Lecture 1 5/4/2015 1Anatomy and physiology of the ear

 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 2Anatomy and physiology of the ear

 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 Anatomy and physiology of the ear3

 The auditory system is divided into - Peripheral component Anatomy and physiology of the ear4

 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 Anatomy and physiology of the ear5

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) Anatomy and physiology of the ear6

7 Deals with processing of auditory information as it is carried up to the brain

 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 nerve Until they are received by the brain Anatomy and physiology of the ear8

 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 Anatomy and physiology of the ear9

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. Anatomy and physiology of the ear10

Anatomy and physiology of the ear11

 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 Anatomy and physiology of the ear12

 Is divided into five anatomical divisions 1. The squamous 2. Mastoid 3. Petrous 4. Tympanic portion 5. Styloid process Anatomy and physiology of the ear13