How The Eye Works

Study Notes

How The Eye Works

Electromagnetic light energy is transduced (converted) into neural electrochemical impulses.
Photoreceptors are responsible for transducing light into neural signals.
Rods are long and thin photoreceptors responsible for night vision and sensitive to light and dark stimuli.
Cones are short and thick photoreceptors responsible for color perception.
Dark adaptation is the recovery of the eye's sensitivity to visual stimuli in darkness after being exposed to bright lights.
Light adaptation is the recovery of the eye's sensitivity to light after exposure to darkness.
Trichromatic theory proposes three types of cones: red, blue, and green.
Opponent-process theory proposes four primary colors with cones arranged in pairs: red and green, blue and yellow.
Color blindness is more common in men than women and is genetically linked.
Rod monochromacy, also called achromacy, is characterized by lack of cones, resulting in monochrome vision.
Cornea protects the eye and focuses most of the light entering the eye.
Aqueous humor provides nourishment.
Pupil allows light to enter the interior of the eye.
Iris controls the size of the pupil, letting more or less light into the eye.
Lens finishes the focusing process begun by the cornea.
Vitreous humor nourishes and gives shape to the eye.
Retina receives light focused by the lens and contains photoreceptors that convert light energy into electrochemical energy.
Photoreceptors are of two types: rods and cones.

Sensation & Perception

Sensation is the process of converting outside stimuli into neural signals in the brain.
Sensory receptors are specialized forms of neurons, stimulated by different kinds of energy rather than neurotransmitters.
Transduction is the process of converting outside stimuli into neural activity.
Sensory thresholds are the minimum levels of stimulation needed for detection.
Just Noticeable Difference (JND) is the smallest detectable difference between two stimuli.
Absolute Threshold is the lowest level of stimulation that can be consciously detected 50% of the time.
Subliminal stimuli are stimuli that are below the level of conscious awareness.
Subliminal perception is the process by which subliminal stimuli act upon the unconscious mind, influencing behavior.
Habituation is the tendency of the brain to ignore constant, unchanging information.
Sensory adaptation is the tendency of sensory receptor cells to become less responsive to a constant stimulus.
Microsaccades are tiny eye movements that prevent sensory adaptation to visual stimuli.

Structure of the Ear

Ear is responsible for hearing.
Outer ear includes the pinna and ear canal.
Middle ear contains the eardrum, hammer, anvil, and stirrup, which transmit vibrations from the eardrum to the inner ear.
Inner ear contains the cochlea, organ of Corti, and vestibular system.

Hearing

Sound is interpreted as frequency, amplitude, and purity.
Frequency is interpreted as pitch.
Amplitude is interpreted as volume.
Purity is interpreted as timbre.
Hertz (Hz) is a measurement of frequency.
Conductive hearing loss is caused by damage to the eardrum or middle ear bones.
Nerve hearing impairment is caused by damage to the inner ear or auditory pathways.
Sensory conflict theory explains motion sickness as a clash between visual and vestibular senses.

Sensory Conflict Theory

Sensory conflict theory explains motion sickness as a clash between visual and vestibular senses.
This clash results in dizziness, nausea, and other physical discomforts.

Perception

Perception is the process by which sensations are interpreted and organized into meaningful patterns.
Knowledge plays a crucial role in perception, influencing how we interpret sensory information.