感觉器官

The pigmentted layer absorbs light that passes completely through the anterior layer, preventing backscatter (blurring of vision)
Contents of eyeball



The Visual Organ 视器
Composition: eyeball and accessory organs of eye Shape of eyeball Has anterior and posterior poles Equator 赤道: an imaginary line encircling the eyeball, midway between anterior and posterior poles Axis of eyeball 眼轴: a line joining the two poles Optic axis 视轴: a line joining the center of the pupil to the fovea centralis
Walls of eyeball
Cornea 角膜 Fibrous tunic of eyeball Sclera 巩膜
Iris 虹膜 Vascular tunic of eyeball Cilliary body 睫状 体 Choroid 脉络膜
Pars iridica retinae Retina 视网膜 Pars caeca retinae Pars ciliaris retinae Pars optica retinae
Aqueous humor 房水
Lens 晶状体
Vitreous body 玻璃体
Aqueous humor 房水
Chamber of eye 眼房－ lies between cornea and lens, and divided by iris into anterior and posterior chambers Aqueous humor 房水 A clear watery fluid that fills chamber of eye Continuously secreted by ciliary body into posterior chamber Passes through pupil into anterior chamber Then it filters though iridocorneal angle into sinus venosus sclerae, this sinus drains via anterior ciliary veins into ophthalmic veins
Sinus venosus sclerae Ciliary Muscle Iridocorneal angle Dilator Pupillae Sphincter Pupillae
Lens ciliary zonule Ciliary Processes Ciliary ring

Choroid 脉络膜



Optic disc 视神经盘 (blind spot), located medial to posterior pole of eye, and consists of optic nerve fibers and central artery of retina Macula lutea 黄斑

Pars optica retinae视网膜视部

Lines the choroidsComposed of two layers

An outer pigment cell layer Inner neural layer (four layers)

The fourth layer consists photoreceptor cells
Vitreous body 玻璃体


Consists of colorless, transparent jelly-like substance in which there is a meshwork of fine fibrils, occupies the vitreous chamber, the space between lens and retina Helps maintain the shape of eyeball and supports the retina
Vascular tunic of eyeball (middle)


Iris 虹膜
Thin contractile membrane anterior to ciliary body, with a central opening, the pupil 瞳孔 Contains sphincter pupillae 瞳孔括约肌(circular fibers) and dilator pupillae 瞳孔开大肌 (radial fibers) Cornea and iris meet to form the iridocorneal angle 虹膜角膜角
Cone cells 视锥细胞are color receptors that function best during the day Rod cells 视杆细胞are dark-light receptors that function best at night and in dim light The third layer consists of bipolar neurons 双极细胞 The second layer is formed ganglion cells 节细胞, whose axons form


optic nerve The first layer consists of nerve axons that collect at the optic disk and pass through the sclera to form the optic nerve
Ganglion cells Bipolar neurons Rod cells Cone cells Pigment cell layer
The Sensory Organs
山东大学医学院 解剖教研室 李振华
The Sensory Organs
Sensory organs include the receptors and accessory organs. The receptors may be divided into three kinds: The exteroceptors 外感受器: receive stimuli such as touch, temperature, pain, light and sound from the external environment The interoceptors 内感受器: pick up information about internal environment The proprioceptors 本体感受器: receive stimuli from muscles, tendons, joints and ligaments


posterior 5/6, consisting of fibrous connective tissue that forms a tough protective covering for eyeball, Contains sinus venosus sclerae 巩膜静脉窦which lies beneath the junction of cornea and sclera

பைடு நூலகம்

Cilliary body 睫状体

Body a ring-shaped thickening anterior to equator, containing smooth muscle fibers called ciliary muscle 睫
状肌


Ciliary processes 睫状突: a series of some 60~80 projections producing aqueous humor Ciliary ring 睫状环
Ophthalmic vein
Functions
• Helps focus light • Helps maintain constant pressure in eyeball • Helps nourish the lens and cornea
Lens 晶状体

Transparent biconvex structure, covered by an elastic transparent capsule Located between iris and vitreous body, and suspended behind pupil by ciliary zonule 睫状小带 Shape 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
Production and circulation of aqueous humor
Ciliary body Posterior chamber