Section 3

Question 1

What does vision require? (general)

Answer 1

• requires special visual receptors (photoreceptors) located at the back of the eye

Question 2

What does the lacrimal gland do?

Answer 2

• produces tears
• keeps the cornea (outside) of the eye moist and clean
• lacrimal apparatus (seen in the anterior view of the eye) is also very important in tear drainage

Question 3

What muscles does the eyelid contain?

Answer 3

• The upper eyelid contains the levator palpebrae superioris muscle and orbicularis oculi muscle
• these control the opening and closing of the eyelid

Question 4

What are the extraocular eye muscles and where are they located?

Answer 4

• located outside of the eyeball itself
• names are based on their location
• medial rectus, inferior rectus, inferior oblique, superior oblique, superior rectus, lateral rectus

Question 5

What are the cavities of the eye?

Answer 5

• They are fluid filled
• There are two (posterior and anterior)
• They are delineated by the lens (seperated?)

Question 6

Describe the anterior cavity.

Answer 6

• composed of the anterior and posterior chambers
• both are filled with aqueous humour (watery type fluid)

Question 7

What is the posterior cavity filled with?

Answer 7

• filled with vitreous humour (gelatinous fluid)

Question 8

What does the lens of the eye seperate?

Answer 8

• separates the anterior cavity of the eye from the posterior cavity

Question 9

What are the three layers (tunics) of the internal portion of the eye?

Answer 9

• Outer layer: Fibrous
• Middle layer: Vascular
• Deep layer: Sensory (Retina)

Question 10

Describe the fibrous layer of the eye.

Answer 10

• It is fibrous tunic
• The most outermost layer of the eye
• Has two portions located internally and externally to the lens: (sclera and cornea). These portions are continuous with one another

Question 11

What is the sclera of the fibrous tunic?

Answer 11

• The internal aspect of the fibrous tunic
• Located posterior to the lens
• Form the white portion of the eye
• A layer of dense connective tissue that acts as a point of attachment for the extrinsic eye muscles

Question 12

What is the cornea of the fibrous tunic?

Answer 12

• The external aspect of the fibrous tunic
• Located anterior to the lens
• Transparent enabling light transmission

Question 13

What is the vascular tunic, and what is it composed of?

Answer 13

• (AKA the uveal tract)
• the middle layer of the eye
• made up of the choroid, the ciliary body and the iris

Question 14

What is the choroid of the vascular tunic?

Answer 14

• contains the blood vessels that supply the eye with oxygen and nourishment

Question 15

What is the ciliary body of the vascular tunic?

Answer 15

• produces aqueous humor
• contains ciliary muscles (intrinsic eye muscles) which control the shape of the lens

Question 16

What is the iris of the vascular tunic?

Answer 16

• contains the sphincter and dilator muscles (intrinsic eye muscles) which control the narrowing and widening of the pupil
• also contains pigments, which give the eye its colour

Question 17

What is the sensory tunic and what does it contain?

Answer 17

• the most innermost layer of the eye
• consists of the neural layer, optic disc, macule, and CN II (optic nerve)
• AKA the retina!!

Question 18

What is the neural layer of the sensory tunic (retina)?

Answer 18

• the outermost region of the neural layer has photoreceptors (rods and cones) which are light sensitive cells.
• these receptors send signals through smaller nerves to the axons of the ganglion cells (innermost layer of the retina) exit the posterior aspect of the globe to the brain to form CN II

Question 19

What is the optic disc of the retina?

Answer 19

• the area where smaller nerve cell axons converge
• it is the location we can see when we look into the eye

Question 20

What is the macula of the retina?

Answer 20

• the central area of the retina, lateral to the optic disc
• central depression of the macula (AKA the fovea) is where fine detailed vision occurs

Question 21

Describe the flow of aqueous humour.

Answer 21

• aqueous humour is produced by ciliary processes in the posterior chamber
• flows through the pupil into anterior chamber and exits at anterior chamber angle (junction of iris, ciliary body and cornea) through trabecular meshwork into Schlemm’s canal and ultimately into episcleral venous channels which drain into the systemic circulation
• probably watch a video on this or something to help

Question 22

Describe glaucoma, and the effects of it.

Answer 22

• Normally, the aqueous humour is able to flow naturally from the eye
• in glaucoma, the flow is blocked, causing excess fluid to accumulate in the chambers of the eye
• this puts increased pressure on the structures in the eye, which can lead to damage of the neural tunic (or retina) and nerves in this layer

Question 23

What symptoms would likely occur in a patient with glaucoma if their lens became disrupted and blood flow to the neural tunic or retina stopped?

Answer 23

Some potential symptoms include damage to the retina or neural tunic, inability to see, distortion of the optic nerve, and reduced vision.