The human body is, in its simplest observation, an extensively vast web of cells. The human body is one of the most complex productions in the world. Looking at just one part of the body such as the eye makes it apparent the complexity of the body’s makeup. The body is comprised of cells that come together to make tissues. These tissues fit together to make organs. The organs coexist to form organ systems. These organ system make up the entire organism that is man.
The Nervous System is the pivotal system of the human body. Everything that goes on in the body is regulated by the nerves of the Nervous System. The nervous system has a few basic building blocks that make it in its entirety. Nerve cells are comprised of a few parts that are vital in their acceptance and sending of stimuli. Close to the body of the cells are small branch like projection called dendrites. Dendrites are the receptors on the cells that take in stimuli sent from the previous cell. Next is the nucleus of the cell situated in the center of the cell body. From the dendrites, the stimuli travel along a long tail like projections of cell called the axon. At the end of the axon there are small branches with bulbs on the end called axon terminal in which the stimuli are sent into a space between cells called the synapse in which the dendrites of another cell picks up and the cycle begins again.
There are two main basic cells: afferent neurons and efferent neurons. Afferent neurons act as the cells that gather the information or stimuli from sensory receptors and take it back to the spinal cord. Efferent neurons do just the opposite. The send a response that is triggered by the spinal cord or brain back to the proper muscles or cells to generate a response. Efferent and afferent neurons are like one way streets. They can only send information one way: either to the spinal cord or back to the location of response. They will not accept stimulus from the opposite direction. All of this information gathering and sending happens in less time than it takes one to blink his or her eye. The processing of the stimuli happens only instantaneously and is extremely difficult to time with sight only.
The nervous system is comprised of two major portions. One is the peripheral nervous system mentioned previously and the central nervous system. The central nervous has two parts: the brain and the spinal cord. The brain is the control center of the body. The brain is fed with information and sends information via the spinal cord. “The brain is the most complex part of the human body. This three-pound organ is the seat of intelligence, interpreter of the senses, initiator of body movement, and controller of behavior. Lying in its bony shell and washed by protective fluid, the brain is the source of all the qualities that define our humanity. (Brain basics: Know your brain1)
The muscular system is a system in the body that is comprised of tissues that make up the muscles. “Muscles are all...