Cranial nerves that do extraocular motility
What structures are responsible for adjusting the exposure?
iris, midbrain, retina, CN 2 and 3
a cascade of reactions that happen in the photoreceptors
light, rhodopsin, transducin, phosphodiesterase, less cGMP, sodium channels close, graded HYPERpolarization
a set of reactions that happen large in the RPE (retinal pigment epithelium)
The reactions of the visual cycle regulate the
11-cis retinal that is necessary for rhodopsin to function
How many neuros are required to detect a photon and transmit the neuronal impulse to the lateral geniculate nucleus in the thalamus?
Altitudinal visual field defects
inside the eye
Unilateral visual field defects
anterior to the chiasm
Bitemporal field defects
at the chiasm
Homonymous visual field defects
behind the chiasm
Total visual field defect
Superior visual field defect
Inferior visual field defect
Congruent visual field defect
A minimum of three neurons (photoreceptor, bipolar cell, and ganglion cell) are involved in the conversion of a light stimulus of the retina into a neurological impulse exiting the eye in the optic nerve. What is each involved in?
The first two of these neurons generate graded potentials while the third generates action potentials.
The retinal pigment epithelium phagocytoses the outer segments of photoreceptors and converts
all-trans-retinal back to 11-cis retinal (the visual cycle).
Accumulation of lipofuscin deposits (drusen) within and beneath the RPE (retinal pigment epithelium) is the hallmark of
age-related macular degeneration, the most common cause of severe visual loss in the developed world.
Decreased aqueous humor outflow leads to
increased intraocular pressure which can injure the optic nerve (glaucoma).
Homonymous visual field defects suggest lesion
s behind the chiasm
altitudinal defects suggest lesions
within the eye.
Carefully examining the pupils for evidence of a _______________ is a rapid and reliable way to evaluate the function of the retina and the optic nerve
relative afferent pupillary defect
The retinal vasculature is the primary site of injury in
diabetic retinopathy (hemorrhages, microaneurysms and neovascularization) and atherosclerotic disease (emboli, artery occlusions);
the choroidal circulation plays a larger role in
age-related macular degeneration (neovascularization).
Are Eye disorders common?
The eye is a window into many physiologic systems including
Central Nervous System (cranial nerves II, III, IV, V, and VI; and the sympathetic chain), Vascular System, Endocrine System, Immune System
Five Components of Vision
Pointing the eye, Focusing the image, Adjusting the exposure, Converting the image from light to neurological impulses, Transmitting these impulses to the brain and interpreting them to create a visual perception
What's the most important info to gather on the eye test?
is there a relative afferent papillary defect
In a pure afferent defect, pupils are
In a pure efferent defect pupils are
This wiring scheme is the basis for an extremely valuable test of visual function, a test for a RELATIVE AFFERENT PUPILLARY DEFECT (also known as a