The ear is the organ of sense of hearing and balance.
It consists of three elements:
1.The external ear
The pavilion of ears made of elastic cartilaginous tissue and plays a role in the sound waves.
The external auditory tube, which is covered with tegument provided with sebaceous bristles and glands, which secrete the cerumen (retain impurities). It has a role in driving the sound waves to the tympanum.
Timpan is the elastic membrane that vibrates at the action of the sound waves, is located between the outer ear and the middle ear.
2. Average ear
The tympanic chamber, which is located in the temporal bone rock, is full of air.
It communicates with:
-Faring: through Eustachio’s trumpet.
-the external squeegee: through the tympanic window
-the inner door: through the oval window and the round window.
It contains three articulated bones (hammer, anvil and scar), which establish contact with the eardrum and membrane of the oval window, ensuring the sound is transmitted to the inner ear.
3. Internal ear
The bone labyrinth that is located in the bone of the temporal bone.
It consists of a series of cameras:
-the bones of the bones
-the three semicircular channels
It contains a liquid called perilimfa.
The membrane labyrinth, which is located inside the bone labyrinth.
It contains a liquid called endolimph.
Is made of:
– the membrane vestibule, which contains two vesicles: sacule and utricular
-the three semicircular channels that open in the utricula
Hearing receivers are organized in the Corti organ, located in the membranous snail and made up of ciliated sensory auditory cell strings, placed on a basal membrane; the tip of the cilia is enveloped in a gelatinous membrane (“tectoria membrane”).
Sounds cause oscillation of the basement membrane. Due to endolimal vibration, the tectonic membrane presses against the cilia, deforming it; nerve impulses are formed, transmitted to the brain through the acoustic nerve.
Balance receptors (vestibular receptors): Cili cells represented in:
-application: at the base of the semicircular channels; the sensory cell cilia are included in a gelatinous crest and deforms to the head’s rotation movements; the signal is taken up by the nerve endings at the base of the receiving cells.
Otolithic mule: in utricula and sacula; are made up of sensory cells with cilia running through a gelatinous layer. Above them are lime beads (otoliti = otolite). When the position of the body changes, the otoliths move in the opposite direction, and the cilia deform. The information is taken over by the nerve endings at the base of the receiving cells.