lecture 1 5/4/2015 1anatomy and physiology of the ear
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Anatomy and physiology of the ear
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Anatomy and physiology of the ear
Lecture 15/4/2015
Anatomy and physiology of the ear
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Anatomy is the study of the structure of living organisms. The study of the form and gross structure of the various parts of the human body
Physiology the science of the functioning of the living organisms and their component parts
Anterior describing or relating to the front portion of the body, describing the front part of any organ
Superior situated in the upper most in the body in relation to another structure or surface
Inferior lower in the body in relation to another structure or surface
Terminology
Anatomy and physiology of the ear
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Lateral situated at, or relating to the side of an organ
Dorsal related or situated at or close to the back of the body or to the posterior part of the organ
Posterior situated at or near the back of the body Afferent designated nerves or neurons that
convey impulses from the sense organs and another receptors to the brain or spinal cord
Efferent designated nerves or neurons that convey impulses from the brain or spinal cord to the muscles, glands or other effectors
Terminology
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The auditory system is divided into- Peripheral component
Overview of the anatomy and physiology of the auditory system
Anatomy and physiology of the ear
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Located in the most part of the temporal bone, its made of
1. The outer ear- Pinna- External auditory meatus (ear canal)- Tympanic membrane (ear drum)2. The middle ear- The tympanic cavity (ossicles and their
associated muscles, tendons and ligaments- Eustachian tube
Peripheral auditory system
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3. Inner ear- begins at the oval window, sensory organ of hearing and balance
- Cochlea is the hearing part of the inner ear- Semisircular canals, utricle and saccule are
the balance part of the inner ear
4. The auditory nerve (acoustic, VIII cranial nerve)
Peripheral auditory system
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Central componentDeals with processing of auditory information as it is carried up to the brain
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Sound impulses pass through the auditory tract where it goes through a number of energy transformation from
Acoustical: in the air into the external ear Mechanical: tympanic membrane and the
ossicles hydraulic : cochlear fluid ( perilymph and
endolymph) Chemical: inner and outer hair cells electrical: auditory nerveUntil they are received by the brain
Sound transmission
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Air conduction (AC) the course of sounds that are conducted from the outer, middle and finally to the inner ear
Bone conduction (BC) the course of sounds that are conducted to the inner ear by way of bones of the skull
The human hearing pathways
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1. Conductive hearing loss (CHL) impaired AC and normal BC. Abnormalities of the outer and/or middle ear causes hearing loss
2. Sensorineural hearing loss (SNHL) impaired AC and impaired BC (sound is perceived of the same loudness) damage of the coclea or the neural structures
3. Mixed hearing loss (MHL) impaired AC and impaired BC with air-bone-gap.
Types of hearing loss
Anatomy and physiology of the ear
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The temporal bone
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The right and the left temporal bones are two of the 22 bones of the skull
The temporal bone forms he inferior portion of the side of the skull
Temporal bone
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Is divided into five anatomical divisions1. The squamous2. Mastoid3. Petrous4. Tympanic portion5. Styloid process
Temporal bone