Hearing, Equilibrium, Olfaction, Gustation, and Visual Receptors

Flashcards covering key concepts related to hearing, equilibrium, olfaction, gustation, and visual receptors from lecture notes.

What nerve transmits nerve signals resulting in the sensations of hearing and equilibrium?

Vestibulocochlear nerve (CN VIII)

Name the three distinct anatomic regions of the ear.

External, middle, and inner ear

What is the skin-covered, elastic cartilage-supported structure on the outside of the body called?

Auricle (pinna)

What is the bony tube that the auricle directs sound waves into?

External acoustic meatus (external auditory meatus)

What glands produce cerumen?

Ceruminous glands

What is the function of cerumen?

May help reduce infection within the external acoustic meatus by impeding microorganism growth

What is the boundary between the external and middle ear?

Tympanic membrane (eardrum)

What two nerves transmit pain associated with trauma to the tympanic membrane?

Vagus (CNX) and trigeminal (CN V) nerves

What is contained in the middle ear?

Air-filled tympanic cavity

What two membrane-covered openings are located in the bony wall separating the middle ear from the inner ear?

Oval window and round window

What is another name for the auditory tube?

Pharyngotympanic tube or Eustachian tube

What part of the throat does the auditory tube extend into?

Nasopharynx

What actions result in air movement through auditory tube in order to equalize pressure on either side of the tympanic membrane?

Chewing, yawning and swallowing

What is Otitis media?

An infection of the middle ear

What is a myringotomy?

A surgical procedure where a ventilation tube is inserted into the tympanic membrane to treat repeated ear infections or chronic infections

Name the three smallest bones in the body, housed in the tympanic cavity.

Malleus (hammer), incus (anvil), and stapes (stirrup)

What is the function of the auditory ossicles?

Amplifying sound waves from the tympanic membrane to the oval window

What movement initiates pressure waves in the fluid within the inner ear?

Movement of the stapes against the oval window

What two skeletal muscles are located within the middle ear, and what is their function?

Tensor tympani and stapedius; they restrict ossicle movement when loud sounds occur

Name the three distinct regions of the bony labyrinth.

Cochlea, vestibule, and semicircular canals

What fluid fills the space between the bony labyrinth and the membranous labyrinth?

Perilymph

What structure is housed within the cochlea?

Cochlear duct (scala media)

What two saclike, membranous labyrinth structures are contained in the vestibule?

Utricle and saccule

Where are hearing organs housed?

Within the cochlea in both inner ears

What is the spiral chamber that 'wraps' around a spongy bone axis?

Cochlea

What membranes form the roof and floor of the cochlear duct?

Vestibular membrane (roof) and basilar membrane (floor)

What is another name for the spiral organ?

Organ of Corti

What tympanic membrane is how many times greater in diameter than the oval window?

20

Where are the spiral ganglia located?

In the modiolus, medial to the cochlear duct

How much are sounds transmitted accross the middle ear amplified?

20-fold

What is the range of sound frequencies that the spiral organ of the human ear can perceive?

20 Hz to 20,000 Hz

What is the perception of a sound as high or low?

Pitch

What unit is frequency expressed in?

Hertz (Hz)

What is the minimum sound (or threshold) that humans can hear measured at?

Zero decibels (dB)

How many sensory neurons make up the auditory pathway?

Four sensory neurons

Where do nerve signals initiated by the stereocilia of the spiral organ hair cells travel to?

Cochlear nucleus within the medulla oblongata

After the cochlear nucleus, where are nerve signals transmitted to?

Inferior colliculus in the midbrain

From the inferior colliculus, where do nerve signals travel to for processing and filtering?

Medial geniculate nucleus of the thalamus

Where are nerve signals relayed from the thalamus?

Primary auditory cortex within the temporal lobe of the cerebrum

What is any hearing loss defined as?

Deafness

Name the two categories of hearing loss.

Conductive deafness and sensorineural deafness

What hearing loss involves interference with the transmission of sound waves?

Conductive deafness

What type of hearing loss involves malformation or damage to the structures of the inner ear or the cochlear nerve?

Sensorineural deafness

What device assists some hearing-impaired people by compensating for damaged or nonfunctioning parts of the inner ear?

Cochlear implant

What condition develops when a person is subjected to acceleration and directional changes with limited or discrepant visual contact?

Motion sickness

What is the term referring to our awareness and monitoring of head position?

Equilibrium

What is the collective name of the sensory receptors in the utricle, saccule, and semicircular ducts that help monitor and adjust our equilibrium?

Vestibular apparatus

What structures detect head position during static equilibrium?

Utricle and saccule

What structures are responsible for detecting angular acceleration or rotational movements of the head?

Semicircular ducts

What is the name of the sensory receptor located along the internal wall of both the membranous utricle and saccule?

Macula

What is the gelatinous layer and the crystals that cover the apical surface of the epithelium?

Otolithic membrane (or statoconic membrane)

What is the result of the bending of stereocilia toward the kinocilium?

Depolarization of the hair cells and increased rate of neurotransmitter release

What does the bending of stereocilia away from the kinocilium cause?

Hyperpolarization of the hair cells and decreased rate of neurotransmitter release

What is the enlarged region at the base of each semicircular canal called?

Ampulla

What is the elevated region within the ampulla covered by an epithelium of hair cells and supporting cells called?

Crista ampullaris (or ampullary crest)

What is the gelatinous dome that the stereocilia and kinocilia are embedded into called?

Cupula

Which neuroglia (within the medulla oblongata) integrate the stimuli from the vestibular apparatus, eyes, and proprioceptors to reflexively control eye movements and skeletal muscle contraction?

Vestibular nuclei

What is the sense of smell called?

Olfaction

What is the sense of taste called?

Gustation

What are volatile molecules detected by chemoreceptors?

Odorants

Name three distinct cell types that composed the olfactory epithelium.

Olfactory receptor cells (olfactory neurons), supporting cells (sustentacular cells), and basal cells

What layer is internal to the olfactory epithelium?

Lamina propria

What are the terminal ends of olfactory tracts located inferior to the frontal lobes of the brain?

Olfactory bulbs

What two structures do axons of olfactory nerves synapse with within the olfactory bulbs?

Mitral cells and tufted cells

What are the spherical structures formed by the synapsing of axons of olfactory nerves with mitral and tufted cells called?

Olfactory glomeruli

Unlike other sensory information, olfactory pathways do not project to what part of the brain?

Thalamus

What is the name of the molecules used to detect different smells in order to ensure different smells are able to be smelled?

Odorant-binding protien

In order, name the three regions that integrate sensory input from the olfactory receptors.

Cerebral cortex, hypothalamus, and amygdala

What are the taste-producing molecules and ions of what we eat and drink called?

Tastants

What are the four types of papillae on the dorsal surface of the tongue?

Filiform, fungiform, foliate, and vallate

What type of papillae do NOT house taste buds?

Filiform papillae

What cells function as neural stem cells to continually replace the relatively short-lived gustatory cells?

Basal cells

Name the five basic tastes that our tongue detects.

Sweet, salty, sour, bitter, and umami

What taste is associated with amino acids, such as glutamate and aspartate?

Umami

Which of the five senses utilizes photoreceptors within the eyes to detect light, color, and movement?

Vision

What is the other word for eyelids?

Palpebrae

What is the name of the space between the open eyelids?

Palpebral (or eyeslit) fissure

What is the name of the small reddish body at the medial commissure?

Lacrimal caruncle

What is the function of eyelashes?

Prevent particulate matter from entering the eye

What glands release an oily secretion at the edge of the eyelid?

Tarsal glands (meibomian glands)

What type of epithelium forms a continuous, transparent lining over the anterior surface of the sclera and the internal surface of the eyelid?

Conjunctiva

What is the function of goblet cells?

Secrete mucus to lubricate and moisten the eye

What does lacrimal fluid contain?

Water, sodium ions, antibodies, and lysozyme

What is the almond shaped and sized gland, which is located within the superolateral depression of each orbit and continuously produces lacrimal fluid?

Lacrimal gland

Lacrimal fluid drains into what?

Drain into the lacrimal puncta

What are the structures that each lacrimal punctum drains lacrimal fluid into?

Lacrimal canaliculus

Where does the nasolacrimal duct drain lacrimal fluid into?

Nasal cavity

What cushions the posterior and lateral sides of the eye, providing support and protection?

Orbital fat

What are the two major tunics of the eye wall?

Fibrous tunic and vascular tunic

What makes up the most internal layer of the eye wall?

Retina

What separates the anterior cavity and posterior cavity?

The lens

The lens is composed of exactly arranged layers of cells with what protein?

Crystallin

What permanent fluid is contained in the posterior cavity?

Vitreous humor

What two chambers are the anterior cavity is subdivided into?

Posterior chamber and anterior chamber

What transparent, watery fluid is continuously produced, circulates within the anterior cavity, and then drains back into the blood plasma?

Aqueous humor

Where does aqueous humor formation occur?

By ciliary processes

Where does resorption of aqueous humor from the anterior chamber occur?

Scleral venous sinus (canal of Schlemm)

What is characterized by increased intraocular pressure?

Glaucoma

What part of the outer layer is part of the fibrous tunic?

Sclera

What part of the fibrous tunic is a convex, transparent structure that refracts light rays coming into the eye?

Cornea