The term "cavity" in human biology usually refers to a hollow space or compartment in the body that contains organs. These cavities protect the organs, hold them in place, and sometimes help them function properly. There are several major cavities in the human body, and each one contains different organ systems.

1. Cranial Cavity

This is the space inside the skull.It contains the brain and is protected by the skull bones and layers of membranes called the meninges. It also has cerebrospinal fluid that cushions the brain.

2. Spinal Cavity (Vertebral Cavity)

This cavity runs through the vertebral column (spine) and contains the spinal cord.The spinal cord is protected by the vertebrae and is also surrounded by cerebrospinal fluid and meninges.

3. Thoracic Cavity

Located in the chest area, this cavity is separated from the lower cavities by a large muscle called the diaphragm.It contains:

• Lungs (in pleural cavities)

• Heart (in the pericardial cavity)

• Major blood vessels like the aorta

• Parts of the windpipe and esophagus

4. Abdominal Cavity

This is the upper part of the abdominopelvic cavity, located below the diaphragm.It contains:

• Stomach

• Liver

• Pancreas

• Small intestine

• Most of the large intestine

• Kidneys

• Spleen

This cavity is lined with a thin protective membrane called the peritoneum.

5. Pelvic Cavity

Located below the abdominal cavity, it forms the lower part of the abdominopelvic cavity.It contains:

• Urinary bladder

• Rectum

• Reproductive organs (like uterus and ovaries in females, and prostate in males)

Unlike the upper cavities, the pelvic cavity has more rigid bone protection from the pelvic bones.

6. Oral Cavity (Mouth Cavity)

This is the space inside the mouth.It contains:

• Teeth

• Tongue

• Salivary glands

It plays a major role in digestion, speaking, and breathing.

7. Nasal Cavity

This is the space inside the nose.It helps filter, warm, and moisten air before it goes to the lungs and also plays a role in the sense of smell.

8. Orbital Cavities

These are the eye sockets in the skull.They contain and protect the eyeballs, optic nerves, and associated muscles and glands.

Summary:

Cavities in the body are empty spaces or compartments that protect, support, and hold organs. Each cavity has specific organs, and together they organize the inside of the body in a very efficient way.