colour vision

photopigments

undergo chemical changes when absorbing light

opsin

light-sensitive proteins that play a crucial role in the visual process

visible light

400nm(violet) to 700nm (red)

cone photoreceptors

responsible for color vision and high visual acuity (sharpness of vision), especially under bright light conditions

red cones

peak sensitivity to green yellow

green cones

peek sensitivity to green

blue

peak sensitivity to blue

ganglia cells

process colour via opponent channels: red-green channel, excited by red, inhibited by green or vice versa

colour blindness

defects in cone receptors

colour consistancy

perceived colour remains constant no matter the lighting

purple and white

not a single wave length but multiple

trichromatic vision

ability to perceive the full spectrum of visible light through the combination of three different types of photoreceptor cells in the retina: meaning we rely on three types of cones to detect light.

external ear

pinna and ear canal, leading to the eardrum, only invoved with hearing

Middle Ear

Air-filled space, containing the ossicles which transmit sound vibrations from the eardrum to the oval window. only involved wiht hearing

Inner Ear

Contains the cochlea (for hearing) and the vestibular apparatus (for equilibrium).

Sound

waves with high-pressure peaks and low-pressure troughs

Human Hearing Range

6 Hz to 20,000 Hz. Highest acuity between 1,000-3,000 Hz.

Hearing Loss

• Conductive: Problem in the external or middle ear.

• Sensorineural: Damage to hair cells or cochlea (common in aging).

• Central: Damage to the auditory cortex or pathways.

eardrum

vibrates, moving the ossicles (malleus → incus → stapes), which amplify sound and transmit vibrations to the oval window.

cochlea

a spiral-shaped organ in the inner ear responsible for hearing. converts sound vibrations into electrical signals by using fluid waves to stimulate hair cells, which send auditory information to the brain.

frequency

number of waves that pass a certain point at a certain time

Auditory Pathway

Auditory nerve → Cochlear nuclei → Midbrain → Thalamus → Primary auditory cortex (temporal lobe)

Vestibular Apparatus

Composed of the utricle, saccule (detect static head position) and semicircular canals (detect rotational motion).

Rinne Test

Tuning fork placed on the mastoid bone and near the ear. If sound is louder through bone, it's conductive hearing loss

Weber Test

• Tuning fork placed at the forehead. Sound louder in the bad ear indicates conductive loss; louder in the good ear indicates sensorineural loss.

Hair Cells

Mechanoreceptors that convert mechanical vibrations into electrical signals

applitude

difference between the high or low pressures created by sound wave

pinna

catches sound waves and passes them deeper into ear

eardrum

boundary between external ear and middle ear

ossicals

small bones inside the ear. conducts vibrations that move onto superior oval window

organ of Corti

hair cells (auditory receptors), which bend in response to pressure waves, triggering electrical signals in sensory neurons

vestibular apparatus

fluid is controlled by the movement of your head