Vision Module 18

Human’s most dominating sense If multiple senses are competing, vision will overwhelm the others baby

The height of a wave gives us its intensity (brightness). The length of the wave gives us its hue (color).

The spectru m of electro magneti c energy Video

Differing Eyes Bee detects reflected ultraviolet wavelengths

The Eye Cornea – Outer transparent coating that protects the eye’s interior and focuses incoming light

The Eye Pupil – Adjustable opening in the center of the eye – Lets light in Iris – Ring of muscle that forms the colored portion of the eye around the pupil – Controls the size of opening allowing various degrees of light in

Just FYI Blue eyes – less pigment in Iris – more susceptible to red eyes Iris does not have enough time to close and adjust…shines to the back of the eye…showing blood vessels and tissue at the back of the eye called the retina

The Eye Lens – Transparent structure behind the pupil – Changes shape through accomodation to focus images on the retina – Cataracts are the clouding of the eye’s lens

The Eye Accommodation – Change in the curvature of the lens that enables the eye to focus on objects at various distances

Vision Impairments Myopia – Nearsightedness – Can’t see far away objects as well Hyperopia – Farsightedness – Decreased vision for up close objects

The Eye Retina – Light-sensitive membrane at the back of the eye – Contains millions of receptors for vision – Begins the processing of visual information

The Eye Optic Nerve – Nerve that carries neural impulses to the brain Dissection Video

The Retina Light energy  rods and cones  bipolar cells  ganglion cells Bipolar cells – Collect neural signals from rods and cones – Transfer messages to ganglion cells Ganglion cells – Organize the neural signals – Axons converge into optic nerve

Receptors in the Eye Rods – Peripheral retina – Detect black, white, and gray – Twilight or low light Cones – Near center of retina – mainly in the fovea – Fine detail and color vision – Daylight or well-lit conditions

Receptors in the Human Eye ConesRods Number Location in retina Sensitivity in dim light Color sensitive?Yes Low Center 6 million No High Periphery 120 million

Vision to the brain Optic Nerve then carries the neural signals to the primary visual cortex Optic chiasm (Ki-asm) crosses to opposite hemisphere of the brain Info is transferred to the thalamus where it is relayed to the visual cortex in the occipital lobes

Vision from the Eye to the Brain

Visual Information Processing Feature Detectors – David Hubel and Torsten Wiesel – Located in the visual cortex – nerve cells in the brain that respond to specific features S hape A ngle M ovement Sam I Am

Visual Information Processing Parallel Processing – Processing of several aspects of an object simultaneously – Crash Course Crash Course