test #3 Flashcards
Paramecium
is a single cell protist (no nervous system).
what happens when when the cell (paramecium) hits an obstacle?
Ca2+ channels mechanically open
The depolarization of the cell then causes what to occur in the cillia?
a reversal in the beating of the cilia the cell retracts.
What happens in order to return cilliary beating to its original direction?
Ca2+ is then pumped out
Reflex
the involuntary movement of skeletal muscles.
Monosynaptic reflex:
requires only two types of neurons
muscle stretch reflex regulates what?
the amount of tension in the muscles of the antagonistic pair that maintains body posture
What does the 1a-afferent neuron do?
receives and relays the stretch signal to the spinal A-motor neuron.
What does the spinal a-motor neuron do?
induces response (quadriceps contraction)
The patellar tendon reflex:
if the muscle is stretched by a mild weight, the 1a-afferent neuron signals the a-motor neuron to induce muscle contraction.
If the loop(neuron, reflex circuit) is interrupted by cutting the afferent neuron what happens?
No response
Muscle spindle
a small group of stretch-sensitive intrafusal fibers (non-muscle fiber cells)
The Muscle spindle is innervated by
1a-afferent neurons
The muscle spindle does not contribute to what?
muscle tension
Extrafusal fibers
muscle fibers
Other components of the neuronal circuit inhibit the activity of the motor neuron to:
prevent the muscle from contracting when the other muscle in the antagonistic pair contracts establish limits to how excited the motor neuron can become
CNS interneurons can modify what?
spinal activity
Divergent axons from motor neurons send excitatory signals to the
interneurons that inhibit them
inhibitory interneurons (Renshaw cells) can also be activated by
second motor neurons
the circuit limits the excitation of
motor neurons
if neurotransmitters from Renshaw cells are blocked with strychnine (a toxin) what happens?
no control of motor neuron activity
What is Strychnine?
a toxic alkaloid from the seeds of Strychnos nux-vomica.
What do Phasic and tonic stretch receptor neurons innervate
the motor neurons of the abdominal muscles of the crayfish and respond to the stretching of the muscles.
stretch receptors react to muscle stretching by doing what?
sending excitatory signals to the motor neurons to make the muscle contract
phasic receptors adapt ____ to a constant stretch of the muscle fiber while tonic receptors produce a _____ response
quickly sustained
if these receptors are stimulated directly by injection of a depolarizing stimulus current (instead of stretching the muscles) what happens?
each cell produces a response similar to the response to stretching the muscles
What does The sustained stretching of an individual crayfish abdominal muscle fiber produce?
reflex inhibition of nearby tonic stretch receptors.
When the crayfish abdomen (but not the isolated fiber) is steadily stretched, the in situ tonic stretch receptor produces what type of electrical activity?
steady electrical activity
If the isolated muscle fiber is also stretched, the frequency of APs in the isolated tonic stretch receptor ____ but _____ in the in situ tonic stretch receptor.
increases, drops
What is an example of lateral inhibition.
the isolated muscle fiber is also stretched, the frequency of APs in the isolated tonic stretch receptor increases but drops in the in situ tonic stretch receptor.
What is lateral inhibition?
disables the spreading of AP’s from excitatory neurons to target tissues
in the absence of the stimulus, all the receptor cells produce___
identical baseline frequency of APs
when the center receptor is stimulated weakly, neighboring receptors are ___
slightly inhibited
when the center receptor is strongly stimulated, its immediate neighboring receptors are completely ______
inhibited
When g-aminobutyric acid (GABA) is applied, what happens?
a depolarizing presynaptic inhibitory potential is produced
what is GABA?
GABA is an inhibitory amino acid neurotransmitter, called g-aminobutyric acid
the CNS can modulate neuronal circuits to allow _____ ______.
voluntary responses
e information can be sent to ______ output neurons (divergence) to form complex responses
multiple
_____ and _____ signals are important to modulate responses
excitatory, inhibitory
Fixed action patterns are motor patterns exhibited by animals in response to ___ ___.
key stimuli.
What are the 6 Fixed Action properties?
- complex motor acts with a temporal sequence of components. 2. start due to key stimuli 3. once started they can’t stop until completed. 4. stimulus threshold varies for each. animal 5. performed almost identically by all members 6. genetically inherited, doesn’t have to have been previously exposed to key stimuli
Describe the Caribbean reef squid’s courtship behavior? (colors)
The squid shows a coppery color to the female to interest her and the other side flashes a blue-silver color to let males know they saw her first.
The aggressive behavior of a courting male stickleback fish against another male occurs in response to seeing what?
the red belly of a fish in horizontal position
Courting songs in males from the species, T. commodus of Teleogryllus crickets
shorter phrase with two pulses
Courting songs in males from the species, T. oceanicus of Teleogryllus crickets sound like?
longer phrase (with about 10 pulses)
F1 individuals from hybrid crosses sing what type of songs?
intermediate length songs (4-8 pulses) that are more similar to the songs of the males of the species of the female parent (songs are inherited maternally)
the length of the phrase is similar which side of the hybrid?
the species of the mother
Hybrid females are more likely to respond to
the song from males from the same hybrid cross (both share the same type of mother)
What is Phototaxis
movement in response to light.
What is Phonotaxis
movement in response to sound.
What is a positive motor output?
movement towards the source
What is negative motor output?
movement away from the source
How does that scorpion sense prey?
each of the eight legs have vibration receptors (mechanoreceptors) compares the timing of the vibration that reaches each leg.
____ _____detect the imparity in time and respond with the appropriate motor output
central neurons
Echolocation is used by what?
bats to find insects.
what is the “waggle dance”
when a bee finds a source of food, it returns to the bee hive and indicates to others the location of the food with a “waggle dance” of the abdomen
The dance is made based on what?
The degrees from the sun the source of food is.
Sensory networks are:
neurons that receive, sort, refine, and modify sensory inputs
Motor networks are:
neurons that generate coordinated movements as response (behavior)
the interface between the two networks occur where?
somewhere in the CNS
What is Sensory processing ?
is the abstracting of features from the mass of information about the environment that is constantly available to the animal.
modality
They category many individual sensory neuron respond to a wide range of stimuli
quality
the quality many individual sensory neuron respond optimally (selectively)
what do tuning curves show?
they plot the relationship between the activity of a sensory neuron and the different qualities of the stimulus that can excite it.
threshold energy
lowest at highest neuron sensitivity
Graphs are plotted as:
threshold energy against stimulus quality
feeding behavior for frogs only is active when:
small dark object is only moving against a light background.
The output of a single photoreceptor stimulated by steady light decreases
if neighboring photoreceptors receive the same stimulus.
a strongly stimulated photoreceptor strongly inhibits
nearby photoreceptors that are receiving weaker stimuli
What is the effect of Lateral inhibition in visual systems
enhanced contrast at the boundaries between objects
Lateral plexus
collateral branches from the axons of eccentric cells
eccentric cells are:
the neurons that receive the outputs from the ommatidia
Lateral plexus send inhibitory neurotransmitters to _______ _____.
neighboring axons
Where does the processing of the visual stimulus begin?
at the first neurons
Transmission of visual information in lower vertebrates is in what?
tectum
Transmission of visual information in birds and mammals on the right side of the field of vision:
received by the left hemiretina of both eyes then sent to the left lateral geniculate nucleus in the thalamus then sent to the left visual cortex.
Transmission of visual information in birds and mammals on the left side of the field of vision:
received by the right hemiretina of both eyes then sent to the right lateral geniculate nucleus in the thalamus then sent to the right visual cortex.
First order cells in the vertebrate retina:
photoreceptors
second order cells in the vertebrate retina:
bipolar cells
Third order cells in the vertebrate retina:
retinal ganglia cells (neurons: their axons make up the optic nerve)
Horizontal cells
receive input from several photoreceptors and synapse with bipolar cells
amacrine cells:
interconnect bipolar and ganglion cells increase retinal connection patterns to increase visual info.
_______ order cells are sufficient for the transmission of visual information to the brain.
1st-3rd
Describe the effects of light on the photoreceptors and bipolar cells:
hyperpolarizes the photoreceptors. which then depolarize on-bipolar cells hyperpolarize off-bipolar cells.
on-center ganglion cells fire what?
APs
the underlying ganglion cells have ______ responses as the bipolar cells above them
identical
Describe the effects of darkness on the photoreceptors and bipolar cells:
Darkness on photoreceptors causes hyperpolarization of on-bipolar cells and depolarization of off-bipolar cells
on-bipolar cells become hyperpolarized in the dark because of:
inhibitory neurotransmitters released by horizontal cells
horizontal cells have an effect on the bipolar cells only in ___
the dark
Horizontal cells have an effect on bipolar cells by:
hyperpolarizing on bipolar cells (+) depolarizing off bipolar cells (-)
on-center retinal ganglion cells are depolarized if:
their photoreceptors are stimulated (light spot) but become hyperpolarized if neighboring photoreceptors are stimulated (due to the inhibiting effect of amacrine cells)