Sunday, April 17, 2016

Introduction to Psychobiology Part 2 (Internal Structure of Neurons)



Internal Structures

For more information about biopsychology, please check out "Physiology of Behavior" by Neil Carson.

In part one we explored the parts of neurons, now we will look inside of them. Maybe you will remember this if you ever took biology. We'll start from the outside and end up on the center of the cell. 

First we have the membrane, which is a double layer of lipid molecules that mark the borders of the neurons. Like a customs officer, it is at the point of entry and decides what comes in and what comes out. 

Then we have the cytoplasm, which is a semi-liquid (thick) substance inside of the cell (1). The enzymes act as a catalyst to either separate or unite substances.

Ribosomes are produced by the nucleolus and they are responsible for the production of proteins (2) translated from mRNA ((1) We call this process protein synthesis). Chromosomes are made up of proteins and a single molecule of DNA ((3) Short for deoxyribunocleic acid). They are found in the nucleus. 

DNA is usually found in the nucleus (it can also be found in the mitochondria) and it contains genetic material (4). The mRNA is the carrier of genetic codes from the DNA in the nucleus to the ribosomes ((5) remember they translate it into proteins). Mitochondria are organelles (little organs) that convert oxygen and nutrients into adenosine triphosphate (ATP(6)), which helps with energy metabolism (when it is broken down it liberates energy (1)).  

More organelles include the Golgi apparatus. This is responsible for transporting proteins and it's located close to the endoplasmic reticulum (7). 

The latter has two forms: smooth and rough endoplasmic reticulum. It is a membrane that has several functions, three of them include the transportation, synthesis, and modification of proteins (8). 

The Golgi apparatus also produces the lysosomes, which are sacs full of enzymes (remember that enzymes either break or unite substances by acting as a catalyst).


And finally the nucleus, in which DNA can be found. It contains the nucleolus and chromosome (1). It usually has a round shape and it is found at the center of the cell, protected by the nuclear membrane (1).

Here is a picture of an axon terminal that was cut open taken from an electron microscope. 
This has to be one of my favorite pictures!


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References

1. "Physiology of Behavior" by Neil Carson

2. http://rna.ucsc.edu/rnacenter/ribosome.html

3. https://www.genome.gov/26524120/chromosomes-fact-sheet/

4. https://ghr.nlm.nih.gov/primer/basics/dna

5. http://www.britannica.com/science/messenger-RNA

6. https://micro.magnet.fsu.edu/cells/mitochondria/mitochondria.html

7. http://www.britannica.com/science/Golgi-apparatus

8. http://www.britannica.com/science/endoplasmic-reticulum