Ear and Nose

What structures make up the external ear?

"Auricle, external acoustic meatus, and tympanic membrane."

What is the function of the auricle?

"Surrounds the entrance to the external acoustic meatus, protects the canal, and provides directional sensitivity."

Where does the external acoustic meatus end?

At the tympanic membrane (eardrum).

What is the function of the tympanic membrane?

Separates the external ear from the middle ear and transmits sound vibrations.

What do ceruminous glands secrete?

Waxy material called cerumen (earwax).

What is another name for the middle ear?

Tympanic cavity.

How does the middle ear communicate with the nasopharynx?

Through the auditory tube (Eustachian tube).

What is the function of the auditory tube?

Equalizes pressure on either side of the tympanic membrane.

What are the three auditory ossicles?

"Malleus (hammer), Incus (anvil), and Stapes (stirrup)."

What is the function of the auditory ossicles?

Conduct vibrations from the tympanic membrane to the inner ear.

What are the two openings in the middle ear?

Round window and oval window.

What is the function of the round window?

Separates perilymph from the air spaces of the middle ear.

What is the function of the oval window?

Transmits vibrations from the stapes to the inner ear.

What is the function of the tensor tympani muscle?

Stiffens the tympanic membrane.

What is the function of the stapedius muscle?

Reduces movement of the stapes at the oval window.

What fluid does the inner ear contain?

Endolymph.

What structure surrounds and protects the membranous labyrinth?

Bony labyrinth.

What are the three main parts of the inner ear?

"Vestibule, Semicircular canals, and Cochlea."

What does the vestibule contain?

Saccule and utricle.

What is the function of the vestibule?

Provides sensations of gravity and linear acceleration.

What is the function of the semicircular canals?

Detect rotation of the head.

What is the function of the cochlea?

Contains the cochlear duct; provides the sense of hearing.

What are the receptors in the inner ear called?

Hair cells.

What happens when stereocilia bend toward the kinocilium?

The hair cell is depolarized and stimulates the sensory neuron.

What happens when stereocilia bend away from the kinocilium?

The hair cell is inhibited and the sensory neuron is not stimulated.

What directs sensations of motion?

Superior colliculi of the midbrain.

What is nystagmus?

Uncontrolled eye movements due to damage to the brainstem or inner ear.

What fluid does the scala vestibuli and scala tympani contain?

Perilymph.

What fluid does the cochlear duct contain?

Endolymph.

What structure in the cochlea contains the sensory receptors for hearing?

The spiral organ (Organ of Corti).

What membrane lies over the hair cells in the cochlea?

Tectorial membrane.

Where are the maculae located?

In the utricle and saccule.

What are otoliths composed of?

Statoconia and a gelatinous layer.

What is vertigo?

A sensation of dizziness or spinning due to dysfunction in the inner ear or vestibular system.

What are the types of vertigo?

"Peripheral (inner ear), Central (brainstem/cerebellum), and Systemic (cardiovascular/metabolic)."

What tests are used to assess vestibulocochlear nerve function?

Rinne test and Weber test.

What are the main functions of the external nose?

"Warms, moistens, and filters air; increases surface area; acts as a resonating cavity for voice."

What bones form the nasal skeleton?

"Frontal bone, maxilla, ethmoid, inferior nasal concha, vomer, and palatine bones."

What forms the floor of the nasal cavity?

Palatine process of maxilla and horizontal plate of palatine bone.

What divides the nasal cavity?

The nasal septum.

What are the three conchae of the nasal cavity?

"Superior, middle, and inferior conchae."

What is a meatus?

The space below each concha in the nasal cavity.

What opens into the inferior meatus?

The nasolacrimal duct.

What opens into the sphenoethmoidal recess?

The sphenoidal sinus.

What opens into the superior meatus?

Posterior ethmoidal air cells.

What opens into the middle meatus?

"Frontal, maxillary, and anterior and middle ethmoidal sinuses."

Where is the maxillary sinus located?

"Within the body of the maxilla, behind the skin of the cheek."

Where does the maxillary sinus drain?

Into the middle meatus of the nose.

What are clinical implications of maxillary sinus infection?

Infections can spread from frontal or ethmoidal sinuses through the semilunar hiatus.

Where are the frontal sinuses located?

"Within the frontal bone, separated by a bony septum."

Where do the frontal sinuses open?

Into the middle meatus.

What complications can arise from frontal sinus infections?

"Orbital cellulitis, epidural/subdural abscesses, or meningitis."

Where are the ethmoidal sinuses located?

In the ethmoid bone between the nose and orbit.

Where do the ethmoidal sinuses drain?

Posterior into superior meatus; anterior and middle into middle meatus.

Where is the sphenoidal sinus located?

In the body of the sphenoid bone below the sella turcica.

Where does the sphenoidal sinus drain?

Into the sphenoethmoidal recess.

What arteries supply the nasal cavity?

"Facial, sphenopalatine, and ophthalmic arteries."

Where does lymph from the nasal cavity drain?

Preauricular and submandibular lymph nodes.

What nerves supply the nasal cavity?

"CN I (olfactory), anterior ethmoidal branch of V1, posterior nasal and nasopalatine branches of V2."

What are the four main tonsils of the lymphatic system?

"Pharyngeal (adenoid), tubal, palatine, and lingual tonsils."

Where is the pharyngeal tonsil located?

On the roof of the nasopharynx under the sphenoid bone.

Where are the tubal tonsils located?

Near the openings of the auditory tubes in the nasopharynx.

Where are the palatine tonsils located?

In the oropharynx between the palatoglossal and palatopharyngeal arches.

Where are the lingual tonsils located?

On the posterior part (dorsum) of the tongue.

What is Waldeyer's tonsillar ring?

"A ring of lymphoid tissue around the naso- and oropharynx formed by pharyngeal, tubal, palatine, and lingual tonsils."