Chapter 21: Hearing Flashcards
Explain the behavior of sound in water
carries in water at 1500 m/s
Speed of sound increases with increasing T, S, & P
TEMPERATURE: warm H2O increases speed of sound while cold H20 decreases speed
SALINITY: The saltier the water due to having the particles closer together allow sound to travel further
PRESSURE: The deeper you get the more pressure and the sound waves travel further
Describe the anatomy of the fish ear
Compare fish ear anatomy of
Agnathans:
Chondrichthyes:
Bony fishes:
AGNATHANS/Jawless:
Inner ear symmetrical & 1 sensory macula
Hagfish- 1 semicircular canal
Lamprey- 2 semicircular canals
CHONDRICHTHYES/Cartilaginous:
Inner ear is embedded in cartilaginous otic capsule of neurocranium.
3 semicircular canals
BONY FISH/Teleost:
osseous labyrinth a cavity including ducts w/in bones of
otic capsule
3 semicircular canals no coclea
Pars superior-mainly equilibrium- 3 canals A, P, H
Pars inferior- hearing- sacculus lagena
What is an otolith?
Hard calcaneus deposits in the inner ear,essential for both hearing and maintenance of balance in fishes.
Differ in size and shape amouns species used to ID fish
The otoliths bend or displace the cilia on the hair cells that are located in the inner ear (Macula and hair cells)
Otoliths of the: utricules, sacculus, lagena
are the : lapillus, sagitta, asteriscus
Explain sound reception of the inner ear in fishes
Fish have bones in the inner ear, called otoliths, which are much denser than H20 and the fish body.
As a result these ear bones move more slowly in response to sound waves than does the rest of the fish.
The difference between the motion of the fish body and the otoliths bend or displace the cilia on the hair cells that are located in the inner ear
Differences between hearing generalists and specialists?
GENERALISTS: (don’t hear as well)
Narrow range frequencies, Higher hearing thresholds, no adaptations that aid in hearing.
SPECIALISTS: (zebrafish weberian ossicles)
Broad range frequencies, Lower hearing thresholds, Possess otophysic connections which allow functional connection between gas bladder and ear
Weberian Apparatus in Otophysi
Ostariophysi –> Goldfish
Minnow (20-700Hz)
Brown bullhead (6-10,000Hz)
Weberian ossicles allow a broader range of Hz
Swimbladder morphology in some cichlids
Deep sea cods
Larger branches of gas badder in contact with skull
Acoustico Lateralis system in menhaden
Ultrasound detection in the Gulf menhaden requires a gas-filled bullae and an intact lateral line allowing for a hearing specialist adaptation
How to perform hearing test in fish?
AEP waveforms
Scary pic
