Neurotransmitters play an important role in maintaining homeostasis and facilitating communication or coordination between different parts of the body. Neurotransmitters are the chemicals that allow the transmission of signals from one neuron to the next neuron across synapses. The neurotransmitter that is present in the nervous system is Acetylcholine. Acetylcholine is released by a nerve cell or neuron and causes muscles to contract, activate pain responses, and regulates endocrine and REM functions. Several diseases such as Parkinson’s disease, drugs such as LSD and neurotoxins influence or change the ability of a neurotransmitter to function. The nervous system has three main functions which are sensory, integration, and motor. The sensory function of the nervous system involves collecting information from sensory receptors that monitor the body’s internal and external conditions. The integration function of the nervous system involves the processing of the many sensory signals that are passes into the central nervous system at any given time. The motor function of the nervous system involves stimulating efferent neurons which carry signals from the gray matter of the central nervous system through the nerves of the peripheral nervous system to the effector cells. The nervous system consists of the brain, spinal cord, sensory organs and all of the nerves that connect to these organs with the rest of the body. These organs are responsible for the control of the body and communication among its parts. There are two parts of the nervous system the central nervous system and the peripheral nervous system. The central nervous system consists of the brain and the spinal cord, since the brain and spinal cord are inside the skull and vertebrae its being protected by the bones. The central nervous system is where information is evaluated and where decisions are made.The peripheral nervous system consists of the sensory nerves and sense organs, they monitor conditions inside and outside of the body and send the information to the central nervous system. The peripheral nervous system also has efferent nerves that carry signals from the control center to the muscles,glands, and organs to regulate their functions. Unlike the central nervous system the peripheral nervous system is not protected by any bones. The central nervous system acts as the control center of the body by providing its processing, memory, and regulation systems. The central nervous system takes all sensory information from the body’s sensory receptors to stay aware of the body’s internal and external conditions. Using this information the, the central nervous system makes decisions to maintain the body’s homeostasis. The peripheral nervous system is help maintain homeostasis in the body because its what connects the brain to the limbs, the peripheral nervous system are the nerves that carry instructions from your brain to the limbs, they work together to maintain homeostasis the central nervous system makes the decisions and the peripheral allows for the decisions to be done. Action potential, is the reversal of electric polarization of the membrane of a nerve cell or muscle cell. In the neuron an action potential produces the nerve impulse, and in the muscle cell it produces the contraction required for all movement. Action potentials are caused when different ions cross the neuron membrane. What causes sodium channels to open up is a stimulus. There are many more sodium ions on the outside and so it makes the outside positively charged, and inside of the neuron is negative, sodium ions rush into the neuron. The neuron becomes more positive and become depolarized because it has a positive charge. It takes longer for potassium channels to open, when they do the potassium rushes out of the cell reversing the depolarization. Sodium channels start to close as well, in which this causes the action potentials to go back to -70mV which is a repolarization. Parkinson’s disease is one of many things that influence or change the ability of a neurotransmitter to function. Parkinson’s disease is a disease that affects movement since it is a disorder in the central nervous system. Parkinson’s disease targets the neurotransmitter dopamine which is produced in the brain and is a chemical messages/signals responsible for the body’s movement.