Transcript Internal Eye Three concentric tunics

Special Senses
Week 12
Exterior Eye Anatomy
1?
3?
2?
Orbicularis oculi
muscle
(Under eyebrow)
Sclera
Cornea
Conjunctiva
Transparent mucus membrane
Covers only the white of the eye
-Produces mucus which prevents
the eyes from drying out
Exterior Eye Anatomy
(palpabrae)
Sebaceous
and sweat
gland
(palpabrae)
Exterior Eye Anatomy
Tears are a dilute
saline solution that
cleans and protects,
moistens and
lubricates the eye
Pin holes
If you have a cold,
the nasal mucosa
becomes inflamed. No
tear drainage into
nose.
Watery eyes
Extrinsic Eye Muscles
A.
B.
C.
D.
E.
F.
G.
Lateral rectus (abducens)
Inferior rectus
Superior rectus
Inferior oblique: up and lateral
Superior oblique: down and lateral (trochlear)
Levator palpebrae superioris
Medial rectus (not shown)
Objective 1: Structures of the Human Eye
Pushing the Limits: Sight, video 3
Internal Eye
Three concentric tunics (layers) of the eye:
• Outer fibrous tunic
• Middle vascular tunic
• Inner sensory tunic
Internal Eye
Three concentric tunics (layers) of the eye:
• Outer fibrous tunic
– sclera, cornea
• Middle vascular tunic
• Inner sensory tunic
Sclera
(white of the eye)
•
•
Lens
Cornea
•
•
•
•
Window
Lets light enter eye
No blood vessels
Can be transplanted easily
Protects the eye
Attaches eye muscles
Internal Eye
Three concentric tunics (layers) of the eye:
• Outer fibrous tunic
• Middle vascular tunic – choroid, ciliary body (ciliary muscle & process), iris
• Inner sensory tunic
Ciliary Body
Sclera
Controls lens shape
Choroid
Ciliary muscle
Ciliary process
Suspensory
ligaments
Makes aqueous humor
Iris
Modulates pupil size
Pupil
Allows light to enter eye
Cornea
Lens
Blood vessel rich,
dark brown
membrane
Pupil dilation & constriction
Internal Eye
Three concentric tunics (layers) of the eye:
• Outer fibrous tunic-connective tissue
• Middle vascular tunic
• Inner sensory tunic
- retina
Sclera
Choroid
Retina
Optic
Nerve
(CN II)
Absorb light and
prevent it from
scattering
Light
Retina
•
•
Rods:
• Night vision
• Peripheral vision
Cones:
• Visual acuity (sharpness)
• Color vision
Human Retina
Retinal
ganglion cells
Bipolar
cell nuclei
Rods & Cones
Nuclei
of rods
& cones
Outer
segments
of rods
& cones
Pigmented
epithelial
layer
Vascular
Tunic
Posterior Wall (fundus) of the Eye
Retina
Macula lutea
Fovea centralis
(all cones)
Optic disk
(blind spot)
(no rods and cones)
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”
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
(Constantly generated and removed)
Posterior segment: area
behind the lens, filled with
vitreous humor
(made once for life)
Anterior Segment
Anterior chamber: between the cornea and iris
Posterior chamber: between iris and lens
•
•
•
Aqueous humor
made by
capillaries in
ciliary process
Drops into
posterior
chamber
Passes to
anterior
chamber
Scleral
venous
sinus
(Canal of
Schlemm)
Suspensory ligaments
Objective 4:
Ear Anatomy
1
(the rim)
2
3
External Auditory Meatus
Middle ear: air filled
(links with nose!)
Inner ear
Vestibular & Cochlear
nerves join to become the
Vestibulocochlear Nerve
(CN VIII)
Cochlear
nerve
Cochlea
S.V.
S.T.
Identify given structures from models and slides
Cochlea
Stapes
Cochlea, cs
(Endoymph)
(Perilymph)
(Perilymph)
Cochlea histology
Cochlea
Endolymph
Perilymph = CSF
Endolymph = intracellular fluid
Hearing physiology
Primary auditory
cortex in temporal lobe
Midbrain
Medulla
Vibrations
Vibrations
Vestibulocochlear
Nerve (VIII)
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