Chapter 13: Sensory System – Vocabulary Flashcards

Vocabulary flashcards covering the sensory system, receptors, sensation and perception, general and special senses, and the eyes and ears.

Sensory system

The body system that allows us to experience the world by detecting stimuli via receptors and processing signals into sensations and perceptions.

Receptors

Cells that detect stimuli and initiate the sensory signal.

Chemoreceptors

Receptors that detect chemical stimuli (e.g., odors, tastes, or chemical changes in the body).

Nociceptors

Pain receptors; free nerve endings that respond to tissue injury or other noxious stimuli.

Thermoreceptors

Receptors that detect heat and cold.

Mechanoreceptors

Receptors that respond to mechanical forces such as touch, pressure, vibration, or stretch.

Photoreceptors

Receptors in the retina that respond to light.

Sensation

Conscious or unconscious awareness of incoming sensory information.

Perception

Conscious awareness and interpretation of a sensation.

Stimulus

Energy or chemical change that initiates a sensory nerve impulse.

Receptor (sensory receptor)

A cell or specialized ending that detects a stimulus.

Sensory nerve

Nerve that transmits sensory information from receptors toward the brain.

Projection

The process by which a sensation is interpreted as occurring in a specific area of the brain.

Adaptation

A decrease in sensitivity to a constant stimulus over time.

General senses

Somatic senses including proprioception, pain, touch, heat, cold, and pressure.

Special senses

Senses including taste, smell, sight, hearing, and balance.

Proprioception

Sense of body position and movement; receptors in muscles, tendons, joints, and the inner ear.

Pain

Sensation produced by nociceptors in response to tissue injury or danger.

Touch

Sensation produced by mechanoreceptors in the skin and subcutaneous tissues.

Temperature

Sensation produced by heat and cold thermoreceptors; extreme temps may trigger pain.

Olfactory sense

Sense of smell; chemoreceptors (olfactory cells) in the nasal cavity; signals to olfactory cortex.

Gustatory sense

Sense of taste; chemoreceptors (gustatory cells) on the tongue.

Sweet, Sour, Salty, Bitter

Primary taste modalities detected by taste buds.

Eye (sclera)

White, fibrous outer layer of the eyeball.

Choroid

Vascular middle layer of the eye between the sclera and retina.

Retina

Inner layer of the eye containing photoreceptors that sense light.

Cornea

Transparent front layer that helps focus entering light.

Pupil

Opening in the iris that regulates light entry into the eye.

Iris

Colored part of the eye; controls pupil size.

Lens

Transparent structure that focuses light by changing shape (accommodation).

Aqueous humor

Fluid in the anterior and posterior chambers that nourishes the cornea and lens; drained via the canal of Schlemm.

Vitreous humor

Clear gel that fills the posterior cavity and maintains eyeball shape.

Optic nerve

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

Optic chiasm

Where optic nerves partially cross; contributes to visual field processing.

Primary visual cortex

Occipital lobe region that processes visual information.

Refraction

Bending of light as it passes through cornea and lens to focus on the retina.

Accommodation

Lens adjustment to focus on near objects by changing shape.

Night vision

Vision mediated mainly by rods, enabling low-light perception.

Color vision

Vision mediated by cones; perception of color in adequate light.

Visual pathway

Retina → optic nerve → optic chiasm → optic tract → thalamus → primary visual cortex.

External ear

Part of the ear outside the eardrum: auricle/pinna and external auditory canal.

Middle ear

Air-filled cavity containing the auditory ossicles (malleus, incus, stapes) and tympanic membrane; includes the Eustachian tube.

Cochlea

Spiral organ of the inner ear responsible for hearing.

Semicircular canals

Three fluid-filled tubes in the inner ear that detect rotational movements for balance.

Vestibule

Part of the inner ear involved in static balance; contains otolith organs.

Organ of Corti

Sensory organ in the cochlea containing hair cells that convert sound to neural signals.

Hair cells

Sensory receptors in the inner ear for hearing and balance.

Endolymph

Fluid within the membranous labyrinth of the inner ear.

Perilymph

Fluid within the bony labyrinth surrounding the membranous labyrinth.

Vestibular nerve

Nerve component of CN VIII that transmits balance information from the inner ear.

Cochlear nerve

Nerve component of CN VIII that transmits hearing information from the cochlea.

Static equilibrium

Balance sense that detects head position relative to gravity via maculae.

Dynamic equilibrium

Balance sense that detects head movement via the semicircular canals.