Transcript Wall of eyeball

Part Ⅳ
Sensory
Organs
SHANDONG UNIVERSITY
Liu Zhiyu
The Sensory Organs
Sensory organs include
• receptors
• accessory organs
The receptors may be divided into three kinds:
• exteroceptors :receive stimuli such as touch,
temperature, pain, light and sound from the external
environment
• interoceptors :pick up information about internal
environment
• proprioceptors :receive stimuli from muscles, tendons,
joints and ligaments
chapter 1 The Visual Organ
The Visual Organ consist of


eyeball
accessory organs
of eyeball
Section 1
Eyeball
Ⅰ. Shape of eyeball
anterior and posterior poles
anterior pole
Axis of eyeball :a line
joining the two poles
Optic axis :a line joining the
center of the pupil to the fovea
centralis
Equator : an imaginary
line encircling the eyeball,
midway between anterior
and posterior poles
posterior pole
Ⅱ.Structure of eyeball
1. Walls of eyeball
Fibrous tunic
of eyeball
Vascular tunic
of eyeball
Cornea
Sclera
Iris
Cilliary body
Choroid
Pars iridica retinae
Retina
Pars ciliaris retinae
Pars optica retinae
Pars caeca retinae
Wall of eyeball
(1) Fibrous tunic
(outer layer)
Cornea :
 anterior 1/6；

a nonvascular, transparent
portion；

Ⅱ
supplied richly by nerves;
because it is curved, the
cornea helps focus light.
Walls of eyeball
(1) Fibrous tunic
Sclera:

posterior 5/6,

consists of fibrous
connective tissue having
protection and surpporting
for eyeball,

posteriorly
it
contineus
with the sheath of optic n.
sinus venous sclerae :
lies beneath the junction of cornea and sclera,
and is irregular circular canal.
cribriform plate of sclera
cornea
Sinus venous sclerae
sclera
Wall of eyeball
(2) Vascular tunic (middle layer):
 iris
lies the anterior part of
the vascular tunic, and is a
thin contractile membrane
with a central opening, the
pupil
iridocorneal angle
sphincter pupillae
dilator pupillae
eyeball
 Ciliary body :
Behind the iris，may be divided into
a) ciliary ring
b) ciliary processes :
60~80, producing
aqueous humor
ciliary muscle ciliary zonules
ciliary zonules
eyeball
 choroid
Thin, highly vascular in
posterior 2/3 of eye
 Contains brown pigmented
cells and dense capillary
plexus

function：
Nutrition
Absorb the disperse light
Wall of eyeball
(3) Internal tunic of eyeball—
retina

division: ora serrata
a. Pars caeca retinae:
pars iridica retinae
pars ciliaris retinae
b. Pars optica retinae:
Wall of eyeball
2) structure: The retina consists of two layers:
 pigment epithelial layer
 nervus layer：consist of three layers of cells

Photoreceptor cells：
Cone cell
Rod cell
Rod cell
Cone cell
Pigment cell layer
Wall of eyeball

bipolar cell

ganglion cell, whose axons form the optic n. fibers
Ganglion cell
Bipolar neuron
Rod cells
Cone cells
Pigment cell layer
Wall of eyeball

Optic disc (blind spot),
located medial to posterior
pole of eye, and consists of
optic nerve fibers and at
where there are central
a.and v. of retina

Macula lutea
– Lies lateral about 3.5 mm
to optic disc, a shallow
depression, and is
yellowish in color
Wall of eyeball
– Fovea centralis, is an
aera of greatest visual
acuity and is completely
free of blood vessels
(concentration of cone
cells).

The pigment epithelial
layerabsorbs light that
enter the eyeball
preventing backscatter
(blurring of vision)
2. Contents of eyeball
(1) Aqueous humor
1) Chamber of eye:
lies between cornea and
lens, and divided by iris into：
anterior chamber
posterior chamber
Contents of eyeball
2) Aqueous humor
•A clear watery fluid that fills
chamber of eye，secreted by
ciliary body.
Functions
• Helps focus light
• Helps maintain constant
pressure in eyeball
• Helps nourish the lens
and cornea
Production and circulation of aqueous humor:
secreted by the ciliary body
anterior chamber
pupil
posterior chamber
iridocorneal angle
sinus venosus sclera
anterior ciliary vein
sinus venosus sclera
ophthalmic vein
Contents of eyeball
(2) Lens

position ： lis behind the iris ，
anterior to the vitreous body

shape：
Transparent biconvex structure,
covered by an elastic transparent
capsule which is connected by
the ciliary zonules (suspensory
lig.)to the ciliary process
Contents of eyeball

Structure:
lens capsule
cortex of lens
lens nucleus
Its shape is changed by the ciliary
muscle:
 for near vision, the ciliary muscle
contracts and the lens rounds up,

while for distant vision the lens flattens
out, so that the eye may be focused on
distant objects

Contents of eyeball
(3) Vitreous body
Consists
of
colorless,
transparent jelly-like substance
in which there is a meshwork of
fine fibrils, occupies the space
between lens and retina
Helps
maintain the shape of
eyeball and supports the retina
Contents of eyeball
(4) Refractive media:include
Cornea 、
aqueous humor 、lens
vitreous body
Bend entering light waves
and focus them on the
retina
Section2. Accessory
organs
Ⅰ. Eyelids: upper and lower ，consist of 5 layers,
①Skin
②subcutaneous adipose
tissue,
③musclar layer:
orbicularis oculi
④tarsus： formed
by dense connective
tissue (tarsal glands)
⑤ palpebral conjunctiva
Accessory organs of eye
Ⅱ.Conjunctiva :
thin mucous membrane
 3 parts:
• Palpebral conjunctiva :
lining inner surface of eyelids;
• Bulbar conjunctiva :
lining anterior part of sclera;
• Conjunctival fornix
(superior and inferior):
the reflected part of the
conjunctiva from the superior
and inferior eyelids onto the
eyeball.
Conjunctival sac
Accessory organs of eye
Ⅲ.Lacrimal apparatus
1. Lacrimal gland:
2. Lacrimal passages:
lacrimal punctum: on each eyelid
margin near medial angle

lacrimal ductules : in each lid,
pass medially, join and enter lacrimal
sac

Lacrimal sac : in fossa for lacrimal
sac, opening into nasolacrimal duct

Nasolacrimal duct : opening into
inferior nasal meatus

Accessory organs of eye
Ⅳ.Extraocular m. : 7


levator palpebrae superioris: elvates the upper eyelid.
Rectuses: 4
superior rectus
inferior rectus
medial rectus
lateral rectus

Obliquuses : 2
Superior obliquus
Inferior obliquus
Accessory organs of eye
Muscle
levator palpebrae superioris
Action
N. supply
elvates upper eyelid
Ⅲ
Superior rectus
turns eyeball superomedially
Ⅲ
Inferior rectus
turns eyeball inferomedially
Ⅲ
Medial rectus
turns the eyeball medially
Ⅲ
Lateral retus
turns the eyeball laterally
Ⅵ
Superior obliquus
turns eyeball inferolaterally
Ⅳ
Inferior obliquus
turns eyeball superolaterally
Ⅲ
Accessory organs of eye
Accessory organs of eye
Ⅴ. Connective Tissues in the Orbit
1. adipose body of orbit
lies between sheath of eyeball
and the orbit acts as a
protective cushion and shock
sorber for the eyeball
2. orbital fasciae
a. periorbita
b. fascial sheath of eyeball
c. sheath of ocular muscles
d . orbital septum
Section 3. The vessels and nerves of eye
Ⅰ. Vessels of eye
1. Artery
(1)Ophthalmic a. :
Arises from the internal carotid a.
Branches:
1) central a. of retina
Enters optic nerve, passes
toward the optic disk and
then fans out to supply the
retina
The vessels and nerves of eye
1) central a. of retina
branches:
superior nasal arteriole of retina
inferior nasal arteriole of retina
superior temporal arteriole of retina
inferior temporal arteriole of retina
The vessels and nerves of eye
2) short posterior ciliary a. :
Choroidal artery
3) long posterior ciliary a.
4) anterior ciliary a.
The vessels and nerves of eye
Ⅱ.Vein
(1） central v. of retina
(2） vortex vein
(3）anterior ciliary veins
(4）Ophthalmic v.
a)Superior ophthalmic v.
b) Inferior ophthalmic v
The vessels and nerves of eye
Ⅲ.Nerves
optic nerve:
oculomotor n.
trochlear n.
abducent n.
ophthalmic n.
facial n.
superior temporal arteriole of retina
superior nasal arteriole of retina
inferior temporal arteriole of retina
inferior nasal arteriole of retina
Sinus venosus sclerae
Ciliary Muscle
Iridocorneal angle
Dilator Pupillae
Sphincter Pupillae
Lens
ciliary zonule
Ciliary Processes
chapter14 视器The Visual Organ
composition
fibrous tunic ：
cornea sclera
iris
walls
vascular tunic：
ciliary body
choroid
retina：
Eyeball
choroidal part: pars opticaretinae
pars ciliaris
pars iridiac
aqueous humor
lens
vitreous body
accessory organs of eyeball
pars caeca
retinae