Physiology Of Vision

Question 1

What is a particle of light called

Answer 1

Photon

Question 2

What is the function of the lens

Answer 2

Focuses light onto the retina

Question 3

What is the function of the cornea

Answer 3

Refracts light entering eye

Question 4

What is lens accomidation

Answer 4

Process where lens curve increases or decreases to focus on an object

Question 5

How does the lens change shape

Answer 5

Ciliary muscles contract

Question 6

How do ciliary muscles attach to the lens

Answer 6

By Zonalas (suspensory ligament)

Question 7

How does the pupil dilate

Answer 7

Radial fibres in iris

Question 8

How does the pupil constrict

Answer 8

Circular fibres in iris

Question 9

Unlike ocular humour, which humour is not constantly replaced

Answer 9

Vitreous humour

Question 10

Which photoreceptor cells are used for bright light

Answer 10

Cones

Question 11

What type of cells are found in the middle layer of the retina

Answer 11

Internet Ron

Question 12

Which layer of the retina are rods and cones found

Answer 12

Outer layer

Question 13

What cells are found in the inner layer of the retina

Answer 13

Ganglion cells

Question 14

What is the optic disc

Answer 14

Blind spot with no photoreceptor cells as is where the optic nerve leaves the eye and blood vessels enter

Question 15

Name the internet Ron cells in the middle layer of the retina

Answer 15

Bipolar neutrons
Horizontal neutrons
Amacrine cells

Question 16

What is the function of interneurons

Answer 16

Connect sensory cells and ganglion axons

Question 17

What is the function of the Macula Lutea

Answer 17

Part of the retina is responsible for detailed vision due to the presence of the Fova Centralis (high conc of photoreceptor cells)

Question 18

Name the photosynthetic pigments found rods and cones

Answer 18

11- cis retinal
All-trans retinal

Question 19

How do rods and cones react to light

Answer 19

Get hyperpolarised
(Light removes cGMP, closes CNG channels, hyper-polarises membrane)

Question 20

Describe how an image is formed

Answer 20

Light passes through cornea
Pass through pupil (size gets altered by radial and circular smooth muscles)
Light strikes lens (curve altered by ciliary muscle in order to converge light onto retina)
Strikes retina and hit photoreceptor cells
Nerve impulses sent from optic nerve to cerebral hemisphere

(Some light reflected back at Tapetum Lucidum in low light)

Question 21

How does the brain process the image from the retina

Answer 21

Inverts it to the correct way using other senses