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Friday, December 26, 2008

Body Cavities

A body cavity is a space within the body that contains internal organs.

A body cavity is any fluid filled space in a multicellular organism, it is located between an animal's outer covering (epidermis) and the outer lining of the gut cavity, where internal organs develop.

"The body cavity" of human body cavities normally refers to the ventral body cavity, because it is by far the largest one in area.

The collective visceral cavity of the trunk (thoracic cavity plus abdominopelvic cavity), bounded by the superior thoracic aperture above, the pelvic floor below, and the body walls (parietes) in between.

Our body consists of five body cavities, such as
1. Cranial cavity
2. Thoracic cavity
3. Abdominal cavity
4. Pelvic cavity
5. Spinal cavity

Now we will study briefly each cavity and the organs within each cavity:

1. Cranial cavity: This cavity consists of brain and pituitary gland.

2. Thoracic cavity: This cavity consists of lungs, heart, esophagus, trachea, bronchial tubes, thymus gland, aorta (largest artery).

Thoracic cavity can also be divided into two other smaller cavities.

a. Pleural cavity: This is a space between the membranes that surround each lung. Two pleural cavities are lined with a double-folded membrane called pleura.

b. Mediastinum: This is the space between the lungs. This space contains the heart, aorta, trachea, esophagus, thymus gland, and bronchial tubes.

3. Abdominal cavity: This cavity consists of stomach, small and large intestines, spleen, liver, gallbladder and pancreas. There is a double-folded membrane surrounding the abdominal cavity.
4. Pelvic cavity: This cavity consists of urinary bladder, ureters, urethra uterus and vagina in the female.

5. Spinal cavity: This cavity consists of nerves of the spinal cord.

We can divide all the body cavities into two according to their location in the body, such as dorsal cavities (posterior) and ventral cavities (anterior). Cranial and spinal cavities are posterior body cavities as they are placed in the back portion of the body and thoracic abdominal pelvic cavities are anterior cavities because they are placed in the front portion of the body.

Mediastinum is the muscular wall that separates abdominal and thoracic cavities. On the other hand abdominal and pelvic cavities are not divided by any wall like structures. These two cavities in combination also called as abdominopelvic cavity.

Now in the next lesson we will study about abdominopelvic regions and its quadrants.

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