Chapter 15 Special Senses Flashcards
Define the term olfaction
smell
Define gustation. Where is the center.
taste, insula
Name the three parts of the ear, list the specific components within each
external ear (3) middle ear (7) inner ear (2)
external = pinna, external acoustic meatus, tympanic membrane
middle = malleus, incus, stapes, eustachean tube, oval & round window, tensor tympani, stapedius muscle
inner = bony & membranous labyrinth
What is the function of the eustacian tube? (2)
- connects middle ear to the nasopharynx
- Equalizes pressure in the middle ear cavity with the external air pressure
Otitis media is an infection of the __. Usually seen in ___ because they put everything in their mouth.
eustachian tube
babies
The cavity of the choclea (of the bony labyrinth) is divided into 3 chambers. What are they? What do they contain?
- scala media = endolymph
- scala tympani = perilymph
- scala vestibuli = perylimph
What does the membranous labyrinth contain?
endolymph
Which structure contains receptor for rotary/angular equilibrium?
hair cells in the crista ampularis (receptor) in semicircular canals
involves the ampula (base of semicircular canal)
What structure detects change in linear acceleration?
hair cells of the macula (receptor) with an otolithic membrane of the saccule & utricle of the vestibule
-involves otoliths made of calcium carbonate
The side to side movement of the head is detected by the ___, and the back and forth of the head is detected by the ___.
side to side = utricle
back and forth = saccule
Name the fluid that fills the cochlear duct
perilymph
***Describe the structure, location and function of the Organ of Corti
- hair cells on top of the basement membrane inside the membranous labyrinth
- when hair cells bend, initiates AP that travels thru the vestibulocochlear nerve to thalamus to the hearing center (temporal lobe)
***Trace the pathway of sound from where sound waves reach the auricle to where to its interpretation site in the brain.
1.Sound waves vibrate the tympanic membrane which vibrates
2.Ossicles vibrate and amplify the pressure at the oval window
3.Pressure waves move through perilymph of the scala vestibuli into the
4. the cochlear duct, vibrating the basilar membrane
(Fibers near oval window Resonate with high-frequency pressure waves. Fibers near cochlear apex resonate with low-frequency pressure waves.
5. causing excitation of Hair Cells in the Spiral Organ. Bending stereocilia opens mechanically gated channels…Inward K+ and Ca2+ current causes a graded potential and the release of NT.
6. Impulses from the cochlea pass to the medulla through the eigth nerve
Impulses then go to the inferior colliculus (auditory reflex center)
7. From there, impulses pass to the auditory cortex via the thalamus
8. Auditory pathways cross over so that both cortices receive input from both ears
What does the endolymph contain?
K
Perilymph is similar to ___.
CSF
What cranial nerve carries impulses for hearing and equilibrium
vestibulocochlear nerve
What might cause conduction deafness sensorineural deafness?
conduction deafness =
What might cause conduction deafness (3) sensorineural deafness (3)?
conduction deafness
- physical blockage of ear with earwav
- tympanic membrane rupture
- middle ear infection (otitis media)
sensorineural deafness
- defect in organ of corti
- defect in auditory nerves
- defect in pathways of the brain
Otoliths are different from ossicle how?
otolith = stone ossicle = bone
Once the mechanoreceptors in the macula or crista ampullaris are stimulated, trace the nerve impulse to its site of interpretation. (5 steps)
- soundwaves are converted into electrical signal
- which generates AP
- goes through the vestibulocochlear nerve to
- thalamus
- primary auditory cortex in temporal lope
Which travels faster: sound waves or light?
light
Name the three tunics (coverings) of the eye, give a general function for each, and name the specific components of each tunic
Fibrous tunic
Sclera
cornea
Vascular tunic (uvea)
Choroid
Ciliary body
Iris
Sensory tunic
retina + optic nerve