Peripheral Nervous System Analysis

The central nervous system (CNS) comprises grey matter, which contains neuron cell bodies and white matter, which contains the nerve axons. Most of the nerve axons are concentrically wrapped around by lipid-rich biological membrane, known as the myelin sheath. In the CNS, myelin is produced by oligodendrocyte. a type of glial cell. (Pfeiffer et al., 1993). These electrical insulating, multilamellar membranes significantly increase the electrical resistance, in which to prevent leakage of electrical currents from the axons, as well as decrease electrical capacitance to reduce the ability of the axons to store electrical energy (Shivane &

The central nervous system is made up of the brain and spinal cord. The brain is connected to the spinal cord. The brain helps interpret information received from the spinal cord. Through the spinal cord signals are sent to the rest of body and back to the brain. Nerve cells (neurons) are found in the nervous system and they help communicate with other cells through electrical signals. Some of the nerve cells are coated with a myelin sheath. Myelinated neurons allow electrical signals to travel at a faster speed. When the myelinated part of the nerve cell is destroyed, Multiple Sclerosis (MS) can be the one to blame.

Myelin, found only in vertebrate nervous systems, is a fatty substance that surrounds the axons and long dendrites of nerves in the brain and spinal cord tissue (4). By lowering the rate at which the axonal membrane absorbs nerve impulses, myelin acts as an insulator, allowing NS potentials to travel rapidly through the nervous system and maintain communication between the brain and the rest of the body (2). This communication between the brain and the rest of the CNS and peripheral nerves is a central

repair or regrowth of the nerves which involves formation of new neurons, axons, myelin, glia or

The peripheral nervous system, or PNS, is the part of the nervous system responsible with carrying sensory information (a person’s senses) and motor information (a person’s coordination) to and from the central nervous system (CNS, the part that takes the information and applies it to the body), as well as throughout the whole body. Both parts of the nervous system are made up of nerve cells, or neurons, which carry the electrical impulses that contain the information sent between the PNS and CNS. The neurons

a. Injured axons activate macrophages which in turn clear myelin and axon debris efficiently away from damaged nerve. Simultaneously, macrophages produce growth factors that facilitate Schwann cell migration and axon regeneration (Rotshenker, S. 2011).

The injuries of nervous system affect many people every year and is estimated that spinal cord injuries alone affect 10,000 each year. Nerve regeneration can be achieved by production of new neurons, glia, axons, myelin, or synapses. There are differences between the functional mechanisms of peripheral nervous system (PNS) and the central nervous system (CNS). PNS has an intrinsic ability for repair and regeneration while CNS usually is incapable of self-repair and regeneration. There is currently no treatment for recovering human nerve function after injury to the CNS. Although, PNS has self-regeneration capacity, much research still needs to be performed for optimizing the environment for maximum regrowth. Injury to PNS immediately elicits the migration of phagocytes, Schwann cells, and macrophages to the lesion site in order to clear away debris such as damaged tissue [56-60].

The myelin sheath is a fatty substance that surrounds the axons of the nerves and provides protection. It allows messages to be sent rapidly and accurately to the axons from long distances (Serono, 2010). The axons are the part of the nervous system that allows electrical transmission of signals throughout the brain and spinal cord. Without these electrical transmissions, the body

The peripheral nervous system (PNS) constitute of the cranial and spinal nerves. The PNS provides the connection between internal or external stimuli

As shown in Figure 1 (Barker 1991), the neuron is composed of three parts: the dendrite, the cell body, and the axon. The dendrites are structures resembling tree branches that receive signals from other neurons and send them to the cell body. The cell body determines which signals among the many that it gets from the dendrites to send to the axon, which sends signals away from the cell body to other neurons (Herlihy, 2000). The axons are sheathed by a layer of fat known as myelin, which protects the axon and increases the speed at which impulses are carried out. However, myelin is formed differently in the central nervous and peripheral systems. In the central nervous system myelin is created by a type of cell known as oligodendrocytes, while in the peripheral system they are formed by Schwann cells (Hall 1991).

The Nervous System is a complex system comprised of two parts: The Central Nervous System and the Peripheral Nervous System. Each system is then comprised of nerves and specialized cells, called neurons. The function of a neuron is to transmit messages throughout the body. The brain has approximately 100 billion neurons, ranging in many different sizes and shapes. Neurons are classified as cells because they have a cell membrane, nucleus, cytoplasm, and mitochondria, as well as carry out many of the same processes as a cell (i.e protein synthesis). But, a neuron is unlike a cell in that they have special structures such as dendrites and axons, communicate through electrochemical processes, and contain special chemicals called neurotransmitters (instead of hormones).

Homeostasis is achieved through the central nervous systems process of receiving, integrates and responding to information (Marieb & Hoehn, 2014). The peripheral nervous system acts as a communication line carrying impulses through nerves extending from the brain, spinal cord and ganglia, transmitting the impulses via the spinal cord and cranial nerves, back and forth from the brain (Marieb & Hoehn, 2014). The peripheral nervous system is subdivided into the sensory and motor divisions. The sensory, which picks up on stimuli, sending impulses from the receptors to the central nervous system (Marieb & Hoehn, 2014). And the motor division, with a motor nerve structure that transmits the impulse from the central nerves system to the effectors known as the muscles and glands (Marieb & Hoehn, 2014), thus allowing movement to occur. The motor division also divides into the somatic nervous system and autonomic nervous system. The somatic nervous system, which is a voluntary response that travels through nerve fibres, allowing conscious control of skeletal muscular movement (Marieb & Hoehn, 2014). The autonomic nervous system unconsciously controls muscle and glands. The visceral motor nerve fibres regulate a person’s smooth

Autonomic Nervous System- the part of the nervous system responsible for control of the bodily functions not consciously directed, such as breathing, the heartbeat, and digestive processes.

The two systems within the peripheral nervous system are somatic nervous system and the central nervous system. The control that somatic nervous system have is the process of reflex arcs and optional muscular systems. The peripheral nerve sends sensory information that predict skeletal muscles to the motor nerve and central nervous.

Mesenchymal stem cells are attractive tools in the clinic and have been isolated from different tissues of the body but to be qualified for use in regenerative medicine, they must in addition to the characteristics described by the international society for cell therapy, be expandable ex vivo with high proliferative potentials, possess multipotent capability, and must be easy to harvest for autologous transplantation.4 The latter characteristic ensures that the donor is not subjected to extreme condition or pain in order to access their stem cell. The site for MSC isolation includes but not limited to; bone marrow, adipose tissue, whartson jelly umbilical cord, and skin.