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Sences [ heaing & taste]
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Sences [ heaing & taste]






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Sences [ heaing & taste] Sences [ heaing & taste] Presentation Transcript

  • Senses (Hearing & Taste) Zulcaif Ahmad 03444737311
  • Hearing sense and Equlilbrium Two important functions of the ear It enables us to hear It functions as the sensory organ of balance or equilibriumLocation of one ear on each side of head produces binaural hearing Hearing from both sides
  • The External EarExternal Ear  Visible portion of the ear not contained within the head  Auricle or pinna Cartilaginous flap that has a fleshy, lower portion called the ear lobe  External auditory canal Tube leading from the auricle to the middle ear Lined with tiny hairs called cilia which aid in transmitting sound waves inward  Tympanic membrane (eardrum) Separates external ear from middle ear
  • Structure:
  • The Middle EarThe tympanic cavity  A small, air-filled space  Located within the petrous portion of the temporal boneMedial wall is penetrated by  Oval window  Round windowPharyngotympanic tube (auditory or eustachian tube)  Links the middle ear and pharynx
  • Structures of the Middle Ear
  • Structure:Middle Ear Contains three tiny bones known as the auditory ossicles Malleus Resembles the shape of a hammer Connected to tympanic membrane and transmits sound vibrations to second auditory ossicle Incus Resembles the shape of an anvil Transmits sound vibrations from malleus to third auditory ossicle
  • Structure:Middle Ear (continued) Stapes Shaped like a tiny stirrup Transmits sound vibrations from incus to the inner ear Eustachian tube Connects the middle ear to the pharynx Also called the auditory tube Oval window Separates the middle ear from the inner ear Base of the stapes fits into the oval window
  • Structure:
  • The Inner (Internal) EarInner ear – also called the labyrinthLies within the petrous portion of the temporal boneBony labyrinth – a cavity consisting of three parts Semicircular canals Vestibule  Cochlea
  • Structure: Vestibule Central portion of the inner ear Located next to stapes and between cochlea and semicircular canals Contains the utricle and saccule-membranous pouches or sacs that aid in maintaining balance Cochlea Snail-shaped bony structure Contains endolymph and perilymph Auditory fluids that aid in transmission of sound vibrations
  • The Cochlea
  • The Cochlea
  • Inner Ear (continued)  Organ of Corti  True organ of hearing  Contained within the cochlea  Here, sound vibrations are converted into nerve impulses that are transmitted to the brain Components of Organ Of Corti i. Hair cells ii. Tectoral membrane iii. Nerve fibers
  • Inner Ear (continued) Semicircular canals: Located behind the vestibule Three bony, fluid-filled loops that help to maintain one’s balance. Lie posterior and lateral to the vestibule Anterior and posterior semicircular canals  Lie in the vertical plane at right angles Lateral semicircular canal  Lies in the horizontal planeMembranous labyrinth  Series of membrane-walled sacs and ducts  Fit within the bony labyrinth  Consists of three main parts Semicircular ducts Utricle and saccule Cochlear duct
  • Inner Ear (continued)Membranous labyrinth (continued) Filled with a clear fluid – endolymph Confined to the membranous labyrinth Bony labyrinth is filled with perilymph Continuous with cerebrospinal fluid
  • Auditory Pathway
  • Structure:
  • Sense of Taste
  • Sense of TasteTaste receptors are chemo receptors that are stimulated by molecules in the solution in the mucous in the nose and saliva in the mouthThe sense that distinguish the sweety, sour, salty and bitter qualities of dissolved substances in contact with the taste bud on tongue
  • Sense Of Taste(cont.0Taste sensation Unami 4 primary 5th basic taste Sweet – tip Deliciousness Sour – sides Salty – tip and sides Bitter – back
  • Classification:Salty (Cl of Na + and K+ Ca++ and Mg++ and many other halides like sulphate, nitrate etc)Sour (H+, strong inorganic acids like HCl, Sulphuric acid etc)Sweet (organic compound like sugar some polysaccharides, glycerol, aldehydes, ketones etc)Bitter (Alkolloids, Brucine, Nicotin)
  • Structure (Taste buds):
  • Taste Buds: Collection of 50 –100 epithelial cells Contain three major cell types (similar in all special senses)  Supporting cells  Gustatory cells  Basal cells Contain long micro villi – extend through a taste pore LINGUAL PAPILLAE  Types of papillae (with taste buds)  Fungi form papillae (Large round and mostly occur at the tip and edges, contain 2-5 taste buds)  Circumvallate papillae (Large size dome shaped, on the back of tongue, contain 100-250 taste buds)  Faliate papillae (present on lateral border of the tongue)  Filiform papillae do NOT contain taste buds • Filiform papillae help you appreciate texture of food
  • Structure (Taste buds):
  • Gustatory Pathway from Taste Buds