Brain Flashcards
What are the 4 general groups of the Spinal nerves
i. General Somatic Afferent
ii. General Visceral Afferent
iii. General Somatic Efferent
iv. General Visceral Efferent - pre-ganglionic autonomic fibres
What fibres do the general somatic efferent fibres contain
They innervate the skeletal muscles and consists of
alpha neurons
gamma neurons
Where are the grey cells of the general visceral efferent and afferent fibres found?
they are found on the levels of T1- L2 and S2-S4
In the spinal cord, What are the additional tracts in the cranial nerves
They are termed as special instead of general
i. Special Somatic Afferent- associated with sight; hearing and equilibrium
ii. Special Visceral Afferent- related to smell and taste
iii. Special Visceral Efferent- Innervate striated muscles from brachial arches.(for larynx, pharynx, and facials)
In the spinal cord, What are the additional tracts in the cranial nerves
They are termed as special instead of general
i. Special Somatic Afferent- associated with sight; hearing and equilibrium
ii. Special Visceral Afferent- related to smell and taste
iii. Special Visceral Efferent- Innervate striated muscles from brachial arches.(for larynx, pharynx, and facials)
What are the Cranial Nerves of the General Somatic Efferent Fibres and it’s location in the spinal cord
The nerves will lie near the midline of the brain near the ventricles or the aquaduct or the floor of the fourth ventricle.
CN III- Occulomotor
CN IV- Trochlear
CN VI- Abducens nerve
CN XII- Hypoglossal
What are the functions of Occulomotor Nerve, it’s origin and course
The Occulomotor nerve is the third cranial nerve
- it innervates all of the internal and external muscles of the ipsilateral eye
- except lateral rectus and superior oblique muscles and dilator papillae
- they originate in the web-shaped oculomotor nucleus @ the ventral(anterior) edge of periductal grey @ rostral midbrain-pontine junction. The nucleus consists of longitudinal cell columns of subnuclei.
It’s course proceeds ventrally and arch through the midbrain tegmentum in separate bundles to join and forms the nerve as it emerges into interpeduncular fossa.
What muscles do the Occulomotor Nerve Supply
i. Levator Palpebrea Superioris- it’s fibres are located in the midline and innervates the muscle bilaterally
ii. Superior Rectus Muscle- the nuclei project towards the contralateral line. It’s function is to
iii. Inferior Rectus Muscle-
iv. Medial Rectus
v. Inferior Oblique Muscle
Parasympathethic- pre-ganglionic neurons (GVE)- comes from the edinger-westphal nucleus into ipsilateral ciliary ganglion.
vi. sphincter pupillae
vii. Ciliary muscles
What muscles do the Trochlear nerve innervate and it’s course?
-supplies the superior oblique muscle- action is it depresses, abducts and internally rotates the contralateral side
it is the only Cranial nerve that originates from the posterior region. turns caudally in
- supplies the contralateral muscle
- smallest cranial nerve and arises in the trochlear nuclei and leaves the brain stem at the pons midbrain junction
It runs anteriorly and inferiorly within the subarachnoid space before piercing the dura mater adjacent to the posterior clinoid process of the sphenoid bone.
The nerve then moves along the lateral wall of the cavernous sinus (along with the oculomotor nerve, the abducens nerve, the ophthalmic and maxillary branches of the trigeminal nerve and the internal carotid artery) before entering the orbit of the eye via the superior orbital fissure.
- inferior collicullus where indents Medial Longitudinal Fasciculus
What is the course of the Abducens nerve; it’s muscle innervation
supplies the Lateral rectus muscle of the eye which functions to abduct the ipsilateral side of the eye.
this is located at the abducens nuclei located cortal pons located at the cortical points of the floor of the 4th ventricle
Where is the origin of the Hypoglossal nerve it’s course and it’s function
It originates at the Hypoglossal nuclei located at the floor of the fourth ventricle and forms an elevation known as the hypoglossal trigone from cortal medulla to the rostral medulla it’s function is to provide Intrinsic and extrinsic tongue muscles
