Vision

Question 1

Thalamus

Answer 1

Responsible for relaying information from the sensory receptors to proper areas of the brain where it can be processed

Question 2

Cornea

Answer 2

Iris (coloured) and pupil - gets life support from aquas humour

Question 3

Sclera

Answer 3

white of the eye

Question 4

Photoreceptors

Answer 4

Rods and Cones

Transform light into neural activity

Information transmitted to the back of the eye

Information leaves the eye and travels to the brain via optic nerve to optic chasm

Question 5

Three principle layers of the retina (back of eye)

Answer 5

1) Photoreceptors
2) Bipolar cell layers
3) Ganglion cell layer

Question 6

Types of cells in the retina

Answer 6

Receoptors (rods and cones) 
Horizontal cells 
Bipolar cells 
Amacrine cells 
Retinal ganglion cells (optic nerve)

Question 7

Information from the eye

Answer 7

Optic nerve to thalamus and then to visual cortex

Question 8

Cones

Answer 8

Sit near the retinas centre and detect fine detail and colour

Can be divided into red, blue, green sensitive types based on light they absorb

Useful in BRIGHT light

Own ganglion cell- 1 to 1

Question 9

Rods

Answer 9

More numerous than cones and v sensitive to light

Not sensitive to colour

Edges of retina

Rule peripheral vision

Share ganglion cells

Question 10

Duplexity theory

Answer 10

The idea that the cone system is active in abundant light and the rod system active in low light

Question 11

How do photo receptors work ?

Answer 11

When there is not light, the vitamin A will attach to a protein to form a photopigment

When a proton strikes a photopigment, it splits the two molecules apart
-Results in transduction

Message sent - bipolar cells ganglian cells - brain

Question 12

Rhodopsin

Answer 12

Rhodopsin is a biological pigment found in the rods of the retina and is a G-protein-coupled receptor (GPCR). It belongs to opsins. Rhodopsin is extremely sensitive to light, and thus enables vision in low-light conditions. When rhodopsin is exposed to light, it immediately photo bleaches.

Question 13

Transmission from eye to the brain

Answer 13

Bipolar cells relay information from receptor to the ganglion cells

The bundles of axons of the ganglion cells forms the optic nerve

Receptors absorbing light activate an action potential in a ganglion cell

These action potentials are transmitted along the axon of the ganglion cell

Question 14

temporal hemiretina

Answer 14

ipsilateral

Question 15

nasal hemiretina

Answer 15

contralateral

Question 16

LGN

Answer 16

The lateral geniculate nucleus (LGN; also called the lateral geniculate body or lateral geniculate complex) is a relay center in the thalamus for the visual pathway. It receives a major sensory input from the retina.

Information leaves LGN neurones via axons

Project to the visual cortex where they form synapses with cortical neurones

Question 17

Two layers of the lateral geniculate nucleus

Answer 17

parvocellular layer
top 4 layers
small
input from cones

magnocellular layers
bottom 2 layers
large
input form rods