Audition (Sens and Problems) PDF

Audition (Sens and problems) Anatomy sense of hearing Hearing loss ▪ Causes ▪ Clinical manifestations ▪ Evaluation ▪ Risk factors ▪ Nursing management Pathologies ...

Audition (Sens and problems) Anatomy sense of hearing Hearing loss ▪ Causes ▪ Clinical manifestations ▪ Evaluation ▪ Risk factors ▪ Nursing management Pathologies  Anatomy of the ear The ear is a neurosensory organ with a dual function: He provides hearing Plays a role in balance a r i ln The ear is divided into 3 parts: J s b The outer ear r M aja The middle ear R The inner ear  External ear The auricle and the external auditory canal a b aj a) Auricle R Composed mainly of cartilage r ln a Except for the fat and J i subcutaneous tissue in the rs earlobe. M Auricle collects the sound waves and directs vibrations into the extrenal auditory canal b) External Auditory Canal Composed of 2-3 cm long ln a r rs J i ExternalM b R a tympanic membrane j a auditory canal ends on Skin of the canal contains hair , sebaceous glands & ceruminous glands.  Middle ear anatomy Includes ja b a) Eustachian tube R a b) tympanic membrane a r Laterally Jil n rs M c) Otic capsule medially (ossicles)  Middle ear is connected to the nasopharynx by the eustachian tube. A) Eustachian tube: Fibro-cartilaginous and bony canal, long (4cm) and narrow, connecting the eardrum a j a b and the back of the nose or nasopharynx. n a r R rs J i l Closed at rest, opens when swallowing, chewing yawning or sneezing. M  Ventilation to balance the pressures on either side of the eardrum due to the passage of air from the Eustachian tube to the eardrum during each swallowing movement. Functions of Drainage for the outflow of normal secretions eustachian from the ear to the pharynx. tube Normal opening of the eustachian tube equalizes atmospheric pressure in the middle ear; closing of the eustachian tube protects the middle ear from unwanted pressure fluctuations and loud sounds. B) (eardrum) tympanique membrane ✓1 cm in diameter and very thin ✓Gray and translucent ✓3 layers of tissue: j a b a r Ra ✓Tympanic membrane protects the s J il n middle ear and conducts sound M r waves from the external canal to the ossicles  B) Ossicles Middle ear contains 3 smallest bones (ossicles): Malleus, incus, stapes. Are held in place by joints, muscles, and ligaments, assist in the a j a b transmission of sound n a r R rs J i l M  Inner ear It contains the noble neurosensory organs for the 2 major functions: hearing and balance. a) Cochlea: There is the bony cochlea made of 2 and a half turns of whorls. a b R aj And the membranous cochlea which contains the cochlear canal which is a sensory organ of a r hearing where the organ of corti is located. iln b) Vestibule: responsible for balance. J rs Bony vestibule: these are the superior, posterior and external semicircular canals. M Membranous vestibule made of saccules and utricles. The first portion of the facial nerve passes between the cochlea and the vestibule vestibulocochlear nerve(cranial nerve VІІІ) In internal auditory canal, the cochlear nerve (acoustic), joins the vestibular nerve to become the vestibulocochlear nerve(cranial nerve VІІІ)  Process of hearing: Sound waves enter your outer ear and travel through your ear canal to the middle ear. The ear canal channels the waves to your eardrum, a thin, sensitive membrane stretched tightly over the entrance to your middle ear. The waves cause your eardrum to vibrate. It passes these vibrations on to the Malleus, one of three tiny bones in your ear. The malleus vibrating causes the incus, the small bone touching the malleus, to vibrate. The incus passes these vibrations to the stapes, another small bone which touches the incus. From the stapes, the vibrations pass into the inner ear. The stapes touches a liquid filled sack and the vibrations travel into the cochlea, which is shaped like a shell. The movement of these particles over small hair cells in the inner ear sends signals to the brain. The brain processes the information from the ear and lets us distinguish between different types of sounds.