资料案例教案讲稿the sensory organs.pptx

The Sensory Organs;The Sensory Organs;a. carotid sinus: pressure receptor blood pressure b. carotid glomus:chemical receptor partial pressure of CO2 partial pressure of O2 hydrogen ion concentration, pH;The Visual Organ ;Section 1 The eyeball;Walls of eyeball;Fibrous tunic of eyeball (outer);Vascular tunic of eyeball (middle);;;;Retina;The fourth layer consists photoreceptor cells Cone cells are color receptors that function best during the day Rod cells are dark-light receptors that function best at night and in dim light The third layer consists of bipolar neurons The second layer is formed ganglion cells, 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;Optic disc (blind spot), located medial to posterior pole of eye, and consists of optic nerve fibers and central artery of retina Macula lutea 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 , aera of greatest visual acuity (concentration of cones), at its center ;Contents of eyeball;Aqueous humor ;Ciliary body ;Lens ;Vitreous body ;Refractive media of eye; Abnormalities.. Astigmatism = distorted vision, due to irregular corneal shape. Emmetropia = normal eye refraction Myopia (nearsightedness) =focus infront of retina. Axis too long. Hyperopia (farsightedness)= axis is too short. Focus behind retina. Presbyopia (old sight) = less effectivity in accomodation ;Accessory organs of eye ;Eyelids ;Conjunctiva ;Lacrimal apparatus ;Lacrimal passages Lacrimal puncta opening to lacrimal ductules, one on each eylid margin near medial angle Lacrimal ductules : one in each lid, pass medially, join and enter lacrimal sac Lacrimal sac within fossa for lacrimal sac, opening into nasolacrimal duct Nasolacrimal duct courses 2 cm inferiorly and opens into inferior nasal meatus;;Ocular muscles ;Ocul