MCQsOnline - Online Collection of MCQs of Medical PG Entrance Exams.

MCQ stands for Multiple Choice Questions sometimes called as Objective type questions. Here we discuss the Old Question Papers, High Yield Points and Strategies with respect to the Indian Medical Post Graduate PG Entrance Exams like AIIMS,AIPG, JIPMER, CMC Vellore, PGI Chandigarh, UPSC, TNPSC, State PG Exams like Tamil Nadu PG (TN PG), Delhi PG, UPPG, Tamilnadu PG (TNPG), Karnataka PG, MAHE, COMED-K etc.

Target PG

PG Preparation

Related Portals

Search This Site

If you cannot locate what you want to find, please search using the box given below

Thursday, October 09, 2008

All of the following are Somatic Efferent except

Question 14
All of the following are Somatic Efferent except
a.       Facial nerve
b.      III Nerve
c.       IV Nerve
d.      VI Nerve
Answer
a) Facial nerve
Reference:
Gray’s Anatomy 38th Edition Pages 238, 241
QTDF
Gray / Neuroanatomy Books
Quality
Thinker
Status
New
Discussion
  • General somatic efferent neurons exit ventrally in a similar manner to those of the spinal cord, comprising the oculomotor, trochlear, abducens and hypoglossal nerves. Thus nerves III, IV, VI and XII parallel the organization of the somatic motor neurons in the spinal cord.
Explanation
Self Explanatory
Comments
  • The second motor component, special branchial efferent, comprises the accessory nerve and the motor parts of the trigeminal, facial, glossopharyngeal and vagus nerves, whose nerve exit points lie more dorsally than the somatic motor system.
  • The cranial nerves also contain a third class of efferent neurons, the general visceral efferent neurons (parasympathetic preganglionic) travelling in nerves III, VII, IX and X, which leave the hindbrain via the same exit points as the special branchial efferent fibres.
  • The most rostral sensory ganglion, the trigeminal (V) comprises both neural crest and placode-derived neurons that mediate general somatic afferent functions. In the case of more caudal cranial nerves (VII, IX and X) the same applies, but the two cell populations form separate ganglia in the case of each nerve. Analogous with the trigeminal, the proximal series of ganglia is neural crest derived (forming the proximal ganglion of VII, the superior ganglion of IX and the jugular ganglion of X) while the distal series derives from placodal cells (forming the geniculate ganglion of VII, the petrosal ganglion of IX and the nodose ganglion of X). These ganglia contain neurons that mediate special, general visceral and somatic afferent functions. The VIIth nerve has a vestibular ganglion containing both crest and placodal cells and an acoustic ganglion from placodal neurons only; it conveys special somatic afferents.
  • Both neurons and supporting cells of the cranial autonomic ganglia in the head and the trunk originate from neural crest cells
Tips
Types of Functional Components in a Nerve
Fibres and Sensation Carried
Nucleus
Sensory or Afferent
Visceral
General
General Visceral Afferent
·        Pain arising from Viscera
·        Dorsal Nucleus of Vagus
Special
Special Visceral Afferent
·        Taste
·        Nucleus Tractus Solitarius
·        Nucleus of Dorsal Visceral Gray
Somatic
General
General Somatic Afferent
·        Exteroceptive impulses – cutaneous sensations of pan, touch and temperature -
·        Proprioceptive impulses arising in muscles, tendon and joints conveying information regarding movement and position of joint
·        Chief Sensory Nucleus (Tactile)
·        Nucleus of Spinal Tract of Trigeminal Nerve (Pain Temp)
·        Nucleus of Mesencephalic Tract of Spinal Nerve (Proprioception)
·         
Special
Special Somatic Afferent
·        Vision
·        Hearing
·        Equilibrium
·        Nucleus of the Vestibulocochlear nerver
Motor of Efferent
Visceral
General
General Visceral Efferent
·        General visceral efferent neurons
·        Parasympathetic preganglionic (III, VII, IX and X)
·        innervate glands of the head,
·        the sphincter pupillae and ciliary muscles,
·        and the thoracic and abdominal viscera.
·        Smooth muscle
·        Cardiac Muscle
·        Glands
·        Dorsal Vagal Nucleus
·        Superior Salivatory Nucleus
·        Inf Salivatory Nucleus
·        Lacrimatory Nucleus
·        Edinger Westpal Nucleus
Special
Special Visceral Efferent
·        (accessory nerve and the motor parts of the V, VII, IX, X nerves)
·        Also called as Branchial Efferent.
·        Striated muscles developing within the pharyngeal (branchial) arches
·        Mucles of Mastication, face, larynx
·        Nucleus Ambigus
Somatic
General
General Somatic Efferent
·        Supply striated muscle now known to be derived from the cranial (occipital) somites and prechordal mesenchyme.
·        Muscles of Body wall and Limbs
·        Eye and Tongue
·         
·        Oculomotor Nucleus (III)
·        Trochlear Nucleus (IV)
·        Abducent Nucleus (VI)
·        Hypoglossal Nucleus (XII)

No comments:

Post a Comment