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Topic: Efferent neuron


  
 Neurology-Info.net: Information on the nervous system, diseases and disorders, treatments
Association neurons, or interneurons are usually found in the spinal cord and brain where they connect sensory afferent neurons to efferent motor or secretory neurons.
An autonomic preganglionic efferent neuron is an example of a Type B fiber and a sensory neuron carrying information about diffuse pain is an example of a slow Type C fiber.
Acetylcholine is the neurotransmitter at the synapse with the long postganglionic neuron which then travels to the target tissue where norepinephrine is released at the majority of sympathetic nerve endings.
http://www.neurology-info.net   (2030 words)

  
 notes4exam4
If there is only one efferent neuron, we must be talking about a somatic, not autonomic reflex, so the target organ must be a skeletal muscle.
Comment: A minimum complete parasympathetic reflex arc starts with a receptor and an afferent neuron, which synapses in the spinal cord (synapse #1) with the pre-ganglionic efferent neuron, which in turn synapses with the post-ganglionic efferent neuron (synapse #2).
Remember that the cervical spinal nerves are named for the vertebra BELOW them, unlike the other areas of the spine.
http://www.msu.edu/~vaishnav/notes4exam4.html   (1831 words)

  
 Online Dictionary for French English, Spanish English, Italian English, and more.
A neuron conducting impulses outwards from the brain or spinal cord; SYN: efferent neuron.
A neuron conducting impulses inwards to the brain or spinal cord; SYN: afferent neuron.
Type or paste a URL to reproduce the page with dictionary-enabling.
http://www.ultralingua.net/?service=ee&text=neuron   (138 words)

  
 Motoneuron - Wikipedia, the free encyclopedia
In vertebrates, motoneurons (also called motor neurons) are efferent neurons that originate in the spinal cord and synapse with muscle fibers to facilitate muscle contraction and with muscle spindles to modify proprioceptive sensitivity.
In addition to voluntary skeletal muscle contraction, alpha motoneurons also contribute to muscle tone, the continuous force generated by noncontracting muscle to oppose stretching.
When a muscle is stretched, sensory neurons within the muscle spindle detect the degree of stretch and send a signal to the CNS.
http://en.wikipedia.org/wiki/Motoneuron   (591 words)

  
 Nerve Tissue
An example of the interaction between afferent and efferent neurons is illustrated by a neural pathway called the reflex arc.
This is in contrast to the efferent innervation of skeletal muscle by cranial and spinal nerves (voluntary control).
When a neuron is not conducting a nerve impulse, its membrane is polarized; that is, it carries a transmembrane potential.
http://anatomy.iupui.edu/courses/histo_D502/D502f02/Nerve/Nerve.htm   (3552 words)

  
 Newton's Apple: Teacher's Guides
Motor (or efferent) neurons carry messages away from the brain and spinal cord.
These neurons are found in the central nervous system, which includes your brain and spinal cord, and the peripheral nervous system, which includes all the nerves that reach your body's extremities.
Sensory (or afferent) neurons carry messages to the brain and spinal cord.
http://www.ktca.org/newtons/13/rlxes.html   (1070 words)

  
 Nerve Tissue
An example of the interaction between afferent and efferent neurons is illustrated by a neural pathway called the reflex arc.
Usually, more than two neurons are involved and such a pathway is said to be polysynaptic.
When a neuron receives an appropriate stimulus, the first thing that happens is that there is a massive influx of Na+ due to an opening of Na+ channels in the membrane.
http://anatomy.iupui.edu/courses/histo_D502/D502f02/Nerve/Nerve.htm   (1070 words)

  
 spinalreflexes.html
motor neurons - (termed efferent arm of reflex) produce muscle contraction, motor response.
Clinical significance - Clasped knife reflex: In Upper Motor neuron lesions, tonus may increase and resistance of muscle to stretch increases; if sufficient force is applied, limb resistance suddenly decreases (like a pocket knife snapping shut); thought to be mediated by reflexes of Golgi tendon organs.
Muscle Tonus - The ongoing activity in muscle spindles is important in maintaining the desired activity  of motor neurons to muscles (because the connection is monosynaptic).
http://musom.marshall.edu/anatomy/grosshom/spinalreflexes.html   (1719 words)

  
 motor neuron: Definition and Much More From Answers.com
In vertebrates, motoneurons (also called motor neurons) are efferent neurons that originate in the spinal cord and synapse with muscle fibers to facilitate muscle contraction and with muscle spindles to modify proprioceptive sensitivity.
In addition to voluntary skeletal muscle contraction, alpha motoneurons also contribute to muscle tone, the continuous force generated by noncontracting muscle to oppose stretching.
When a muscle is stretched, sensory neurons within the muscle spindle detect the degree of stretch and send a signal to the CNS.
http://www.answers.com/topic/motoneuron-1   (743 words)

  
 SPINAL MOTOR STRUCTURES
The efferent neuron is the motor neuron, which causes the muscle to twitch.
At segments that control a limb, the motor neurons are large and numerous.
The afferent neuron is connected to a muscle spindle, which detects stretch in the muscle.
http://thalamus.wustl.edu/course/spinal.html   (1662 words)

  
 SPINAL MOTOR STRUCTURES
The efferent neuron is the motor neuron, which causes the muscle to twitch.
The afferent neuron is connected to a muscle spindle, which detects stretch in the muscle.
One of the most familiar reflexes is the stretch reflex, also known as the knee-jerk reflex and the myotatic reflex.
http://thalamus.wustl.edu/course/spinal.html   (1662 words)

  
 The Whitaker Foundation: Research Grants Approved April 2003
However the state of the muscle spindle sensory neuron is under efferent control exerted by the CNS.
Extensive neuronal death and loss of axons across the site of damage directly contribute to functional impairment, in particular because after injury, nerves of the central nervous system (CNS) do not spontaneously regenerate their axons.
To provide injured neurons with growth-promoting cues while they are surrounded by inhibitory cues, we must understand how neurons integrate the myriad molecular signals present in the injured CNS.
http://www.whitaker.org/abstracts/rgapr03.html   (6787 words)

  
 Multipotency - encyclopedia article about Multipotency.
There are three classes of neurons: afferent neurons, efferent neurons, and interneurons.
In recent stem cell experiments, scientists have been able to persuade blood stem cells to behave like neurons, or brain cells.
In vertebrates, they are found in the brain, the spinal cord and in the nerves and ganglia of the peripheral nervous system.
http://encyclopedia.thefreedictionary.com/Multipotency   (6787 words)

  
 Efferent nerve - Wikipedia, the free encyclopedia
The motor nerves are efferent nerves involved in muscular control.The cell body of the efferent neuron is found in the central nervous system, where it is connected to a single,long axon and several short dendrons projecting out of the cell body itself.
In the nervous system, efferent nerves otherwise known as motor or effector neuron carry nerve impulses away from the central nervous systemto effectors - either muscles or glands.
This axon then forms a neuromuscular junction with the effectors.The cell body of the motor neuron is satellite-shaped.
http://en.wikipedia.org/wiki/Efferent   (180 words)

  
 Case History
The efferent (output) axon of motor neurons that innervates skeletal muscle is an A alpha fiber.
The term lower motor neuron simply refers to any neuron that directly innervates striated muscle.
Note: The Alpha Motor Neuron is the neuron that exerts finite biochemical and physiological control over the skeletal muscle innervated.
http://cats.med.uvm.edu/cats_teachingmod/neurobiology/histology_lab/nerve_terminations/history.html   (994 words)

  
 Nervous tissue
Efferent or somatic motor neurons transmit the impulse from the central nervous system to a muscle (the effector organ) which then react to the initial stimulus.
Because of their structure they are often referred to as unipolar neurons.
Motor neurons, which have numerous cell processes (an axon and many dendrites) are often referred to as multipolar neurons.
http://www.botany.uwc.ac.za/sci_ed/grade10/mammal/nervous.htm   (994 words)

  
 Nervous tissue
Efferent or somatic motor neurons transmit the impulse from the central nervous system to a muscle (the effector organ) which then react to the initial stimulus.
Because of their structure they are often referred to as unipolar neurons.
Motor neurons, which have numerous cell processes (an axon and many dendrites) are often referred to as multipolar neurons.
http://www.botany.uwc.ac.za/sci_ed/grade10/mammal/nervous.htm   (600 words)

  
 APStracts 2:0183N, 1995.
We suggest that spindle waves and the bicuculline-induced slow oscillation propagate through the thalamus by progressive recruitment of neighboring neurons into the oscillation and that synchrony of neuronal activity results from a large degree of overlap in efferent and afferent connections.
This oscillation, however, could not be initiated by burst firing in a single PGN neuron.
The local antagonism of non-NMDA receptors in the PGN results in the dorsal and ventral aspects of the LGNd slice behaving as independent spindle wave generators, even if prior to application of CNQX they were not.
http://www.uth.tmc.edu/apstracts/1995/jn/July/183n.html   (632 words)

  
 Zoology 214 Lecture 26: October 12, 2001
The soma for the efferent neuron may be in the spinal cord or brain
The efferent neuron exits the CNS and terminates in an autonomic ganglion (define ganglion)
Autonomic postganglionic neurons do not generally form a model synapse as we saw in neurons or skeletal muscle
http://www.humboldt.edu/~bao3/214lectures/214Lecture26.htm   (451 words)

  
 The ANS
The sympathetic nerves reach their end-organs through more devious pathways down the spinal cord to clusters of sympathetic nerve bodies (ganglia) alongside the spine where the messages are relayed to other nerve bodies (or neurons) that travel to a large extent with the blood vessels to all parts of the body.
Similarly, the stimuli associated with the entry of food into the stomach are conveyed by afferent fibers of the vagus nerve to the command station or nucleus of the vagus in the brain whence messages are automatically conveyed through efferent fibers of the vagus back to the stomach.
The impulses of the parasympathetic system reach the organs of the body through the cranial nerves # 3, 7, 9, and 10, and some sacral nerves to the eyes, the gastrointestinal system, and other organs.
http://www.ndrf.org/ans.htm   (451 words)

  
 NERVES
The simpilest imaginable reflex would be a sensory (afferent) neuron synapsing with a motor (efferent) neuron.
A neuron will have 100-1000 dendrites, which means it can receive signals from that many other neurons!
An axon is the length of the neuron is the structure that carries the action potential signal from one area of the body to another.
http://www.mrs.umn.edu/~goochv/AnimalPhys/nerves/nerves.html   (451 words)

  
 Nerve - Enpsychlopedia
Efferent nerves enter the spinal cord through the dorsal (i.e.
These signals, sometimes called nerve impulses, are also known as action potentials : Rapidly traveling electrical waves, which begin typically in the cell body of a neuron and propagate rapidly down the axon to its tip or "terminus." The signals cross over from the terminus to the adjacent neuron through a gap called the synapse.
Afferent nerves convey sensory signals to the brain, for example from skin or organs, while efferent nerves conduct stimulatory signals from the brain to the muscles and glands.
http://www.grohol.com/wiki/Nerve   (451 words)

  
 Somatic nervous system - Wikipedia, the free encyclopedia
The basic route of the efferent somatic nervous system includes a two neuron sequence.
The somatic nervous system consists of afferent fibers that receive information from external sources, and efferent fibers that are responsible for muscle contraction.
The first is the upper motor neuron, whose cell body is located in the precentral gyrus (Brodman Area 4) of the brain.
http://en.wikipedia.org/wiki/Somatic_nervous_system   (270 words)

  
 Nerve - Wikipedia, the free encyclopedia
Afferent nerves convey sensory signals to the central nervous system, for example from skin or organs, while efferent nerves conduct stimulatory signals from the central nervous system to the muscles and glands.
These signals, sometimes called nerve impulses, are also known as action potentials: rapidly traveling electrical waves, which begin typically in the cell body of a neuron and propagate rapidly down the axon to its tip or "terminus." The signals cross over from the terminus to the adjacent neuron through a gap called the synapse.
Nerves are part of the peripheral nervous system.
http://en.wikipedia.org/wiki/Nerve_ending   (277 words)

  
 Anatomy Chapter 9 Nervous Tissue
The ____ consists of efferent neurons that conduct impulses from the central nervous system to skeletal muscles.
The ____ conducts nerve impulses from the neuron to the dendrites, the cell body of another neuron or an effector organ of the body such as a muscle or a gland.
_______ neurons conduct impulses to effectors such as muscles or glands..
http://watson2.arsc.k12.ar.us/wchs/potillo/tests/anatomy_chapter_9_notes_test.htm   (791 words)

  
 Dorlands Medical Dictionary
Motoneuron shown as the efferent neuron in a three-neuron reflex arc.
in a reflex arc, a motoneuron that receives impulses from interneurons.
(mo´ro) [Ernst Moro, Austrian pediatrician, 1874–1951] see under reflex.
http://www.mercksource.com/pp/us/cns/cns_hl_dorlands.jspzQzpgzEzzSzppdocszSzuszSzcommonzSzdorlandszSzdorlandzSzdmd_m_20zPzhtm   (3297 words)

  
 Á¦ 5Àå ¿îµ¿»ý¸®
¨ê Efferent Nerve Fibers (efferent pathway, motor axons, postganglionic fibers)
Static Nuclear bag fiber : ㄃ Static Motor Neuron/ Ia afferent fiber
Basic pattern of locomotion : programmed at the level of the spinal cord.
http://etgr.wkhc.ac.kr/lect/ElectroPhysiology/NP05.htm   (3297 words)

  
 Autonomic NS
Preganglionic neuron and fiber; cell body and preganglionic fiber originate in the brain and the spinal cord.
It is a solely efferent system, however, afferent visceral fibers, associated with the spinal nerve, travel with the efferent fibers and provide information to the CNS concerning the state of the viscera.
Preganglionic parasympathetic fibers leave the spinal nerve as the pelvic splanchnic nerves (to be learned later) but never reenter it to be distributed to the periphery.
http://wings.buffalo.edu/smbs/ana/newpage41.htm   (3297 words)

  
 THE MERCK MANUAL, Sec. 14, Ch. 183, Disorders Of The Peripheral Nervous System
In motor neuron disorders, efferent innervation of the anterior horn cell is lost.
In some disorders, the upper motor neurons from the motor cortex to the brain stem (corticobulbar tracts) or spinal cord (corticospinal tracts) are also involved; in others (bulbar palsies), cranial nerve motor nuclei in the brain stem (bulbar nuclei) are selectively affected.
The efferent motor fibers originate as anterior horn cells in the gray matter of the cord; the cell bodies of the afferent sensory fibers lie in dorsal root ganglia.
http://www.merck.com/mrkshared/mmanual/section14/chapter183/183a.jsp   (647 words)

  
 Synapse
If the efferent fiber is a lower motor neuron, then this is Renshaw inhibition.
a) Soma = the cell body of the neuron
The interneuron is then said to be a "renshaw cell." In strychnine poisoning, strychnine competes with glycine (an inhibitory neurotransmitter) thus undoing Renshaw inhibition.
http://www.vin.com/vin_ce/abvp/html/synapse.html   (297 words)

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