Visual Pathway and Optic Reflexes Flashcards
Individual cones are connected singly and directly through _______ cells to ganglion cells via ______ cell interneurons
Individual cones are connected singly and directly through bipolar cells to ganglion cells via amacrine cell interneurons
Photoreceptors that mediate light perception
Rods
Origin of optic tracts
Optic chiasma
Optic fibers continue without any interruption behind the optic chiasma as two diverging optic tracts that go to the left and right _______ of the thalamus
lateral geniculate body
Cortical area that receives visual impulses from the upper quadrants of the ipsilateral side of both retinas
Cuneus
Cortical area that receives impulses from the lower quadrants of the ipsilateral side of both retinas
Lingual gyrus
Cortical area responsible for recognition of objects and perception of color
Visual association area (B18 and B19)
A blind spot or partial loss of vision in what is otherwise a perfectly normal visual field
Scotoma
These are blind spots that flicker and waver between light and dark
Scintillating scotoma
Congenital hydrocephalus may result into this visual defect:
Binasal hemianopsia
Strokes involving MCA may result to this visual defect
Upper Homonymous Quandrantanopsia
Damage to Meyer’s loop may result to which visual defect?
Upper homonymous quadrantanopsia
A visual defect that may result with sensory defects
lower homonymous quadrantanopia
Paired structure involved in incorporating environmental stimuli and coordinating gaze shifts, involving both eye and head movements
Superior colliculi
LGB has neurons that give rise to fibers that form the _________ tract
geniculocalcarine tract
Geniculocalcarine tract passes posteriorly through the ___________ part of the internal capsule and terminates in the visual cortex (BA 17)
retrolenticular part
Midbrain structure involved in visual attention processing.
Superior colliculus
Specific pretectal nuclei for pupillary light reflex
Olivary pretectal nuclei
All visual nuclei of the midbrain connect substantially with the __________ and with each other
intergeniculate leaflet (IGL)
Contains a group of parasympathetic preganglionic cells that innervate the ciliary muscle and the pupillary constrictor
EDINGER-WESTPHAL NUCLEUS
Axons of cholinergic preganglionic neurons of EWN synapse with _______ cells in the ciliary ganglion
ganglion cells
The visual fibers that cross the median plane do so close to the cerebral aqueduct in the ____________ commissure
posterior commissure
In corneal reflex, internuncial neurons connect with the motor nucleus of the facial nerve on both sides through the _____________
medial longitudinal fasciculus
Visual body reflexes follow the following to which structure of the midbrain?
superior colliculi
Impulses of visual body reflexes are relayed to the ______________ tracts and to the neurons of the anterior gray horns of the spinal cord and cranial motor nuclei
tectospinal and tectobulbar (tectonuclear)
Spinal cord segments containing lateral gray horns for Pupillary skin reflex
T1 and T2
For Pupillary skin reflex, the white rami communicantes of T1-T2 segments pass to the sympathetic trunk, and the preganglionic fibers ascend to the ____________ ganglion.
superior cervical sympathetic
For Pupillary skin reflex, the postganglionic fibers pass through the ____________ plexus and ___________ nerves to the dilator pupillae muscle of the iris.
Internal carotid plexus
long ciliary nerves
Optic reflexes present and absent respectively in ARGYLL ROBERTSON PUPIL
Present: Accommodation
Absent: Pupillary light reflex
Area damaged in ARGYLL ROBERTSON PUPIL
Pretectal nuclei
ARGYLL ROBERTSON PUPIL is typically seen with what condition?
Tertiary neurosyphilis
Other causes: diabetes, Wernicke’s encephalopathy, midbrain tumors
