parasympathetic nervous system

(noun)

One of the divisions of the autonomic nervous system, based between the brain and the spinal cord, that slows the heart and relaxes muscles.

Related Terms

Examples of parasympathetic nervous system in the following topics:

  • 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 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 may also be known as the parasympathetic division.
    • The parasympathetic nervous system, shown in blue, is a division of the autonomic nervous system.

  • Parasympathetic (Craniosacral) Division

    • Parasympathetic ganglia are the autonomic ganglia of the parasympathetic nervous system that lie near or within the organs they innervate.
    • Parasympathetic ganglia are the autonomic ganglia of the parasympathetic nervous system, blue fibers).
    • Because of its location, the parasympathetic system is commonly referred to as having craniosacral outflow, in contrast to the sympathetic nervous system, which is said to have thoracolumbar outflow.
    • The parasympathetic nervous system, shown in blue, is a division of the autonomic nervous system.
    • Describe features of the parasympathetic division of the autonomic nervous system

  • Divisions of the Autonomic Nervous System

    • The autonomic nervous system (ANS) contains two subdivisions: the parasympathetic (PSNS) and sympathetic (SNS) nervous systems.
    • The autonomic nervous system (ANS) 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.
    • In the autonomic nervous system, preganglionic neurons connect the CNS to the ganglion.
    • Distinguish between the parasympathetic and sympathetic subsystems of the autonomic nervous system

  • 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.
    • The effect of parasympathetic stimulation is to increase activity in the entire enteric nervous system The proximal half of the nervous system is innervated from the cranial parasympathetic nerve fibers via the vagal nerve.

  • Comparing the Somatic and Autonomic Nervous Systems

    • 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 somatic nervous system consists of three parts:
    • The ANS 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.

  • Autonomic Interactions

    • The sympathetic and parasympathetic autonomic nervous systems cooperatively modulate internal physiology to maintain homeostasis.
    • Some processes that are modulated by the sympathetic and parasympathetic systems but that are not easily labeled as fight or rest include the maintenance of blood pressure when standing and the maintenance of regular heart rhythms.
    • Some typical actions of the sympathetic and parasympathetic systems are listed below.
    • In the autonomic nervous system, preganglionic neurons connect the CNS to the ganglion.
    • Describe the interactions between the sympathetic and parasympathetic divisions of the autonomic nervous system

  • 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).
    • In truth, the functions of both the parasympathetic and sympathetic nervous systems are not so straightforward, but this division is a useful rule of thumb.
    • The enteric nervous system (ENS) controls the gastrointestinal system and is sometimes considered part of the autonomic nervous system.

  • Preganglionic Neurons

    • In the autonomic nervous system (ANS), nerve fibers that connect the central nervous system to ganglia are known as preganglionic fibers.
    • In the autonomic nervous system (ANS), fibers from the central nervous system to the ganglion are known as preganglionic fibers.
    • All preganglionic fibers, whether they are in the sympathetic nervous system (SNS) or in the parasympathetic nervous system (PSNS), are cholinergic—that is, these fibers use acetylcholine as their neurotransmitter—and are myelinated.
    • Sympathetic preganglionic fibers tend to be shorter than parasympathetic preganglionic fibers because sympathetic ganglia are often closer to the spinal cord while parasympathetic preganglionic fibers tend to project to and synapse with the postganglionic fiber close to the target organ.
    • The site of synapse formation and this divergence for both the sympathetic and parasympathetic preganglionic neurons does, however, occur within ganglia situated within the peripheral nervous system.

  • Enteric Nervous System

    • The enteric nervous system (ENS) is a subdivision of the autonomic nervous system (ANS) that directly controls the gastrointestinal system.
    • The gastrointestinal (GI) system has its own nervous system, the enteric nervous system (ENS).
    • It normally communicates with the central nervous system (CNS) through the parasympathetic (e.g., via the vagus nerve) and sympathetic (e.g., via the prevertebral ganglia) nervous systems.
    • The parasympathetic nervous system is able to stimulate the enteric nerves in order to increase enteric function.
    • An illustration of neural control of the gut wall by the autonomic nervous system and the enteric nervous system.

  • Autonomic Ganglia

    • They are essentially a junction between autonomic nerves originating from the central nervous system and autonomic nerves innervating their target organs in the periphery.
    • In the peripheral nervous system, afferents refer to the axons that relay sensory information into the central nervous system (i.e., the brain and the spinal cord).
    • Sympathetic ganglia are the ganglia of the sympathetic nervous system.
    • Parasympathetic ganglia are the autonomic ganglia of the parasympathetic nervous system.
    • Efferent parasympathetic nerve signals are carried from the central nervous system to their targets by a system of two neurons.