Week 9: Sensory Systems mechanical

external stimulus behavior mechanosensory systems environmental link highly selective

external stimulus (filtered) energy transduction electric signal sensory neuron

electrical current inside the neuron membrane potential, V m = outside (0 mV) to inside (– mV) = electrical difference = resistance VmVm stimulus

electrochemical component across the membrane stimulus resting (-) up-spike (++) down-spike (- -) reset (-)

= Electrical Auditory = Gustatory smell sightelectric movement hearing taste visual chemical mechanical electrical

mechanosensory organs lateral line inner ear

cilia ~ gelatin, mucous mechanoreceptor cells with cilia =neuromasts =hair cells

= displaces cilia inhibits (-) excites (+) sensitive to: velocity pressure particle movement (displacement) all editions

inhibits (-) excites (+)

all editions

mechanoreceptory organs lateral line inner ear

density differences air: water vertebrate ear

= displaces cilia inhibits (-) excites (+) sensitive to: velocity pressure particle movement (displacement) all editions

mechanical displacement

cypriniform perciform

xzyxzy 3 otolithic organs 3 semicircular canals

x, y, z Antimora sp. flat nose cod Moridae, Gadiformes lamprey ~ 2 hagfish ~ 1 3 otolithic organs

lagena sacculus utriculus x-axis canal z-axis canal y-axis canal DORSAL (pars superior) balance ~ equilibrium ~ gravity 3 semicircular canals

3 semicircular canals (labyrinths) ~ 3 planes: x, y, z x: pitch up/down y: yaw side/side z: roll head/tail z-axis canal longitudinal x-axis horizontal y-axis vertical head deviations from...

yxzyxz 3 otolithic organs 3 semicircular canals

Antimora sp. flat nose cod Moridae, Gadiformes 3 otolithic organs

blue gourami 3 otolithic organs utriculus lagena sacculus

otolith otolithic organs mineralized deposit denser ~2 nd data point sacculus contains sagitta

Cb = cilia bundle OM = otolithic membrane

lagena sacculus utriculus DORSAL (pars superior) balance ~ equilibrium ~ gravity

Ventral (pars inferior) sound utriculus lagena sacculus otolith (largest)

WaterAir 800 x density least (0°C) expands most (4°C) contracts solid, liquid, gas Absorbs more energy (light, radiation, heat) Holds more energy (light, radiation, heat) Dissolves more molecules (nutrients, toxins) Conducts more energy (sound, electricity) farther ~5 x faster (according to T, P, salinity) Aquatic Habitats

Sound fields: near far crenulated, nondivergent smooth, spherical… particle displacement pressure wave intensity (decibels, dB) vs. range (length) vibration compression volume/pressure

yxzyxz ventral otolithic organs detect near-field particle displacement

yxzyxz gas bladder detects far-field pressure wave

Sound fields: near far crenulated, nondivergent smooth, spherical… particle displacement pressure wave intensity (decibels, dB) vs. range (length) Detector: inner ear gas bladder

pikeperch carpherring gas bladders = acoustically transform far field pressure wave to near-field particle displacement

African knifefish (Osteoglossomorpha) gas bladder throughout body

Weberian ossicles gas bladder inner ear

xzyxzy acoustically transform far field pressure wave

vibrates in response to far-field pressure waves

no gas bladder no mineralization sand grains for near field dorsal tympanic membrane for far field ~near field: low frequency 10 to 600 Hz Chondrichthyes

Sound fields: near far particle displacement pressure wave Detector: inner ear gas bladder low frequency: long wavelength large near field~~~~~~~~~~~~~~~~~~)))))) high frequency: short wavelength large far field ~~~~~~))))))))))))))))))))))))) Sound type:

goldfish (O) salmon (Pr) cod (Pa) damselfish (Ac) = Stegastes tuna (Ac) herring (100,000+) ~bottlenose dolphin low: larger near field high: larger far field favors inner ear favors gas bladder

pikeperch carpherring

herring

American shad gas-filled bulla

Week 9: Activities