What Are Body Cavities?
The human body, like that of many other multicellular organisms, is divided into a number of body cavities. A body cavity is a fluid-filled space inside the body that holds and protects internal organs.
Human body cavities are separated by membranes and other structures.
The two largest human body cavities are the ventral cavity and the dorsal cavity. These two body cavities are subdivided into smaller body cavities. Both the dorsal and ventral cavities and their subdivisions are shown in figure.
Figure 10.5.210.5.2: The ventral cavity includes the thoracic and abdominopelvic cavities and their subdivisions. The abdominopelvic cavity is further divided into abdominal and pelvic cavities. The dorsal cavity includes the cranial and spinal cavities.
Ventral Cavity
The ventral cavity is at the anterior, or front, of the trunk. Organs contained within this body cavity include the lungs, heart,
stomach, intestines, and reproductive organs. You can see some of the organs in the ventral cavity in Figure 10.5.310.5.3.
The ventral cavity allows for considerable changes in the size and shape of the organs within it as they perform their functions. For example, organs such as the lungs, stomach, or uterus can expand or contract without distorting other tissues or disrupting the activities of nearby organs.
Figure 10.5.310.5.3: Some of the major organs such as the spleen, stomach, pancreas, gallbladder, liver, lungs, and heart inside the ventral cavity of the human body.
The ventral cavity is subdivided into the thoracic and abdominopelvic cavities.
Thethoracic cavity - fills the chest and is subdivided into two pleural cavities and the pericardial cavity. The pleural cavities hold the lungs, and the pericardial cavity holds theheart.
Theabdominopelvic cavity - fills the lower half of the trunk and is subdivided into the abdominal cavity and the pelvic cavity. The abdominal cavity holds digestive organs and the kidneys, and the pelvic cavity holds reproductive organs and organs ofexcretion.
Dorsal Cavity
The dorsal cavity is at the posterior, or back, of the body, including both the head and the back of the trunk. The
dorsal cavity is subdivided into the cranial and spinal cavities.
Thecranial cavity - fills most of the upper part of theskulland contains thebrain.
Thespinal cavity - is a very long, narrow cavity inside thevertebral column. It runs the length of the trunk and contains thespinal cord.
The brain and spinal cord are protected by the bones of the skull and the vertebrae of the spine. They are further protected by the meninges, a three-layer membrane that encloses the brain and spinal cord.
A thin layer of cerebrospinal fluid is maintained between two of the meningeal layers. This clear fluid is produced by the brain, and it provides extra protection and cushioning for the brain and spinal cord.