neuroanatomy of cranial nerves. cns brain and spinal cord information processing/interneurons...
TRANSCRIPT
Neuroanatomy of Cranial Nerves
CNS
Brain and Spinal Cord
Information processing/Interneurons
Sensory/Afferent
•General Sensory (Somatic and Visceral)
•Special Sensory
RECEPTORS
Motor/Efferent
•Somatic Motor
•Visceral Motor (ANS)
PNS
Nerves
EFFECTORS
Overview
Functional Components of Nerves• General sensory
– Somatic sensory (GSA)– Visceral sensory (GVA)
• Special sensory (SSA, SVA)• Somatic motor (GSE)
– Branchial motor (SVE) to skeletal muscles derived from branchial arches
– Somatic motor (GSE) to skeletal muscles derived from other sources
• Visceral motor (GVE) to smooth muscle and glands
Cranial Nerves
• Carry 1-4 functional components– General sensory– Special sensory– Somatic motor– Visceral motor
What to Know About Cranial Nerves• Name and Number• Origin from brain• Functional components• Location of cell bodies
– Nucleus– Ganglion
• Foramen of exit from cranial cavity• Distribution: branches, targets, and
functions• Testing and lesions
Cell Bodies of Cranial Nerves
• General sensory neurons – in a sensory ganglion (no synapses, pseudounipolar)
• Special sensory neurons – in a sensory ganglion or in the sensory organ
• Somatic motor neurons – in a nucleus
• Visceral motor neurons– – Preganglionic – in a nucleus– Postganglionic – in an autonomic ganglion
(synapses)
General Sensory Pathways• Neurons
– Primary/peripheral– Secondary– Tertiary (cell body in
thalamus)
L 1-23
Voluntary Motor Pathway
• AKA Pyramidal system
• Upper motor neurons• Lower motor neurons
L Fig 1-23
• I Olfactory• II Optic• III Oculomotor• IV Trochlear• V Trigeminal• VI Abducens• VII Facial• VIII Vestibulocochlear• IX Glossopharyngeal• X Vagus• XI Spinal accessory• XII Hypoglossal
Special Sensory
• CN I – Olfactory (olfaction)
• CN II – Optic (vision)
• CN VIII – Vestibulocochlear (hearing, equilibrium)
• CN’s VII, IX, X - taste
General Sensory
• CN V – Trigeminal– V1
– V2
– V3
– Sensory neuron cell bodies in trigeminal ganglion
• Other cranial nerves with general sensory fibers – CN’s VII, IX, and X
Somatic Motor
• CN’s III, IV and VI ocular muscles• CN XI SCM and trapezius• CN XII tongue muscles
• CN V3 (arch I) muscles of mastication, etc.
• CN VII (arch II) m’s of facial expression, etc.• CN IX (arch III) stylopharyngeus• CN X (arches IV, VI) m’s of soft palate, pharynx,
and larynx
Visceral Motor(Parasympathetic)
• CN’s III, VII, IX, X• Ganglia:• Targets:• Postganglionic
parasympathetics tend to follow branches of the trigeminal nerve.
L 1-25
Sympathetics to the Head• Origin:• Ganglia:• Targets:• Postganglionic
sympathetics follow branches of carotid arteries (in a perivascular plexus)
L 1-26
CN’s Carrying All Four Functional Components
• CN VII
• CN IX
• CN X
Branches of Cranial Nerves May Serve Different Functions
V3
Netter Plate 42
References
• Regional anatomy – Liebgott Chapter 7
• Systemic anatomy – Liebgott Chapter 8
• Images – Netter Plates 112-125