Vision

Question 1

Anterior chamber of the eye is filled with? Made by?

Answer 1

Aqueous fluid

- ciliary body

Question 2

If fluid drainage is reduced in the eye what develops?

Answer 2

Increased pressure of fluid -> GLAUCOMA

Question 3

2 layers of pigmented smooth muscle is describing?

Answer 3

Iris

-eyecolour

Question 4

T or F

Sympathetic simulation causes pupil constriction

Answer 4

False!

dim light or excitement -> sympathetic nerves ->contraction

Question 5

What structure divides the anterior and posterior chambers

Answer 5

Lens

Question 6

What is the condition that develops when the lens becomes opaque and no longer allows light to pass?

Answer 6

Cataracts

Question 7

Name the vascular layer of the eyeball

Answer 7

Choroid

Question 8

Which one is the false statement

Rods = high intensity light
Rods = no colour discrimination
Rods = peripheral vision & motion detection
None of the above

Answer 8

Rods = high intensity light

Cones detect high intensity light

Question 9

T or F

Cones picks up colour

Answer 9

True

C for C

Question 10

T or F

Horizontal and Amacrine cells modify signals from ganglion cells to bipolar cells.

Answer 10

False!

Modify signals from bipolar cells to ganglion cells

Question 11

Name some other functions of Horizontal cells

Answer 11

Participate in lateral inhibition
Assist isn providing sharp contrast between visual images
Vary in rates of adaptation & direction they respond to

Question 12

Which cells of the eye are responsible for producing action potentials?

Answer 12

Ganglion cells

Question 13

T or F

Fovea centralis = region of retina with greatest concentration of rods

Answer 13

False

Cones

Question 14

Visual acuity depends on: (3)

Answer 14

1. Lens shape
2. density of cones within the region the image is focused on.
3. the number of rods and/or cones reporting to a single ganglion cell

Question 15

Where do the ganglia axons converge to join the optic nerve

Answer 15

Optic disc

Question 16

Irregular shaped cornea = ?

Answer 16

Astigmatism

- abnormal refraction

Question 17

T or F

Light rays from near object need more bending and a more flat lens

Answer 17

False!

SPHERICAL LENS

Question 18

What determines the shape of the lens?

Answer 18

Ciliary muscle (spherical sphincter)

Question 19

How do you relax the elastic suspensory ligaments ?

Answer 19

Contraction of the ciliary muscle

Question 20

Will relaxation of the ligaments allow for a flatter or rounder lens?

Answer 20

Rounder

Question 21

T or F

Sympathetic -> contraction of ciliary muscle -> near vision

Answer 21

False!

PARASYMP -> contraction of ciliary muscle -> near vision

Question 22

Describe what happens with presbyopia

Answer 22

with age - near point accommodation declines due to lose of elasticity of lens -> can’t return to spherical shape -> harder time focusing on close objects

Question 23

Emmetropia = ?

Answer 23

normal vision

Question 24

T or F

Myopia = far sighted - lens too flat

Answer 24

False

NEAR SIGHTED

Question 25

What happens to cause myopia?

Answer 25

Lens is too round or the eye itself has too great a length from front to back -> bends rays too much

Question 26

What is it called when someone is far sighted

Answer 26

Hypermetropia

Question 27

T or F Only cones contain opsin

Answer 27

False! Both rods and cones

Question 28

What is opsin?

Answer 28

photosensitive pigment that change their chemical composition when they interact with light of specific wave lengths.

Question 29

T or F Rods & cones cannot produce action potentials but they can release NT to influence the activity of the ganglion cells

Answer 29

False! influence the activity of the bipolar cells

Question 30

On average do more rods or cones converge onto a ganglion cell

Answer 30

Rods - about 60 onto 1 | Cones - about 2 to 1 or 1 to 1 -> higher detail info: colour

Question 31

What is the aka for "Dark Current"

Answer 31

Na+ current

Question 32

In darkness what is released by the membrane to inhibit bipolar cells from generating action potentials

Answer 32

Glutamate

Question 33

In darkness what do the rods and cones produce that binds to and opens leak Na+ channels

Answer 33

Cyclic GMP

Question 34

Rhodopsin activates ________ that activates a _____________ to destroy ___________.

Answer 34

Transducin (a Gprotein) Cyclic GMP phosphodiesterase cyclic GMP

Question 35

What does the destruction of cyclic GMP do to the retinal cells?

Answer 35

Na+ channels close -----> rod cell membrane hyper polarizes ----> decreased glutamate release -----> bipolar cells have action potentials

Question 36

Where do the nasal retina receive their visual images from? Temporal retina?

Answer 36

nasal retina = temporal visual fields temporal retina = nasal visual fields

Question 37

Where does the optic nerve project to in the brain?

Answer 37

Lateral Geniculate Body LGB of the thalamus

Question 38

T or F R LGB receives info from the R field of vision

Answer 38

False! R LGB = L FoV L LGB = R FoV

Question 39

Where is the visual cortex located?

Answer 39

The Occipital lobe

Question 40

Images are process for what characteristics?

Answer 40

``` Colour Form Depth Movement **each of which is handled in a different region of the brain ```

Question 41

If you see a car and a building and the car looks bigger what does our brain interpret?

Answer 41

The car is closer

Question 42

When moving the head what images move more rapidly across the retina near or far?

Answer 42

Near | - helps in depth perception

Question 43

What controls sleep wake cycles?

Answer 43

Hypothalmic Supra Chiasmatic Nucleus

Question 44

What colours are our cones most sensitive to?

Answer 44

Red Blue Green

Question 45

T or F | Differences in sensitivity are due to the rods and cones themselves more than the convergence of pathways

Answer 45

False Convergence of pathways is what is responsible for the differences in sensitvity

Question 46

Lack of Vitamin A =

Answer 46

Night blindness

Question 47

Which one is false: ``` hue = intensity brightness = intensity hue = wavelength ```

Answer 47

hue = intensity

Question 48

Are these matched correctly: Deuteranomalous - poor discrimination of green Protanomalous - poor discrimination of blue Tritanomalous - poor discrimination of red

Answer 48

No deut = green pro = red trit = blue

Question 49

What is anomalous trichromatic?

Answer 49

Mutation of protein of one cone

Question 50

What is the complete loss of a cone pigment called?

Answer 50

Dichromate

Question 51

T or F A tritanope has full spectrum of wavelengths due to spread for red and blue cones - but won't distinguish colours between reds and blues

Answer 51

False! This is describing Deuteranope

Question 52

What is the most rare kind of Dichromate colour blindness

Answer 52

Tritanope

Question 53

Astigmatism aka _____________

Answer 53

Ametropia