Nervous system + motor system
F
True false: Assuming concentration is normal, a toxin that disrupts the electrochemical gradient will depolarize a neuron at typical a resting state
T.
True of false? A toxin keeping the inactivation gate of the K+ channel closed all the time will allow for a longer Action potential
F
True or False. Most of the current in a mylenated axon leaves the neuron in the internodal region
T
True or false Destruction of microfilaments will remove the template for a muscle to contract.
F. Calcium is stored in sarcoplasmic reticulum. Plus the calcum pump in myofiber is within the sarcoplasmic reticulum and it allows for transfer of calcium into SR lumen for storage.
True or false Toxin that blocks the calcium pump in a myofibril will decrease the storage of Calcium in the T tubule. Explain briefly either answer.
T
True or false. Assuming only the chloride channel opens, an Immersion of a neuron into a concentration of chloride solution will prevent the generation of an action potential when electrical signals run through solution.
F. Calcium is only involved in the release of neurotransmitters not necessarily depolarization that occurs along the axon that propagates the signal
True or false: A blockage to the voltage gated calcium channel will not allow for depolarization of the pre-synaptic neuron.
F
True or false: A stronger stimulus will magnify the affect of an action potential and increase its strength
T
True or false: Assuming the electrochemical gradient is normal, a toxin that disrupts prevents K+ exit will depolarize the cell
T
True or false? A membrane that is 5 times more permeable to potassium will make it harder for a action potential to be stimulated
The myometrium of the uterus structure. During pregnancy, they form gap junctions to allow for cohesive "contractions". They are fast then. Smooth muscles are typically either neurogenic or myogenic.
What are some examples of smooth muscle
The action potential might go change directions as now the refractory period is no longer in place.
A axon potential is propagating itself along an axon. A toxin is introduced to keep the sodium-potassium pump activated behind the head of the action potential. What might happen?
The man must of ate something yesterday that called for excess depolarization of his neurons. His muscle is contracting uncontrollably, so possibly a toxin was eaten that did something to keep the guys muscle constantly contracting, such as a toxin that kept the AP signal long, allowing for a constant CA+ release that would leave the muscle fiber in a low energy myosin and actin bound state.
A couple went on a cruise to the Caribbean for their 30th anniversary. As they go around to eat at several restaurants and very good food. The next day when they wake up, the wife sees that his husband is in a fit of distortion where he can not control his body movement. His body seems to be spasaming. Luckily, there is a nearby doctor that can treat the patient quickly. The doctor comes and quickly performs and test and figures out that his muscles are over contracting. What might of happened the day before?
C
A group of scientist were studying the effects of a new safe toxin to be introduced to treat muscle spasticity, which is a disorder in which the muscle is constantly contracting. Which of the following results of the toxin will least likely provide evidence that it is a useful medication to treat muscle spasticity? A) Toxin binds to calcium pump B) The toxin binds to some of the essential proteins that allow pre-synaptic vescile fusion, inactivating them C) The toxin causes increase premeability of T tubule membrane D) The toxin lowers permeability of T tubule E) all of the above are useful
The neuron will be depolarized and will cause consistent contraction
A neural disorder in which the postsynaptic membrane NA+ channel is always open occurs. What are the possibly effects of this?
Exocytosis of the neurotransmitters was not successful
A neuron propogates its action potential down its axon. As this occurs, calcium channels are stimulated and they open, allowing for an influx into the neuron. However, there is no generation of a Postsynaptic potential in the postsynaptic cell. Why might a postsynpatic potential not have been generated?
C
A toxious substance known colloquially as "7 rings" is a new toxin that has been shown to decrease the permeability of the K+ ion at its voltage gated channel? Once a stimulus is introduced to the neuron, which of the following is least likely to occur to the signal produced? A) the signal will create a positive change for a longer time B) the AP will be longer than usual C) The hyperpolarization will be greater. D) The net inward current will remain positive longer.
if the ratio of ions is less than 1, then it is negative. If the ratio of ions is greater than 1, then the membrane potential will be +
How can you tell when concentrations will be negative or positive without explicitly calculating the nernst equation
C+ 273
How do you convert celcius to kelvin?
A and B are both EPSP, C is an IPSP, and The super high part, A+B, is a sign of spatial summation.
Label the following points with their correct effect
A is the threshold point that will cause an Action potential to occur since the stimulus is big enough to allow this to occur. B is the peak point where sodium has reached its equilibrium point and repolorization will occur. C is where repolirzation occurs. D is where hyperpolarization will bring it below the resting potential as K + efflux occurs. A refractory period follows. E is the resting membrane potential restablishing itself as sodium potassium and k leakage bring it back to normal levels.
Label the parts of this action potential graph with respect to time
The Z line will move closer together, the I band will shorten, and as well as the h zone. The Actin and myosin won't change in size but rather they will overlap. The more forceful the contractions, the more the overlap.
Looking at this picture of a sarcomere. If the muscle were to contract, which zones will change in size?
Towards the bottom of the neuron, the axon hillock, will have the area where the stimulus will have the greatest affect. This is because their is a high concentration of sodium channels there, often referred to as the "heminode". Since their is a great concentration, it will largely determine whether the stimulus will produce a gradient large enough that a AP will propogate down the axon.
This is a neuron from a human body Knowing the general neuron structure of animals and humans, where would you expect their to be the greatest affect of the stimulus? Why would the stimulus be the highest herE?
After the contraction, ATP binds to Myosin head and reduces its angle. The muscle structure is in a low energy state. After atpase splits ATP in ADP and P, the muscle enters into a high energy state with a more perpendicular myosin head to the actin filament. After release of Calcium, it binds to troponin complex to move the tropomyosin preventing myosin head binding. As the myosin head binds, it is almost read for contraction. Through some processes the ADP + Pi is removed and this causes shift of the thin filaments. When ATP bound, it is low energy and has a low actin afinity. When it is ADP+Pi there is a high afinity to actin filament. Afinity to ADP+ Pi is changed as actin and myosin bind.
What are the 4 stages of the cross-bridge cycle? When is it high vs low energy?
The snake has a multilayered sensory system. It is divided mainly into a normal visual layer, and then a thermo, decision and motor control layer. In the snake, inputs from both the sensory, the eyes, and the thermal, the hole below the eye, have to spatially sum and agree whatever stimulus is "right". Then these two stimulus spatially sum at the decsion layer. The decision layer will decide whether the "stimulus" is correct and then send a signal to the motor control layer that will produce a response, like lunge to prey or something.
What are the concepts present in the snake sensory system.
Muscle fiber, muscle cell, and myofiber
What are the different ways to call a muscle fiber?
There are skeletal, cardiac, and smooth muscle. Skeletal and cardiac muscles are both striated. Smooth muscle has no noticable striations because their structures are not as organized. Skeletal muscles are multinucleated due to how their precursor cells, myoblast, fuse. Cardiac muscles are all verly closely together and have gap junctions in their SA nodes...
What are the three type of muscles? What are some of their characteristics?
A local graded potential does not regenerate itself. It tends to decay with distance. An Action potential tends to regenerate itself as it travels along and axon, giving it the ability to travel long distances.
What is the main difference between a local graded potential and an action potential?
A stimulus is introduced that causes the activation gate of the sodium channel to open, causing an inward current to depolarize the cell. As the sodium reaches its equillibrium point, the potassiym activation gate and sodium inactivation close, causing a net outward current, repolarizing the cell. After this, the inactivation gate of the K+ channel closes, preventing any movement of K+ out. In the background sodium potassium pump works to restablish concentration gradients. At the same the inactivation gate of K+ closes, na+ activation gate closes, causing the "absolute refractory period. As the concentrations get restablished, the Inactivation gate of K+ and Na+ reopen and the membrane is back at resting.
What is the order in which gates open due to a propagation of an action potential?
D. Current direction is dependent on wording. Outword current can mean exit of positive ions or entrance of negative ions, therefore repolorization/hyperpolarization. Inward current can be entrance of positive ions or exit of negative ions, so depolarization. Using other terms such as negative just makes the phrase mean the opposite
Which of the following action and result is correctly paired? A)Outward current: Depolarization B) Outward negative current: Hyperpolarization C) Inward negative current: repolarization/hyperpolarization D) Net inward currents: Depolarization E) None of the above actions and results are correctly paired
E
Which of the following concerning the chemical and electrical synapse are true? A) chemical synapse involves tight junctions and the electrical synapse involves gap junctions B) Chemical synapse allow for faster transmission of AP than electrical synapse C) A toxin that prevents formation of gap junctions will have a larger effect on the function of chemical synapse than electrical synapse D) Electrical synapse are more diverse in function than chemical synapse E) none of the above are true
D. It is in resting phase. All other are true. Negative movement to the left is the same as positive to the right and depolarization. B would be disadvantageous because more energy would be expended.
Which of the following statements is false concerning the propogation of the action potential? A) A movement of negative charge to the left will allow for action potential to be propogated along an axon B) Most of the current flow is concentrated in the internodal regions C)More of the extracellular current flowing immediately outside the membrane is carried by potassium D) The membrane on the right of the action potential, considering its movement from left to right, is in its refractory period E) all of the above are true
F
Which of the following would most likely occur if there was an increased permeability to Cl- in the postsynaptic neuron through a leaky channel A) the neuron will have a more positive resting membrane potential B) Hyperpolarization will occur C) It summation of the next stimulus will have to be greater in order to create another action potential D) A E) A + B F) B + C G) All of the above
It is needed for the exocytosis of neurotransmitters from the pre-synaptic neuron. Without it, action potentials can not stimulate other neurons, therefore preventing signal transduction between neurons.
Why is calcium essential to the functionality of chemical synpases?
This is a comparison of charge between the outside and inside. As the outside has high concentration of NA and the inside K+ is higher, there is a difference of charge. At the same time the K+ leakge established the resting membrane potential by giving it a more negative value when compared to the more abundant NA+ concentration outside. Also, since the Na+ and k+ pump are working in the background, there is a net +1 charge going out per pump, so it makes sense that the outside is more positive when compared to the inside.
Why is it that the inside of a cell is more negative than the outside?
this is because the cell is going from a resting membrane potential. The K+ volatage gates is closed while the NA+ rushes in as a stimulus hits the channels. This in turn causes depolarization that stimultes calcium influx in the neuron as the calcium volate gated channel opens. This is why their is a calicum increase. This calcium increase will allow for neurotransmitters to be released. tih is because as Na+ reaches eqillibirum, it will cause K+ permeability to increase dramatically and NA+ permeability to decrease, causing repolarization,
Why is their a K+ decrease little bit after 0 seconds? How about in increase in Ca2 at the same time? Why is their an increase in K+ permeability at the end
