Anatomy and physiology of ENT

A basic information to gain knowledge about ENT

1. ANATOMY AND PHYSIOLOGY OF ENT Amrutha Nayaka P , 3 rd year Bsc(N), Kidwai College Of Nursing, Bengaluru.

2. EAR ANATOMY OF EAR The ear is the organ of hearing and balance. The parts of the ear include: 1. External Ear 2. Middle Ear 3. Internal Ear   1. EXTERNAL EAR *Pinna *External auditory meatus *Tympanic membrane   2. MIDDLE EAR *Auditory ossicles   3. INTERNAL EAR *cochlea *Vestibule * Semicircular canals

3. External or outer ear, *Pinna This is the outside part of the ear. * External auditory canal or tube. This is the tube that connects the outer ear to the inside or middle ear. * Tympanic membrane (eardrum). The tympanic membrane divides the external ear from the middle ear . Middle ear (tympanic cavity), Ossicles . Three small bones that are connected and transmit the sound waves to the inner ear. The bones are called: * Malleus * Incus * Stapes Eustachian tube: A canal that links the middle ear with the back of the nose. The eustachian tube helps to equalize the pressure in the middle ear. Equalized pressure is needed for the proper transfer of sound waves. The eustachian tube is lined with mucous, just like the inside of the nose and throat.  

4. Inner ear, Cochlea: This contains the nerves for hearing. Vestibule: This contains receptors for balance. Semicircular canals: This contains receptors for balance PHYSIOLOGY OF EAR   1.Tympanic membrane : It consists of connective tissue and is kept in the position by the handle of the malleus. It forms the lateral wall of middle ear.   Functions: *It acts as a pressure receiver i.e it is extremely sensitive to pressure changes prodced by sound waves on its external surface. *It acts as a resonator i.e it starts vibrating (in and out movements) freely when the sound waves strike. *It critically dampens(stops the vibrations of) the sound waves i.e. strectching the tympanic membrane, its vibrations are stopped almost immediately .

5. 2.Ear ossicles or auditory ossicles : There are three minute bones(ear) ossicles , *Malleus(hammer) *incus(anvil) *stapes(stirrup ). 3.Pharyngo tympanic tube/Eustachian tube : It is 4-5 cm in length and connects the middle ear cavity with the pharynx. It serves to equalize the pressure on the two sides of the tympanic membrane when atmospheric pressure(high altitude) or increases(deep sea diving).   4.Two skeletal muscles : 'Tensor tympani' and ' stapedius ' a) Tensor tympani: It is sttached to the neck of malleus b) Stapedius : It is attached to neck of the stapes.   Function: Both the muscles, the tensor tympani and stapedius can be reflexly activated by loud sounds and this reflexly decreases the amplitude of sound vibration of the tympanic membrane. thus they serve a protective function by protection of the internal ear by loud sounds.(tympanic reflex or acoustic reflex).

6. DISORDERS OF EAR Acute Otitis media : Inflammation in the middle ear lasting less than 6 weeks . 2. Cholesteatoma : Tumor of the middle ear or mastoid, or both , that can destroy structures of the temporal bone . 3. Chronic Otitis media : Repeated episodes of acute otitis media causing irreversible tissue damage and persistent tympanic membrane perforation . 4. Conductive Hearing loss : loss of hearing in which efficient sound transmission to the inner ear is interrupted by some obstruction or disease process . 5. Tympanoplasty : Surgical repair of the tympanic membrane.  

7. ANATOMY OF NOSE Nose is a pyramidal shaped structure lying between the two eyes on the face . It is partly bony and partly cartilaginous. It has an apex the root of nose present between the two eyes and a base which has two anterior nasal apertures . Each nasal aperture leads to nasal cavity. The two nasal cavities are separated from each other by medial wall know as nasal septum. Each nasal cavity is bounded laterally by lateral wall which has bony shelf like projections, the nasal conchae the part of nasal cavity inferior to the nasal turbinates is the meatus of nose. Each nasal cavity has three turbinates superior, middle and inferior tubinates and three meatuses superior, middle and inferior meatuses. Part of the nasal cavity opposite mucosa (responsible for smell) lines this part of nasal cavity and is of yellow colour.

8. PHYSIOLOGY OF NOSE   Breathing Air conditioning of inspired air Protection of lower airway Ventilation and drainage of p.n.s. Olfaction Nasal resistance Vocal resonance Nasal refluxes

9. DISORDERS OF NOSE 1.Common cold 2. Sinusitis 3. Epistaxis : bleeding from nose 4. Foreign body in nose 5. Infection of sinuses and other upper respiratory tract infections 6. Polyps in the nasal sinuses 7. Rhinitis : Inflammations of the mucous membrane of the nose. 8. Deviated nasal septum : when nasal septum is not in the midline  

10. ANATOMY OF TONGUE     Tongue is a muscular organ lying in the oral cavity proper. It is a mass of muscle lined superiorly and inferiorly by mucous membrane. It is divided into anterior 2/3 rd and posterior 1/3 rd by V shaped depression known as sulcus terminalis . The superior surface of anterior 2/3 rd of tongue is rough while inferior surface is smooth. Whereas the posterior end of the ueg is attached to hyoid bone, the anterior end of the tounge is free. Superior surface of the tongue is rough because of projection of mucosa known as the papillae . There are three types of papillae i.e. 1.Filiform 2. Fungiform 3. C ircuvallate papillae.  

11. a) Filiform papillae: They are conical, present all over anterior 2/3 rd of tongue. They are most numerous and do not possess taste buds(structures for tasting things ) b) Fungiform papillae: They are mushroom shaped papillae present over anterior 2/3 rd of tongue. They possess taste buds . c) Circumvallate papillae: They are visible by naked eyes. They are present just anterior to sulcus terminalis . They are circularand are surrounded by a circular depression the moth. Their walls possess taste buds . PHYSIOLOGY OF TONGUE   1.Taste 2.Helps in speech 3.Helps in swallowing food. 4.Helps in sensation of thirst.    

12. DISORDER OF THE THROAT 1. Tonsillitis 2. Laryngitis ( inflammation of the larynx) 3. Laryngeal Cancer 4. Tracheostomy

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