Special Senses of CNS

Question 1

eyelids composed of four layers

Answer 1

skin, muscles (orbicularis oculi), connective tissue (tarsal glands), conjunctiva (mucous membrane)

Question 2

lacrimal apparatus

Answer 2

lacrimal gland- secretes tears
lysozyme- antibacterial component of tears
canaliculi- collect tears
lacrimal sac- collects tears from canaliculi
nasolacrimal duct- collects and empties tears from lacrimal sac into the nasal cavity

Question 3

extrinsic eye muscles

Answer 3

superior rectus- rotates eye up and medially
inferior rectus- rotates eye down and medially
medial rectus- rotates eye medially
lateral rectus- rotates eye laterally
superior oblique- rotates eye down and laterally
inferior oblique- rotates eye up and laterally

Question 4

structure of eye

Answer 4

outer tunic: cornea & sclera
middle tunic: choroid coat & ciliary body
inner tunic: retina, macula lutea, optic disc,

Question 5

cornea

Answer 5

*anterior most, transparent portion of outer tunic
*provides window that focuses entering light rays

Question 6

sclera

Answer 6

*posterior 5/6th of outer tunic
*white portion of eye responsible for protection
*attachment site for extrinsic muscles

Question 7

choroid coat

Answer 7

*posterior 5/6th of the globe of the eye
*loosely joins the sclera
*blood vessels provide nourishment to surrounding tissue
*produces melanocytes that absorb excess light and helps keep the inside of the eye dark

Question 8

ciliary body

Answer 8

*thick part of middle tunic
*forms inner ring around the front of the eye
*contains 2 distinct muscle groups

Question 9

suspensory ligaments

Answer 9

thin fibers that hold the transparent lenses of the eyes

Question 10

iris

Answer 10

*colored portion of the eye that is mostly composed of connective tissue and smooth muscle fibers
*dim light stimulates radial muscles which cause the pupil to dilate
*bright light stimulates circular muscle which causes the pupil to constrict

Question 11

pupil

Answer 11

*circular opening in the iris
*dilates and constricts due to iris muscles

Question 12

anterior chamber

Answer 12

between the iris and the cornea

Question 13

posterior chamber

Answer 13

between the iris and the vitreous humor

Question 14

aqueous humor

Answer 14

fluid that helps give the cornea its shape and provides nutrients

Question 15

inner tunic

Answer 15

retina- visual receptor cells, continuous with the optic nerve
macula lutea- central, yellowish spot of the retina,
fovea centralis- center of macula lutea that produces the sharpest vision
optic disc- blind spot that contains no visual receptors