SENSES PART 2

 Tunics of the eye:  Fibrous Tunics  Sclera  Cornea  Vascular Tunics  Choroid  Iris  Ciliary Body  Nervous Tunic  Retina ANATOMY OF THE EYE

CONTRACTION OF THE IRIS

 Chambers of the eye:  Lens: Flexible and Biconcave  Pupil: Hole that lets light pass through  Optic Nerve: Sends images to the brain  Retinal Blood Vessels: ANATOMY OF THE EYE

 Eye Structures:  Anterior Chamber:  Posterior Chamber:  Vitreous:  The Anterior and Posterior Chambers are filled with Aqueous Humor  The Vitreous is filled with Vitreous Humor ANATOMY OF THE EYE

 Photoreceptors:  Rod: Detect Light (Dark and Light)  Cons: Detect Color 1.Red 2.Blue 3.Green PHOTORECEPTORS OF THE RETINA

 Eye Functions much like a camera  Iris allows light into the eye  Cornea and lens focus the image on the retina  Retina projects the image by activating action potentials that are then sent to the brain. FUNCTION OF THE EYE

 Light Refraction: Is the bending of light the site where two light rays converge is called the focal point (FP) this converging of the focal point is called focusing.  The further the distance the flatter the lens becomes moving the focal point posteriorly and the closer the image the rounder the lens becomes moving the focal point anteriorly.  The image being viewed is projected upside down or inverted. LIGHT REFRACTION

 Each visual field is divided into temporal and nasal halves  After passing through the lens light travels to opposite sides of the retinal  Optic nerve sends message to the Optic Chiasm  In the Optic Chiasm messages from the nasal part of the retina travel to the opposite side of the brain. And messages from the temporal part of the brain do not cross  The Right part of the visual field projects on the left side of the brain and the left side of the visual field projects on the right side of the brain NEURONAL PATHWAY FOR VISION

 External Ear:  Auricle  External Auditory Canal  Tympanic Membrane  Middle Ear:  Malleus  Incus  Stapes  Oval Window  Eustachian Tube  Inner Ear  Cochlea  Semicircular Canals  Vestibular Nerve  Cochlear Nerve ANATOMY OF THE EAR

 Steps to hearing:  Sound is heard  Sound waves hit Tympanic Membrane  Tympanic membrane hits Malleus  Malleus hits Incus  Incus hits Stapes  Stapes hits the Oval Window and makes sound waves  Perilymph in the cochlea vibrate cause endolymph to vibrate  Cochlear nerve and auditory nerve send messages to the brain to the vestibulocochlear nerve (VIII) NEURONAL PATHWAY OF HEARING

 The higher the frequency the faster and more frequent the waves  The lower the frequency the slower and less frequent the waves HEARING FREQUENCY

DETECTING FREQUENCIES

DECIBEL SCALE