The elongated cells or fusiform are elongated cellular structures size with various functions, the main constitution of muscle tissue. Cells are the functional unit of life. They are the smallest anatomical particles capable of acting autonomously.
They form the basic element for the most complex structures of the human, animal and plant body. All complex cells have two parts: nucleus and cytoplasm. These are called eukaryotic cells. Prokaryotes, for their part, do not have a nucleus.
Elongated cell
Elongated cells are eukaryotic cells and therefore have a rounded nucleus and a cytoplasm. Another more specialized name by which they are known is spindle cells. This appearance occurs mostly in smooth muscle fibrocells and in connective tissue fibrocytes.
If a longitudinal section is made, we could see how the cell has a dilated profile at the tips, while its nucleus, located in the middle of the cell, is more oval and thick.
But in a cross section the perspective would be different. The structure would look like a circular shape, both in the core and its envelope. In this view, the nucleus continues to occupy the central part of the organization.
Function of elongated cells
Cells can join together to form more complex structures. Some of these combinations are the organs, such as the heart; tissues, such as nerve tissue; or devices, such as the reproductive system.
The elongated cells are specially designed naturally to form fibers. This is thanks to the fact that its smooth shape allows greater support. An example is the blood vessels or the skin.
The elongated cells found in the skin have the function of contracting the layers of the dermis in motor movement.
In muscles, these cells are especially important as muscle fibers require their shape to form smooth tissues.
There, the elongated cells are woven into a kind of criss-cross to compact and unify their structure. Its arrangement places the part of the nucleus, with more volume, between two thin ends of neighboring cells.
In this way the cells are interspersed with each other and fully coupled. A wide center next to two thin ends and two thin points among other round nuclei. This allows full contact between all the cells arranged in the fibers. These unions constitute the so-called “links” and “focal contacts”.
Muscles can contract, stretch or deform thanks to this coupling described above.
People have millions of elongated cells in their bodies, enough to weave the 650 muscles that make up the human system.
Other forms of cells
In addition to the elongated ones, cells can have other physical shapes:
The spherical ones are the most common, which are found in liquid media such as blood. They have nuclei and other scattered structures. The flattened ones are more similar to a mosaic. They are found in the linings of the skin.
The stellate cells are highly irregular and without a defined shape, they can have ramifications. The best known are the neurons that make up the nervous system and whose star shape is easily distinguishable.
Lastly, there are the proteiform cells. They do not have a single definite shape and can change depending on the environment where they are. This ability to change allows them to move easily.
References
- Elongated Cell. (1998). Dictionary of Biology. Editorial Complutense. Recovered from books.google.co.ve
- Spindle Cells. (2010). University of the Andes. School of Medicine. Department of Morphological Sciences - Chair of Histology. Recovered from medic.ula.ve
- Córdoba García, F. (2003). The human body. University of Huelva. Recovered from uhu.es
- Fortoul, T and others. (2001). The cell: its structure and function. Histology manual. Recovered from facmed.unam.mx
- The muscles. (2013). Recovered from es.scribd.com.