Eyeball Flashcards
What are the names of the layers of the eyeball?
Fibrous tunic, uveal tract and retina
What are the parts of the uveal tract of the eyeball?
Iris, ciliary body, choroid and pupil
What are the receptor neurons of the second cranial nerve?
Rod and cone photoreceptor cells
What is the function of the cone cell?
Provide vision in bright light conditions and mediate color vision
What is the function of the rod cell?
Provide vision in dim light conditions
What is the most numerous photoreceptor cell?
Rod cell
What is the primary afferent neuron of the second cranial nerve?
Bipolar cells
What is the secondary sensory neuron of the second cranial nerve?
Ganglion cell
What forms the optic nerve?
Axons of ganglion cells
What is the location for tertiary neurons of the visual pathway?
Lateral geniculate body
Axons from the lateral geniculate nucleus will synapse in what specific location?
Primary visual cortex, calcarine sulcus of the occipital lobe of the cerebrum
What is the location of the anterior chamber of the eyeball?
Between the cornea and the iris
What is the location of the posterior chamber of the eyeball?
Between the iris and lens
What is contained in the anterior chamber of the eyeball?
Aqueous humor
What is contained in the posterior chamber of the eyeball?
Aqueous humor
What is the name given to the chamber behind the lens?
Vitreous chamber
What is the location of the vitreous chamber?
Behind the lens, in front of the retina
What fills the vitreous chamber?
Vitreous body
What are the functions of the vitreous body?
Maintain retinal curvature; allow minimal light distortion from lens to retina
What are the common characteristics in origin and insertion of all rectus extra ocular muscles?
They all originate from a common annular tendon in the orbit
They all insert into the sclera in front of the coronal equator of the eyeball
What is the common characteristic regarding the insertion of both oblique extra ocular muscles?
Both insert onto sclera on the lateral margin of the eyeball behind the coronal equator
At its apparent origin cranial nerve III conveys which classification of neural pathways?
Somatic efferent (SE) and visceral efferent (VE) pathway
What is the source of innervation of the specific intrinsic eye muscles?
Parasympathetic fibers from oculomotor nerve- ciliairs, pupillage sympathetic fibers from internal carotid artery plexus- dilator pupillae
What is/are the target organ(s) for the somatic efferent fibers carried in the third cranial nerve?
Medial rectus, inferior rectus, superior rectus, and inferior oblique extrinsic muscles of the eyeball and the legator palpebrae superiors muscle of the eyelid
Does the apparent origin of cranial nerve III contain somatic afferent fibers?
NO
The fourth cranial nerve’s apparent origin is from what location?
Dorsal surface of the midbrain
What unique feature of the fourth cranial nerve occurs within the midbrain?
It decussates
What are the two unique features of the fourth cranial nerves?
It is the only cranial with an apparent origin from the dorsal surface of the brain; it is the only cranial efferent nerve to decussate within the midbrain from its nucleus
Does the apparent origin of cranial nerve IV contain somatic afferent fibers?
NO
What part of the III, IV, or VI cranial nerve contains somatic afferent (SA) fibers?
Only the distal part of the nerve
Peripheral sensory processes conveyed in the III, IV, or BI cranial nerve will communicate with which cranial nerve branch?
Ophthalmic division of trigeminal
Typically, primary afferent neurons of the III, IV, or VI cranial nerve located in the semilunar ganglion, Gasserian ganglion or trigeminal ganglion will synapse in what nucleus?
Spinal trigeminal nucleus
Recently, peripheral sensory processes conveyed in the III, IV, or VI cranial nerve have been shown to originate from primary afferent neurons in which location?
Mesencephalic nucleus of the trigeminal nerve
What type of motor pathway innervates smooth muscle?
Visceral efferent (VE)
Intrinsic muscles of the eyeball are innervated by which visceral efferent pathways?
Ciliaris and sphincter pupillage are innervate by parasympathetic visceral efferents; dilator pupillage is innervated by sympathetic visceral efferents
Visceral efferent fibers conveyed in the third cranial nerve originate from what nucleus?
Accessory oculomotor nucleus of Edinger/Westphal
What is the location of synapse for preganglionic parasympathetic efferent fibers of the third cranial nerve?
Ciliary ganglion
Postganglionic parasympathetic efferent fibers of the third cranial nerve are carried in which nerve?
Short ciliary nerve
What vessel supplies the inner tunic of the eyeball?
Central artery of the retina
What are the drainage patterns of the superior ophthalmic vein?
Into cavernous dural venous sinus or into facial vein
What are the drainage patterns of the inferior ophthalmic vein?
Into cavernous dural venous sinus or into pterygoid venous plexus
