Special senses pre-practical anatomy

Question 1

List the 3 main foramen leading into the orbit of the eye

Answer 1

– Optic foramen
– Superior orbital fissure
– Inferior orbital fissure.

Question 2

What nerves and vessels enter the optic foramen?

Answer 2

Optic nerve

Opthalmic artery

Question 3

What nerves and vessels enter the superior orbital fissure?

Answer 3

Motor nerves to the eye (III, IV, VI)
Branches of ophthalmic division of V
Ophthalmic veins

Question 4

What nerves and vessels enter the inferior orbital fissure?

Answer 4

Branches of maxillary division of V

Question 5

What foramen does the opthalmic veins go through?

Answer 5

Superior orbital fissure

Question 6

Describe the components of the vascular later of the eye

Answer 6

Ciliary body - Suspends the lens and produces Aqueous Humor

Choroid - Supplies blood to outer layers of retina

Iris - Controls the diameter of the pupil and thereby controls the amount of light rays entering the eyeball

Question 7

What two humors are in the eye?

Answer 7

The aqueous humor is a watery fluid anterior to the lens. It helps maintain intraocular pressure.

The vitreous humor is a transparent gel posterior to the lens. It helps cushion the retina.

Question 8

What are the functions of the extrinsic and intrinsic muscles of the eye?

Answer 8

• Intrinsic muscles – control pupil diameter & helps alter lens curvature to enable us to see near objects
• Extrinsic muscles – move the eye.

Question 9

What are the 3 intrinsic muscles of the eye?

Answer 9

Ciliaris muscle - in ciliary body, allows focussing on nearby objects

Constrictor pupillae - in iris, circular around pupillary border

Dilator pupillae - radially running muscle in iris

Question 10

Describe the 6 extrinsic muscles of the eye

Answer 10

4 Straight muscles called recti:
o	Medial rectus (MR)
o	Lateral rectus (LR)
o	Inferior rectus (IR)
o	Superior rectus (SR)

2 oblique muscles:
o Superior Oblique (SO)
o Inferior Oblique (IO)

Question 11

What muscle closes the eyelids?

Answer 11

orbicularis oculi

Question 12

How do the straight and oblique extrinsic muscles differ in their attachment?

Answer 12

• The recti muscles insert onto sclera anteriorly

* Obliques insert posteriorly onto the sclera

Question 13

How do the 2 extrinsic oblique muscles differ in their bony attachment?

Answer 13

• The superior oblique muscle arises from the roof of the orbit posteriorly
• The inferior oblique muscle arises from the floor of the orbit anteriorly

Question 14

Describe the innervation of the lacrimal gland

Answer 14

• Parasympathetic from Facial nerve.

Question 15

What do the tears enter the eye through?

Answer 15

punctae on the medial side of each eyelid

Question 16

What part of the temporal bone houses the middle and inner ear?

Answer 16

Petrous part of the temporal bone

Question 17

When does the anterior fontanelle fuse?

Answer 17

18 months old

Question 18

When does the posterior fontanelle fuse?

Answer 18

1-3 months, usually 8 weeks

Question 19

How can you tell histologically between the 3 salivary glands?

Answer 19

Parotid - dark staining, serous secretions

Sublingual - pale staining, mucus secretions

Submandibular - mixed staining, secretes mucus and serous secretions

Question 20

What type of epithelium is found on the tongue?

Answer 20

Stratified squamous epithelium – filiform papillae (keratinised)