Tissues are groups of cells that work together to perform specific functions. There are four main types of tissues: connective tissue provides structure and connects other tissues like bones and tendons; epithelial tissue covers internal and external surfaces and lines body cavities; muscle tissue allows movement by contracting and stretching; and nervous tissue carries signals between the brain and body parts as nerve cells in the brain, spinal cord and fibers.

1. Tissues
Because cells cannot work alone, groups of cells with
similar functions combine together to form tissues.
Connective tissue provides an anchor, connects and also
supports other body tissue. Bones, tendons, ligaments, and
cartilage are connective tissues. Blood is also a form of
connective tissue.
Epithelial tissue covers internal and external body
surfaces.
Epithelial tissue lines the nose, mouth, respiratory tract,
intestines and stomach.
Muscle tissue allows the body to move by contracting and
stretching.
Nervous tissue carries and receives impulses between the
brain and body parts. Nerve tissue makes up the brain,
spinal cord and nerve fibres.