“Reflex arc or reflex action is when people respond to something really quickly and in an involuntary way, this method ensures that people are well protected from causing any further damage or harm to their bodies. 

The steps in a reflex arch are, firstly it generates stimulus in the body; usually very strong, it sends a signal to inform the body that something is causing damage or harm to it. Then the impulse goes down the sensory neurone is a part of peripheral nervous system, the stimulus then reaches an inter neurone or relay neuron which is part of the central nervous system (CNS) and is found usually in the spinal cord. However, the inter neurone signal up to the brain but that is just to let the brain know what is going on, it does not wait from the brain to make a response, the inter neurone passes the signal straight on to a motor neurone it is also a part of the peripheral nervous system, and from the motor neurone the signal is get send to the effector; is like a muscle which will eventually contract and make people move a way preventing any kind of further damage."

starting at time point: 0.30-5.4 

This video seemed to be a truth worthy because it is produced by professional scientists. The video contained an excellent grasps of knowledge, pictures and diagrams relevant to the content animation. However, the information were presented in unprofessional style, the person tone of voice indicating that he was not certain about what he was saying, it might be because the video was not produced by him in the first place as he mentioned in the video. 

Himme B. (2013). Reflex arch. [Online]. Available: https://www.youtube.com/watch?v=_K68aKJoxDY . Last accessed 13th December 2017.

The nerves cells have two main settings for communicating with each other, depending on how fast the messages need to travel. Some synapses are electrical, and others are chemical synapses.

The electro synapses send an ion current flowing directly from the cytoplasm of one nerve cell to another, through small window called gap junctions. They are fast because the signal is never form its pure electrical state to any other kind of signal. All of the synapses are not electrical, due to the control matter with such a direct connection between cells. 

Chemical synapses however, are much more abundant, but also slower, they are more precise and selective in what messages they send where. These synapses use neurotransmitters, or chemical signals, that diffuse across a synaptic gap to deliver their message". 

 Starting at time point: 3.0-7.0.

The video appeared to be trustworthy because it is produced by a scientific website for education purposes. However, the information was presented in a semi-professional manner; the jokes within the video were not really relevant to the content. And the explanation of the ways in which molecules are transmitted from presynaptic to the postsynaptic cell was too vague to understand, that is why I included these steps in clearer way in other slides.  

Dr. Boyed. (2015). Nervous System, part 3-synapses. [Online]. Available: https://www.youtube.com/watch?v=VitFvNvRIIY . Last accessed 13/12/2017.

This video seemed to be trustworthy because it has been made by a professional website for education purposes. The information was presented in such organised manner and a professional style. The presenter tone of voice was clear, also it was easy to track the steps he followed while explaining the different structures and the functions of each section on the brain.  He explained 17 parts of the brain and included structure function links for each part.  The presenter little activity at the end was really helpful. It highlighted the most important information, given a sense of refreshments for the memory and it has made the video even more interesting.

Although the video has covered all the brain structures, some of the information was vague. The video gave an outline of the role of specific sections but did not dig into the detail for each one. Especially the sections on the lobes, the somatosensory cortex and the motor cortex. 

 Mr Anderson. (2014). The brain structure and function, [online]. Available: https://www.youtube.com/watch?v=kMKc8nfPATI . Last accessed 13th December 2017.

Nerouns are mainly located in the Central Nervous System but can be found on the Spinal Cord and the Brain. The Neurons contain dendrites which is attached to other neurons and works as neurotransmitters to connect information. 
The axon is where the body transmitted information, it begins at the axon hillock and is moving to the terminals, in the terminals there are synapses which connect the body to other neurons, but the signals is moving and taking information from the dendrites, the cell body and then the information get send to the next neuron through an action potential. The axon is wrapped with myelin sheath. It works by putting the voltage-gated channels in between the axon, it allows information to travel down the axon”

Neurons are classified in 2 ways first way is due to their structural classification, for example the most common ones are;  the multipolar neurons, Bipolar neurons, Unipolar neurons and axonic neurons.
Neurons can also be classified according to their functional classification.

In the central nervous system (CNS), The neurons which bring information in are known as the sensory neurons or afferent neurons.

The information is back out from 2 effectors in the body, to the muscles or glands via the motor neuron, or the afferent neurons. The connections between the sensory and motor neuron is known as the relay or inter neuron, is responsible for transmitting stimulus from the sensory neuron to the brain and also to the motor neurons".
 
Starting at point 0.35-4.45, the video has covered the basic anatomy of a neuron; including the dendrites, cell body, axon hillock, axon, and axon terminal. He also described how neurons are classified both structurally and functionally. The video seemed to be trustworthy because it has been produced by a professional website for education purposes. The information was presented in a professional style, the presenter tone of voice was clear and it was easy to follow the steps of his explanation. At the start of the video the presenter has explained the structure of the neuron for a nematode worm, although this was not related to the real content, but it gave sense refreshment before he can dig into the right information. At the end of the video the presenter has asked some questions, this will make people think and check how much they were listening also the questions highlighted the important information on the video.     

 Andreson P . (2017). The neuron .[Online] Available: https://www.youtube.com/watch?v=HZh0A-lWSmY . Last accessed 14th December 2017.

"The Spinal Cord is the route in which signals transfers to different parts of the body, it’s attached to 31 pairs of nerves (12 pairs attached to the Cranium). At the base of the Spinal Cord there is the Cluster where sensitivity is high. The bones that surround the Spinal Cord are called Vertebrae and they are used for protection. 
The Spinal Cord consists of 4 sections. At the top, the Cervical Nerves which send impulses to the head, neck, diaphragm etc. Below it, the Thoracic Reigon (contains 12 Thoracic Nerves) which connects data to the abdominal muscles and chest. The Lumber Reigon contains 5 Nerves. It sends messages to the leg muscles. The Sacral Reigon receives and sends information from reproductive organs, intestines etc."

starting at point, 0.4-2.30.

The video appeared to be reliable because it has been made for educational purposes by a professional website. The presenter’s tone of voice appeared to be clear, but not professional. Moreover the video was supposed to cover the structure of the spinal cord; the presenter has went off the topic by explaining the common disease on the Spinal Cord and preventions, instead of focusing on the structure and function. It is beneficial to know about diseases but it does not parts of the video’s real context. 

 Unknown. (2011). the spinal cord structure and function. [Online] Available at: https://www.youtube.com/watch?v=BGprgmzu5-4 . Last accessed 14th December 2017.

·         The membrane starts in its resting state (polarised) with the inside of the cell being -60 mV compared to the outside.

·         Sodium ion channels open and some sodium ions diffuse into the cell.

·         The membrane will (depolarises); it becomes less negative and reaches the threshold value of -50mV.

·         Voltage gated sodium ion channels will open and many sodium ions will flood in. then the cell becomes positively charged inside compared to the outside.

·         The potential difference across the plasma membrane reaches +40mV. The inside of the cell is positive compared with the outside.

·          The sodium ion channels close and potassium channels open.

·         Potassium ion diffuse out of the cell bringing the potential difference back to negative inside compared with outside, this known as repolarisation.

·         The potential difference overshoots slightly, making the cell hyperpolarised. 

·         The original potential difference is restored so that the cell returns to its resting state.

After each action potential there is a refractory period, this to make sure the cell is only stimulated once, and ensures that action potential is transmitted in one direction only”.

 From a biology book page 15.

The book has structured all the elements and the stages on how the action potential is generated. t is written in a professional style by professional biologists. Books are always a trustworthy resources for researches, because all the information presented are reliable. The ironic movements are explained in such a simple way which makes it understandable. The language is not complicated or ambiguous. The book also contains a diagram to support the information. However, the diagram could be hard to understand and could come across as confusing.

Hocking et al (2008). OCR Biology A2 Exclusively by OCR for GCS. Edinburgh: Pearson Education Limited. 15.

“The transmission of a signal across the synaptic cleft is done through steps; these include: 

v  Firstly an action potential will arrive at the synaptic knob.

v  Then the voltage-gated calcium ion channels will open.

v  The calcium ions cause the synaptic vesicles to move and fuse with the presynaptic membrane.

v  Acetylcholine molecules will then bind to the receptor sites on the sodium ion channels in the postsynaptic membrane.

v  The sodium ion channels will open.

v  Sodium ions diffuse across the postsynaptic membrane into the postsynaptic neurone.

v  A generator potential or excitatory postsynaptic potential (EPSP) is created.

v  Lastly a new action potential is created in the postsynaptic neurone. 

 The role of acetylcholinesterase: 

It is an enzyme found in the synaptic cleft. It hydrolyses the acetylcholine to ethanoic acid and choline. This stops the transmission of signals so that the synapse does not continue to produce action potentials in the postsynaptic neurone”.

The picture is from a reliable and a trustworthy OCR biology book page 19. Books usually are reliable sources because the content is produced by a professional biologists and it is presented on a professional style. In many cases books are perfect example for research, because it contains an excellent source of information. Books are also well referenced and well reviewed before publication to avoid mistakes and playgrism. This attached page for example; the process of the transmission was so clear and understandable. It was not written in an ambiguous way. It made it easier to understand what is really going into the synapses.
 Hocking et al (2008). OCR Biology A2 Exclusively by OCR for GCS. Edinburgh: Pearson Education Limited. 19. 

Sodium/potassium ion pumps use ATP to pump three sodium ions out of the cell for every two potassium ions that pumped in. The plasma membrane is more permeable to potassium ions than to sodium ions and many diffuse out again. If some of the sodium ion channels are open then sodium ions will quickly diffuse down their concentration gradient into the cell from the surrounding tissue fluid. This causes depolarisation of the membrane. 

 A small depolarisation will have no effect on the voltage-gated channels. However, if the depolarisation is large enough to reach threshold potential, it will open some nearby voltage-gated channels. This causes a large influx of sodium ions and the depolarisation reaches +40 mV, which is an action potential. Once this value is reached the neurone will transmit an action potential because many voltage-gated sodium ion channels open."

This picture is a perfect explanation to some parts for the transmission of an impulse a long a neurone; particularly the resting potentials and action potentials. It covers the way in which resting potential is established and maintained as well as how action potential is generated. The information were presented in a professional style, as well as the books are
trustworthy sources because it is been produced by professional biologists and many researchers has been done before publishing the information.

Hocking et al (2008). OCR Biology A2 Exclusively by OCR for GCS. Edinburgh: Pearson Education Limited. 14.

“A synapse is a junction between two or more neurones it is the place where one neurone can communicate with, or signal to another neurone. Between the 2 neurones is a small gap called the synaptic cleft. It is approximately 20 nm wide. Synapses that use acetylcholine as the neurotransmitter are called cholinergic synapses.  

The presynaptic neurone ends in a swelling called the synaptic knob. The knob consists of a number of specialized features: 

·         Many mitochondria, to indicate the active process is supplied with enough ATP (energy).

·         Lots of smooth endoplasmic reticulum.

·         Vesicles of a chemical known as acetylcholine. It is the transmitter substance that will diffuse across the synaptic cleft.

·         Voltage-gated calcium ion (Ca+) channels in the membrane.

The postsynaptic membrane contains specialized sodium ion (Na+) channels that can respond to the transmitter substance.”

The page has given an excellent grasps of relevant knowledge related to the structure of the synapse. The book is absolutely a trustworthy and always a reliable source to use for research and education purposes. The book has references and it shows clearly where the picture is came from. This book has clear pages and explanations of contents. The writing is clear the it’s straightforward. The diagram for the synapse is an excellent example for how a synapse structure. It gives a clear image and has clear labels pointing to specific parts and identifying them.

 Hocking et al (2008). OCR Biology A2 Exclusively by OCR for GCS. Edinburgh: Pearson Education Limited. 18. 

Picture 4 provides information on how an action potential is transmitted in a myelinated neurone:

“The myelin sheath is an insulting layer of fatty material. Sodium and potassium ions cannot diffuse through this fatty layer. As a result, the ionic movements which create an action potential cannot occur over much of length of the neurone. The gaps in myelin sheath are called nodes of Ranvier. The ionic exchanges cause an action potential to only occur at the node of Ranvier.
Because the action potential can only occur at the gaps between the Schwann cells that make up the myelin sheath. This helps to speed up the transmission of the action potential. This is why myelinated neurons conduct action potentials more quickly than non-myelinated neurons.”

The picture is from a biology book, the information are trustworthy and it been made for education categorizes in a professional style. The book is well known and approved by many researches and biologists. The book also shows clear representation of how transmission occurs as well as the irons involved and their charge.
Hocking et al (2008). OCR Biology A2 Exclusively by OCR for GCS. Edinburgh: Pearson Education Limited. 17.

ü  One presynaptic neurone might diverge to several postsynaptic neurones. This would allow one signal to be transmitted to several parts of the nervous system. This is useful in a reflex arc. One postsynaptic neurone elicits the response while another informs the brain.

ü  Synapses ensure that signals are transmitted in the correct direction, only the presynaptic knob contains vesicles of acetylcholine.

ü  Synapses can filter out unwanted low-level signals. If a low-level stimulus creates an action potential in the presynaptic neurone it is unlikely to pass across a synapse to the next neurone, because several vesicles of acetylcholine must be released to create an action potential in the postsynaptic neurone.”

From page 20.

Books are a reliable sources of information. The information are written in professional style. And the way the information were structured has made it even more easier to know which roles goes where. However, the content on the page is too much and it might make people feel less intrigued to read the book.

Hocking et al (2008). OCR Biology A2 Exclusively by OCR for GCS. Edinburgh: Pearson Education Limited. 20.

It is divided into 2 different structures; they are the sympathetic system and the parasympathetic system. They are different from each other in certain ways for example:

The length of their axon is also different. In the sympathetic the preganglionic fibres are much shorter than the postganglionic, because sympathetic ganglia are close to the spinal cord, and the axons do not have to go very far from the central nervous system, but they have a lot of distance to cover to reach the effector. However, the parasympathetic is the opposite, because the parasympathetic ganglion is so close to their effector organs, its preganglionic fibres are a lot longer than the postganglionic fibres. The postganglionic fibres are just long enough to communicate with their effector. " 

Starting at time point: 0.54-7.14 
The video appeared to be reliable because, it has been done by a professional website for education purposes. The source of the video could be trusted. The presenter was clear while conveying the information which made it easier to understand. The use of colours and diagrams made the video more interesting which encourages people to watch it. However, it has been done in unprofessional way. This could make the audience less likely to take the video seriously and could lose focus.

 Thomas, F. (2015). Autonomic nervous system. [Online]. Available: https://www.youtube.com/watch?v=71pCilo8k4M . Last accessed 17th december 2017.

 

When stress action occurs, the brain send action potentials down the spinal cord and preganglionic neuronal axons. When the signals reach the synapse, inside the ganglia, the nerves fibres then release a neurotransmitter called acetylcholine. Which crosses the synapse, and if there is enough of it, it can stimulate action potentials in several neurons on the postganglionic fibres. 

The postganglionic neurones then carry the action potentials to the effector organs and it releases a different neurotransmitter called norepinephrine, it is what creates a response in the effector.”

Starting from 0.29-9.30
The video seeded to be trustworthy, because it has been produced by a professional website for education categories. However, the presentation of the information was been done on unprofessional manner. The presenter's jokes were meant to make the video more interesting but most of the sentences were irrelevant to the actual content. The explanations about the endocrine section here was so vague to be undestood. Using straightforward and simple language could result in more positive results and better understanding. 

Frank, T. (2015). Sympathetic nervous system. [Online]. Available: https://www.youtube.com/watch?v=0IDgBlCHVsA . Last accessed 17th December 2017. 

The nerves of the parasympathetic division are craniosacral and most of them never go through the spinal cord. Instead they run right from the brain and all the way to other effectors. There are 12 of the cranial nerves, they based on a ventral view of the brain. They are: firstly the olfactory nerve, it takes scent information gathered by the nose and sends it to the brain. Followed by; the optic nerve, it is associated with visual data. Then there is oculomotor it controls four of the six muscles that control the movement of the eyes. Next is the trochlear nerve, it control signal muscle in the eye. Bellow it is the trigeminal nerve, it branches into 3 main stands, it innervates the face and jaw muscles. After it is the abducens, it stimulates the muscles of the eyes to move from side to side. Next is the facial nerve which operates the muscles that make most facial expression possible. Next to it is the auditory nerve. 

The rest of the nerves travel to innervate the lower and more posterior portions of the head. They include: the glossopharyngeal nerve, it leads to the tongue and the pharynx. It followed by the vague nerve. Next is the spinal accessory nerve. It helps to move the head and shoulders. Lastly is the hypoglossal, it allows swallowing and talking.”  

Starting at 0.30-7.30 
Crash course videos are always so helpful on many education contexts. It is a reliable website and has been made by professional biologists. The information is easy to understand and easy to fins. However the presentation of the contents were done in unprofessional way. The presenter has used lot's of humorous on many stages within the video, this has made it difficult to track the points he was following.

Frank, T. (2015). Parasympathetic nervous system. [Online].Available: https://www.youtube.com/watch?v=qqU-VjqjczE . Last accessed 17th December 2017.

Starting at time point 0.1-1.30

Although the video has provided the essential basic elements of the subject, it does not seemed to be trustworthy. The name of the author and the website has not been identified. The video has been produced for educational purposes, the information was presented in unprofessional style: the comparison have been summarized.

Unknown. (2015). Involuntary vs voluntary muscle control.[Online] Available: https://www.youtube.com/watch?v=glVfEW3DPv8 . Last accessed 17th December 2017.
 

ü  In the motor neurone.

ü  In the brain. 

ü  In the autonomic nervous system in the sympathetic (in ganglion neurotransmitter). In the parasympathetic (in both ganglion and final production).

Acetylcholine is used in treatment of 

ü  Alzheimer’s disease.

ü  Dementia.

Serotonin: is found in:

ü  The brain.

ü  Is involved in Limbic function(which regulates emotion/mood, hunger, sex and temperature)

Serotonin is used in treatments for:

ü  Depression.

ü  Sleep regulation.

Dopamine: is found in the:

ü  Brain and brainstem.

Dopamine issued in the treatment of:

ü  Schizophrenia, psychosis.

ü  Parkinson’s disease.

Norepinephrine, is found in:

ü  Brain.

ü  Automatic nervous system; in the sympathetic neurones.

Norepinephrine is in treatment of:

ü  ADHD.

ü  Anxiety.

ü  Cardiac failure"
starting from time point 0.11-11.07

The video contains clear presentation about the neurotransmitter and it breaks information into smaller sections which makes it easier to process. The diagrams on the video makes it more interesting and watchable. The presenter speaks in a clam and clear manner which encourages people to watch it. The content and reliability of the information could be questioned because the video does not reference the information clearly and it does not specify where it came from. The video was posted on YouTube which could be questioneable as anyone could post their version of the video.
 

Unknown. (2015). Neurotransmitter of human body. [Online]. Available: https://www.youtube.com/watch?v=ijLdLjl_wTQ . Last accessed 17th December 2017.