Opthamology normal

Question 1

the depression in the macula in which light is focused is called the

Answer 1

fovea

Question 2

humor that fills the anterior chamber? the posterior chamber?

Answer 2

Anterior chamber filled by aqueous humor

Posterior chamber filled by vitreous humor

Question 3

Rods have low thresholds, are sensitive to ____intensity light, function well in ______

Answer 3

Rods: sensitive to low-intensity light, function well in the dark

Question 4

Cones have a higher threshold for light than rods, operate best in

Answer 4

Daylight

Cones have higher visual acuity ad participate in color vision

Question 5

Retina to cortex pathway

Answer 5

Information received by retina–>axons of retinal gangion cells carry info to CNS–> optic nerve to optic chiasm to optic tract (being aware of where things cross)–> dorsal lateral geniculate nucleus of the thalamus–>visual cortex

Question 6

Many rods synapse on a single bipolar cell which accounts for the lower _______ of rods

Answer 6

acuity

Question 7

the Higher acuity of cones can be attributed to

Answer 7

less synapses per bipolar cell.

Question 8

Steps in photoreception

Answer 8

11-cis-retinal
light converts to all-trans retinal
Metarhodopsin II
Activation of transducin (G protein)
Activation of Phosphodiesterase 
Decreased cycline GMP
Closer of Na+ channels
HYPERPOLARIZATION OF PHOTORECEPTOR MEMBRANE
Decrease release of glutamate which does 2 things

Question 9

What are the two things that happen after hyperpolarization of photoreceptor membrane and decreased release of glutamate?

Answer 9

decrease in excitatory glutamate response (ionotropic receptor) which hyperpolarizes bipolar an horizontal cells (inhibition)

Decrease in inhibitory glutamate (metabotropic receptor)
depolarizes bipolar and horizontal cells

Question 10

Parasympathetic innervation of the eyes

Answer 10

Mediated by CNIII

Edinger-Westphal nucleus–>ciliary ganglion–>short ciliary nerve–>pupillary sphincter muscle–> miosis

Als Edinger-Westphal nucleus–>ciliary ganglion–>short ciliary nerve–>ciliary muscle–>accommodation of lens

Question 11

Pupillary light reflect pathway

Answer 11

Retina receives light–>CN II–>
Pretectal nucleus midbrain–>fibers travel to both ipsilateral and contralateral Edinger-westphal nucleus–>
CNIII to ciliary ganglion bilaterally–> short ciliary nerve–> pupillary sphincter muscle–>miosis

Question 12

Horizontal gaze pathway

Answer 12

Right Frontal eye field–>
Left paramedian Pontine Reticular Formation in the pons–> Left Abducens Nucleus CNVI abducts the left eye

Left PPRF also–>Medial Longitudinal Fasciculus–>Right medial rectus subnucleus in the midbrain (CNIII)

Question 13

Sympathetic Innervation of the visual pathway

Answer 13

1st neuron exits Hypothalamus–>Lateral tegmentum–>lateral horn gray matter of C8-T2–>
2nd neuron exits at T1 to enter sympathetic chain–>superior cervical ganglion at C2–>
long ciliary nerve–>pupillary dilator muscle–>mydriasis

Question 14

Pathway of nerves involved in visual field defects

Answer 14

macula–>optic nerve–>optic chiasm–>optic tract–>Lateral geniculate nucleus branches–>1. Meyer’s Loop and 2. Dorsal Optic radiation

Question 15

The Macula is supplied by the _______ and damage to the PCA results in what visual deficits?

Answer 15

PCA, central scotoma