Download (layers) of the eye

Special Senses
Week 12
OBJECTIVES
• Identify the macro-structures of the eye
– Diagrams
– Models
– Dissecting cow’s eye
• Identify the microscopic structures of the retina
• Identify the macro-structures of the ear
• Identify the microscopic structures of the cochlea
Objective 1: Structures of the Human Eye
Internal Eye
Three concentric tunics (layers) of the eye:
• Outer fibrous tunic – sclera and cornea
• Middle vascular tunic - choroid
• Inner sensory tunic - retina
sclera
choroid
retina
Optic
Nerve
(CN II)
Light
Retina
Human Retina
Retinal
ganglion cells
Bipolar
cell nuclei
Rods & Cones
Nuclei
of rods
& cones
Outer
segments
of rods
& cones
Pigmented
epithelial
layer
Vascular
Tunic
Internal Eye
Three concentric tunics (layers) of the eye:
• Outer fibrous tunic
• Middle vascular tunic
• Inner sensory tunic
– choroid, ciliary body (ciliary muscle & process), iris
Ciliary Body
Choroid
Ciliary muscle
Ciliary process
Suspensory
ligaments
Iris
Lens
Pupil dilation & constriction
Internal Eye
Three concentric tunics (layers) of the eye:
• Outer fibrous tunic
• Middle vascular tunic
• Inner sensory tunic
– sclera, cornea
– choroid, ciliary body (ciliary muscle & process), iris
- retina
Sclera
Cornea
Posterior Wall (fundus) of the Eye
Retina
Macula lutea
Fovea centralis
Optic disk
(blind spot)
Optic nerve
The optic disc is the region were:
• The optic nerve exits the eye
•The central artery and vein of the retina enter and exit the eye
•There are no photoreceptors, the “blind spot”
Light
Ophthalmoscope View
Fovea centralis & Macula lutea
The macula lutea is an oval region lateral to the optic disc,
at it’s center lies the fovea centralis, the area of greatest
cone density in the retina.
Segments of the Eye
Vitreous
humor
Anterior segment: area in
front of the lens, filled with
aqueous humor
Posterior segment: area
behind the lens, filled with
vitreous humor
Anterior Segment
Anterior chamber: between the cornea and iris
Posterior chamber: between iris and lens
Canal of
Schlemm
Suspensory ligaments
Glaucoma
Fluid
drainage is
blocked
Optic nerve
fibers
damaged
Exterior Eye Anatomy
1?
3?
2?
Orbicularis oculi
muscle
Sclera
Cornea
Conjunctiva
Exterior Eye Anatomy
(palpabrae)
(palpabrae)
Exterior Eye Anatomy
Extrinsic Eye Muscles
A.
B.
C.
D.
E.
F.
G.
Lateral rectus
Inferior rectus
Superior rectus
Inferior oblique
Superior oblique
Levator palpebrae superioris
Medial rectus (not shown)
Objective 4:
Ear Anatomy
1
2
3
External Auditory Meatus
Middle ear
Otitis media
Normal
Otitis media
The tympanic membrane is
bulging and hyperemic ( blood),
and yellow purulent fluid is seen
in the middle ear space.
Inner ear
Vestibular & Cochlear
nerves join to become the
Vestibulocochlear Nerve
(CN VIII)
Cochlear
nerve
Internal Acoustic Meatus
Petrous portion of Temporal bone
Superior view
Pharyngotympanic tube
M
I
External
Auditory
Meatus
(Canal)
Internal
Acoustic
Meatus
S
Inner ear
Tympanic
membrane
Middle
ear
Petrous portion of Temporal bone
Bony Labyrinth
Petrous portion of Temporal bone
Membranous Labyrinth
Cochlea
Endolymph
Cochlea histology
Cochlea, cs
(Endoymph)
(Perilymph)
(Perilymph)
Cochlea
S.V.
S.T.
Identify given structures from models and slides
Hearing physiology
Balance & Equilibrium
Inner Ear
Vestibule – utricle & saccule
Static equilibrium
Responds to changes in linear movement (vertical & horizontal)
Monitor head position, posture
Semicircular Canals - ampulla
Dynamic equilibrium
Responds to changes in rotational movement
Balance
Objective 2:
Cow Eye Dissection
Identify all external
and internal structures
listed!
lens
Follow the directions
given in the Lab
Manual!
retina
Tapetum lucidum
Iridescent portion
(retina removed)
Not present in humans
Objectives 3 & 5:
Experiments
E
HN
PTXZ
UZDTF
D
F
N P
T
H
Lab Activity:
• Dissect cow’s eye
• Perform visual, auditory & balance experiments and
analyze
On the Practical:
• Identify the macro-structures of the eye from models
and the cow eye
• Identify the macro-structures of the ear from models
• Identify the microscopic structures of the retina and
cochlea