Tissue is an ensemble of similar cells and their extracellular matrix, which work together to perform specific functions in the body. Tissues are organized into four basic types:
1. **Epithelial Tissue**: Covers body surfaces, lines body cavities, and forms glands. It serves as a protective barrier and is involved in absorption, secretion, and sensation.
2. **Connective Tissue**: Supports, binds, and protects other tissues and organs. It includes bone, blood, cartilage, and adipose (fat) tissue.
3. **Muscle Tissue**: Responsible for movement and force generation. It is categorized into three types: skeletal muscle (voluntary movement), cardiac muscle (heart function), and smooth muscle (involuntary movement in organs).
4. **Nervous Tissue**: Comprises neurons and supporting cells (glial cells). It is responsible for receiving, processing, and transmitting electrical signals throughout the body.
Each type of tissue has a unique structure and function, contributing to the body's overall health and functionality.