Sensory Receptors Receptors specific for given stimulus Strong
stimulation Greater frequency of action potentials Greater number
of neurons Sensory adaptaion Frequency of AP decrease or stop w/
constant simulus
Slide 7
Somatic Start at sensory neurons Different sensors to different
part of brain Somatosensory cortex
Slide 8
Somatic Body surface Free nerve endings Meissner corpuscles
Pacinian corpuscles Thermoreceptors Bulb of Krause Ruffini
endings
Slide 9
Somatic Muscles Mechanorecptors Motion Position in space
Stretch
Slide 10
Somatic Painperception of injury Nociceptors Somaticskin,
skeletal muscle, joints, tendons Visceralinternal organs Fewer
nocieptors Referred pain Cell damage releases bradykinins
Bradykinins stimulate nearby nociceptors Stimulus perceived by
brain as pain
Slide 11
Olfaction Smell Social communication Find mates Find prey Avoid
predators
Slide 12
Olfaction Well-developed in most mammals Especially carnivores
& ungulates Non-existent in cetaceans (whales, dolphins, etc.)
Canines 100,000-1 million times better than humans Bloodhounds
10-100 million times
Slide 13
Olfaction Poorly developed in most birds Well-developed in fish
SalmonID and return to home streams CatfishID others, maintain
social order
Slide 14
Olfaction Chemicals inhaled Must be dissolved in liquid (mucus)
Binds to membrane proteins Triggers depolarization of neurons
Different combinations of receptor activation recognized as
patterns by brain
Slide 15
Olfaction
Slide 16
Pheromones Air-borne chemical that triggers behavioral response
in same species Alarm Food trail Sex Territorial
Slide 17
Taste Differentiate nutrition vs. noxious Receptors on various
organs Antennae Tentacles Tongue Legs
Slide 18
Taste Five tastes in humans Sweet Sour Salty Bitter Umami
Slide 19
Chemoreceptors Antennae Most arthropods Multiple functions
Smell & taste most important Also touch, air motion, vibration,
heat Olfactory receptors bind to odor molecules Sends signal to
antennal lobe in brain
Slide 20
Chemoreceptors Vomeronasal organ Many animals (including
humans) Certain smells Many pheromones May be involved in
triggering some aggression & mating
Slide 21
Chemoreceptors Vomeronasal organ Flehmen response In cat In
deer
Slide 22
Hearing Detect vibrations Interpret as sound Amplitude
(loudness) Frequency (pitch) Important for communication Important
for finding prey Important for avoiding predators
Slide 23
Hearing Sonichuman frequencies 15 Hz-20,000 Hz Best at
2,000-4,000 Hz Ultrasonicabove human frequencies Bats, dogs
Subsonicbelow human frequencies Snakes (sense through bellies)
Whales, giraffes, elephants (communication)
Hearing Vibrations coming down ear vibrate ossicles Stapes
vibration pushes on oval membrane on cochlea Fluid in cochlea moves
at specific frequency Fluid wave moves tectorial membrane Movement
of tectorial membrane stimulates nerve impulse
Slide 27
Hearing,,,
Slide 28
Hearing Equilibrium Vestibular organs (semicircular canals)
Static equilibrium Linear movement of head Otolithic membrane
movement triggers hairs Dynamic equilibrium Rotation, acceleration,
deceleration Fluid bends hairs in crista ampullaris
Slide 29
Hearing Echolocation Dolphis, shrews, bats, most whales Active
sonar Sounds sent out Hear reflection of sounds (echo) Able to
triangulate sounds
Slide 30
Hearing Lateral line Detect vibrations in water Along sides of
many fish Similar to certain aspects of hearing &
equilibrium
Slide 31
Vision Photoreceptors Part of brain that can interpret pattern
of nerve impulses Pigment molecules absorb incoming photons Convert
photons into action potential
Slide 32
Vision Invertebrate Simple Photosensitive receptors Do not form
images Light & dark Ocellus
Slide 33
Vision Invertebrate Compound Arthropods Multiple facets Each
has own lens & photoreceptor cells Very sensitive to motion 360
o field of vision Multiple images integrated in brain Poor image
resolution
Slide 34
Vision Invertebrate Mollusks Many have lens eyes (similar to
vertebrates) Cephalopods have most developed Hunters, 3 dimensions,
often move fast
Vision Rods Low light Night vision No color Cones Bright light
Day vision Color
Slide 38
Vision Accommodationthe process by which an eye changes to keep
an object in focus as it moves closer or further away. Fish,
reptilesLens moves forwards & backwards in eye Birds,
mammalsciliary muscles change shape of lens.
Slide 39
Vision Photons enter through cornea Are focused by lens
Absorbed by cells in retina Photon activity stimulates receptors to
generate action potential
Slide 40
Vision Eye placement Forward-facing Predators Depth perception
Side-facing Prey Wide field of vision
Slide 41
Other Senses Electroception Detect electrical fields Sharks,
skates, rays Lungfish, coelacanths, sturgeons Monotremes
(especially platypus) Activegenerate own field Electric eels &
fish Communication Passivesense other fields Chondrichthyes
Slide 42
Other Senses Magnetoception Mostly birds Very important to
migration Some bees Detect magnetic fields Magnetite Found in many
rocks & minerals Source of iron ore Identified in brains of
birds, bees, and humans When magnetite aligns w/ Earths magnetic
field, stimulates nerve impulse Poorly understood sense
