FACTOID # 15: A mere 0.8% of West Virginians were born in a foreign country.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Cranial nerves
Cranial nerves

Cranial nerves are nerves that emerge directly from the brain in contrast to spinal nerves which emerge from segments of the spinal cord. Although thirteen cranial nerves in humans fit this description, twelve are conventionally recognized. The nerves from the third onward arise from the brain stem. Except for the tenth and the eleventh nerve, they primarily serve the motor and sensory systems of the head and neck region. However, unlike peripheral nerves which are separated to achieve segmental innervation, cranial nerves are divided to serve one or a few specific functions in wider anatomical territories. Image File history File links Brain_human_cranial_nerves. ... Image File history File links Brain_human_cranial_nerves. ... Nerves (yellow) Nerves redirects here. ... The human brain In animals, the brain (enkephalos) (Greek for in the skull), is the control center of the central nervous system, responsible for behavior. ... The term spinal nerve generally refers to the mixed spinal nerve, which is formed from the dorsal and ventral roots that come out of the spinal cord. ... The Spinal cord nested in the vertebral column. ... List of bones of the human skeleton Human anatomy is primarily the scientific study of the morphology of the adult human body. ... The brain stem is the lower part of the brain, adjoining and structurally continuous with the spinal cord. ... Structure of a skeletal muscle Muscle is one of the four tissue types. ... The human eye is the first element of a sensory system: in this case, vision, for the visual system. ... Head and neck anatomy is a specialized study of the human body quite frequently studied in depth by surgeons, dentist, and dental technicians. ... 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--to serve the limbs and organs, for example. ... Segmental innervation refers to the distribution (innervation) of nerves within an organ or muscle. ...

Contents

Names of Nerves

The 12 pairs of cranial nerves are traditionally abbreviated by the corresponding Roman numerals. They are numbered according to where their nuclei lie in the brain stem, e.g. Cranial Nerve III (the Oculomotor nerve) leaves the brainstem at a higher position than Cranial nerve XII, whose origin is located more caudally (lower) than the other cranial nerves. The system of Roman numerals is a numeral system originating in ancient Rome, and was adapted from Etruscan numerals. ... In neuroanatomy, a nucleus is a central nervous system structure that is composed mainly of gray matter, and which acts as a hub or transit point for electrical signals in a single neural subsystem. ...

# Name Nuclei Function
0 Cranial nerve zero (CN0 is not traditionally recognized.)[1] olfactory trigone, medial olfactory gyrus, and lamina terminalis

Still controversial The terminal nerve, or cranial nerve zero, was discovered by German scientist Gustav Fritsch in 1878. ... The olfactory trigone is a small triangular area in front of the anterior perforated substance. ... The median portion of the wall of the fore-brain vesicle consists of a thin lamina, the lamina terminalis, which stretches from the interventricular foramen to the recess at the base of the optic stalk. ...


New research indicates CN0 may play a role in the detection of pheromones [2][3]

I Olfactory nerve Anterior olfactory nucleus Transmits the sense of smell
II Optic nerve Lateral geniculate nucleus Transmits visual information to the brain
III Oculomotor nerve Oculomotor nucleus, Edinger-Westphal nucleus Innervates levator palpebrae superioris, superior rectus, medial rectus, inferior rectus, and inferior oblique, which collectively perform most eye movements
IV Trochlear nerve Trochlear nucleus Innervates the superior oblique muscle, which depresses, pulls laterally, and intorts the eyeball
V Trigeminal nerve Principal sensory trigeminal nucleus, Spinal trigeminal nucleus, Mesencephalic trigeminal nucleus, Trigeminal motor nucleus Receives sensation from the face and innervates the muscles of mastication
VI Abducens nerve Abducens nucleus Innervates the lateral rectus, which abducts the eye
VII Facial nerve Facial nucleus, Solitary nucleus, Superior salivary nucleus Provides motor innervation to the muscles of facial expression and stapedius, receives the special sense of taste from the anterior 2/3 of the tongue, and provides secretomotor innervation to the salivary glands (except parotid) and the lacrimal gland
VIII Vestibulocochlear nerve (or auditory-vestibular nerve or statoacustic nerve) Vestibular nuclei, Cochlear nuclei Senses sound, rotation and gravity (essential for balance & movement)
IX Glossopharyngeal nerve Nucleus ambiguus, Inferior salivary nucleus, Solitary nucleus Receives taste from the posterior 1/3 of the tongue, provides secretomotor innervation to the parotid gland, and provides motor innervation to the stylopharyngeus (essential for tactile, pain, and thermal sensation). Sensation is relayed to opposite thalamus and some hypothalamic nuclei.
X Vagus nerve Nucleus ambiguus, Dorsal motor vagal nucleus, Solitary nucleus Supplies branchiomotor innervation to most laryngeal and pharyngeal muscles; provides parasympathetic fibers to nearly all thoracic and abdominal viscera down to the splenic flexure; and receives the special sense of taste from the epiglottis. A major function: controls muscles for voice and resonance. Symptoms of damage: dysphagia (swallowing problems).
XI Accessory nerve (or cranial accessory nerve or spinal accessory nerve) Nucleus ambiguus, Spinal accessory nucleus Controls muscles of the neck and overlaps with functions of the vagus. Examples of symptoms of damage: inability to shrug, weak head movement, velopharyngeal insufficiency)
XII Hypoglossal nerve Hypoglossal nucleus Provides motor innervation to the muscles of the tongue and other glossal muscles. Really important for swallowing (bolus formation) and speech articulation.

The olfactory nerve is the first of twelve cranial nerves. ... The anterior olfactory nucleus is a cranial nucleus for the olfactory nerve. ... This article is about the anatomical structure. ... Grays FIG. 719– Hind- and mid-brains; postero-lateral view. ... The oculomotor nerve () is the third of twelve paired cranial nerves. ... The fibers of the oculomotor nerve arise from a nucleus in the midbrain, which lies in the gray substance of the floor of the cerebral aqueduct and extends in front of the aqueduct for a short distance into the floor of the third ventricle. ... The Edinger-Westphal nucleus is the accessory parasympathetic nucleus of the oculomotor nerve, supplying the constricting muscles of the iris. ... The fourth of twelve cranial nerves, the trochlear nerve controls the function of the superior oblique muscle, which rotates the eye away from the nose and also moves the eye downward. ... The nucleus of the trochlear nerve is located in the midbrain, at the level of the inferior colliculus. ... 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... The principal sensory nucleus (or chief sensory nucleus) receives information about discriminative sensation and light touch as well as conscious proprioception of the jaw. ... The sensory trigeminal nerve nucleus is the largest of the cranial nerve nuclei, and extends through the whole of the brainstem, midbrain to medulla. ... The sensory trigeminal nerve nucleus is the largest of the cranial nerve nuclei, and extends through the whole of the brainstem, midbrain to medulla. ... The sensory trigeminal nerve nucleus is the largest of the cranial nerve nuclei, and extends through the whole of the brainstem, midbrain to medulla. ... The sixth of twelve cranial nerves, the abducens nerve is a motor nerve that innervates the lateral rectus muscle and therefore controls each eyes ability to abduct (move away from the midline). ... The abducens nucleus is the originating nucleus from which the abducens nerve emerges - a cranial nerve nucleus. ... The facial nerve is the seventh (VII) of twelve paired cranial nerves. ... The cranial nerve motor nucleus of the facial nerve is located in the lower pons. ... The solitary nucleus and tract are structures in the brainstem that carry and receive visceral sensation and taste from the facial (VII), glossopharyngeal (IX), vagus (X) cranial nerves, as well as the cranial part of the accessory nerve (XI). ... The Superior salivary nucleus (or superior salivatory nucleus) of the facial nerve is a visceromotor cranial nerve nucleus located in the pontine tegmentum. ... The vestibulocochlear nerve (also known as the auditory or acoustic nerve) is the eighth of twelve cranial nerves, and is responsible for transmitting sound and equilibrium (balance) information from the inner ear to the brain. ... The nuclei of the vestibular nerve. ... The cochlear nuclei consist of: (a) the dorsal cochlear nucleus, corresponding to the tuberculum acusticum on the dorso-lateral surface of the inferior peduncle; and (b) the ventral or accessory cochlear nucleus, placed between the two divisions of the nerve, on the ventral aspect of the inferior peduncle. ... The glossopharyngeal nerve is the ninth of twelve cranial nerves. ... The nucleus ambiguus (literally ambiguous nucleus) is a region of histologically disparate cells located just dorsal (posterior) to the inferior olivary nucleus in the lateral portion of the upper (rostral) medulla. ... The inferior salivatory nucleus is one of the components of the glossopharyngeal nerve, which stimulates secretion from the parotid gland. ... The solitary nucleus and tract are structures in the brainstem that carry and receive visceral sensation and taste from the facial (VII), glossopharyngeal (IX), vagus (X) cranial nerves, as well as the cranial part of the accessory nerve (XI). ... The vagus nerve (also called pneumogastric nerve or cranial nerve X) is the tenth of twelve paired cranial nerves, and is the only nerve that starts in the brainstem (within the medulla oblongata) and extends, through the jugular foramen, down below the head, to the abdomen. ... The nucleus ambiguus (literally ambiguous nucleus) is a region of histologically disparate cells located just dorsal (posterior) to the inferior olivary nucleus in the lateral portion of the upper (rostral) medulla. ... The posterior nucleus of vagus nerve (or dorsal motor nucleus of vagus) is a cranial nerve nucleus for the vagus nerve that arises from the floor of the fourth ventricle. ... The solitary nucleus and tract are structures in the brainstem that carry and receive visceral sensation and taste from the facial (VII), glossopharyngeal (IX), vagus (X) cranial nerves, as well as the cranial part of the accessory nerve (XI). ... Anatomy and Physiology of the A.N.S. In contrast to the voluntary nervous system, the involuntary or autonomic nervous system is responsible for homeostasis, maintaining a relatively constant internal environment by controlling such involuntary functions as digestion, respiration, and metabolism, and by modulating blood pressure. ... Grays Fig. ... In anatomy, the accessory nerve is a nerve that controls specific muscles of the neck. ... The nucleus ambiguus (literally ambiguous nucleus) is a region of histologically disparate cells located just dorsal (posterior) to the inferior olivary nucleus in the lateral portion of the upper (rostral) medulla. ... The spinal accessory nucleus lies within the cervical spinal cord (C1-C5) in the ventral horn. ... The hypoglossal nerve is the twelfth cranial nerve. ... The hypoglossal nucleus extends the length of the medulla, and being a motor nucleus, is close to the midline. ...

Cranial nerves in non-human vertebrates

Human cranial nerves are evolutionarily homologous to those found in many other vertebrates. Cranial nerves XI and XII evolved in the common ancestor to amniotes (non-amphibian tetrapods) thus totalling twelve pairs. These characters are synapomorphies for their respective clades. In some primitive cartilagenous fishes, such as the dogfish (Squalos acanthos), there is a terminal nerve numbered zero (as it exits the brain before the first cranial nerve). This article is about evolution in biology. ... In biology, homology is any similarity between structures that is due to their shared ancestry. ... This article does not cite any references or sources. ... Living subgroups Class Synapsida    Class Mammalia (mammals) Class Sauropsida    Anapsida        Testudines (turtles)    Diapsida        Lepidosauria           Squamata (lizards & snakes)           Sphenodontida (tuatara)        Archosauria           Crocodilia (crocodiles)           Class Aves (birds) The amniotes are a taxon of tetrapod vertebrates that include the Synapsida (mammals) and Sauropsida (reptiles and dinosaurs, including birds). ... Shared characteristics that define a cladistic grouping. ... Greek clados = branch) or phylogenetic systematics is a branch of biology that determines the evolutionary relationships of living things based on derived similarities. ... This article does not cite any references or sources. ... The terminal nerve, or cranial nerve zero, was discovered by German scientist Gustav Fritsch in 1878 in the brains of sharks. ...


Mnemonic devices

As the list is important to keep in mind during the examination of the nervous system, there are many mnemonic devices in circulation to help remember the names and order of the cranial nerves. Because the mind recalls rhymes well, the best mnemonics often use rhyming schemes. The best known example is, "On Old Olympus' Towering Top A Finn And German Viewed Some Hops,"[4] where And represents auditory vestibular and Some represents spinal accessory. For other uses, see Mnemonic (disambiguation). ...


Another to help remember the types of information these nerves carry (sensory, motor, or both) is thus:

  • Some Say Money Matters, But My Brother Says Big Brains Matter More.

For additional memonics, see b:Transwiki:List of mnemonics for the cranial nerves


See also

A cranial nerve nucleus is a collection of neurons (gray matter) in the brain stem that is associated with one or more cranial nerves. ...

External links

The University of Toronto (U of T) is a public research university in the city of Toronto, Ontario, Canada. ... Georgetown University is an elite private research university located in Georgetown, Washington, D.C., United States. ...

References

  1. ^ Fuller GN, Burger PC. "Nervus terminalis (cranial nerve zero) in the adult human." Clin Neuropathol 9, no. 6 (Nov-Dec 1990): 279-283.
  2. ^ Merideth, Michael. "Human Vomeronasal Organ Function." Oxford Journals: Chemical Senses, 2001.
  3. ^ Fields, R. Douglas. "Sex and the Secret Nerve." Scientific American Mind, February 2007.
  4. ^ Herlevich NE (1990). "Reflecting on old Olympus' towering tops". Journal of ophthalmic nursing & technology 9 (6): 245–6. PMID 2254946. Retrieved on 2007-11-06. 

  Results from FactBites:
 
Cranial Nerve > Anatomy (940 words)
Cranial nerves 5, 6, 7, and 8 are located in the pons and give us a view of this level of the brainstem.
The axons for the descending tract of the 5th nerve (pain and temperature) descend to the level of the upper cervical spinal cord before they synapse with neurons of the nucleus of the descending tract of the 5th nerve.
This cranial nerve has a motor component for muscles of facial expression (and, don't forget, the strapedius muscle which is important for the acoustic reflex), parasympathetics for tear and salivary glands, and sensory for taste (anterior two-thirds of the tongue).
IX. Neurology. 5. The Cranial Nerves. Gray, Henry. 1918. Anatomy of the Human Body. (344 words)
The area of attachment of a cranial nerve to the surface of the brain is termed its superficial or apparent origin.
The sensory or afferent cranial nerves arise from groups of nerve cells outside the brain; these nerve cells may be grouped to form ganglia on the trunks of the nerves or may be situated in peripheral sensory organs such as the nose and eye.
The nuclei of origin of the motor nerves and the nuclei of termination of the sensory nerves are brought into relationship with the cerebral cortex, the former through the geniculate fibers of the internal capsule, the latter through the lemniscus.
  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