The human body is made up of microscopic cells. These building blocks of life combine and work in harmony to form the functioning human body. While many cells make up simple body parts, such as tissues, some complete more complex and specialized tasks. These specialized cells are specially designed to perform the functions for which they are intended. Each of these cell types are formed and operate differently, ensuring that the cell can carry out the necessary body function that it is intended to complete.

Neurons are specialized cells that carry messages within the human brain. These cells come in an assortment of shapes and sizes. While these cells do share some similarities with other cells, they also have specialized features that enable them to complete the necessary communicative functions. These cells have extensions called dendrites and axons that bring information into and, release information from, the cell itself. Some also contain structures and carry chemicals that are specialized for electrochemical communication, allowing them to communicate with each other and making basic thought and body functioning possible.

Muscle cells make movement possible. These cylindrical cells are made up of banded fibers that allow for contraction. Through the functioning of these specialized cells the human body can complete an assortment of movement-based tasks. These cells, like many in the human body, join together to create larger body structures.

Specialized sperm cells are necessary for human reproduction. These cells are made up predominantly of a nucleus. Unlike some stationary cells, these cells are highly mobile as they must move to locate an egg for fertilization to occur. The mitochondria within the sperm cell provides the energy that specialized cells of this type require to move at such high rates of speed.

Red blood cells carry oxygen around the body, delivering it to organs that require this life-giving gas. These cells lack an assortment of pieces commonly associated with cells, including mitochondria and a nucleus. The absence of these organelles allows the cell to carry more oxygen around the body. Cells of this type are predominantly composed of hemoglobin, a chemical that allows for the uptake and carrying of oxygen.

Leukocyte cells work to keep the human body free of infection. These cells find and destroy microbes within the human body, responding to and treating infection. Because these cells must move to the site of infection, they are highly mobile and even capable of pushing through capillary walls when necessary to reach sites of infection. Leukocyte are highly flexible, capable of shifting shape as necessary as they move throughout the body.