The cell types of the human body
The cell is the smallest living unit in every living organism. The human body is made of approximately 5×1015 cells, in a great variety according to function as well as feature. We mostly distinguish different cell groups called tissues which means mostly functional difference, but of course function and different features are many times strongly connected, however some tissues like the nervous tissue still shows huge differences in function and features of the contained cells as well.
As we start to discuss tissues, we can distinguish many types int he human body. I would like to have a few words about the most important ones according to our studies in this semester, but of course, there are more (bone cells, immune cells, etc.).
The first of these are the epithelial cells. We can mosly find them in the human skin. It has the main function of protecting the human body from the different mechanic, chemical, bacterial etc. effects. This function obviously requires strong boundaries, connections between the cells.
Also one of the most known type of cells is the muscle cell. These are closely attached to bones and responsible for movement by contractions of our muscles. We distinguish three main types of muscle cells, according to their structure. They are called striated, smooth and cardiac muscle. Smooth muscles are mostly for longer contraction, striated muscles are much stronger, but they tire much sooner. The cardiac muscle cells show an easily recognisable Y shape. They are located int he hearth, created for continuos, hard work.
The cell type that we will speak about the most in this semester is the nervous tissue. Right at the beggining we should distinguish two kind of cells: neurons and glial cells. As we look at the function of the nervous tissue, we can say that it has function in signaling processes and making it possible to get sensory inputs from our enviroment, and use these informations to create the best reaction to them. But neurons and glial cells have clearly different function in these processes: while neurons are responsible of signal transmitting, glial cells have the roll of covering, protecting and supporting neuron sin many ways, like providing the ideal enviroment for neurons, and making the the transmitting process much faster.
We also distinguish blood cells which are essential in transporting oxigen and all the necessary materials that other cells need. There are two main types of cells int he human blood, called the red and the white cells. While red cells have their main roll in transporting oxigen, white cells are more likely parts of the immun system. They have special abilities to recognise bacteria and every other dangerous thing in our circulating system to separate and destroy them.
During the semester we will also speak about the endocrine system, which contain cells that are secreting hormons as chemical messengers to message other cells int he human body by making them travel with the blood flow.
Sources: Röhlich Pál: Szövettan, Lecture slides