The elongated cells or spindle are cellular structures of elongated size with diverse functions, among the main the constitution of muscular tissue.
Cells are the functional unit of life. They are the smallest anatomical particles capable of acting autonomously.
They conform the basic element for the most complex structures of the human, animal and vegetal body.
All complex cells have two parts: nucleus and cytoplasm. These are called eukaryotic cells. Prokaryotes, for their part, do not have a nucleus.
The elongated cells are eukaryotic cells and therefore have a rounded nucleus and a cytoplasm. Another more specialized name with which they are known is the one of fusiform cells.
This appearance occurs mostly in smooth muscle fibrocells and in fibrocytes of the connective tissue.
If a longitudinal cut 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 cut the perspective would be different. The structure would look like a circular shape, both in the core and in its wrapping. In this view, the core still occupies the central part of the organization.
Function of elongated cells
Cells can be joined together to form more complex structures.
Some of these combinations are organs, such as the heart; tissues, such as nerve tissue; or appliances, such as the reproductive apparatus.
Elongated cells are specially designed to form fibers. This is thanks to its smooth shape allows for greater support. An example are 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 because the muscle fibers require their shape to form smooth tissues.
There, elongated cells are woven into a kind of crusader to compact and unify their structure. Its arrangement locates the part of the nucleus, with more volume, between two thin ends of a neighboring cells.
In this way the cells are intercalated with each other and are fully coupled. A wide center next to two thin ends and two thin tips between other round nuclei.
This allows full contact between all the cells arranged in the fibers. These unions form the so-called"nexus"and"focal contacts".
The muscles can contract, stretch or deform thanks to this coupling described above.
People have millions of elongated cells in their body, enough to weave the 650 muscles that make up the human system.
Other forms of cells
In addition to elongated cells, the cells may have other physical forms:
The spherical ones are the most common, which are found in liquid media such as blood. They have core and other scattered structures.
The flattened ones are more similar to a mosaic. They are found in skin linings.
The stars are extremely irregular cells with no definite shape, they can have ramifications. The best known are the neurons that make up the nervous system and whose star shape is easily distinguishable.
And, finally, are the proteiform cells. They do not have a single defined shape and can change according to the medium where they are. This ability to change allows them to move easily.
References
- Extended Cell. (1998). Dictionary of Biology. Editorial Complutense. Retrieved from books.google.co.ve
- Fusiform cells. (2010). University of the Andes. School of Medicine. Department of Morphological Sciences - Chair of Histology. Recovered from medic.ula.ve
- [Links] The human body. University of Huelva. Recovered from uhu.es
- Fortoul, T and others. (2001). The cell: its structure and function. Manual of histology. Recovered from facmed.unam.mx
- The muscles. (2013). Retrieved from www.scribd.com.