SENSES PART 2

Tunics of the eye:Fibrous Tunics

ScleraCornea

Vascular TunicsChoroid IrisCiliary Body

Nervous TunicRetina

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 fi lled with Aqueous Humor

The Vitreous is fi lled with Vitreous Humor

ANATOMY OF THE EYE

Photoreceptors:Rod: Detect Light

(Dark and Light) Cons: Detect Color

1. Red2. Blue 3. Green

PHOTORECEPTORS OF THE RETINA

Eye Functions much like a camera Iris allows light into the eyeCornea and lens focus the image on the retinaRetina 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 fi eld 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 fi eld projects on the left side of the brain and the left side of the visual fi eld 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

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