The Internal Structure of Neurons - Introduction to Psychobiology (Part 2)

-

Internal Structures

In the previous post, we explored the structure of a neuron. Now, we will take a look at its internal components starting from the outermost part of the soma and ending in the nucleus. 

First, we have the membrane, which is composed of a lipid bilayer that forms a border between the intra and extracellular space.  It allows small molecules, like water, to enter the cell, but regulates the entrance/exit of molecules based on their size and charge.  A  molecule's ability to cross the membrane is known as permeability. In the case of neurons, their membranes are semipermeable and are highly permeable to potassium (K+) and slightly permeable to Chloride (Cl−) and Sodium (Na−). Outside of the neuron, there is a balance between the high concentration of Na and Cl. Inside of it, there is a high concentration of K. This is relevant in understanding how neurons communicate, but we will explore this relationship later on.
The neuron
Then we have the cytoplasm, which is a semi-liquid substance inside of the cell (1) that contains the organelles. These are sub-units that are responsible for specific  functions within a cell. One type of organelles is ribosomes. These are produced by the nucleolus and are responsible for the production of proteins (2). 

DNA, which contains the genetic material of an organism, is usually found in the nucleus, but can also be found in the mitochondria of a cell(4). The latter, also known as the powerhouse of the cell, are organelles that convert oxygen and nutrients into adenosine triphosphate (ATP(6)), which aids with energy metabolism. Moreover, mRNA carries the genetic codes from the DNA in the nucleus to ribosomes ((5) in order to translate it into proteins.  


More organelles include the Golgi apparatus, which 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 lysosomes, which are sacs full of enzymes, which aid in the breaking or uniting of chemicals by acting as a catalyst. Finally, there is the nucleus, which as previously stated contains DNA. Additionally, it contains the nucleolus and chromosomes (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!


Don't forget to follow us by email and feel free to leave comment, questions, concerns, or suggestions.

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

Comments

Post a Comment

Popular posts from this blog

Psychoanalytic Therapy

-
Image
A comparison between psychoanalysis, medication, and cognitive-behavioral therapy. The effectiveness of medication, cognitive-behavioral therapy, and psychoanalysis will be compared to each other in order to describe the most helpful form of treatment. Effectiveness is going to be measured by the effect sizes and the limitations of each treatment; success is going to be measured by relapse and remission rates as well as the increase or decrease of benefits over time and side effects. The first form of treatment that will be explored revolves around psychopharmacology. The article “Selective Publication of Antidepressant Trials and Its Influence on Apparent Efficacy” will provide the effect sizes of antidepressants, the number of positive and negative published and unpublished studies done by the FDA, and it will compare the long--term outcomes of using medication as a form of treatment. Turner, along with the other authors, looked at all registered FDA antidepressant studie
Read more

The Five Lectures of Freud: An Introduction to Psychoanalysis

-
Image
     Sigmund Freud, a neurologist and the founder of psychoanalysis, made his first and only trip to the United States in 1909  (Jay, 2016).  Stanley Hall, who  was the first person to receive a PhD degree in psychology in the U.S., and the first president of the American Psychological Association, had invited Freud to  Clark University to lecture on psychoanalysis ( Encyclopædia Britannica, 2016c) . The lectures were part of the university celebrating its twentieth anniversary in which prominent figures spoke about their field (Burnham, 2012). The purpose of this essay is to explore each of Freud’s lectures in detail  in order to introduce psychoanalysis.      Before describing the lectures, it is important to understand how Freud mapped the mind. He divided it into three parts twice. The first time, he categorized it into the conscious, preconscious, and unconscious (Freud, 1938). The conscious layer contains everything that an individual is aware of, such as immediate physica
Read more

Introduction to Neuroanatomy - Part 3 (Brain Structures - Telencephalon and Diencephalon)

-
Image
Brain Structures and their Functions To learn more about neuroanatomy, please check out: "Neuroanatomy Text and Atlas," by John H. Martin. In the last post, we ended explaining the development of the spinal cord. We will continue this discussion by exploring the structures of the brain from a bottom-up perspective and describe their functions.  Cranial and Non-cranial Nerves If you read the last post (Here is the link:  http://hbookreviews.blogspot.com/), you should remember that the spinal cord was divided by two plates: basal and alar. When we move up from the spinal cord into the brain we would observe a collection of structures known as the brainstem. In here, the plates become nerves. The alar plate becomes the cranial nerve sensory nuclei and the basal becomes the cranial nerve motor nuclei. Remember that a nerve is a bundle of axons in the central nervous system (CNS) and that nuclei are a collection of cell bodies that are also located in the CN
Read more