Eye and Ear

1. Eye 1)  The wall of eyeball

① Fibrous tunic: DCT ---cornea: ---sclera: DCT ---corneal limbus(corneoscleral limbus)Cornea:/anterior 1/6 of fibrous tunic, transparent, bulges

slightly anteriorly/connect with sclera

/five layers: corneal epithelium:

i. stratified, squamous non-keratinising epithelium

ii.  5-6 layers of regular arranged cells iii. basal cells have remarkable regeneratin

g ability iv. rich in nerve terminal

anterior limiting lamina: i.  a clear uniform membrane, 10-16u

m thick ii.  contain collagenous fibrils and ma

trix iii.  cannot regenerate

corneal stroma: corneal propria

i.    constitute 90% of corneal thickness

ii.   composed of layers of collagenous fibrils

iii.  keratocyte: similar to fibroblast

iv.  matrix, no BV

posterior limiting lamina: i.  a clear homogenous membrane, 5-10

um thick ii.   consists of collagenous fibril and matri

xcorneal endothelium:

i.    simple squamous epi. ii. EM: mito, pinocytotic vescles, Golgi a

nd RER iii.Active function of transporting, synthes

izing and secreting protein

* transparency of the cornea: due to absence of BV non-pigmented epi, regular organization of collagen fibrils maintenance of hydration of ground substance

② Vascular tunic(uvea): LCT with BV and melanocytes

---iris

---ciliary body

---choroid

③ retina: ---pigment epithelium:

outerest layersimple low columnar epi:

-culomnar cell: thin, long processes at apical surface

-round or ovoid N -EM: SER, Golgi, rough round or ovoid pigme

nt granules

-function:

i.  protect visual cell

ii. involve in replace of membranous disc

iii. store vitamin A and involve in the synthesis of rhodopsin

---visual cell: photoreceptor cell/cell body:/inner process: form synapse with bipolar cell a

nd horizontal cell/outer process: -outer segment: contain membranous disc -inner segment: contain mito, RER, Golgi and

MT

/rod cell:-110,000,000-120,000,000-deep-stained N-outer process: cylindrical-outer segment: membranous disc-invagination

of cell membrane but separated with cell membrane(exfoliated and ingested by pigment cell) -rhodopsin(visual purpke)= 11-cisretinal(retinene) + opsin

-inner process: spherule(end in a terminal expansion)

-feel dim light

/cone cell: -6,500,000-7,000,000-large N, paler-stained-outer process: conical-outer segment: membranous disc, not separate

d, no exfoliation of disks-iodopsin(photopsin)= 11-cisretinal + opsin(diffe

rent)-inner process: pedicle-feel blight light(red-558nm, green-531nm, blue-

419nm)

---bipolar cell: /large N/contain RER,mito and Golgi/dendrite: synapse with photoreceptor and horiz

ontal neuron/axon: form synapse with dendrite of ganglion c

ell/classification: -rod bipolar cell -midget bipolar cell -flat bipolar cell

---ganglion cell:

/multipolar neuron:

/dendrite: synapse with bipolar, amacrine cell and interplexiform cell

/axon: make up optic nerve

/classification: midget ganglion cell and diffuse ganglion cell

---interneurons: /located in layer of bipolar cell/horizontal cell, amacrine cell, interplexiform cell---radial neuroglia cell: Muller cell/neuroglial cell/thin and long cell, with ovoid, deep-stained N/processes: end at outer limiting membrane and

inner limiting membrane/function: supporting, protecting, nourishing and

insulating function

Under LM: retina can be divided into ten layers i.  layer of pigment epithelium: pigment epithelial

cell ii. layer of rods and cones iii. outer limiting membrane: outer processes of

Muller cell iv. outer nuclear layer: N of visual cells v. outer plexiform layer: inner process of visual c

ell, dendrites of bipolar cell and processes of horizontal cell

vi. inner nuclear layer: cell body of bipolar cell, horizontal cell, amacrine cell and interplexiform cell and Muller cell

 vii.inner plexiform layer: axon of bipolar cell, dendrites of ganglion cell, processes of amacrine cell and interplexiform cell

viii. layer of ganglion cells: cell body of ganglion cell

ix. layer of optic fibers: axons of ganglion cell

x.inner limition membrane: formed by connection each other of inner processes of Muller cells

* macula lutea:/definition: a small area of retina at posterior po

lar of retina, contains a yellow pigment and is non-vascularised, so called yellow spot

/3mm in D/central fovea: shallow depression, 1.5mm in D/thinnest retina: 0.1mm/contain only cone cell, no rod cell/one visual cell connects with one bipolar cell, a

nd one bipolar cell forms synapse with one ganglion cell

/have most clear vision

* papilla of optic nerve: optic disc

/1.5 mm in D

/3 mm medial to macula lutea

/place where the optic nerve leave out

/no photoreceptors: so called blind spot

2. Ear

---the external ear---the external ear

---the middle ear---the middle ear

---the inner ear---the inner ear

1) inner ear: labyrinth

---osseous labyrinth: a system of canals and cavities in compact bone

the vestibule

semicircular canal

cochlea

---membranous labyrinth: usually lined by simple squamous epi. except:

membrane semicircular canal: crista ampullaries

saccule and utricle: macula utriculi and macula sacculi

cochlear duct: spiral organ

-triangular in cross-section-three walls: i.   roof: vestibular membrane ii. outer wall: stratified columnar epi. with

BV distributed- stria vascularis(secrete endolymph) and spiral ligament

iii. floor: osseous spiral lamina and membranous spiral lamina – basilar membrane

a. crista ampullaris:---supporting cell: /columnar, with basal ovoid nucleus, rest

on basal lamina/microvilli, granules: lipid-liked and glycos

aminoglycan granules

---hair cell: /amongat supporting cell/pear-shaped: short neck and globular base/has about 50-110 stereocilia and one kinociliu

m(embedded in cupula)/terminal of peripheral process of neuron of vest

ibular nerve ganglion distributed at basal portion of hair cell

---cupula: gelatinous mass of mucopolysaccharide substance

---function: receptors for kinetic balance, feel angular acceleration or deceleration of the head

b. macula utriculi and macula sacculi: macula acustica---supporting cell---hair cell: 30-60 stereocilia

and one kinocilium

---otolithic membrane: gelatinous mucopolysaccharide substance containing small crystalline bodies of calcium carbonate---function: receptors of static balance, feel linear acceleration or deceleration and change in position of the head

c. spiral organ: Corti organ---supporting cell:

pillar cell:-two rows: inner and outer pollar cell: tall, colum

nar in shape, -inner tunnel

phalahgeal cell:-inner phalangeal cell: one row, is situated

next to inner pillar cell-outer phalangeal cell: 3-5 rows, lateral to

the outer pillar cells-tall columnar cells rest on basilar membr

ane-phalangeal process: enclosed the low pa

rt of hair cell

---hair cell: -inner hair cell: a row of pear-shaped cell, supp

orted by inner phalangeal cell-outer hair cell: 3-5 rows, supported by outer ph

alangeal cell-“V” or “W” shaped-arranged stereocilia on free

surface---peripheral processes of neuron of spiral gangl

ion distribute at basal portion of hair cell---tectorial membrane---auditory string: 2000, located in basilar memb

rane, collagen-liked thin filament---function: receptor of sound