The Central Nervous System controls (CNS) most of the functions that are happening in and around our body. The CNS consists of two important components which are the spinal cord and the brain. The brain interprets information from main senses such as eyes, ears, mouth etc. and also internal organs such as stomach, liver and bladder. The spinal cord is a communication system between the brain and the body, if this were somehow disrupted then information would not be exchanged between them, the cause of this might be a spinal cord injury during an accident. The CNS controls all voluntary movements within the body such as walking and involuntary movements like blinking and breathing.

https://www.christopherreeve.org/living-with-paralysis/health/how-the-spinal-cord-works
(Accessed: 25/10/18)

Although this picture gives a clear understanding of the nervous system I feel that it can be improved. It is very brief and does not detail the functions of the nervous system. The words also are very difficult to understand, if a person was looking at this for the first time they would not get a clear explanation of what the nervous system is.
The resource however is trustworthy and reliable for information, it is from openstax. All the authors are university graduates and also used by college boards of education.

Motor neurones are neurones that convey messages to its designated place for example to your muscles or organs. These types of neurons get information from other neurons and pass it on. In the instance of the hot coal example the motor neurones would send a message to your muscles in your fingers which in turn would allow you to move your fingers or hand away from the coal.
Connector neurons are interneurons that allow communication between the sensory and motor neurone. They process information and allow you to come to conclusions. For the example with the hot coals it may be to remove the hand or also come to a conclusion “that things that looked like hot coals are not good to pick up”
https://www.khanacademy.org/science/biology/human-biology/neuron-nervous-system/a/overview-of-neuron-structure-and-function 
(Accessed: 25/10/18)

This website is excellent because it allows you to get all the relevant information clearly. It contains diagrams of each neurone which is labelled accordingly for example if you wanted to find information on the motor neurone, from the website I would be able to say the following:

The motor neurone is an efferent neurone which means that it will be moving away from the neurone. The function of the motor neurone is to relay messages from the brain or spinal cord to the muscles or organs. From the diagram I can locate where the Schwann cell nucleus is on the motor neurone as well as myelin sheath. The motor neuron has short dendrites and long axons.
I chose this website because it was easy for me to retain the information; it is put in clear and simple language that anybody can understand. The website is also designed for those who study A-level biology, which means its relevant. It highlights the main points of each neurone. The language format is fairly good as it is easily understandable in the sense that if someone who does not study biology reads this, they will be able to understand fairly quickly. 

The only critique is that they do not go into too much detail about the complexity of the neurone; they do not talk about the functions in detail either. It is brief and simple.

During 1:00 in the video there is an animation that shows what would happen when you touch the stimulus which is, going from the receptors in your finger to the spinal cord. He goes on to talk about how reflex arcs are built in or innate behaviours which means that they are not learned from before.

I had decided to pick this resource because the information was easily understood; he was clear in what he was saying. The way the information was read out was slow enough so that the listener keeps up or makes notes if needed. If the reading was too fast then it would be hard to keep up with, you would have to keep pausing and going back to each part of the video and this was not the case. Another good reason I had chosen this video was because if you did not understand what was being said you can click in the description, there is all the information typed up for you. The vocabulary used was relevant and easily understandable, in the sense that if someone who was not studying biology watched the video, they would have a rough idea of what a reflex arc is.

One of the disadvantages of this video is that lack of any detail about any of the neurons; they roughly mention the roles of each neuron. They also put a diagram of the reflex arc which they also could have explained thoroughly but they used an animation video instead. I feel that they could have talked more of what happens during each stage of reflex arc for example what happens when the sensory neuron sends electrical charges.

BBC Bitesize - GCSE Combined Science - How does the nervous system help us respond? - OCR 21C - Revision 3
https://www.bbc.com/bitesize/guides/ztjrng8/revision/3
(Accessed 26/10/18

These are main stages of action potentials:

Depolarisation, this is the flow of sodium ions inwards that increases the concentration gradient. If the potential difference reaches threshold then the sodium ion channels which are also voltage gated open up and diffuses in the neuron.

Repolarisation, this is when sodium ion channels close and potassium channels open, the membrane of the neurone is permeable so that potassium ion channels can diffuse out. When this happens the membrane is at resting potential.

Resting potential occurs when all the ion channels have been reset; the sodium potassium pump has returned to the membrane and upholds resting potential until it is excited by another stimulus. (-70millivolts).
Transmission of Nerve Impulses . 2018.  Transmission of Nerve Impulses . [ONLINE] Available at: https://www.cliffsnotes.com/study-guides/anatomy-and-physiology/nervous-tissue/transmission-of-nerve-impulses. [Accessed 29 October 2018].

At 6:00 into the video there is a graph which is used as an animation to show how action potentials work and what happens at each gradient. He explains that when an environmental stimulus occurs thus causing the sodium ion channels to open. This then increases the charge inside the membrane. At threshold the voltage gated sodium ion channels open and all positive sodium ion channels diffuse inside. This is the stage of depolarisation where is at the potential of 40 millivolts. The process of repolarisation kicks in and the voltage gated potassium ions open letting out potassium ions to rebalance the charges. This then leads to hyperpolarisation where the voltage drops to -70 millivolts before all gates close. The sodium potassium pumps then brings everything back to resting level. 

An interesting fact I learned from this resource was that the strength of the action potential always remains the same no matter what the stimulus may be. Signals can either be weak or intense depending on the stimulus, the example that was given in the video was: for a weak signal and low frequency it would be something like picking up an egg. If it was something trying to crush a can, there is a high frequency and therefore the signal intensifies.  

This video is precise and straight to the point, all the information that was given was relevant and on topic. Although it was easy to understand the language may have been too technical for someone who does not study biology. The video also started off with something off topic, I understand he was trying to make us understand the similarities between voltage and potential, but it was time consuming to get to the main part of action potential. The information was clear but it was read out too fast.

It is reliable and trustworthy as the information is coming from reliable sources such as hank green who was the producer of this source. Hank green is a graduate in biochemistry, therefore making his videos dependable.
 The Nervous System, Part 2 - Action! Potential!: Crash Course A&P #9  

This is a great resource because all the information is set out properly and organised. The definitions are first which allows you to go in sequence, you learn the meanings first. Then there is a table with the comparisons, the differences between the two actions. There is also a video in the case that you don’t understand the written form, this is good because some students might learn better visually rather than written language. It is easy to understand and meets the criteria. The language is not difficult to understand because it is not too technical.
This is reliable and trustworthy because it is a blog written by a biology graduate in America. Its clear and precise matching to the criteria.
http://thumbiology.blogspot.com/2011/03/voluntary-and-involuntary-actions.html
(Accessed:27/10/18

The resource I have chosen is a website that meets the criteria of 2.1 because it explains the role of the autonomic nervous system. It starts by explaining what the autonomic nervous system’s role actually is. “The autonomic nervous system plays an essential role in keeping the body's internal environment (temperature, salt concentration, blood sugar, oxygen and carbon dioxide level in blood, etc) in proper balance, a condition called homeostasis”. This is very crucial because without this regulator is temperature got too low or high then you may get hypothermia which is fatal and life threatening. 

They also explain the 2 different parts of the ANS which are the sympathetic and parasympathetic nervous system. The systems have opposing effects on the internal organs they act on. They state that the sympathetic nervous system (SNS) is in control of emergencies, it prepares the body to give out energy and protect on effects of injury. This is called the fight or flight response, it prepares for intense activities. The roles the source described for this system is that “It shuts the gut down, speeds up the heart, increases blood pressure, dilates (makes bigger) the pupils of the eyes, makes more glucose. However the parasympathetic does the complete opposite, it looks after your body during rest and restoration. The resource calls the PNS the housekeeping system. Its action is (almost always) the opposite of the sympathetic division. It activates the gut for digestion, slows the heart rate, decreases the blood pressure, etc.

I chose this resource because it is easily understandable and simple, the language is technical but not over the top where no one can understand. They also have diagrams which are great for people who like to see visual images to learn. It was helpful to understand the separate roles of each system as it separated the information nicely.

This resource is somewhat reliable because it does have all the correct information, but it may not be trustworthy because it is not a professional website and also does not state who curated the information.
Indianaedu. 2018. Indianaedu. [Online]. [30 October 2018]. Available from: http://www.indiana.edu/~p1013447/dictionary/ans.htm
(Accessed:28/10/18)