Body cavity
Body cavity | |
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oligochaete worm. The worm's body cavity surrounds the central typhlosole. | |
Identifiers | |
FMA | 85006 |
Anatomical terminology] |
A body cavity is any space or compartment, or potential space, in an animal body. Cavities accommodate organs and other structures; cavities as potential spaces contain fluid.
The two largest human body cavities are the ventral body cavity, and the dorsal body cavity. In the dorsal body cavity the brain and spinal cord are located.
The membranes that surround the
In amniotes and some invertebrates the peritoneum lines their largest body cavity called the coelom.
Mammals
Mammalian embryos develop two body cavities: the
Human body cavities
The dorsal (posterior) cavity and the ventral (anterior) cavity are the largest body compartments.
The
The
Human body cavities and membranes | ||||
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Name of cavity | Principal contents | Membranous lining | ||
Dorsal body cavity | Cranial cavity | Brain | Meninges | |
Vertebral canal
|
Spinal cord | Meninges | ||
Ventral body cavity | Thoracic cavity | Lungs
|
Pericardium Pleural cavity | |
Abdominopelvic cavity | Abdominal cavity | Peritoneum | ||
Pelvic cavity | reproductive organs
|
Peritoneum |
Ventral body cavity
The ventral cavity has two main subdivisions: the thoracic cavity and the abdominopelvic cavity. The thoracic cavity is the more superior subdivision of the ventral cavity, and is enclosed by the rib cage. The thoracic cavity contains the
The abdominopelvic cavity is the largest cavity in the body occupying the entire lower half of the trunk. Although no membrane physically divides the abdominopelvic cavity, it can be useful to distinguish between the abdominal cavity, and the pelvic cavity. The abdominal cavity occupies the entire lower half of the trunk, anterior to the spine, and houses the organs of digestion. Just under the abdominal cavity, anterior to the buttocks, is the pelvic cavity. The pelvic cavity is funnel shaped, and is located inferior and anterior to the abdominal cavity, and houses the organs of reproduction.[2]
Dorsal body cavity
The dorsal body cavity contains the
In the dorsal cavity, the cranial cavity houses the brain, and the spinal cavity encloses the spinal cord. Just as the brain and spinal cord make up a continuous, uninterrupted structure, the cranial and spinal cavities that house them are also continuous. The brain and spinal cord are protected by the bones of the skull and vertebral column and by cerebrospinal fluid, a colorless fluid produced by the brain, which cushions the brain and spinal cord within the dorsal body cavity.[2]
Development
At the end of the third week of
The lateral body wall folds, pulling the amnion in with it so that the amnion surrounds the embryo and extends over the connecting stalk, which becomes the umbilical cord, which connects the fetus with the placenta. If the ventral body wall fails to close, ventral body wall defects can result, such as ectopia cordis, a congenital malformation in which the heart is abnormally located outside the thorax. Another defect is gastroschisis, a congenital defect in the anterior abdominal wall through which the abdominal contents freely protrude. Another possibility is bladder exstrophy, in which part of the urinary bladder is present outside the body. In normal circumstances, the parietal mesoderm will form the parietal layer of serous membranes lining the outside (walls) of the peritoneal, pleural, and pericardial cavities. The visceral layer will form the visceral layer of the serous membranes covering the lungs, heart, and abdominal organs. These layers are continuous at the root of each organ as the organs lie in their respective cavities. The peritoneum, a serum membrane that forms the lining of the abdominal cavity, forms in the gut layers and in places mesenteries extend from the gut as double layers of peritoneum. Mesenteries provide a pathway for vessels, nerves, and lymphatics to the organs. Initially, the gut tube from the caudal end of the foregut to the end of the hindgut is suspended from the dorsal body wall by dorsal mesentery. Ventral mesentery, derived from the septum transversum, exists only in the region of the terminal part of the esophagus, the stomach, and the upper portion of the duodenum.[4]
Function
These cavities contain and protect delicate internal organs, and the ventral cavity allows for significant changes in the size and shape of the organs as they perform their functions.
Anatomical structures are often described in terms of the cavity in which they reside. The body maintains its internal organization by means of membranes, sheaths, and other structures that separate compartments.
The lungs, heart, stomach, and intestines, for example, can expand and contract without distorting other tissues or disrupting the activity of nearby organs.[2] The ventral cavity includes the thoracic and abdominopelvic cavities and their subdivisions. The dorsal cavity includes the cranial and spinal cavities.[2]
Other animals
Organisms can be also classified according to the type of body cavity they possess, such as
Coelom
In amniotes and some invertebrates, the coelom is the large cavity lined by mesothelium, an epithelium derived from mesoderm. Organs formed inside the coelom can freely move, grow, and develop independently of the body wall while fluid in the peritoneum cushions and protects them from shocks.
See also
References
This Wikipedia entry incorporates text from the freely licensed Connexions [1] edition of Anatomy & Physiology [2] text-book by OpenStax College
- ^ a b Ehrlich, A.; Schroeder, C.L. (2009), "The Human Body in Health and Disease", Introduction to Medical Terminology (Second ed.), Independence, KY: Delmar Cengage Learning, pp. 21–36
- ^ a b c d "Anatomy & Physiology". Openstax college at Connexions. Retrieved November 16, 2013.
- ^ Sadler (2012). LANGMAN Embriología médica. Vol. I (12 ed.). Philadelphia, PA: The Point.
- ^ Tortora, Gerard; Derrickson, Bryan (2008). Principios de anatomía y fisiología. Vol. I (11 ed.). Buenos Aires: Panamericana.
- ^ "Animals III — Pseudocoelomates and Protostome Coelomates". Archived from the original on 2009-04-06.