The eye and vision

___are involved in the perception of colors.

Cones

The __ allows us to focus on objects that are any distance from us.

lens

__ are the key to seeing well at night.

Rods

Stimulus, receptor, and processed for vision

Stimulus = Light waves

Receptor = Rods and Cones

Processed = Occipital Lobes

Stimulus, receptor and processed for hearing

Stimulus : sound waves

Receptor: hair cells on basilar membrane in cochlea 

Processed: Temporal Lobes

Stimulus, receptor, and processed for taste

stimulus : chemicals

receptor : taste buds

Processed : gustatory cortex ( frontal lobe ) 

Stimulus, receptor, and processed for smell

stimulus : chemicals

receptor : olfactory hair cells

processed : olfactory bulb 

Stimulus, receptor, and processed for skin senses

Stimulus : external contact

Receptor: nerves in skin, joints

Processed : somatosensory cortex

Name all the eyes parts ( 8 ) with descriptions

1. Cornea = transparent portion of sclera through which light enters

2. Iris = pigmented muscle that gives the eye its color and regulates the size of the pupil

3. Pupil = opening in the iris that light passes through

4. Lens = transparent shape that changes shape to bring objects into focus

5. Retina: layer containing photoreceptors, rpds, and cones that transduce light energy to electrochemical energy; operates like film in a camera

6. Fovea = minute area in the center of retina where vision in shaped, point of central focus 

7. Optic nerve to visual cortex: location on the retina where the optic nerve leaves the eye on its way to the brain 

8. blind spot = nerve that leads out of eye toward the brain carrying information about light 

In the retina

• rods and cones are receptor cells at the back of the retina 

• light energy triggers chemical here ( sparking neural signals ) 

• ganglion cells are specialized neurons in the retina 

Cones ( location, processes, works in )

Location : fovea

Processes : colar, detail

works in : high light

Rods ( location, processes, works in ) 

Location : periphery 

processes : shapes, movement, light and dark adaptation

works in : low light

Further from center of eye means there are more __ than __

rods than cones ( can see outline of things in dark = rods )

wavelength= __ and amplitude = __, ( both are related to vision )

wavelength = colors, amplitude = brightness

Transduction of light wave steps

1. light through cornea and pupil

2. lens focuses on retina 

3. light goes to cones, rods for chemical reaction 

4. neural impulse sent through optic nerve

5. neural impulse sent to thalamus 

6. neural impulse sent to visual cortex 

Accomodation

The process by which the eyes and lens change shape to help focus near or far objects on the retina 

Young-Helmholtz Trichromatic Theory

• Cones in the retina are specific based on red, green, or blue 

  • work together to allow us to perceive color

• each handles a range of wavements 

  • red = lon g

  • green = medium 

  • blue = short 

Opponent Process Theory

• Two color opponent process in ganglion cells

  • red vs green 

  • yellow vs blue 

  • white vs black 

• afterimages: when you look at the same color long enough, tire out the ganglion cells for that color - when we look at white ( which contains all colors ) , we see the opponent color

Color blindness

• Occurs when one type of colo receptor ( cone ) is not functioning 

• ex: if red cones not functions ( cant see long wavelength colors ) → will have difficulty telling red and green apart 

• most common: malfunction of green cone system 

Colors is a two step process, describe the steps 

1. Retina’s cones respond in varying degrees to different color stimuli 

2. their signals then processed by nervous system’s ganglion cells