Here's a breakdown:

* Epithelial tissue: This tissue covers surfaces, lines cavities, and forms glands. It's made of tightly packed cells with little to no intercellular space.

* Connective tissue: Connective tissue supports and connects other tissues. It's diverse, with various cell types embedded in a matrix of protein fibers and ground substance.

* Muscle tissue: This tissue is responsible for movement. Muscle cells (muscle fibers) are specialized to contract.

* Nervous tissue: Nervous tissue conducts electrical impulses throughout the body. It contains neurons (nerve cells) and glial cells, which support and protect neurons.

While the specific cell types vary between tissues, the fundamental building block of every tissue is the cell.