Sensory innervation of the face is as a result of which nerve?
Trigeminal nerve (CN V)
Which regions of the face does the opthalmic nerve provide sensory innervation to?
- Upper eyelid
- Skin of root/bridge/tip of nose
Which regions of the face does the maxillary nerve nerve provide sensory innervation to?
- Skin over lower eyelid
- Skin over maxilla
- Skin over ala of nose
- Skin/mucosa of the upper lip
Which regions of the face does the mandibular nerve provide sensory innervation to?
- Skin over mandible*
- Skin over TMJ
(*Excludes angle of mandible)
What is the function of the blink/corneal reflex?
Describe the path of a sensory action potential during the blink/corneal relfex
- Cornea via CN V1 branches
- Trigeminal ganglion
- CN V
During the blink/corneal relfex, which nerve carries the motor response?
(to eyelid part of orbicularis oculi)
Sympathetic axons can exit the spinal cord between whcih levels?
Where can sympathetic signals pass?
- Up/down sympathetic chain
- Spinal nerves via anterior/posterior rami
- Splanchnic nerves
Where do presynpatic sympathetic axons synapse?
Superior cervical sympathetic ganglion
How do post-synaptic sympathetic axons travel to organs in the head?
Via internal and external carotid arteries
Parasympathetic axons leave the spinal cord via which nerves?
- Cranial nerves III, VII, IX and X
- Sacral spinal nerves
Where does the oculomotor nerve connect with the CNS?
Junction between midline and pons
Where does the oculomotor nerve enter the orbit?
Superior orbital fissure
(via cavernous sinus)
What does the oculomotor nerve supply?
Somatic motor to:
- Superior rectus (superior division)
- Levator palpebrae superioris (superior division)
- Medial rectus (inferior division)
- Inferior rectus (inferior division)
- Inferior oblique (inferior division)
It also innervates the ciliary ganglion (inferior division)
What is the function of ciliary nerves?
Supply autonomic axons to control iris diameter and refractive shape of lens
What types of innervation do long ciliary nerves provide?
- Somatic sensory
- Sympathetic (to dilator pupillae muscle)
What types of innervation do short ciliary nerves provide?
- Parasympathetic (ciliary body and iris)
What are the main autonomic reflexes of the eye?
- Maximal eyelid elevation (fight or flight)
- Pupillary dilation/constriction (light reflex)
- Focussing lens far and near (accomodation reflex)
- Tear production (lacrimation reflex)
- Turns eyes in opposite direction to head movement to maintain gaze (vestibulo-ocular reflex)
- Reflex bradycardia in response to tension on extraocular muscles or pressure on eye (oculocardiac reflex)
The sympathetic system functions to focus on _____ objects
The sympathetic system functions to focus on far objects
Which muscle is involved in widening the eyes during sympathetic stimulation?
Levator palpebrae superioris
(contains both skeletal and smooth muscle)
Which branch of the autonomic nervous system will dilate the pupil?
Which types of drugs dilate the pupil?
Which muscle will dilate the pupil?
Dilator pupillae muscle
What is the term used to describe a non-physiologically constricted pupil?
Which muscle is responsible for constricting the pupil?
Sphincter pupillae muscle
The pupillary light reflex involves a _-neurone chain
The pupillary light reflex involves a 4-neurone chain
Describe the pathway of the neurones involved in the pupillary light reflex
- Optic nerve
- Synapse in midbrain
- Pass (via 2nd neurone within midbrain) and synapse in Edinger-Westphal nucleus
CN III inferior division
- Synpase in ciliary division
- Coarse in short ciliary nerves to sphincter pupillae muscles
When does the the ciliary muscle contract?
Under parasympathetic stimulation
(To focus on near vision)
What are the three components of the accomodation reflex?