visual systems Flashcards
where does visual perception occur
Thalamocortical neurons projected to primary visual cortex in the occipital lobe of the cerebral hemisphere
where do Fibers of the optic nerve undergo hemi-decussation and project to
in the optic chiasma and project to the lateral geniculate nucleus of the thalamus.
what are Circular fibers innervated by
postganglionic parasympathetic neurons
what is the function of circular fibers
act to constrict the pupil and reduce the amount of light falling upon the retina.
what are radial fibers innervated by
postganglionic sympathetic neurons
what is the function of radial fibers
dilate the pupil
Muscle fibres of the iris are controlled by which system
the autonomic nervous system.
the ciliary body is controlled by which system
from the parasympathetic nervous system.
what divides the eyeball into anterior and posterior parts
lens and suspensory ligament
what drains Aqueous humor
by small ducts the canal of Schlemm
where are rods most abundant
Rods are more abundant in peripheral parts of the retina but less prevalent towards the macula whereas cones are abundant.
where do 1st order neurons of the visual pathway lie
in the retina
where are 2nd order neurons in the visual pathway
the axon of the 2nd order neuron or ganglion cell forms the optic nerve.
what are the name of the interneuron between photoreceptors and bipolar cells
horizontal cells
what is the name of the interneuron between bipolar cells and ganglion cells in the visual pathway
amacrine cells
what are the retinal ganglion cells
midget cells and parasol cells
what are the retinal interneuron cells
association neurons
what are midget cells
process slow moving stimuli
colur and not sensitive to low contrast
what are parasol cells
process large fast moving stimuli
no colour and sensitive to low contrast
what feedbacks between amacrine and horizontal cells
interplexiform cells
where does the optic tract terminate
mainly in the lateral geniculate nucleus within the lateral geniculate body of the thalamus
