ENT ANATOMY AND PHYSIOLOGY Flashcards
Inner ear
Contains three fluid-filled structures and what are they?
- Vestibule
- Semicircular canals
- Cochlea
Blood supply to the ear
Two branches of the external carotid artery. What are they?
- Posterior auricular artery
2. Superficial temporal artery
What nerve supply the external ear?
4
- Auriculo-temporal branch of the trigeminal nerve,
- greater auricular nerve,
- lesser occipital nerve
- auricular branch of the vagus nerve
What nerves supply the middle ear?
2
- Chorda tympani nerve
2. Tympanic plexus nerve
What nerves supply the inner ear?
- Facial nerve (VII)
2. Vestibulocochlear nerve (VIII)
What is the concave cartilaginous structure that collects and directs sound waves traveling in the air into the ear canal?
Pinna/Aurical
- How long is the ear canal?
- How long is the ear canal?
- 2/3 is embedded where?
1/3 is embedded where?
- Pinna/Aurical
Concave cartilaginous structure that collects and directs sound waves traveling in the air into the ear canal
Ear canal
2. Approximately 1.25 in long
- Inner 2/3 of ear canal is embedded in the temporal bone
Outer 1/3 of the canal is cartilage
Functions of the ear canal?
3
- Ear canal resonates sound waves and increases loudness of tones in the 3000-4000 hz range
- Maintains proper conditions of temperature & humidity to preserve elasticity of the TM
- Contains glands that produce wax (cerumen) and contains tiny hairs which provides added protection against insects or foreign particles from damaging the TM
What is the middle ear composed of? 2
Composed of the TM and cavity which houses the ossicular chain
- The TM divides what?
2. What is it very sensitive to?
- Divides external & middle ear
2. Very sensitive to sound waves and vibrates back- and- forth as sound waves strike it
- Where is the middle ear cavity located?
- The cavity is an extension of what?
- Functions of the eustachian tube? 3
- Located in the mastoid process of the temporal bone
- The cavity is an extension of the nasopharynx via the Eustachian tube (ET)
ET
- Air exchange: keeping the air pressure on both sides of the TM equal
- Excretory: drainage for the middle ear
- Defense: helps in preventing infection
- Function of the ossicular chain?
- What does it consist of? 3
- What are the two muscles that attach to the ossicles?
- Helps connect and transmit sound from middle to inner ear
- Consist of the malleus, incus, stapes
- Malleus: attached to TM
- Incus: lies in the middle between the malleus & stapes
- Stapes: footplate inserts into the oval window of the inner ear - Two tiny muscles attach to the ossicles
- Stapedius
- Tensor tympanic
What is the inner ear composed of? 2
- Composed of the cochlea (hearing) and vestibular system (balance)
Both systems are have separate functions but are housed in the same area and share the same fluid
The cohclea is compised of three fluid filled chambers. What are they filled with? 2
- Two outer chambers are filled with perilymph fluid
2. Third chamber in the center secretes endolymph, this area is called the cochlear duct
Inner ear (cont’d)
Cochlear duct contains a basilar membrane which lies the Organ of Corti
The “pitch” of the impulses relayed depends on what?
which area of basilar membrane or which portion of the Organ of Corti is stimulated
Apical portion (most curled) transfers 1.______ frequencies and the basal end relays 2.______ frequencies
VIII cranial nerve carries the impulses to the 3.____________of the brain to be interpreted
- lower
- higher
- temporal lobe
- What is the vestibular system composed of? What are they? 3
- Function?
- Composed of
- three semi-circular canals
- Utricle
- Saccule - Helps to maintain balance regardless of head position or gravity in conjunction with the eye and somatosensory input
The nose and nasopharynx have several functions:
4
- Identification of odors
- Passageway for inspired and expired air
- Humidification, filtration, and warmth of inspired air
- Resonance of laryngeal sound
The roof of the nasal cavity is divided into three parts. What are they?
3
What does the floor of the nasal cavity consist of? 2
- Frontonasal
- Ethmoidal
- Sphenoidal
Floor:
- consists of palatine process of maxilla and
- horizontal plate of palatine bone
What makes of the medial walls of the nasal cavity? 5
What makes up the lateral walls of the nasal cavity?
- Medial:
- nasal septum,
- ethmoid bone,
- vomer,
- nasal crest of maxillary and
- palatine boned - Lateral: hallmarked by 3 nasal conchae, which divide nasal cavity into 4 passages that have openings to paranasal sinuses