FACTOID # 1: Idaho produces more milk than Iowa, Indiana and Illinois combined.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
 
WHAT'S NEW
RELATED ARTICLES
People who viewed "Nociceptor" also viewed:
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Nociceptor

A nociceptor is a sensory receptor that sends signals that cause the perception of pain in response to potentially damaging stimulus. Nociceptors are the nerve endings responsible for nociception, one of the two types of persistent pain (the other, neuropathic pain, occurs when nerves in the central or peripheral nervous system are not functioning properly). When they are activated, nociceptors can trigger a reflex. In a sensory system, a sensory receptor is a structure that recognizes a stimulus in the internal or external environment of an organism. ... Hurting redirects here. ... Nerves (yellow) Nerves redirects here. ... Pain is both a sensory and emotional experience, generally associated tissue damage, or inflammation. ... Neuropathy is a disease of the peripheral nervous system. ... A diagram showing the CNS: 1. ... The peripheral nervous system or PNS, is part of the nervous system, and consists of the nerves and neurons that reside or extend outside the central nervous system (the brain and spinal cord) to serve the limbs and organs, for example. ... A reflex action or reflex is a biological control system linking stimulus to response and mediated by a reflex arc. ...

Contents

Location

Nociceptors are sensory neurons that are found in external tissues such as skin, cornea and mucosa as well as in internal organs, such as the muscle, joint, bladder and gut. The cell bodies of these neurons are located in either the dorsal root ganglia or the trigeminal ganglia. Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. ... Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... It has been suggested that this article or section be merged with Epidermis (skin). ... The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber, providing most of an eyes optical power [1]. Together with the lens, the cornea refracts light and, as a result, helps the eye to focus. ... The mucous membranes (or mucosa) are linings of ectodermic origin, covered in epithelium, that line various body cavities and internal organs. ... A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ... A joint is the location at which two or more bones make contact. ... A bladder is a pouch or other flexible enclosure with waterproof or gasproof walls. ... For the Physics term GUT, please refer to Grand unification theory The gastrointestinal or digestive tract, also referred to as the GI tract or the alimentary canal or the gut, is the system of organs within multicellular animals which takes in food, digests it to extract energy and nutrients, and... This is a dorsal root ganglion (DRG) from a chicken embryo (around stage of day 7) after incubation overnight in NGF growth medium stained with anti-neurofilament antibody. ... The trigeminal nerve is the fifth (V) cranial nerve, and carries sensory information from most of the face, as well as motor supply to the muscles of mastication (the muscles enabling chewing), tensor tympani (in the middle ear), and other muscles in the floor of the mouth, such as the...


Types and functions

There are several types of nociceptor and they are classified according to the stimulus modalities to which they respond: i.e. thermal, mechanical or chemical. Some nociceptors respond to more than one of these modalities and are consequently designated polymodal. Other nociceptors respond to none of these modalities (although they may respond to stimulation under conditions of inflammation) and have thereby earned the more poetic title of sleeping or silent nociceptors (Kandel et al, 2000). Thermal nociceptors are activated by noxious heat or cold, temperatures above 45°C and below 5°C (Kandel et al, 2000). Mechanical nociceptors respond to excess pressure or mechanical deformation. Polymodal nociceptors respond to damaging stimuli of a chemical, thermal, or mechanical nature (Kandel et al, 2000). Nociceptors may have either Aδ fiber axons or more slowly conducting C fiber axons. Thus, pain often comes in two phases, the first mediated by the fast-conducting Aδ fibers and the second part due to C fibers. Silent nociceptors do not usually fire action potentials, though they are much more likely to do so in the presence of inflammation or damaging chemicals (Kandel et al, 2000). Together these nociceptors allow the organism to feel pain in response to damaging pressure, excessive heat, excessive cold and a range of chemicals, the majority of which are damaging to the tissue surrounding the nociceptor. Aδ fibres are thin, myelinated fibers with a fast conduction velocity, or speed of travel of a nerve signal (2 to 30 m/s) and are associated with acute pain, the sharp pain that triggers reflexes which result in the pulling away from the stimuli (ie: yanking hand away from... C-fibers are unmyeliniated and as a result, have a slower conduction velocity, lower than 2 m/s. ... A. A schematic view of an idealized action potential illustrates its various phases as the action potential passes a point on a cell membrane. ... An abscess on the skin, showing the redness and swelling characteristic of inflammation. ...


Pathway

Afferent nociceptive fibers (those that send information to, rather than from the brain) travel back to the spinal cord where they form synapses in its dorsal horn. The cells in the dorsal horn are divided into physiologically distinct layers called laminae. Different fiber types form synapses in different layers. Aδ fibers form synapses in laminae I and V, C fibers connect with neurons in lamina II, Aβ fibers connect with lamina IV. Information is then sent from the spinal cord to the thalamus and the cerebral cortex in the brain, and then produces pain everywhere in your body. The mechanism of the reflex arc In the nervous system, afferent neurons--otherwise known as sensory or receptor neurons--carry nerve impulses from receptors or sense organs toward the central nervous system. ... The Spinal cord nested in the vertebral column. ... The posterior horn (posterior column, posterior cornu, dorsal horn) of the spinal cord is dorsal (more towards the back) to the anterior horn. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hook from Micrographia which is the origin of the word cell. Cells in culture, stained for keratin (red) and DNA (green). ... Illustration of the major elements in a prototypical synapse. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Location of the cerebral cortex Slice of the cerebral cortex, ca. ...


See also

Hurting redirects here. ... The phrase Transient receptor potential or TRP is appended to at least three classes of ion channels which mediate the response of a cell to external stimuli (electrical charge, substances, and forces) by increasing or decreasing its selective permeability to particular ions. ... The chemical compound capsaicin (8-methyl-N-vanillyl-6-nonenamide) is the active component of chili peppers, which are plants belonging to the genus Capsicum. ... The chili pepper, or more simply just chili, is the fruit of the plant Capsicum from the nightshade family, Solanaceae. ... R-phrases , , S-phrases , , , , Flash point 16 °C RTECS number TM3500000 Related compounds Related compounds pyridine pyrrolidine piperazine Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references Piperidine is an organic compound with the molecular formula C5H11N... Binomial name Piper nigrum L. Black pepper (Piper nigrum) is a flowering vine in the family Piperaceae, cultivated for its fruit, which is usually dried and used as a spice and seasoning. ...

References

  • Kandel E.R., Schwartz, J.H., Jessell, T.M. (2000) Principles of Neural Science, 4th ed., pp.472-479. New York: McGraw-Hill. ISBN 0838580343

  Results from FactBites:
 
Nociceptor (598 words)
A nociceptor is a sensory receptor that sends signals that cause the perception of pain in response to potentially damaging stimulus.
Nociceptors are the nerve endings responsible for nociception, one of the two types of persistent pain (the other, neuropathic pain, occurs when nerves in the central or peripheral nervous system are damaged)..
Pain —; Pain's an unpleasant sensation which may be associated with actual or potential tissue damage and which may have physical and emotional components.
nociceptor - Search Results - MSN Encarta (126 words)
A nociceptor is a sensory receptor that sends signals that cause the perception of pain in response to potentially damaging stimulus.
Nociceptors are the nerve endings responsible for nociception, one...
In medicine, the pupillary reflex or pupillary light reflex, is the reduction of pupil size in...
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m