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 Cornea Sclera Iris Cilliary body Choroid Vascular tunic of eyeball Pars iridica retinae Pars ciliaris retinae Pars optica retinae Pars caeca retinae Retina

(1) Fibrous tunic (outer layer) Cornea : anterior 1/6； Ⅱ Wall of eyeball (1) Fibrous tunic (outer layer) Cornea : anterior 1/6； a nonvascular, transparent portion； supplied richly by nerves; because it is curved, the cornea helps focus light. Ⅱ

(1) Fibrous tunic Sclera: Walls of eyeball posterior 5/6, consists of fibrous connective tissue having protection and surpporting for eyeball, posteriorly it contineus with the sheath of optic n.

cribriform plate of sclera 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

iris (2) Vascular tunic (middle layer): iridocorneal angle 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

Behind the iris，may be divided into 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

choroid function： Nutrition Absorb the disperse light 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

(3) Internal tunic of eyeball— retina Wall of eyeball (3) Internal tunic of eyeball— retina division: ora serrata a. Pars caeca retinae: b. Pars optica retinae: pars iridica retinae pars ciliaris retinae

The retina consists of two layers: 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

ganglion cell, whose axons form the optic n. fibers 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

Helps maintain constant pressure in eyeball 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: pupil secreted by the ciliary body posterior chamber anterior chamber  iridocorneal angle sinus venosus sclera anterior ciliary vein ophthalmic vein sinus venosus sclera

position：lis behind the iris，anterior to the vitreous body 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

Helps maintain the shape of eyeball and supports the retina 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

(4) Refractive media:include 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

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

Ⅲ.Lacrimal apparatus 1. Lacrimal gland: 2. Lacrimal passages: 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

Ⅳ.Extraocular m. : 7 Rectuses: 4 superior rectus Obliquuses : 2 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 Action N. supply levator palpebrae superioris 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

Ⅴ. Connective Tissues in the Orbit 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 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 Processes ciliary zonule

chapter14 视器The Visual Organ composition    fibrous tunic ： vascular tunic： retina： cornea sclera iris ciliary body choroid walls choroidal part: pars opticaretinae pars ciliaris pars iridiac Eyeball accessory organs of eyeball pars caeca retinae aqueous humor lens vitreous body