Ch 7: Clinical Correlates pg 177-180

Question 1

besides the cerebral cortex, what other regions receive direct visual inputs?

Answer 1

suprachiasmatic nucleus (in hypothalamus), pretectal nucleus (in midbrain), superior colliculus

Question 2

suprachiasmatic nucleus has a role in what?

Answer 2

regulates circadian rhythms by synchronizing body functions with periods of light and dark

Question 3

pretectal nuclei have a role in what?

Answer 3

pupillary light reflex

Question 4

superior colliculus functions in what?

Answer 4

conjugate gaze

Question 5

what is hyperopia and what does it result from?

Answer 5

farsightedness

flat cornea with too little refractive power–>focuses object behind the retina

Question 6

what is myopia and what does it result from?

Answer 6

nearsidedness

too round cornea w/ too much refractive power–>focuses object in front of retina

Question 7

what is astigmatism and what does it result from?

Answer 7

irregularly shaped cornea that transmits distorted images

Question 8

what innervates the dilator pupillae muscle and where do they synapse?

Answer 8

preganglionic sympathetic fibers from T1 segment of spinal cord and postganglionic sympathetic axons from superior cervical ganglion

Question 9

what innervates the sphinctor pupillae muscle and where do they synapse?

Answer 9

preganglionic parasympathetic fibers from Edinger-Westphal nucleus that exit midbrain in CN III and postganglionic parasympathetic axons from ciliary ganglion

Question 10

what are the symptoms of Horner’s?

Answer 10

seriously if i don’t know this by now….

miosis, ptosis, anhydrosis

Question 11

what axons can be lesioned to cause Horner’s

Answer 11

1: descending hypothalamic axons in CNS
2: preganglionic sympathetic axons from T1 segment of spinal cord
3: cervical sympathetic trunk or superior cervical ganglion

Question 12

mydriasis is associated with a compression of what nerve? common causes of compression are?

Answer 12

CN III *parasym fibers are most superficial

uncal herniation or berry aneurysm (*posterior communicating)

Question 13

an increase in intraocular pressure can cause what?

Answer 13

glaucoma

*compression of longest axons in optic nerve–> loss of peripherial vision

Question 14

what causes open-angle glaucoma?

Answer 14

obstruction of canal of Schlemm (allows aqueous humor to flow from pupil)

Question 15

what causes closed-angle glaucoma?

Answer 15

increase in intraocular pressure secondary to an adhesion of the peripheral part of the iris to the cornea which prevents aqueous humor from reaching the trabecular meshwork–>canal of Schlemm

Question 16

what is presbyopia? what is it caused by?

Answer 16

lens becomes less elastic–>reduced ability to focus on near objects

Question 17

what are floaters?

Answer 17

accumulations of debris too large for phagocytic removal form the vitreous matrix