Carnivore Anatomy Lab 24 Introduction

CONTENTS:

Lab Objectives
Anatomical Terms
Instructor Commentary
Dissection Steps
Dissection Videos
Dissection Images

Lab Objectives:

• Examine the orbit and its contents:
      - eyeball and optic nerve
      - muscles, vessels, and sensory & motor nerves
      - lacrimal gland, fat, and the deep part of the third eyelid

• Identify features of the eyeball:
      - fibrous layer (cornea & sclera)
      - vascular layer (iris, ciliary body, & choroid)
      - retina and optic disc
      also, aqueous humor chambers, lens, vitreous body

• Superficial veins of the head:
      - external jugular v. (from maxillary v. & linguofacial v.)
      - linguofacial v. (from lingual v. & facial v. )
      also, observe angularis oculi v.

CONTENTS

Anatomical Terms:

Eye & adnexia
        orbit [palpate]
                periorbita
        lacrimal gland
        superficial gland of the third eyelid

        Muscles:
        levator palpebrae superioris m.
        rectus muscles (dorsal, ventral, medial, & lateral)
        retractor bulbi m.
        ventral oblique m.
        dorsal oblique m.
                trochlea

        Eyeball:
        bulbus oculi (eyeball) [palpate]
                external fibrous coat
                        cornea [palpate]
                        sclera [palpate]
                                limbus (corneoscleral junction)
                middle vascular coat (uvea)
                        iris [palpate]
                                pupil [palpate]
                        choroid
                                tapetum lucidum
                        ciliary body
                                ciliary processes
                                       zonule (zonular fibers)
                internal coat (retina)
                        ora serrata (margin of the optic part of the retina)
                        fundus
                                optic disk

                lens
                anterior [palpate] & posterior chambers
                        aqueous humor
                vitreous chamber
                        vitreous body

        Head: superficial veins
        external jugular vein
                linguofacial vein
                        lingual vein
                        facial vein
                                dorsal nasal v.
                                angularis oculi v.
                maxillary vein

        Note:
             uvea [from Latin: uva = grape] = the vascular layer of the eyeball
             uvula [Latin = little grape] = small mass on the human soft palate
             vitreous [Latin: vitreus = glassy] e.g.. vitreous body
             hyaline [Greek:hyalos = glass] e.g., hyaline cartilage
             humor [Latin = a liquid] e.g., aqueous humor

CONTENTS

Instructor Commentary:

Seven muscles attach to the eyeball of domestic mammals (four recti, two obliques, and one retractor). The purpose of the retractor bulbi m. is to force the third eyelid across the surface of the cornea as a protective mechanism. Humans lack a third eyelid and a retractor bulbi m., and have only six muscles attaching to each eyeball.

The gland associated with the third eyelid is called "superficial" even though it is located deep because some species, such as the pig, have two glands, and the second is still deeper than the superficial gland of the third eyelid.

CONTENTS

Dissection Steps:

Click to view a PDF list of dissection procedures for this lab:

Show List of Dissection Steps (PDF)

Dissection Videos:

CONTENTS

Dissection Images:

Note: Click an image to see it enlarged, view its caption, and toggle its labels.