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)
off-center retinal ganglion cells are hyperpolarized if:
their photoreceptors are stimulated (light spot)
In both cell types,(on center and off center) complete illumination (circle) results in:
an intermediate response (both excitatory and inhibitory signals are present)
the type of a ganglion cell (on or off) is determined by
the type of bipolar cell that directly modulates it
Hierarchic organization of motor control systems:
- motor neuron (reflex) is the lowest level 2. central pattern generator (repetitive motor outputs) 3. highest centers: conscious choices
All 3 motor control systems relay their outputs through:
motor neurons
feedback to the highest centers can come from:
the CPG or from muscles, activity, and environment via sensory networks
Effect of sensory feedback on grasshopper flight
Flight is initiated if air stimulates facial receptor hairs
Wingbeats of the grasshopper stops with stimulation of the:
foot mechanoreceptors
in the experiment if the afferent stretch receptor neurons are cut what is seen?
wingbeat frequencies drop to 50% and flight time is shorter. (even if stimulus is continued)
In a semi-intact insect missing the stretch receptor, feedback to CPG can be:
restored with electrical stimulation of the remaining axon root.
blue line:
period of electrical stimulation
red line:
resulting wingbeat frequency
When electrical stimulation of the remaining axon root is suspended,what happens?
feedback to the CPG is interrupted and wingbeat frequency decreases.
describe the Organization of the flight motor output in the grasshopper (a circe flow chart)
chart:
what is “a” ?
field of vision
what is “b”
Temporal hemiretina
what is “c”?
optic nerve
what is “d” ?
lateral geniculate nucleus
what is “e” ?
Primary visual cortex
What is “f” ?
optic tract
what is “g” ?
optic chiasm
what is “h”?
nasal hemiretina
What type of organ does the heart, of the systemic circulatory system act as?
propulsive organ
What does the arteries, of the systemic circulatory system act as?
act as a pressure reservoir and transport blood away from the heart
What does the capillaries, of the systemic circulatory system act as?
transfers substances from blood to tissues.
What does the veins, of the systemic circulatory system act as?
return blood to the heart and serve as a blood reservoir
Blood is oxygenated in the organs of gas exchange (lungs or gills), returned by the _____ to the heart, and pumped to the systemic ____.
veins, arteries
Open circulation occurs in whom?
most invertebrates
open circulation means that the blood does what?
is emptied from the arteries into an open space and bathes tissues directly, no capillaries.
Blood pressure is generated by what in mollusks?
contraction of the foot muscles
Closed circulation occurs in whom?
vertebrates and some invertebrates
Closed circulation consists of what?
arteries, capillaries and veins
Closed circulation in water-breathing teleost fishes occurs by?
blood is ejected from the ventricle into the bulbus and then into a short ventral aorta
respiratory (gill ) circulation
blood flows through the gill capillaries and becomes oxygenated by absorbing O2 from the water
blood is then delivered to a long dorsal aorta which carries it to the somatic tissues
systemic circulation
blood flows through all the tissues and becomes deoxygenated as cells absorb blood O2
Systemic circulation in mammals
oxygenated blood leaves the left side ofthe heart (through aorta)
systemic arteries force blood into capillaries which provide blood to tissues
blood O2 is replaced with CO2
blood flows into right side of heart via systemic veins (low pressure)
the pressure in the arteries generated by
heart
blood O2 is unloaded into tissues and replaced with ____.
CO2
deoxygenated blood flows back to ____
the right side of the heart, through systemic veins
Respiratory circulation in mammals
blood leaves the right side of heart and circulated through lung tissue. we breath, CO2 is removed and replaced by O2 (oxygenated) goes to the left side of the heart (through pulmonary veins). deoxygenated
Lymphatic system in mammals
recovers fluid lost from blood to tissues and returns it through the thoracic duct.
contains white blood cells.
•lymph in mammals contains what?
white blood cells no red blood cells
The highest proportion of blood at any time is in
What is the pacemaker?
a group of cells capable of spontaneously generating electrical activity.
cells may be neurons (in neurogenic hearts) of muscle cells ( in myogenic hearts-vertebrates!!!)
The generation of a heartbeat
Propagation of electrical activity occur through what?
gap junctions between cells
Where are small myocardial cells and what do they do?
They are in the sinoatrial and atrioventricular
nodes and are weakly contractile
What are large myocardial and what do they do?
cells in the inner wall of the ventricles: weakly contractile but fast in electrical conduction
What are intermediate size myocardial cells and what do they do?
(the bulk of the heart): strongly contractile cells
Pacemaker potential
is a depolarization of the membrane of a pacemaker cell that precedes an action potential.
• not an AP
The generation of an action potential in pacemaker cells:
After AP: high conductance of K+ and (moderately) Ca2+
Ca2+ conductance doesn’t fall right after an AP
K+ conductance drops and depolarization again.
Na+ and Ca2+ channels open (rising phase of AP)
K+ conductance increases (falling phase)
Pacemaker potential causes:
Parasympathetic regulation of heart rate is by _____
Sympathetic regulation of heart rate
Norepinephrine (NE) is released from sympathetic terminals and binds adrenergic receptors on the pacemaker cells.
it activates Ca2+ channels, accelerating depolarization (the pacemaker potential)
Unlike in skeletal muscle, cardiac muscle contraction is
__________.
plateau phase, sustained depolariation, occurs after rising phase of AP due to what?
plateau phase, a sustained depolarization
WHat are the results of a plateau phase?
membrane remains at the refractory period longer, preventing subsequent APs. brief contraction occurs.
Circulation through the right side of the heart:
Circulation through the left side of the haert:
Pulmonary veins
—> left atrium
—> left ventricle
—> aorta
The contraction of the ventricle
The relaxation of the ventricle
Describe the circulation through linear heart chambers:
systole occures, atrioventricular valves close, force blood through the arteries (high pressure), atrium fills with blood (low pressure)
diastole occurs, atrioventricular valves open and forces blood from atrium to ventricle.
Circulation through a sinuously looped heart means there is no_____ flow.
bilateral
describe Right atrium filling during ventricular systole
Swirling blood inside the atrium; no bilateral circulation
Atrioventricular valve opens: blood flows into the ventricle.
Left ventricle filling during ventricular diastole
As the ventricle relaxes, blood swirls inside.
Ejection through the aorta during ventricular systole
Blood flows out with high pressure.
What is cardiac outputs:
Stroke volume:
the volume of blood ejected from a ventricle during one beat of the heart.
What does norepinephrine do?
What happens during exercise
What are some limits to the heart rate?
How does the disatole shortening limit heart rate?
How does coronary circulation limit heart rate?
Mid diastole
relaxed ventricles, closed outflow valves, and high blood pressure in the outflow channels (aorta and pulmonary arteries).
Atrial contraction:
high atrial pressure forces the blood into the ventricles.
Isometric ventricular contraction
the atrioventricular valves close when ventricle myocardial cells contract, but no change in volume occurs because the outflow valves are still closed.
reasons for Isometric ventricular contraction
Ventricular ejection (systole):
When the pressure in the ventricles exceeds the pressure inside the the outflow channels, the aortic valves are forced to open and blood escapes through the outflow channels:
isotonic contraction of the ventricle.
Ventricular diastole:
When the pressure inside the outflow channels exceeds the pressure inside the ventricles, the aortic valves close (blood flow in the aorta is actually reversed).
Sequence of events in a heartbeat
- Mid diastole
- Atrial contraction
- Isometric ventricular contraction
- Ventricular ejection (systole)
- Ventricular diastole
- more pressure builds in the left ventricle and aorta (systemic circulation) during _____.
- lower pressure in the ___ ____ and ____ ______ (pulmonary circulation)
systole.
right ventricle and pulmonary arteries
The stroke volume is the same for both sides, but;
•the aortic pressure is higher than in the pulmonary arteries,
so the left ventricle must reach a higher pressure to exceed
the aortic pressure and open the aortic valve
if there is high arterial blood pressure then:
What is an electrocardiogram?
summation of electrical activities of al cells within each region of the heart, detected as small potential shanges from points all over the body.
What are the three modes of blood flow
Laminar flow, pulsative flow and turbulent flow.
describe blood pressure and area in the aorta
Describe the bloodflow and area of the capillaries
Describe bloodflow and area in the vena cava
Describe the Laminar blood flow
Describe the pulsative blood flow
Describe turbulent blood flow
Laminar flow is characteristic of what vessels?
what is viscosity
Pulsative flow is characteristic to what vessels?
Turbulent flow occurs where?
at points distal to aortic and pulmonary valves, with higher pressure points and/or with decreased blood viscosity.
in which system does high blood pressure occur?
arterial
What are the 4 functions of the arterial system?
describe continuous capillaries?
least permeable type
occur in muscles, neuronal tissues, lungs, connective tissue and exocrine glands
describe fenestrated capillaries
Do the fetal and maternal circulatory system merge?
•deoxygenated blood that is ejected by the right ventricle through the pulmonary artery is diverted into the aorta through the _____ _____
•oxygenated blood is coming from the umbilical veins into the right atrium, and some of it passes to the left atrium through the ______ ____ so that oxygenated blood can be delivered to the systemic circulation.
foramen ovale
•the flow is turbulent at the base of the ___
aorta
flow is pulsative in the rest of the aortas
tunica intima
tunica media
tunica adventitia
•outer fibrous coat
pericytes are :
•there are three types of capillaries according to their location along the flow path:
filtration pressure is opposed by the:
•if the blood pressure inside the capillary is higher than the value of the colloidal osmotic pressure:
filtration of fluids into the interstitial space
•where the blood pressure inside the capillary falls bellow the value of the colloidal osmotic pressure:
uptake of fluids into the blood from the interstitial space
Functions of lymphocytes:
B cells, Tc cells and Th cells.
B cells:
TC cells:
TH cells:
after recognizing an antigen, these cells secrete cytokines, which promote the growth and responsiveness of both B and TC cells.
Extravasation is:
What does P-selectin do
binds lymphotcytes and slows down their flow
also
Regulation of circulation: the priorities are:
1- Supply blood to the brain and the heart.
2- Supply blood to all other organs.
3- Deliver capillary pressure to maintain tissue volume and the composition of the interstitial fluid.
Autonomic effectors:
•Baroreceptors:
•pressor center:
•depressor center:
parasympathetic activation and decrease in pressure
Control of smooth muscle cell relaxation by nitric oxide:
- NO is produced by endothelial cells (the inner layer of arteries and arterioles) and diffuses to the surrounding smooth muscle cells
- unstable
- it activates guanylate cyclase: GTP => cGMP
Effects of cGMP:
- phosphorylation of myosin light chains by activating a protein kinase
- inhibition of PLC: no IP3, no Ca2+ release
- opening of K+ channels: hyperpolarization
The functions of gas transfer systems in vertebrates:
absorption of Q2 and the elimination of CO2
Components of the gas transfer systems in vertebrates
Dalton’s law:
the partial pressure of each gas in a mixture is independent of other gases present, so that the total pressure equals the sum of the partial pressures of all thegases present.
Henry’s law:
the quantity of gas that dissolves in liquid at a given temperature is proportional to the partial pressure of that gas in the gas phase.
What type of binding is O2 to hemoglobin
Myoglobin
is a different protein that stores O2 in muscle cells, similar in structure to a single globin.
The order of the genes on the chromosome corresponds to ______
Environmental factors that can reduce the affinity of normal hemoglobin for O2
- increse in temp
- decrease in pH (bhor effect)
- increse in CO2 conc.
4.
The affinity of hemoglobin for O2 increases with
The affinity of hemoglobin for O2 decreases when
when CO2 conc. increases
CO2 exists in the blood in five forms:
carbon dioxide
carbonic acid
bicarbonate
carbonate
carbamino complexes
