-
the auditory system
location
are
- sits behind the eye
- holes in the temporal bone
-
outer ear contains
- the pinna (auricle)
- external auditory meatus (EAM or ear canal)
-
ismiss
- junction between bone and cartilage in the EAM
- there is hair where the cartilage is but not where the bone is
-
-
there is a ___ in the ear canal to ______
- bend
- protect the ear drum
-
tympanic membrane
ear drum
-
draw the typanic membrane
slide 9
-
draw the quadrants of the tympanic membrane
slide 10
-
draw the middle ear
slide 12
-
the middle ear has
2 fibrous layers
-
what holds the ossicles in place
10 ligaments and 2 muscles (tensor tympani and stapedius)
-
eustachien tube
location
function
- at the anterior wall of the middle ear
- pressure device (not drainage)
-
ossicles
malleus, incus, stapes
-
ossicles
movement
shape (draw)
- 2,000/sec
- inner places are not circular but bean shaped which makes them lighter but with the same stability
-
the two middle ear muscles
- these hold ossicles in place
- tensor tympani - connected to malleus which is connected to a tympanic membrane (connected to CN V Trigeminal)
- stapedius - connected to stapes (acoustic reflex - atomatic contraction) connected to CN VII Facial
-
tensor tympani
draw
- encased in bone
- very powerful
- tendons slow it down
- we cannot hear it
- slide 15
-
the stapedius
draw
- encased in bone
- very powerful
- tendons slow it down
- cannot hear it
- slide 16
-
the bony labyrinth 3 parts
- the semicircular canals
- the vestibule
- the cochlea
-
three scala of the cochlea
- scala vestibuli
- scala media (membranous labyrinth)
- scala tympani
-
three fluids of the cochlea
- perilymph
- endolymph
- cortilymph? unknown (perilymph)
-
-
three membranes of the cochlea
- Reissner's (Vestibular) membrane
- tectorial membrane
- basilar membrane
-
other important structures of inner ear
- stria vascularis
- limbus
- organ of corti
-
organ of corti
draw
slide 28 and 29
-
hair cells fit through
meticular lamina
-
afferent
from ear to brain
-
95% of afferent system goes to
hair cells
-
# fibers/hair cell
20 fibers / hair cell
-
efferent
from brain to ear
-
afferent v. efferent neurons
- 31,000 afferent
- efferent 1,000
-
central auditory system
draw
last slide
-
right ear hitched to
left brain and vice versa
-
reticular activating system
consciousness
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