Nervous System

Nerve Histology

 Nervous tissue has a similar arrangement to muscle tissue. Each axon is surrounded by connective tissue, and then bundled into a larger group, a fascicle, which itself is surrounded by connective tissue. This is then arranged together into the larger working nerve unit, also surrounded by connective tissue. The endoneurium surrounds each nerve cell, the perineurium surrounds each fascicle, and the epineurium surrounds each nerve as a whole. In muscle tissue, these connective tissue sheaths are the fascial surroundings of the muscle fiber, fascicle, and whole muscle.
Nerves connect to the spine via thicker ganglia areas. As the nerve travels through the body, various neurons innervate specific areas and the bundle as a whole thins.
Multiple Sclerosis is a serious disease that affects the myelin sheathing of neurons. The ability to transmit signals becomes progressively impaired. People with MS have symptoms that can vary day-to-day, but generally include sensitivity to temperature extremes, muscle weakness, vision problems, and difficulty coordinating movements.

 Anatomy of a Neuron

 
 Sensory neurons carry information from their specialized receptors to the CNS. They are located in the skin, and throughout the body, including within organs and around blood vessels. They can sense pressure, temperature, pain, etc. and are the information-carriers that keep the CNS apprised of our internal and external environments. Motor neurons innervate skeletal and smooth muscle, and carry the CNS's instructions and reactions to all parts of the body. Interneurons integrate the information between the two, ensuring that the appropriate response is matched with the appropriate stimulus. They are also the coordinators of spinal reflexes.

Reaction Time Rulers

	Visual Stimulus		Auditory Stimulus		Tactile Stimulus
	Person 1	Person 2	Person 1	Person 2	Person 1	Person 2
Trial 1	R-3”  L-2.25”	R-3” L-6”	R-2” L-1”	R-5”  L-2”	R-13.5”  L-10”	R-3”  L-6”
Trial 2	R-1” L-3.25”	R-5” L-14”	R-2”  L-5.75”	R-3.25”  L-2.5”	R-2”  L-8”	R-2.5”  L-3.75”

                                                                                                                                                                                                
My hypothesis had been that visual stimuli would process faster as a large part of our brains are dedicated to visual processing. Visual stimulus did work well for me, but not so much with my partner, who has some visual impairments (possible explanation). My quickest reaction times were visual and audio, and she did well with audio and tactile. To be honest, beyond her slight visual issues, I have no explanation for why we differed. Perhaps genetic tendencies, or training of certain stimuli over the years makes a difference. We also might both be different about how we administered the test. Having a third person test both of us might have given better data.
Nerves take a bit to create a reaction because the sensory input must travel biochemically along a sensory nerve to the CNS, where it is processed by interneurons and sent either back out to the appropriate muscles (a reflex) or up to the brain and then back down the spinal cord and out. All this is done through action potentials. While they do not take long to generate, they do take some time, and therefore we don't have instantaneous reactions, even with reflexes.
My hypothesis was not supported, and this data would lead me to create a more definite experiment.

                                                Somatic division                                                                              Autonomic division

		Sympathetic	Parasympathetic
Function	Works with Skeletal Muscles	Arousal, mental acuity, flight-or-fight	Relaxation, repair, digestion and basic functions
Neurotransmitter	Acetylcholine	Norepinephrine	Acetylcholine