Tissues are indeed groups of cells that perform the same function and work together to carry out a specific task in the body. They are considered the basic units of structure and function in multicellular organisms. There are four main types of tissues in animals:
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Epithelial Tissue: This type covers and lines surfaces, serving roles in protection, absorption, secretion, and sensation. Examples include skin, the lining of the gastrointestinal tract, and glands.
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Connective Tissue: This tissue supports, binds together, and protects tissues and organs of the body. It includes a variety of types such as bone, adipose (fat) tissue, blood, and cartilage.
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Muscle Tissue: Responsible for movement, muscle tissue can be further classified into three types: skeletal muscle (voluntary movement), cardiac muscle (found in the heart, involuntary), and smooth muscle (involuntary, found in walls of hollow organs).
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Nervous Tissue: Composed of neurons and supporting glial cells, nervous tissue is responsible for transmitting electrical signals throughout the body and processing information.
In plants, tissues are also organized groups of cells that work together to carry out specific functions, such as xylem and phloem for transport, or epidermis for protection.