Overview
This lecture introduces the major body cavities, their subdivisions, and associated membranes, with definitions and key distinctions crucial for anatomy and physiology students.
Introduction to Body Cavities
- Body cavities are internal spaces that house and protect organs.
- Cavities help separate, protect, and support different organ systems.
Major Body Cavities
- The body is divided into dorsal and ventral cavities.
- Dorsal cavity is located along the back and includes cranial and spinal cavities.
- Ventral cavity is positioned at the front and includes thoracic and abdominopelvic cavities.
Dorsal Cavity Details
- The cranial cavity is within the skull and contains the brain.
- The spinal (vertebral) cavity runs within the vertebral column and protects the spinal cord.
Ventral Cavity Details
- The ventral cavity is larger than the dorsal cavity and subdivided by the diaphragm.
- The thoracic cavity (above the diaphragm) contains the heart and lungs within pleural and pericardial cavities.
- The abdominopelvic cavity (below the diaphragm) houses digestive, urinary, and reproductive organs.
- The abdominal cavity contains the stomach, liver, intestines, and other digestive organs.
- The pelvic cavity contains the bladder, some reproductive organs, and rectum.
Membranes of Body Cavities
- Cavities are lined by serous membranes to reduce friction between moving organs.
- The pleura surrounds the lungs; the pericardium surrounds the heart; the peritoneum lines the abdominal cavity.
Key Terms & Definitions
- Body Cavity — an internal space within the body that houses organs.
- Dorsal Cavity — cavity on the back side of the body; includes cranial and spinal cavities.
- Ventral Cavity — cavity on the front side; includes thoracic and abdominopelvic cavities.
- Cranial Cavity — cavity within the skull, containing the brain.
- Spinal (Vertebral) Cavity — cavity within the vertebrae, housing the spinal cord.
- Thoracic Cavity — upper ventral cavity; contains heart and lungs.
- Abdominopelvic Cavity — lower ventral cavity; contains digestive, urinary, and reproductive organs.
- Serous Membrane — thin tissue lining body cavities and covering organs, reducing friction.
Action Items / Next Steps
- Review diagrams of major body cavities and their membranes.
- Memorize the subdivisions and organs contained within each cavity.
- Practice labeling blank diagrams for self-assessment.