Senses and Perception part 2 (chapter 4)

Retina

Innermost layer of the eye that converts incoming light into nerve impulses.

Fovea

Central area of the retina where light rays are most sharply focused; contains the greatest density of cones.

Vitreous humour

Jelly-like liquid that nourishes and gives shape to the eye.

Blind spot

Where the optic nerve leaves the eye; there are no photoreceptor cells here.

Cornea

Transparent protective layer that bends light rays inwards, through the pupil.

Pupil

Opening in the center of the iris that changes size depending on the amount of light in the environment.

Lens

Transparent disc that changes shape to bring objects into focus on the retina.

Rods

Light sensitive receptors in the retina that respond to black and white and encode in shades of grey.

Cones

Receptor cells in the retina that help see colour and fine detail; concentrated at the fovea.

Myopia

Nearsightedness; distance through the eyeball is too short, causing distant images to be blurry.

Hyperopia

Farsightedness; focal image longer than the eye can handle, causing close objects to be blurry.

Auditory System

System responsible for hearing; relies on the physical properties of sound waves.

Decibel (dB)

Unit to measure the loudness of sound; each increase of 10 dB makes a sound 10 times louder.

Cochlea

Fluid-filled, snail-shaped chamber in the inner ear that produces electrical impulses transmitted to the brain.

Place Theory

Theory that explains how we hear individual pitches based on the location along the basilar membrane that vibrates.

Frequency Theory

Theory that explains how we perceive frequencies based on the stimulation of hair cells.

Vestibular System

System key to our sense of balance and awareness of body position in space.

Somatosensory System

Sensory system that responds to stimuli applied to skin, temperature, and injury.

Gate Control Model

Theory that suggests neural mechanisms in the spinal cord regulate the awareness of pain.

Olfaction

Sensation of smell; a chemical sense involving the olfactory epithelium.

Gustation

Sense of taste; involves basic tastes: sweet, sour, salty, bitter, and umami.