Senses System: Taste and Hearing

1. Describe the structure of the tongue -Formed of muscle -attached by its base to hyoid bone -part of its floor is attached with the throat through a fold, the frenulum 2. What are papillae Projections which contain taste receptors: vallate, fungiand what do they form, filiform contain? 3. What are the functions of the tongue? -Chewing (mastication) -swallowing (deglutition) -speech -taste 4. What are the 4 types of papillae? -Circumvallate papillae: largest, 8-12, semicircular, near the base of the tongue -Fungiform papillae: like the heads of a mushroom, many lies at the tip and sides of the tongue -foliate papillae: leaf like, 3-4 pairs, lies on sides of the tongue -filliform: minute, found all over the surface of the tongue 5. Do filliform papil- No lae have taste buds? 6. What are the 3 -buds for bitter taste: base of the tongue types of taste -buds for sweet and salty taste: tip of the tongue buds and where -buds for sour taste: sides of the tongue are they found? 7. What is the func- -Collect sound waves and convert into other vibrations, tion of the ear? first by small bones (the middle ear), then by fluid (the inner ear) -finally convert the fluid vibration into nerve impulses 1/4 8. Describe and explain the structure of the external ear -The auricle (pinna): irregular shaped framework, elastic cartilage covered with skin, directs sound waves into the external auditory meatus -The lobule: extends from the lower margin of the auricle, skin-covered connective tissue - the external auditory meatus (canal): curved (s-shaped), approx 2.5 cm long, extend from the auricle to the eardrum, lined with skin and near its entrance are fine hair and sebaceous glands, also has ceruminous glands (modified sweat glands) which secrete ear wax (cerumen), traps insects and prevents small foreign particles from reaching eardrum 9. Describe the structure of the middle ear -small air-filled chamber in the temporal bone -separated from the external auditory meatus (external ear) by the tympanic membrane -separated from the internal air by a bony wall with 2 openings: fenestra vestibuli (the oval window), fenestra cochleae (the round window) -another opening connects middle ear chamber with auditory tube, leading to nasopharynx, helps equalise air pressure in middles ear with the atmospheric pressure 10. What are the 3 ear ossicles and describe the functions and structures? They are the middle ear bones: -malleus: hammer shaped -incus: anvil shaped -stapes:stirrup shaped -forms a bridge across the middle-ear chamber between the Tympanic membrane and the oval window -ossicles picks up vibrations of the tympanic membrane and transmits to the oval window 11. What does the in- -osseous labyrinth (bony labyrinth):hollowed out of the ternal ear consist bone; filled with perilymph, divided into vestibule, semicirof? cular canals, cochlea, has low concentration of potassium ions and high sodium ions -membranous labyrinth: located within the osseous labyrinth, filled with endolymph 12. 2/4 How is the osseous labyrinth divided? 13. What is the vestibule? Into 3 areas: Vestibule, semicircular canals and cochlea -Vestibule: a chamber medial to the middle ear chamber, contains the 2 enlargements of the membranous labyrinth the utricle and the saccule, contains receptors that detect position and movements of head, vibration of the oval window transmitted to the perilymph of the vestibule 14. What are -3 semicircular canals (anterior, posterior and lateral) the semicircular -detects movement of the head (equilibrium) canals? -contains membranous semicircular ducts -semicircular ducts contains enlarged ampulla which contains receptors 15. What is the cochlea? -Associated with hearing -snail shell like shape -divided into 3 longitudinal tunnels: scala vestiboli, cochlear duct and scala tympani -Has vesicular membrane -has basilar membrane:the organ of cortisol containing receptors of hearing 16. Define hearing process of perceiving sound 17. Describe the mechanism of hearing -sound waves enters the external auditory canal -strikes the tympanic membrane and gets converted to vibrations -vibratory movements of tympanic membrane are transmitted across the middle ear cavity by the ossicles to the oval window of the inner ear -causes movements in the perilymph, pushing the perilymph along the scale vestibule, through helicotrema and into the scale tympani -sensory cells of the organs of cord vibrate and when these touch the tectorial membrane an impulse is generated -this impulse is carried to the brain and translates to hearing 3/4