1. Acetylcholine Dominic and Marlon
Acetylcholine also known as ACh, is the most common neurotransmitter. It is located in the CNS, as well as in the  peripheral NS, which are all nervs outside the CNS.
Discovered in 1914 by Henry Hallett Dale, it was the first neurotransmitter identified. The existence was later confirmed by Otto Loewi. Both were awarded the Nobel Prize for their discovery.
In the CNS, acetylcholine acts as part of a neurotransmitter system and plays a role in attention and arousal. In the peripheral nervous system, this neurotransmitter works to activate
Dominic and Marlon

2. Where is it located?
Central Nervous system – Red + brain Peripheral Nervous system – Blue
Acetylcholine receptors are found on the surface of muscle cells, concentrated in the synapse between nerve cells and muscle cells. A similar form is also found in the central nervous system, relaying messages from nerve to nerve

3. What it looks like/what they are
These acetylcholine receptors are composed of five protein chains, arranged in a long tube that crosses the cell membrane. Two of these chains, colored orange here, have binding sites for acetylcholine on the side, colored here in red. When acetylcholine binds to these two chains, the shape of the entire receptor changes slightly, opening the channel. This allows positively charged ions, such as sodium, potassium, and calcium, to cross the membrane. Muscles are constantly pumping sodium out of their cells, so when they are relaxed, there is more sodium outside than inside. When they get the signal from the nerve, however, the channels open and sodium ions to rush back inside, starting the process that will lead to muscle contraction.

4. How the process works
Nerve cells need to be able to send messages to each other quickly and clearly. One way that nerve cells communicate with their neighbors is by sending a burst of small neurotransmitter molecules. These molecules diffuse to the neighboring cell and bind to special receptor proteins in the cell surface. These receptors then open, allowing ions to flow inside. The process is fast because the small neurotransmitters, such as acetylcholine, diffuse rapidly across the narrow synapse between the cells. The channels open in milliseconds, allowing ions to flood into the cell. Then, they close up just as fast, quickly terminating the message as the neurotransmitters separate and are removed from the synapse.

5. A Study on the role on neurotransmitters on memory in 1991 by Martinez and Kesner
Rats where trained to go through a maze
They where divided into 3 groups
One group was injected with scopolamine
Another was injected with Physostigmine
The third group was not injected with anything
Results:
The rats that where injected with the physostgmine completed the maze the fastest
The rats with the scopolamine took the longest and made the most errors
The control group was in-between the two
In 1991 Martinez and Kesner conducted a study of the role of neurotransmitters in learning an memory.
The aim of this study was to determine the effect that Acetylcholine had on the memory
To test this rats where trained to go through a maze and once a rat had completed the maze it would receive food. Once the rats where able to do this, a third of them where injected with Scopolamine which blocks the ACh receptor sites and reduce the amount of available Acetylcholine. Another third where injected with physostigmine, this prevented the Cholinesterate production, this stopped the cleaning up of the Acetylcholine and increased the levels of Ach in the body. The third group which was the control group was not given any injections
The three groups where then sent through a maze and the results where recorded
The records show that the group that had the heightened Ach levels due to being injected with physostigmine made the least errors and solved the maze the fastest . The Group with the lowered levels of Ach made the most mistakes and was also the slowest. The control group on the other hand made less mistakes than the group with the lowered ACH levels but more than the group with the heightened ACh levels.
This lead the researchers to determine a positive correlation between the level of Acetylcholine in the body and how good the memory was.
The strength of the study lies in the experimental design due it being easily replicated, yet it is not clear to what extend this can be applied to humans
Even though this might not be applied directly to humans, the effect of ACh on memory could assist in treating memory related disorders.

6. What happens if you have too much or too little of it?
Every little nerve signal will affect your muscles contractions
paranoia
The neural functions will be delayed or even stop
paralysis
What happens if too much or too little Acetycholine is in your body?
If there is too much, basically every little nerve signal will affect your muscles, sodium will enter and the muscle contracts.
If there is too little, the neural functions will be delayed or even stop.
Affects on the memory would be paranoia if there is too much, and paralysis if there is too little.
There always needs to be a balance for the body to control areas such as heart rate, bladder function and secretions in the digestive system.