Theories of vision and hearing

sensory organs

Organs that detect stimuli and send signals to the brain.

Computer Vision Syndrome (CVS)

A condition caused by eye strain from prolonged screen use.

common symptoms of CVS

Burning or itching eyes, sensitivity to light, blurred vision, headaches, eye fatigue.

glare

Harsh light that can increase eye strain.

contrast

The difference in luminance that makes an object distinguishable.

blink

The rapid closing and opening of the eyelids.

vision

The main sense used by most people to gather information about their environment.

light

A form of energy that travels as electrical and magnetic waves.

amplitude

The height of a wave, affecting brightness.

wavelength

The distance between wave peaks, affecting color.

frequency

The number of waves per second.

visible light

The part of the electromagnetic spectrum that humans can see.

visible spectrum

The range of visible light wavelengths that humans can see.

infrared (IR)

Wavelengths too long to be seen by the human eye.

ultraviolet (UV)

Wavelengths too short to be seen by the human eye.

cornea

The clear, tough, protective layer at the front of the eye.

pupil

The hole in the center of the eye that controls light entry.

iris

The colored part of the eye that controls pupil size.

accommodation

The process by which the lens changes shape to focus images clearly.

retina

The layer of cells at the back of the eye where transduction occurs.

myopia

Nearsightedness; distant objects look blurred.

hyperopia

Farsightedness; close objects look blurred.

presbyopia

An age-related condition where the lens loses elasticity.

lens

A transparent, elastic structure that bends light to focus images on the retina.

photoreceptors

Cells in the retina that detect light; includes rods and cones.

rods

Photoreceptors sensitive to low levels of light; important for night vision.

cones

Photoreceptors responsible for color vision and sharp detail.

color vision

Perception of color through specialized retinal cells.

neural signals

Electrochemical impulses that convey information to the brain.

optic nerve

The nerve that carries visual information from the retina to the brain.

transduction

The conversion of light energy into electrochemical nerve impulses.

ganglion cells

Retinal neurons that form the optic nerve and fire action potentials.

fovea

The area of the retina that provides sharpest and most detailed vision.

dark adaptation

The process of adjusting from bright to dark conditions in vision.

light adaptation

The process of adjusting from dark to bright conditions in vision.

sound

The movement of air molecules traveling in a wave pattern.

pitch (frequency)

The perception of how high or low a sound is, determined by frequency.

loudness (amplitude)

The perception of how loud or soft a sound is, determined by amplitude.

timbre (complexity)

The quality or texture of sound caused by a mixture of different wavelengths.

pinna

The visible part of the ear that gathers sound waves from the environment.

auditory canal

Tube-like structure that directs sound waves towards the eardrum.

eardrum (tympanic membrane)

Thin membrane that vibrates in response to sound waves.

ossicles

Three tiny bones in the middle ear that transmit and amplify sound vibrations.

malleus

The hammer-shaped ossicle that receives vibrations from the eardrum.

incus

The anvil-shaped ossicle that transfers vibrations from the malleus to the stapes.

stapes

The stirrup-shaped ossicle that connects to the oval window of the inner ear.

oval window

Membrane-covered opening to the inner ear that receives vibrations from the stapes.

cochlea

A fluid-filled, snail-shaped chamber in the inner ear that processes sound.

basilar membrane

Flexible membrane that moves in response to fluid waves in the cochlea.

hair cells (cilia)

The sensory receptors for hearing that bend in response to fluid movement.

transduction in hearing

The process by which sound energy is converted into neural impulses.

auditory nerve

Nerve that transmits auditory information from the cochlea to the brain.

thalamus

A brain structure that relays sensory information to the cerebral cortex.

primary visual cortex

Part of the occipital lobe responsible for processing visual information.

feature detectors

Neurons that respond to specific visual features, like edges or motion.

place theory

Theory that pitch is determined by where the basilar membrane vibrates.

frequency theory

Theory that pitch is determined by the rate of vibration of the entire basilar membrane.

dual theories of pitch perception

Modern understanding that combines place and frequency theories for a complete explanation.

lock-and-key theory (olfaction/taste)

Theory explaining how specific molecules fit into receptors for smell and taste.

neuromatrix theory (pain)

Theory stating that pain is a complex experience processed by multiple brain systems.

vestibular sense

Sense that provides information about balance and spatial orientation.

kinesthesia

Sense that informs about body posture and movement.

chemical senses

Senses of smell (olfaction) and taste (gustation) based on chemical molecules.

neural pathways

The routes followed by sensory information as it travels to the brain.

sensory processing

The interpretation of sensory signals in the brain.

cerebral cortex

The outer layer of the brain where sensory information is processed.

occipital lobes

Regions at the back of the brain that process visual information.

temporal lobes

Regions located on the sides of the brain that process auditory information.

limbic system

Brain structures involved in emotion and memory, linked to olfactory processing.

somatosensory cortex

Part of the cortex responsible for processing touch and bodily sensations.

thalamic relay

The process by which sensory information is routed through the thalamus.

exception to thalamus routing

Smell does not pass through the thalamus before reaching the cortex.

amplitude measurement

Loudness of sound measured in decibels (dB).

frequency measurement

Pitch of sound measured in Hertz (Hz).

pupil dilation

The increase in pupil size to let more light in, typically occurring in low light.

pupil constriction

The decrease in pupil size to let less light in, typically occurring in bright light.

3 types of cones

S cones (blue), M cones (green), L cones (red); responsible for color vision.

auditory cortex

Part of the temporal lobe responsible for processing auditory information.