Ch. 47 Animal Sensory System Flashcards
ability to sense a change in the environment depends on:
1) transduction
2) amplification
3) transmission
transduction
the conversion of info from one mode to another
- requires a sensory receptor cell to convert stimulus into electrical signal
(ie) a stimulus outside a cell is converted into a response by the cell
amplification
increase effect
transmission
the passage or transfer of (1) disease from one individual to another or (2) electrical impulses from one neuron to another
- signal to the CNS
types of sensory receptors
1) nociceptor
2) thermoreceptor
3) mechanoreceptor
4) chemoreceptor
5) photoreceptor
6) electroreceptor
7) magnetoreceptor
nociceptor
a sensory cell or organ specialized to detect tissue damage
- sense harmful stimuli
(ie) senses pain & tissue injury
thermoreceptor
a sensory cell or organ specialized for detection of changes in temperature
mechanoreceptor
a sensory cell or organ specialized for detecting distortions caused by touch or pressure
(ie) hair cells in the cochlea
(ie) statocyst of a crab
chemoreceptor
a sensory cell or organ specialized for detection of specific molecules or classes of molecules
photoreceptor
a molecule, a cell, or an organ that is specialized to detect light
- responds to particular wavelengths of light
- forms a layer at the back of the retina
electroreceptor
a sensory cell or organ specialized to detect electric fields
magnetoreceptor
a sensory cell or organ specialized for detecting magnetic fields
If ion flows cause the interior to become more positive (less negative), the membrane is __________ (depolarized/hyperpolarized).
depolarized
If ion flows cause the interior to become more negative, the membrane is __________ (depolarized/hyperpolarized).
hyperpolarized
statocyst
a sensory organ detects the animal orientation in space
- sac filled w/ fluid
- lined w/ pressure receptor cells
- contains Ca+ rich substance that rests on the bottom
- flipped over: Ca+ substance bumps up against the receptor cells, which send an action potential to the brain
- signals crab to turn upright
- found in arthropods (crabs)
(ie) whether the animal is flipped upside down
pressure-sensing systems can be used for:
1) hearing
2) physical pressure on the skin
3) the movement of muscles
4) the stretching of blood vessels
hair cell
a pressure-detecting sensory cell
- has tiny “hairs” (stereocilia) jutting from its surface
- some have kinocilium
- mechanoreceptor
- pressure receptor cells
- found in: inner ear, lateral line system & ampullae of Lorenzini
stereocillicium
one of many stiff outgrowths from the surface of a hair cell that are involved in detection of sound by terrestrial vertebrates or of waterborne vibrations by fishes
kinocillium
a single cilium that juts from the surface of many hair cells
- tallest kinocillium extends into the fluid chambers
- FCN: detection of sound or pressure
ways depolarization of hair cell causes a movement of calcium ions
1) causes an increase in release of nts @ synaps btwn the hair cell & the sensory
2) the postsynaptic cells become excited & fire an action potential to the brain, affecting afferent neurons
3) the afferent neurons are part of the PNS, which conveys information to the CNS
If hyperpolarization occurs, the action potential is _____.
inhibited
how nts are released
1) pressure wave bends stereocillia
2) potassium channels open
3) membrane depolarizes
4) calcium flows in
5) synaptic vesicles fuse
6) neurotransmitter is released
hearing
the sensation of the wavelike changes in air or water pressure called sound
- mechanoreceptor
sound
wavelike changes in air or water pressue
- different frequencies = different pitches
frequency
the number of wave crests per second traveling past a stationary point
- determines pitch of sound & color of light
pitch
the sensation produced by a particular frequency of sound
- low frequency = low pitches
- high frequency = high pitc
parts of the human ear
1) outer ear
2) middle ear
3) inner ear
* separated by from others by a membrane
outer ear
external potion of the ear
- collects pressure waves
- funnels pressure waves into the ear canal
(ie) ear lobe
tympanic membrane
the membrane separating the middle ear from the outer ear in terrestrial vertebrates, or similar structures in insects
- 15x larger than oval window (amplifies sound by 15x)
(aka) eardrum
middle ear
the air-filled middle portion of the mammalian ear
- contains three small bones/ossicles
- transmits & amplifies sound from the tympanic membrane to the inner ear
- connected to the throat via the eustachian tube
ear ossicle
*from outermost to innermost ossicle
1) mallus
2) incus
3) stapes
stapes
the last of three small bones (ossicles) in the middle ear of vertebrates
- receives vibrations from the tympanic membrane
- vibrates against the oval window
- passes vibrations to the cochlea
oval window
a membrane separating the fluid-filled cochlea from the air-filled middle ear
- sound vibrations pass through it from the middle ear to the inner ear in mammals
cochlea
the organ of hearing in the inner ear of mammals, birds & crocodilians
- a coiled, fluid-filled tube
- contains specialized pressure-sensing neurons (hair bcells) that detect sounds of different pitches
basilar membrane
the membrane on which the bottom portion of hair cells sits in the vertebrate cochlea
- varies in stiffness
- sounds of different frequencies cause membrane to vibrate maximally in specific spots along its length
- goes from narrow to wide
tectorial membrane
a membrane located in the vertebrate cochlea
- takes part in the transduction of sound by bending the stereocilia of hair cells in response to sonic vibrations
narrow part of basilar membrane detects ______ frequencies
higher
wide part of basilar membrane detects _______ frequencies
lower
infrasound
sound frequencies too low for humans to hear
- elephants use this to communicate over long distances
ultrasonic sound
sound frequencies too high for humans to hear
- bats use this to echolocate
echolocation
the use of echoes from vocalizations to obtain info about locations of objects in the environment
lateral line system
a pressure-sensitive sensory organ found in many aquatic vertebrates
(ie) aquatic animals get info about pressure changes @ specific points along the head & body
compound eye
an eye formed of many independent light-sensing (ommatidia)
- composed of hundreds of thousands of light-sensing columns (ommatidia)
- occurs in arthropods. insects & crustaceans
ommatidia
a light-sensing column in arthropod’s compound eye
- each ommatidia has a lens that focuses light onto a smaller number of receptor cells that in turn send axons to the brain
- each ommatidia contributes info about one small piece of the visual field
camera eye
a structure that focuses incoming light onto a layer of receptor cells
(aka) simple eye
parts of the eye
1) schlera
2) cornea
3) iris
4) pupil
5) lens
6) retina
sclera
the outermost layer of the eye
- tough, white tissue
cornea
the transparent sheet of connective tissue at the very front of the eye in vertebrates & some other animals
- protects the eye & helps focus light
iris
a ring of pigmented muscle just behind cornea in the vertebrate eye
- contracts or expands to control the amount of light entering the eye through the pupil
- colored part of the eye
pupil
the hole in the center of the iris through which light enters a vertebrate or cephalopod eye
lens
a transparent structure that focuses incoming light onto a retina or other light-sensing apparatus of an eye
retina
a thin layer of light-sensitive cells (rods and cones) and neurons @ the back of a simple eye
- incoming light gets focused here
cell layers in the retina
1) photoreceptors
2) bipolar cells
3) ganglion cells
bipolar cell
an intermediate layer of connecting neurons in the retina
- the postsynaptic cell
ganglion cell
(in the retina) a type of neuron whose axons form the optic nerve
optic nerve
a bundle of neurons that runs from the eye to the brain
blind spot
the photoreceptor-free area where the optic nerve leaves the retina
cephalopod mollusk camera eya
no blind spot
- photoreceptor cells form a continuous layer on the inside of the retina
rod
a photoreceptor cell w/ a rod-shaped outer portion
- sensitive to dim light
- not used to distinguish colors
cone
a photoreceptor cell w/ a cone-shaped outer portion
- sensitive to bright light of a certain color
fovea
(vertebrate eye) a portion of the retina where incoming light is focused
- contains a high proportion of cone cells
- no rods
opsin
a transmembrane protein that is covalently linked to retinal, the light-detecting pigment in rod & cone cells
retinal
a light-absorbing pigment that is linked to the protein opsin in rods & cones of the vertebrate eye
- two-molecule complex
how light shuts down nt release
1) light causes retinal to change shape, rhodopsin activated
2) rhodopsin activates transducin, which activates phosphodiesterase (PDE)
3) PDE breaks down cyclic guanosine monophosphate (cGMP) to guanosine monophosphate (GMP)
4) as cGMP levels decline, cGMP-gated sodium channels in the plasma membrane of the rod cell close
5) when sodium channels close, Na+ entry decreases & membrane hyperpolarizes, decreasing nts released
6) nt decrease indicates the postsynaptic cell (bipolar cell) that rod absorbed light
7) action potentials sent to brain via ganglion cells
transducin
a protein that activates phosphodiesterase (PDE) when light hits rhodopsin
phosphodiesterase (PDE)
an enzyme that breaks a phosphodiester bond
cyclic guanosine monophosphate (cGMP) -> guanosine monophosphate (GMP)
gustation
the perception of taste via chemoreceptors
olfaction
the perception of odors via chemoreceptors
taste bud
a taste-sensing chemoreceptor
- found chiefly in the mammalian tongue
- contains spindle-shaped cells that respond to chemical stimuli
1 taste bud = 100 taste cells
taste cell
taste receptors that synapse to sensory neurons
basic tastes
salty sour bitter sweet umami
What causes the sensation of salty?
result of sodium ions dissolved in food
- sodium ions flow into taste cells through open sodium ion channels & depolarize the cell membrane
