Anatomy Of The EAR Flashcards
What three parts are the ear divided into?
External,Middle and Internal Ear
What is the Auricle also known as?
The Pinna
What is the Pinna?
It is a flashy cartilage which surrounds the entrance to the external acoustic meatus
What is the function of the Pinna?
It provides directional sensitivity and protects the opening of the canal
What is the external acoustic meatus?
It is an external passageway which ends at the tympanic membrane(eardrum) and is lined with projecting hairs and these hairs trap debris and provides an increased tactile sensitivity through their root hair plexus
What is the tynpanic membrane?
A thin semitransparent membrane sheer that separates external ear from the middle ear
What are the Ceruminous glands?
They are interumentary glands along the acoustic external meatus
What do the cerumnious glands secrete?
They secrete cerumen
What is the purpose of cerumen?
Keeps foreign objects away from the tynpanic membrane
Slows growth of micro organisms in the ear canal
Reduces chance of infection
Prevents water from lodging in the ear
What is the middle ear known as?
Tympanic cavity
What is the structure of the middle ear?
It’s an air filled chamber which is separated from the external ear by the tynpanic membrane
What is the purpose of the tympanic cavity?
It communicates with nasopharynx through the Eustachian tube and allows for equalization of pressures on either side of the eardrum and also communicates with the mastodon air cells through small connections
What are the auditory ossicles?
Malleus
Incus
Stapes
What is the purpose of the auditory ossicles?
They connect the eardrum with one of the receptors complexes of the inner ear through the oval window
What is the vibration of the tympanic membrane?
It converts arriving sound waves into mechanical movements
Then the auditory ossicles conduct the vibrations to inner ear
The ear drum is larger and heavier than oval window and considerable amplification happens so we can hear faint noises
What are the small muscles that protect the eardrum and ossicles from violent movements?
Tensor tympani muscle (It stiffens the eardrum)
Stapedius muscle (Reduces movement of the stapes at the oval window
What does the inner ear do?
This is where sense of equilibrium and hearing happen as they are provided by receptors in the inner ear
What are the superficial contours of the inner ear formed by?
Dense bone known as Bony Labryinth
What is the purpose of Bony Labryinth?
It surrounds and protects membronous labyrinth(delicate and is an interconnected network of fluid filled tubes
Where are the receptors of the inner ear found?
In the membrounous labyrinth
What flows between Bony and membronous labyrinth?
Perilymph(which is a liquid that closely resembles csf)
What does the membronous labyrinth contain?
It contains endolymph which is a fluid with electrolyte concentrations which are diffrent from those of typical body fluids
What are the subdivisions of the Bony Labryinth?
Vestibulae
Semicircular canals
Cochlea
What is the oval window?
It is a window formed by Collagen fibers and it connected at the base of the stapes
