peripheral nervous system

Examples of peripheral nervous system in the following topics:

• Development of the Peripheral Nervous System

  • The peripheral nervous system develops from two strips of tissue called the neural crest, running lengthwise above the neural tube.
  • In vertebrates, the first sign of the nervous system is the appearance of a thin strip of cells along the center of the back, called the neural plate.
  • The inner portion of the neural plate (along the midline) is destined to become the central nervous system (CNS), the outer portion the peripheral nervous system (PNS).
  • Subsequently, neural crest cells from the roof plate of the neural tube undergo an epithelial to mesenchymal transition, delaminating from the neuroepithelium and migrating through the periphery where they differentiate into varied cell types, including pigment cells and the cells of the peripheral nervous system.
  • The neural tube will give rise to the central nervous system, while the neural crest will give rise to the peripheral nervous system.

• Comparing the Somatic and Autonomic Nervous Systems

  • The peripheral nervous system includes both a voluntary, somatic branch and an involuntary branch that regulates visceral functions.
  • The peripheral nervous system (PNS) is divided into the somatic nervous system and the autonomic nervous system.
  • The somatic nervous system (SoNS) is the part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles.
  • The autonomic nervous system (ANS) is the part of the peripheral nervous system that acts as a control system, functioning largely below the level of consciousness and controlling visceral functions.
  • The enteric nervous system is sometimes considered part of the autonomic nervous system, and sometimes considered an independent system.

• Neuroglia of the Peripheral Nervous System

  • Schwann cells provide myelination to peripheral neurons.

• Regeneration of Nerve Fibers

  • The peripheral nervous system is able to repair and regenerate itself, but the central nervous system is incapable of doing so.
  • Neuroregeneration differs between the peripheral nervous system (PNS) and the central nervous system (CNS) by the functional mechanisms and especially by the extent and speed.
  • The nervous system is divided into two parts: the central nervous system, which consists of the brain and spinal cord, and the peripheral nervous system, which consists of cranial and spinal nerves along with their associated ganglia.
  • Neuroregeneration in the peripheral nervous system (PNS) occurs to a significant degree.
  • Unlike peripheral nervous system injury, injury to the central nervous system is not followed by extensive regeneration.

• Organization of the Nervous System

  • A nervous system is what allows us to react to the changing environment around us.
  • The nervous system is an organ system that coordinates our actions by transmitting signals between different parts of our bodies.
  • In most animals, including humans, the nervous system consists of two parts: central and peripheral.
  • The peripheral nervous system (PNS) consists of sensory neurons, motor neurons, and neurons that communicate either between subdivisions of the PNS or connect the PNS to the CNS .
  • Gross organization of the nervous system, with the peripheral nervous system, the spinal, and the cortical levels.

• Autonomic Nervous System (ANS)

  • The autonomic nervous system is a part of the peripheral nervous system that controls visceral functions such as heart rate and digestion.
  • The autonomic nervous system (ANS or visceral nervous system or involuntary nervous system) is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness and controls visceral functions .
  • It is classically divided into two subsystems: the parasympathetic nervous system (PSNS) and sympathetic nervous system (SNS).
  • The enteric nervous system is sometimes considered part of the autonomic nervous system, and sometimes considered an independent system.
  • An illustration of neural control of the gut wall by the autonomic nervous system and the enteric nervous system.

• Characteristics of Nervous Tissue

  • Nervous tissue is the main component of the nervous system, which includes the brain, spinal cord, and nerves.
  • Nervous tissue is one of four major classes of tissues.
  • It is specialized tissue found in the central nervous system and the peripheral nervous system.
  • The nervous system is responsible for the control of the body and the communication among its parts.
  • In the peripheral nervous system, Schwann cells are neuroglia cells that support neuronal function by increasing the speed of  impulse propagation.

• Clusters of Neuronal Cell Bodies

  • In the peripheral nervous system, a cluster of neurons is called a ganglion.
  • They are the intermediary connections between the peripheral and central nervous systems.
  • Satellite glial cells are a type of glial cell that line the exterior surface of neurons in the peripheral nervous system (PNS) .
  • They are thought to have a similar role to astrocytes in the central nervous system (CNS).
  • Satellite glial cells are expressed throughout the sympathetic and parasympathetic ganglia in their respective nervous system divisions.

• Subdivisions of the Nervous System

  • The nervous system is comprised of two major subdivisions, the central nervous system (CNS) and the peripheral nervous system (PNS).
  • The PNS is further subdivided into the autonomic nervous system (ANS) and the somatic nervous system.
  • The ANS is classically divided into two subsystems: the parasympathetic nervous system (PSNS) and sympathetic nervous system (SNS).
  • The enteric nervous system (ENS) controls the gastrointestinal system and is sometimes considered part of the autonomic nervous system.
  • The left-right pair of cranial nerves, spinal nerves, and ganglia make up the peripheral nervous system (shown in dark gold).

• Parasympathetic Responses

  • The parasympathetic nervous system regulates organ and gland functions during rest and is considered a slowly activated, dampening system.
  • The parasympathetic nervous system (PSNS, or occasionally PNS) is one of the two main divisions of the autonomic nervous system (ANS).
  • The autonomic nervous system (ANS, or visceral nervous system, or involuntary nervous system) is the part of the peripheral nervous system that acts as a control system, functioning largely below the level of consciousness and controlling visceral functions.
  • The sympathetic nervous system can be considered a quick response, mobilizing system; and the parasympathetic system is a more slowly activated, dampening system.
  • The parasympathetic nervous system, shown in blue, is a division of the autonomic nervous system.