the sensory organsm-learning.zju.edu.cn/g2s/ewebeditor/upl… · ppt file · web view ·...
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The 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 ligaments
The Visual Organ 视器Composition: eyeball and
accessory organs of eyeShape 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
Fibrous tunic of eyeball
Cornea 角膜Sclera 巩膜
Vascular tunic of eyeball
Iris 虹膜Cilliary body 睫状体Choroid 脉络膜
Retina 视网膜Pars iridica retinae
Pars ciliaris retinae
Pars optica retinae
Pars caeca retinae
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 sclera
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
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
Ciliary Processes
Sphincter PupillaeDilator Pupillae
Sinus venosus sclerae
ciliary zonule
Ciliary ring
Ciliary Muscle Iridocorneal angle
Lens
Choroid 脉络膜 Thin, highly vascular in
posterior 2/3 of eye Contains brown
pigmented cells and dense capillary plexus
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)
The 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 nerve
Pigment cell layer
Cone cells
Rod cells
Bipolar neurons
Ganglion cells
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 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)
Contents of eyeballAqueous 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
Ciliary body Posterior chamber Anterior chamber
Sinus venosus sclera Anterior ciliary vein
Ophthalmic vein
Iridocorneal angle
Pupil
Production and circulation of aqueous humor
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
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Bend entering light waves and focus them on the retina
Cornea Aqueous humor Lens Vitreous body
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 orbit
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 eye
Tarsus 睑板
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 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 eye
Lacrimal 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 meatus
Tear is produced by lacrimal gland
Passes through superior conjunctival fornix into conjunctival sac
Then it is drained through lacrimal punctum, lacrimal ductule, lacrimal sac and nasolacrimal duct into inferior nasal meatus.
Ocular muscles 眼球外肌Muscle Action Nerve supply
levator palpebrae superioris
Raises upper eyelid Ⅲ
Superior rectus Turns eyeball superomedially Ⅲ
Inferior rectus Turns eyeball inferomedially Ⅲ
Medial rectus Turns eyeball medially Ⅲ
Lateral retus Turns eyeball laterally Ⅵ
Superior obliquus Turns eyeball inferolaterally Ⅳ
Inferior obliquus Turns eyeball superolaterally Ⅲ
Ocular muscles 眼球外肌
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 eyeball
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 retina
Four branches: superior and inferior nasal or temporal arteriole of retina
Ophthalmic 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 sinus
The Vestibulocochlear Organ
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 hearing
External ear 外耳 Auricle 耳廓 External acoustic meatus 外耳道 Tympanic membrane 鼓膜
Auricle 耳廓
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 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
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 An air-containing cavity
locates within petrous portion of temporal bone
WallsRoof
Floor
lateral wallMedial wall
Posterior wall
Anterior wall
Walls 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
Posterior 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 superiorly
Medial 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
Acute otitis media Perforation, inflammation ortrauma
Auditory 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 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 adult
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 bone
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 organs
Bony labyrinth 骨迷路 Cochlea 耳蜗 Vestibule 前庭 Bony semicircular canals 骨半规管
Cochlea 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
Vestibule 前庭 Hollow bony space Contains utricle 椭圆囊 and saccule 球囊
Semicircular 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 Cochlear duct 蜗管 Utricle and saccule 椭圆囊和球囊 Semicircular ducts 膜半规管
Cochlear duct 蜗管 Contains spinal organ 螺旋器 (of Corti), the sound
receptors lies on tympanic wall of cochlear duct
Utricle 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 gravity
Semicircular 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 sound
Air-conduction of sound
Sound wavesCochlear nerve
Bony- conduction of sound
Sound waves Skull Bony labyrinth Perilymph
Endolymph within cochlear duct Spinal organ
Cochlear nerve
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 meatus