Vision and the ANS

Question 1

What are the Accesory structures of the Eye?

Answer 1

Eyelids, lashes, Brows, Lacriminal apparatus (Tear producer) & The extrinsic Eye mm’s.

Question 2

What does the Eyelid consist of?

Answer 2

The Palperbral Fissure, Palperbral Conjunctiva & Bulbar Conjunctiva.

Question 3

What is the Eyelid used for?

Answer 3

Shades eye during sleep, Protects eyes from too much light & objects, spreads lubercating secretions around the eyeball.

Question 4

What is the “Palperbral Fissure”?

Answer 4

This is the space between the Upper & Lower Eyelid that exposes the eyeball.

Question 5

What is the “Bulbar Conjunctiva”?

Answer 5

Passes from the eyelids onto the surfaces of the eyeball, where it covers the Sclera.

Question 6

What is the “Palperbral conjunctiva”?

Answer 6

Lines the inner aspects of the eyelids.

Question 7

What are Eyelashes and Eyebrows used for?

Answer 7

They project from the boarder of each eyelid, and above the eyelids are the brows.
They help protect the eyeball from intruding objects.

Question 8

What are “Sebaceous Ciliary Glands”?

Answer 8

Found at the base of hair follicles of the eyelashes.

They release a lubercating fluid onto the follicles.

Question 9

What is the “Flow of Tears”?

Answer 9

Lacrimal Gland (Secrets tears), Lacrimal Ducts (Distributes), Sup & Inf Lacrimal Canaliculi (Drain Tears), lacrimal Sac (Drains tears), Nasallacrimal Duct (Drains tears), Nasal Cavity.

Question 10

What are the Extrinsic Eye muscles?

Answer 10

Super / Inferior / Lateral / Medial Rectus

Superior and Inferior Oblique

Question 11

What is the Anatomy of the Eyeball?

Answer 11

3 layers:

Fibrous tunic, Vascular tunic, and Retina (Inner tunic).

Question 12

What does the Fibrous Tunic Consist of?

Answer 12

Cornea and Sclera.

Question 13

What is the Cornea?

Answer 13

Apart of the Fibrous Tunic of the Eye, This is the transparent coat that covers the coloured Iris, Because it is curved it helps direct light onto the Retina.

Question 14

What is the Sclera?

Answer 14

Apart of the Fibrous Tunic of the Eye, This is a layer of dense CT.
Covers the entire eyeball besides the Cornea.
Gives the eyeball shape and protects its inner parts & serves as a site of attachment for the Eye mm’s.

Question 15

What does the Vascular Tunic Consist of?

Answer 15

Composed of 3 parts:

Choroid, Ciliary body, and the Iris.

Question 16

What is the Choroid portion of the Vascular Tunic in the eye?

Answer 16

This is the part of the Eye that contains Melanin.
Helps absorb stray light rays, this helps prevent scattering & reflecting of light within the eye giving a sharper and clear image.

Question 17

What is the Ciliary body of the Vascular Tunic in the eye?

Answer 17

This part of the Eye has something called a Ciliary Muscle.
It is a circular band of smooth mm that can alter the shape of the lens in the eye.
Adapting for near / Far vision.

Question 18

What is the Iris of the Vascular Tunic in the eye?

Answer 18

Suspended between the Cornea and lens attached to ciliary processes.
The prime function is to help regulate how much light is entering the eye through the pupil.

Question 19

What does the “Retina” consist of?

Answer 19

Inner layer, Photoreceptors, Optic Disc.

Question 20

What is the Photoreceptor portion of the Retina?

Answer 20

These are specialized cells that begin the the process by which light rays are converted into nn impulses.
Including 2 types of receptors:
Rods & cones.

Question 21

What do Rods in the Retina do for vision?

Answer 21

Rods allow us to see in dim light, because Rods don’t provide coloured vision, in the dark we can only see darker shades less colour.

Question 22

What do Cones in the Retina do for vision?

Answer 22

Brighter lights stimulate cones which produce coloured vision.
They’re 3 types of cones:
Blue, green & red.

Question 23

What is the “Lens” within the Eye?

Answer 23

Helps focus light onto the retina and to facilitate clear vision.

Question 24

What is involved in “Image Formation”?

Answer 24

There is 3 processes to image processing:

Refraction, Accommodation & Constriction of the Pupil.

Question 25

What is involved in Refraction of Image formation?

Answer 25

When the light passes through 2 different transparent substances they bend at the junction between the 2.
As light enters the eye they are refracted onto the anterior and posterior surfaces of the cornea.

Question 26

What is involved in Accommodation of image formation?

Answer 26

Accommodation is changing the shape of the Lens.
Changing the shape of the lens’s curvature gives it ranges of focusing power.
This increase in Curvature of the lens for near vision is called “Accommodation”.

Question 27

What is involved in Constriction of the Pupil of image formation?

Answer 27

Constriction of the pupil occurs at the same time as Accommodation and prevents light rays from entering the eye through the periphery of the lens.

Question 28

What happens in Image Formation if objects are 20 feet or more away from the perceiver?

Answer 28

Light Rays reflected are nearly Parallel.
The Lens must bend these parallel objects just enough so that they fall exactly focused on the “Central Fovea” where the image is the sharpest .

Question 29

What happens in Image Formation if objects are 20 feet or more away from the perceiver?

Answer 29

Light Rays reflected are nearly Parallel.
The Lens must bend these parallel objects just enough so that they fall exactly focused on the “Central Fovea” where the image is the sharpest .

Question 30

What happens to Ciliary mm’s when you view a close object?

Answer 30

They contract.
This action releases tension on the lens and Zonular fibers.
The lens becomes more convex, this increase the focusing power and causes greater convergence of the light rays.

Question 31

What is the shape of the lens of the Eye?

Answer 31

It is convex, it can constrict to have increased focusing power.

Question 32

What is it called when both eyes on only one set of objects?

Answer 32

This is called “Binocular Vision”.

Question 33

As we move closer to an object, what direction do the eyes move to keep the proper focus?

Answer 33

They would rotate medially if light rays are to hit the same points on both retinas.

Question 34

What does the term Convergence refer to?

Answer 34

This is referring to the medial rotation the eyes must take for the focus to continue on an object.

Question 35

What is the Visual Pathway?

Answer 35

Consist of Brain pathways & Visual fields.

Question 36

What does the Brain pathway in the Visual pathway consist of?

Answer 36

Axons within the Optic nn pass through “Optic Chiasm”.
Now apart of the Optic Tract, enter the brain and most of them terminate on the “Lateral Geniculate Nucleus” of the Thalamus.
Here they synapse with neurons of the “Optic Radiations” which project to the “Primary Visual areas”.

Question 37

Where are the Primary Visual areas of the Brain pathway for “Visual Pathway”?

Answer 37

They can be found in the Occipital Lobes of the Cerebral Cortex.
This is where visual interpretation takes place.

Question 38

What does the Visual Field of the Visual Pathway consist of?

Answer 38

The Visual field for each eye is divided into 2 Regions.

Nasal / Central half & temporal / Lateral Half.

Question 39

What does the central / Nasal half of the Visual field consist of?

Answer 39

For each eye light rays in the nasal half of the visual field fall on the temporal region of the retina.

Question 40

What does the Lateral / temporal Half of the visual field consist of?

Answer 40

For each eye light rays in the Temporal half of the visual field fall on the Nasal region of the retina.