感觉器

nullSensory Organs Sensory Organs 潘爱华 博士 Aihua Pan MD & PhD Department of Anatomy & Neurobiology, Xiangya School of Medicine, CSU aihuap@xysm.net, Oct , 2010The Sensory Organs 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 ligamentsThe Visual Organ 视器 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 eyeballWalls of eyeballFibrous tunic of eyeballCornea 角膜Sclera 巩膜Vascular tunic of eyeballIris 虹膜Cilliary body 睫状体 Choroid 脉络膜 Retina 视网膜Pars iridica retinaePars ciliaris retinaePars optica retinaePars caeca retinaeFibrous tunic of eyeball (outer) Fibrous tunic of eyeball (outer) Cornea 角膜: anterior 1/6, a nonvascular, transparent portion, richly supplied by nerves; because it is curved, the cornea helps focus light Sclera 巩膜 (white of eye, opaque portion): 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 scleraVascular tunic of eyeball (middle)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nullCilliary 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nullVascular Tunic -- Muscles of the IrisVascular Tunic -- Muscles of the IrisConstrictor pupillae (circular) are innervated by parasympathetic fibers while Dilator pupillae (radial) are innervated by sympathetic fibers. Response varies with different levels of lightnullnullChoroid 脉络膜 Thin, highly vascular in posterior 2/3 of eye Contains brown pigmented cells and dense capillary plexus Retina 视网膜Retina 视网膜Pars caeca retinae视网膜盲部 Pars iridica retinae 视网膜虹膜部 Pars ciliaris retinae 视网膜睫状体部 Pars optica retinae视网膜视部 Lines the choroids Composed of two layers An outer pigment cell layer Inner neural layer (four layers)nullnullThe fourth layer consists photoreceptor cells 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 nerveBrain Pathways of VisionBrain Pathways of VisionnullOptic 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 Lies lateral about 3.5 mm to optic disc, a shallow depression, it is completely free of blood vessels and is yellowish in color Fovea centralis 中央凹, aera of greatest visual acuity (concentration of cones), at its center The pigmentted layer absorbs light that passes completely through the anterior layer, preventing backscatter (blurring of vision)Nervous Tunic -- RetinaNervous Tunic -- RetinaContents of eyeballContents of eyeballAqueous humor 房水 Lens 晶状体 Vitreous body 玻璃体 Aqueous humor 房水 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 Production and circulation of aqueous humor Production and circulation of aqueous humor Ciliary body Posterior chamber Anterior chamber Sinus venosus sclera Anterior ciliary vein Ophthalmic vein FunctionsHelps focus lightHelps maintain constant pressure in eyeballHelps nourish the lens and corneaLens 晶状体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 objectsVitreous body 玻璃体 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 Refractive media of eye折光装置Refractive media of eye折光装置Bend entering light waves and focus them on the retina Cornea Aqueous humor Lens Vitreous bodynullAccessory organs of eye 眼副器Accessory organs of eye 眼副器Eyelids 眼睑 Conjunctiva 结膜 Lacrimal apparatus 泪器 Ocular muscles 眼球外肌 Connective tissue in the orbitEyelids 眼睑Eyelids 眼睑（from without inwards ） Skin, extremely thin Subcutaneous areola tissue, loose and delicate Muscular layer: orbicularis oculi Tarsus 睑板, formed by dense connective tissue in which the tarsal glands睑板腺embedded Lined by palpebral conjunctiva 睑结膜 Function: to protect, open, and close eyenullTarsus 睑板Conjunctiva 结膜 Conjunctiva 结膜 Three parts Palpebral conjunctiva 睑结膜: lining inner surface of eyelids Bulbar conjunctiva 球结膜: lining anterior part of sclera, up to corneal margin Conjuntival fornix 结膜穹(superior and inferior): line of reflection of bulbar and palpebral conjunctiva Conjunctival sac 结膜囊Lacrimal apparatus 泪器 Lacrimal apparatus 泪器 Lacrimal gland 泪腺 Oval 2-cm, occupies fossa for lacrimal gland Ducts (6~10 in number): empty into anterior region of superior fornix of conjunctiva Secrets tears, which move across eyeball to medial angle,protect and moisten eyenullLacrimal passages 泪道 Lacrimal puncta 泪点 opening to lacrimal ductules, one on each eylid margin near medial angle Lacrimal ductules 泪小管: one in each lid, pass medially, join and enter lacrimal sac Lacrimal sac 泪囊 within fossa for lacrimal sac, opening into nasolacrimal duct Nasolacrimal duct 鼻泪管courses 2 cm inferiorly and opens into inferior nasal meatusnull 泪腺 分泌泪液 结膜囊 上、下泪小管 鼻泪管 下鼻道泪囊 上、下泪点 泪腺睑结膜眶下神经上泪小管泪囊下泪小管泪点鼻泪管下鼻甲下鼻道Ocular muscles 眼球外肌Ocular muscles 眼球外肌Ocular muscles 眼球外肌Ocular muscles 眼球外肌nullConnective tissue in the orbit Connective tissue in the orbit Sheath of eyeball 眼球筋膜鞘: a thin membrane, which surrounds the eyeball from optic nerve to corneoscleral junction, permits the eyeball to move in the orbit without friction Adipose body of orbit 眶脂体: lies between sheath of eyeball and the orbit acts as a protective cushion and shock sorber for the eyeballVessels of eye Vessels of eye Ophthalmic artery眼动脉 Branch of internal artery Branches－central artery of retina 视网膜中央动脉 Enters optic nerve, passes toward the optic disk and then fans out to supply the retinanullFour branches: superior and inferior nasal or temporal arteriole of retina nullOphthalmic vein 眼静脉 Superior ophthalmic vein communicates with facial vein anteriorly, exits posteriorly via superior orbital fissure to drain into cavernous sinus Inferior ophthalmic vein lies on floor of orbit and communicates with pterygoid plexus, exits via superior orbital fissure to drain into cavernous sinusThe Vestibulocochlear Organ The Vestibulocochlear Organ General features General features Three parts External ear 外耳: collects sound waves Middle ear 中耳: transmits sound waves Internal ear 内耳: contains the vestibulocochlear organ concerned with equilibration and hearingExternal ear 外耳External ear 外耳Auricle 耳廓 External acoustic meatus 外耳道 Tympanic membrane 鼓膜 External acoustic meatus 外耳道 External acoustic meatus 外耳道 A slender canal that extends from external acoustic pore to tympanic membrane Two parts Cartilaginous part－ lateral 1/3 Bony part－medial 2/3 Lined by a layer of thin skin. This S-shaped passage medially, at first forward and upward, then backward and, finally forward and downward. Tympanic membrane 鼓膜 Tympanic membrane 鼓膜 A thin oval membrane Two parts Flaccid part 松弛部: upper 1/4 Tense part 紧张部: lower 3/4 Umbo of tympanic membrane 鼓膜脐 Cone of light 光锥nullMiddle ear 中耳 Middle ear 中耳 Tympanic cavity 鼓室 Auditory tube 咽鼓管 Mastoid antrum 乳突窦and mastoid cells 乳突小房 Tympanic cavity 鼓室Tympanic cavity 鼓室An air-containing cavity locates within petrous portion of temporal bonenullnullWalls Roof or tegmental wall 鼓室盖壁 formed by tegmen tympani, separates tympanic cavity from middle cranial fossa Floor or jugular wall 颈静脉壁separates the cavity from superior bulb of internal jugular vein Anterior wall or carotid wall 颈动脉壁separates tympanic cavity from carotid canal, superiorly lies two openings: Upper opening for tensor tympani muscle Lower opening for auditory tube, which communicates with nasopharynx nullPosterior wall or mastoid wall 乳突壁 Aditus of mastoid antrum Pyramid 锥隆起 lateral wall or membranous wall 膜壁－tympanic membrane with epitympanic recess superiorlynullMedial wall or labyrinthine wall 迷路壁 Promontory 岬 Fenestra vestibuli 前庭窗 Fenestra cochleae 蜗窗covered by secondary tympanic membrane 第二鼓膜 Prominence of facial canal 面神经管凸 nullAcute otitis media Perforation, inflammation or traumanullAuditory ossicles 听小骨 Consists of chain of three bones: Malleus 锤骨 Incus 砧骨 Stapes 镫骨 Articulate by synovial joints Transmit vibration of tympanic membrane to footplate of stapes in fenestra vestibule. Muscles of auditory ossicles Tensor tympani 鼓膜张肌 Stapedius 镫骨肌Auditory tube 咽鼓管Auditory tube 咽鼓管About 3~4 cm long, extends from nasopharynx posteriorly, laterally, and upward to tympanic cavity Two parts Bony part: posterolateral 1/3 Cartilaginous part: medial 2/3 Functions to equalize air pressure on either side of tympanic membrane In childhood, it is shorter, wider and more horizontal than in adultnullMastoid antrum 乳突窦and mastoid cells 乳突小房 Mastoid antrum 乳突窦and mastoid cells 乳突小房 Mastoid antrum乳突窦: a small chamber between tympanic cavity and mastoid cells Mastoid cells乳突小房: contain a group of air cells within mastoid process of temporal bonenullnullInternal ear 内耳 Internal ear 内耳 General features Lies within the petrous portion of temporal bone Key contents of internal ear Bony labyrinth 骨迷路 contains perilymph Membranous labyrinth 膜迷路is filled with endolymph and contains the sensory organsBony labyrinth 骨迷路 Bony labyrinth 骨迷路 Cochlea 耳蜗 Vestibule 前庭 Bony semicircular canals 骨半规管nullCochlea 耳蜗 It somewhat resembles a snail’s shell Consists of Modiolus 蜗轴 Cochlear spiral canal 蜗螺旋管makes two and one-half spinal turns around the modiolus Osseous spiral lamina 骨螺旋板 Scala vestibuli 前庭阶 Scala tympani 鼓阶nullVestibule 前庭 Hollow bony space Contains utricle 椭圆囊and saccule 球囊nullSemicircular duct in each Canal at right angles to each other Dilated ampulla in each canal，called bony ampullar 骨壶腹 Bony semicircular canals 骨半规管 (anterior, posterior, and lateral) posteriorly Membranous labyrinth 膜迷路 Membranous labyrinth 膜迷路 Cochlear duct 蜗管 Utricle and saccule 椭圆囊和球囊 Semicircular ducts 膜半规管 nullCochlear duct 蜗管 Contains spinal organ 螺旋器 (of Corti), the sound receptors lies on tympanic wall of cochlear ductnullUtricle and saccule 椭圆囊和球囊 Contain macular utricli 椭圆囊斑and macular sacculi 球囊斑, end organs of balance, which respond to linear acceleration and deceleration, static of gravitynullSemicircular ducts 膜半规管 Each duct has a membranous ampullae 膜壶腹 Containing crista ampullaris 壶腹嵴, receptors of balance that respond to rotational acceleration in three different planes Conduction of soundConduction of soundAir-conduction of sound Sound wavesCochlear nerveBony- conduction of soundBony- conduction of soundSound waves Skull Bony labyrinth Perilymph Endolymph within cochlear duct Spinal organCochlear nerveInternal acoustic meatus 内耳道Internal acoustic meatus 内耳道Extends from internal acoustic pore to fundus of internal acoustic meatus Facial, vestibulocochlear nerves and vessles of labyrinth pass through the fundus of internal acoustic meatusnullTHANKS