BIO 446L 1st Edition Lecture 16 Outline of Last Lecture I. Autonomic Nervous System contda. Parasympathetic continuedi. CraniosacralII. Special Senses—Visiona. Layersi. Fibrousii. Vasculariii. Nervousb. Fibrousi. Sclera and corneac. Vasculari. Cilliary bodyii. The iris and pupild. The lense. The vitreousf. Nervous layeri. retinaOutline of Current Lecture I. Vision Continueda. Rods and conesb. Extraocular musclesc. Visual pathwaysi. Visual fieldII. Auditorya. Anatomy of the earb. Organ of hearingi. Cochleac. Organ of balancei. Semicircular canalsii. Stereocilia and kinociliaiii. MaculaeCurrent LectureThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Vision continued- The retinao Pigmented cells collect lighto Photoreceptor cells Rods—photoreceptor sensitive to low light- Found in periphery of the retina- Rodoxin pigment Cones—photoreceptors that transduce bright light and color- Visible light—red, blue, and green- Concentrated in macula- Iodoxin pigment- Extraocular muscleso Cranial nerve 3 innervated Inferior oblique Superior rectus muscle—looking up Inferior rectus muscle—looking down Medial recture—looking middleo Cranial nerve 4 innervaqted Superior oblique—looking down and in- Visual pathwayso Visual field—left and right side Each with a temporal and nasal field Image is projected upside down and backwards on the retina Nasal field light projects to temporal retina and temporal field light projects to nasal retina Optic chiasm- Axons from nasal retina cross and continue on the opposite side ofthe brain- Epsilateral- If cut, you would not be able to see temporal visual fieldo Because nasal retina receives image from temporal visual field Visual cortex- If primary visual cortex is affected, what can’t you see?Auditory—Hearing and Balance- Anatomy of the earo Tempanic membraneo Ear drum separates outer and inner earo Middle ear: maleus, incus, and stapes (contacts structures in bony labyrinth)o Bony labyrinth Semicircular canals- Vestibule, cochlea, and sacculeo Membraneous labyrinth Fluid typed- Perilymph—like plasma membrane- Endolymph—like intracellular fluid- Organ of hearing—cochleao Signal transduced perilymph of cochlea Vibrates with sound- Filled with perilymph- scala vestibule and tympani also vibrate- endolymph vibrateso spiral organ hair cells—primary sensory cell, sound transduced by hair cells strongly associated with support cells and make contact with sensory axons, which go to cochlear nerve and then the brain hair cells are rigid- moving can cause change in membrane potential hair cells project cilia and stereocilia in tectorial membrane so vibration can be picked up by endolymph and perilympho frequency distribution in the cochlea fluid moves through cochlea with vibration cochlear nerve joins vestibular nerve- = cochlearvestibular nerveo CNS pons- Organs of balanceo Semicircular ducts—at bases have ampullae Utricle and saccule- Stereocila= connected with each other by myosin and move together- Kinocilia= tallest one, on its own- Maculae—hair cells with kinocilia and stereocilia stick up into thick gelatinous masso Mass filled with weightso This is how movement of body causes movement of cilia Cristae of the semicircular canals- Cristae ampullae—sensory organs, structured like maculaeo Hair cells projecting in endolymph- Semicircular canals—sensitive to rotationo CNS
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