Sensory organs. Visual Organ
Sensory organs. Visual Organ
Sensoryorgans Receptors:receivethestimulationfromtheexternal orinternalenvironmentofthebodyand convertit into nerve impulseAccessoryorgans
① Receptors: receive the stimulation from the external or internal environment of the body and convert it into nerve impulse. ② Accessory organs Sensory organs
Classificationofthereceptors:·Exteroceptors---intheskin,mucous,visual &auditoryorgansfeel touch,temperature,pain,lightand soundInteroceptors----inviscera,heart,bloodvesselsacceptthephysicalandchemical stimulation.Proprioceptors--inthemuscles,tendons,joints,ligaments&internalearsmonitortheposition&movementofthelimbsandtrunkOROELaaok
Classification of the receptors: • Exteroceptors- in the skin, mucous, visual & auditory organs. feel touch, temperature, pain, light and sound. • Interoceptors- in viscera, heart, blood vessels. accept the physical and chemical stimulation. • Proprioceptors- in the muscles, tendons, joints, ligaments & internal ears. monitor the position & movement of the limbs and trunk
Visual organWall:Fibrous tunic,vasculartunic,retinaEyeballContents:aqueoushumor,lens,vitreousbodyAccessoryorgans:eyelid,conjunctiva,lacrimalapparatus,extraocularM·Receivethestimulationoflight.Transformthestimulationintonerve impulse
• Receive the stimulation of light • Transform the stimulation into nerve impulse Accessory organs: eyelid, conjunctiva, lacrimal apparatus, extraocular M. Eyeball Wall：Fibrous tunic, vascular tunic, retina Contents: aqueous humor, lens, vitreous body Visual organ
Section 1 EyeballWallofeyeball1.External/fibroustunic2.Middle/vasculartunic3.Innertunic/retinaOpticN
Ⅰ. Wall of eyeball 3.Inner tunic / retina 1.External / fibrous tunic 2.Middle / vascular tunic Section 1 Eyeball Optic N
1.Fibroustunic（1)Cornea（anterior1/6）Transparent,non-vascularSensitiveto stimulation·HighlycurvedScleraOpticN
• Transparent, non-vascular • Sensitive to stimulation • Highly curved 1. Fibrous tunic （1）Cornea （anterior 1/6） Optic N. Sclera
(2)Sclera（posterior5/6）.White,dense,opaque·Maintainingtheformoftheeyeball.Sinus venosus sclerae a circularcananl drainingthe aqueous humour·ispiercedbytheopticnervefibers and continuouswithduramaterPOTaCanat ot SohinnAteriorchembeDitatorta)Sphinctior (M)SoaX华Lengry epithelum (B)Caliarymuscle (M)Optic N
• White, dense, opaque • Maintaining the form of the eyeball • Sinus venosus sclerae ①: a circular cananl draining the aqueous humour • is pierced by the optic nerve fibers and continuous with dura mater （2）Sclera （posterior 5/6） Optic N. ①
2.Vasculartunic·Brown,richinbloodvessels&pigmentcells·Provide the nutritionfor thetissues insidethe eyeballAnterior→posterior:iris,ciliarybody,choroid①Iris②Ciliarybody③Choroid
2. Vascular tunic • Brown, rich in blood vessels & pigment cells. • Provide the nutrition for the tissues inside the eyeball. • Anterior → posterior：iris, ciliary body, choroid ① Iris ② Ciliary body ③ Choroid
(1)Iris.The anterior coloured part ofthe vasculartunic·isacircularperforateddiaphragmwithcoronaryposition·near its centeris around aperturenamed pupi·The colourofiris variesfromdifferentracesIrisLens
• The anterior coloured part of the vascular tunic • is a circular perforated diaphragm with coronary position • near its center is a round aperture named pupil •The colour of iris varies from different races （1） Iris Iris Lens
.Pupillary sphincterM.decreasesthepupil:bright light,look at nearobject.Pupillary dilatorM.enlarges thepupil:dim light,look at distant objectPupilPupil constrictsasPupil dilates ascircularmusclesofirisradialmusclesofiriscontract(parasympathetic)contract(sympathetic)Bright lightDim lightNormal light
• Pupillary sphincter M. decreases the pupil: bright light, look at near object • Pupillary dilator M. enlarges the pupil: dim light, look at distant object