A cell is the basic structural, functional and biological unit of all known living organisms. Cells are often called the “building blocks of life.” A cell is a smallest unit of life that can replicate independently. There are a lot of biomolecules, such as proteins and nucleic acids, in a cell. In comparison with the size of these molecules, the size of a cell is huge.
There are many functional parts inside the cell. For easy understanding, imagine a cell as a giant factory with many plants that manufacture a huge range of biomolecules, from very simple things to big protein complexes. As with every factory, the cell cannot work and live without the roads provided by the cytoskeleton.
Cytoskeleton
The cytoskeleton is a crucial part of a cell with the following key functions: maintaining integrity of a cell and transporting biomolecules from one part of the cell to another. There are three types of cytoskeleton structures: microtubules, actin filaments and intermediate filaments.
While the cytoskeleton holds parts of a cell separate from each other, the cell membrane separates the interior of a cell from the outside environment.
Cells of bull’s pulmonary artery: actin microfilaments colored red, microtubules colored green and the cell’s nuclei colored blue.
Cell Membrane
The cell membrane physically separates the interior of all cells from the outside environment. This is a strong border with a lot of checkpoints. The membrane represents a bilayer of phospholipid molecules that are hydrophobic on one side and hydrophilic on the other side. Also, the cell membrane contains transport proteins called ion channels and protein complexes called receptors.
The cell membrane is selectively permeable and able to regulate what enters and exits the cell. The movement of substances across the membrane can be passive, occurring without the input of cellular energy, or active, requiring the cell to expend energy to transporting it.
To fully describe the main theme of this paper, I should disclose the concept of signaling pathways.
Signaling Pathways
A signaling pathway is a cascade of molecules through which the information from the cell receptor transmits into the cell. The signaling pathway is a cornerstone of the biochemistry of the cell. The signal goes from one molecule to another in a strictly defined order that describes the signaling pathway. Many of the signaling pathways can be started in response to extracellular signals such as neurotransmitters, hormones and growth factors. In other cases, the signaling pathways start the action prior to intracellular activation. The result of a signaling pathway is the production of new chemical compounds and a long-lasting change in the cell’s behavior. As I said before, to start the signaling pathway, a receptor and a ligand are required.
What Is a Cell Receptor?
Receptor Types
Model of Neuronal Bursting
FURTHER EXPLORATIONS
Research Another Neuron Model
Reference:
J. L. Hindmarsh and R. M. Rose, “A Model of Neuronal Bursting Using Three Coupled First Order Differential Equations,” in Proceedings of the Royal Society of London, Series B, Biological Sciences, 221(1222), 1984 pp. 87-102. fge.if.usp.br/~reynaldo/verao/hr_3d.pdf