic from abdominopelvic.
- Serous membranes line ventral cavities: parietal layer lines the cavity wall, visceral layer covers the organ. Fluid between them reduces friction.
- Clinical quadrants: right upper, left upper, right lower, left lower. The appendix is in the right lower quadrant.
Practice
A cut that separates the body into superior and inferior portions is a:
A transverse (horizontal) plane runs across the body, dividing top from bottom.
A patient has pain in the right lower quadrant with suspected appendicitis. In which cavity is the appendix?
The appendix is part of the digestive tract, located in the abdominopelvic cavity.
The thin serous layer that directly covers the surface of the lungs is the:
The visceral layer covers the organ itself, while the parietal layer lines the cavity wall.
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