Chapter 24 Notes: Taste & Smell, Hearing & Balance, Vision (A&P II)

Vocabulary flashcards covering key terms from taste, smell, hearing/balance, and vision topics in Chapter 24.

Anosmia

Inability to smell; may result from head trauma, respiratory infections, aging, etc.; may cause depression.

Transduction

Process by which sensory receptors translate stimulus energy into action potentials for the nervous system to interpret.

Olfactory epithelium

Tissue containing olfactory neurons with receptors for specific smells.

Olfactory receptor neurons

Olfactory neurons that bind odor molecules and transmit signals to the brain.

Olfactory bulb

Brain structure where olfactory signals are first processed after receptor activation.

Olfactory tract

Pathway from the olfactory bulb to olfactory cortex, frontal cortex, and limbic system.

Olfactory cortex

Brain region that interprets smell information.

Limbic system

Brain system involved in emotions and memory; smells can trigger memories and emotions.

Umami

Fifth basic taste; savoriness; found especially in mushrooms and anchovies.

Salty

One of the five basic tastes; involves sodium channels in gustatory cells.

Sweet

One of the five basic tastes.

Sour

One of the five basic tastes; involves a proton channel pathway.

Bitter

One of the five basic tastes.

Cranial nerves VII, IX, X

Facial, glossopharyngeal, and vagus nerves; involved in transmitting taste impulses to the brain.

Taste buds

Specialized epithelial structures containing gustatory cells that detect tastants.

Gustatory cells

Taste receptor cells within taste buds.

Digestive enzymes release

Taste-related neural impulses can stimulate digestive enzyme release in the brain’s signaling pathways.

Organ of Corti

Hair-cell receptor region in the cochlea that transduces sound vibrations into neural signals.

Hair cells

Sensory receptors in the organ of Corti that convert mechanical vibrations to nerve impulses.

Basilar membrane

Membrane in the cochlea that vibrates in response to different frequencies, stimulating hair cells.

Cochlear nerve

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

Pinna

External, funnel-shaped part of the ear that collects sound waves.

External acoustic meatus

Ear canal that channels sound to the tympanic membrane.

Tympanic membrane

Eardrum; vibrates in response to sound, transmitting vibrations to the auditory ossicles.

Malleus

Hammer-shaped middle ear bone; one of the auditory ossicles.

Incus

Anvil-shaped middle ear bone; one of the auditory ossicles.

Stapes

Stirrup-shaped middle ear bone; footplate at the oval window.

Oval window

Membrane-covered opening that transmits vibrations from the middle ear to the inner ear.

Labyrinth

Inner ear; complex system involved in hearing and balance.

Cochlea

Spiral, snail-shaped organ of hearing containing the sensory organs for sound.

Scala vestibuli

Upper chamber of the cochlea filled with perilymph.

Scala media

Cochlear duct; middle chamber containing endolymph and the organ of Corti.

Scala tympani

Lower chamber of the cochlea filled with perilymph.

Vestibular apparatus

Inner-ear system that helps with balance and spatial orientation.

Utricle

Vestibular organ that detects horizontal head movements and gravity.

Saccule

Vestibular organ that detects vertical head movements and gravity.

Semicircular canals

Three orthogonally oriented canals that detect head rotation and angular acceleration.

Motion sickness

Nausea caused by sensory conflict between motion cues from the inner ear and other senses.

Retina

Layer at the back of the eye containing photoreceptors that convert light to neural signals.

Rods

Photoreceptors that are highly light-sensitive, provide peripheral and grayscale vision.

Cones

Photoreceptors responsible for color vision and high-acuity vision in bright light.

Photoreceptors

Rods and cones; cells that detect light and begin visual processing.

Bipolar neurons

Second-order neurons in the retina that connect photoreceptors to ganglion cells.

Ganglionic neurons

Retinal ganglion cells whose axons form the optic nerve, transmitting visual information to the brain.

Optic nerve

Nerve carrying visual information from the retina to the brain.

Thalamus

Brain relay center that forwards visual information to the visual cortex.

Visual cortex

Cerebral area (occipital lobe) that processes visual information.

Fibrous layer

Outer eye layer consisting of sclera and cornea.

Vascular layer

Middle eye layer (choroid, ciliary body, iris) rich in blood vessels.

Inner layer

Retina; innermost eye layer with photoreceptors and neurons.

Sclera

White of the eye; protects the eyeball and provides shape.

Cornea

Transparent outer layer that begins the focusing of light onto the retina.

Choroid

Vascular layer supplying blood to the retina.

Ciliary body

Structure around the lens that changes lens shape for focusing.

Iris

Colored part of the eye; smooth muscle that adjusts pupil size.

Pupil

Opening in the iris that allows light to enter the eye.

Lens

Transparent structure that focuses light onto the retina.