Vision. Structure of the Eye. Flashcards Preview

Physiology 2. Neurophysiology. > Vision. Structure of the Eye. > Flashcards

Flashcards in Vision. Structure of the Eye. Deck (34)
Loading flashcards...
1
Q

What are the specialised senses of the body?

A

Vision.

Hearing.

Balance.

Taste.

Smell.

2
Q

The organs that give rise to special senses are all located in what part of the body?

A

The head.

3
Q

What kind of nerves carry information relating to the specialised senses?

A

Cranial nerves, not spinal nerves.

4
Q

Do cranial nerves have 1st, 2nd and 3rd order neurons?

A

Yes.

5
Q

What is the major difference between the nerves that carry specialised senses and normal nerves?

A

The nerves that carry specialised senses have a specialised receptor cell that picks up the stimulus.

6
Q

What name is given to the ganglia in the brain?

A

Nuclei.

7
Q

Where are sensory and motor nuclei located within the brain?

A

Sensory nuclei are located dorsally within the brainstem.

Motor nuclei are located ventrally within the brainstem.

8
Q

What part of the brain will most cranial nerves originate from?

A

The nuclei of the brain stem.

9
Q

Where do the 1st order neurons of special sensory organs run from and to?

A

From the sensory organs will travel into the brainstem.

10
Q

For specialised sensory information, where does synapsis from 1st to 2nd order neurons occur?

A

In the brainstem.

11
Q

Where do the 2nd order neurons of special sensory organs run from and to?

A

From the brainstem to the thalamic region.

12
Q

For specialised sensory information, where does synapsis from 2nd to 3rd order neurons occur?

A

In the thalamus.

13
Q

Where do the 3rd order neurons of special sensory organs run from and to?

A

From the thalamus to the area of the cortex that corresponds to the location where the stimulus was generated.

E.g. The visual cortex.

14
Q

What cranial nerves do not have a specialised area of the cortex?

A

Cranial nerves 1 and 2.

15
Q

What is vision?

A

The ability to see light.

16
Q

What is light?

A

An electromagnetic wave.

17
Q

How does light get into our eyes?

A

The elctromagnetic wave is emitted by a source travels until it bounces off an object.

It is only when it has bounced off that object that we are able to see it.

18
Q

What happens to light as it enters the eye?

A

It is refracted and forced through the pupil.

19
Q

Why is light refracted by the pupil of the eye?

A

It concentrates the incoming light and allows it to fall onto the retina.

20
Q

Where in the eyeball is the retina located?

A

At the back of the eye.

21
Q

What is the job of the retina?

A

To transduce the electromagnetic energy into electrical impulses which can be sent to the brain.

22
Q

What determines the amount of light that enters the pupil?

A

The lens of the eye.

23
Q

What part of eye allows us to focus on objects at different distances?

A

The lens.

24
Q

What animals are able to change the curvature of their lens?

A

Birds.

Reptiles.

Mammals.

25
Q

What animals are able to change the distance between the retina and the lens?

A

Most invertebrates.

26
Q

What is the lens of the eye composed of?

A

4 refractive indices.

27
Q

What area of the eye has a pigmented epithelium?

A

The retina.

28
Q

What part of the eye contains the rods and cones?

A

The retina.

29
Q

What part of the eye absorbs the incoming light?

A

The rods and cones of the retina.

30
Q

What happens in the eye once the rods and cones have picked up the light?

A

They activate a ganglion cell (1st order neuron) which will then travels to the brain.

31
Q

How do the first order neurons (ganglia) leave the eye?

A

They leave the eye separately and then join together to form the optic nerve.

32
Q

A ganglion cell (first order neuron) receives inputs from how many photoreceptor cells?

A

From multiple photoreceptor cells.

33
Q

What name is given to the collection of photoreceptor cells that innervate a ganglion (1st order neuron)?

A

The receptive field.

34
Q

What kind of synapses do the photoreceptors have with 1st order neurons (ganglions)?

A

Inhibitory and excitatory synapses.