Visual System Part 1

Question 1

Sensation vs. Perception

Answer 1

Sensation is stimulation of a sensory receptor. This produces neural impulses that the brain interprets.
Sensation occurs when sensory organs absorb energy from a physical stimulus in the environment.

Perception is when the brain organizes info and interprets it to something that can be rationalized by us. More psychological.

Question 2

Spatial processing determines this

Answer 2

location, movement, spatial transformation and relation

Question 3

Object processing determines this

Answer 3

color, texture, pictorial detail, shape, size

Question 4

Object processing is in this stream

Answer 4

Ventral

Question 5

Spatial processing is in this stream

Answer 5

Dorsal

Question 6

Eye/orbit is composed of these 3 layers

Answer 6

Fibrous coat (dura), vascular coat (arachnoid/pia), nervous coat (CNS)

Question 7

Sclera is composed of this coat

Answer 7

Fibrous (dura). Contains blood vessels

Question 8

These 2 structures are part of the fibrous coat

Answer 8

Sclera and Cornea

Question 9

This portion of the fibrous coat is avascular and allows for diffusion from the aqueous humor

Answer 9

Cornea

Question 10

This is function of the aqueous humor

Answer 10

Carries nutrients to the cornea. Is derived from blood

Question 11

The Vascular coat (Uvea) is composed of these 3 things

Answer 11

Choroid layer, ciliary body, iris

Question 12

Neural coat is this structure

Answer 12

Retina

Question 13

________ and ________ refract light from objects onto the retina

Answer 13

Cornea and Lens

Question 14

Most refraction of light occurs by this structure

Answer 14

Cornea

Question 15

This structure is involved in fine tuning

Answer 15

Lens

Question 16

Cornea epithelium is this cell type

Answer 16

Stratified squamous, non-keratinizing. Essentially clear.

Question 17

Bowman’s membrane of the cornea forms a barrier for this

Answer 17

Decreases infections and prevents regeneration

Question 18

Thickest part of the cornea

Answer 18

Stroma. Composed of keratocytes.

Question 19

Endothelium of cornea has this

Answer 19

Simple squamous cells. They allow for diffusion from aqueous humor

Question 20

Limbus is this junction

Answer 20

Connection between cornea and conjunctiva

Question 21

Stem cells are in this corneal section

Answer 21

Corneoscleral limbus. Stem cells differentiate and eventually slough off.

Question 22

Keratitis

Answer 22

Inflammation due to herpes or contacts. Cornea has sensory neurons to detect irritation

Question 23

Lasik surgery corrects this structure

Answer 23

Stroma

Question 24

Suspensory ligaments (zonule fibers) connect these structures

Answer 24

Ciliary body and lens

Question 25

Lens derives nutrients from this

Answer 25

Aqueous humor

Question 26

Ciliary body is this mass of tissue

Answer 26

Smooth muscle and connective tissue with connective suspensory ligaments

Question 27

Lens capsule increases this feature

Answer 27

Convexity

Question 28

Cataracts occur from this

Answer 28

Opaqueness of the lens. We create new fibers but do not get rid of old ones. Oxidative damage (iron-catalyzed free radical reactions) create an opaqueness

Question 29

Increased convexity results in this vision impairment

Answer 29

Near vision. Decreased convexity results in far vision

Question 30

This changes the lens shape

Answer 30

Ciliary muscle essentially creates a sphinchter around the lens

Question 31

Relaxed ciliary muscles cause this on the lens

Answer 31

Tension

Question 32

To see something close-up, your lens should be

Answer 32

Relaxed. The suspensory ligaments contract and the lens is more convex and allow for more refraction. This takes energy.

Question 33

Myopia

Answer 33

Near sighted. Eyeball too long. Refraction focuses before the retina

Question 34

Hyperopia

Answer 34

Far sighted. Eyeball too short. Refraction focuses behind the retina

Question 35

Schlemm's canal function

Answer 35

Aqueous humor fluid passes through this collection of veins to flow out of the sclera. Fluid comes out of ciliary body, flows up around the iris, flows up to Schlemm's canal

Question 36

Glaucoma

Answer 36

Build-up of aqueous humor. Adherence of iris blocks access of aqueous humor to schlemm's canal. Intraocular pressure can damage optic nerve. Pressure also builds up on vitreous humor

Question 37

Iris primary function

Answer 37

Determines how much light goes into the pupil

Question 38

Iris is composed of this

Answer 38

Stroma- CT with melanocytes Smooth muscle Pigment epithelium (black screen 'behind' iris)

Question 39

Stroma is composed of this

Answer 39

CT ridges, blood vessels. This is the patterning seen on the iris. Fibroblasts with matrix in between

Question 40

Rayleigh scattering

Answer 40

Pattern of light that determines what we see as a result of the light's refraction. Blue refracts more than red.

Question 41

Eye color is determined by this

Answer 41

Concentration of melanocytes in the stroma. This is at the bottom epithelial layer of the stroma.

Question 42

Stroma, not melanin, scatters _____ light

Answer 42

Blue | No melanin in stroma

Question 43

Why is melanin brown?

Answer 43

It's a mix of black, red, and yellow. | It absorbs blue/green. Reflects yellow/red

Question 44

Sphinchter pupillae is ruled with __________ nerves

Answer 44

Parasympathetic

Question 45

Dilator pupillae is ruled with _________ nerves

Answer 45

Sympathetic

Question 46

Depth of field increase when the pupil does this

Answer 46

Pupil size decreases

Question 47

Ciliary ganglion is controlled by

Answer 47

Parasympathetic pathway. Component of the oculomotor nerve.

Question 48

Superior cervical ganglion is controlled by

Answer 48

Sympathetic pathway. Send axons out along the blood vessels to pass through the choroid and dilate the pupil.

Question 49

Vitreous body and humor composed of this

Answer 49

hyaluronic acid and type II collagen fibrils

Question 50

Eye floaters are this

Answer 50

Collagen fiber bundles cast shadows on retina

Question 51

The eye is an extension of the brain, coming from the neural tube. True or False?

Answer 51

True. The neural and pigmental layer come from this

Question 52

Lens is derived from _______, not neural tissue

Answer 52

Ectoderm

Question 53

Hyaloid artery is embryonic artery connecting these structures

Answer 53

vitreous body and lens | Hyaloid artery becomes hyaloid canal; remnants are floaters