Practice Exam 2

The Na/K transporter (pump) is blocked by:

nAChR channels at the endplate:

Axons X and Y are myelinated and of equal diameter, suppose that, in X the internodal distance is 10 nm while in Y the internodal distance is 20 nm. Based on this information:

As a result of repetitive activity the K concentration immediately outside the nerve terminal rises to 10 meq whereas the K concentration inside decreases to 100 meq. Thus: (hint: log 10=1)

The fate of Na and K ions that enter and leave respectively during the action potential:

Which of the following statements is/are incorrect:

Which of the following statements is/are incorrect:

If the voltage-regulated sodium channels failed to become inactivated, then the duration of action potential

What would happen to a muscle action potential if 50% of the sodium channels are blocked?

Postsynaptic density (opacity) is due to the presence of ______ in the membrane:

Multiple sclerosis (MS):

The resting membrane potential of a nerve is:

Which of the following statement(s) is/are True?

The inhibitory postsynaptic potential (IPSP):

The refractory periods (RP):

Long-term potentiation (LTP)

Depolarization of the terminal button leads to release of neurotransmitter in the following way:

Presynaptic inhibition:

While studying the transport of molecule B across the cell membrane, you discover that as you increase the concentration of B in the extracellular fluid, the rate of transport also initially increases. If the concentration of extracellular B is further increased, the rate becomes constant. Based on this information, which of the following statements best describe this situation?

A man falls into deep sleep with one arm under his head. This arm is paralyzed when he awakens, but it tingles, and he can feel pain sensation in it. The reason for the loss of motor function without loss of pain sensation is that:

Which of the following statement(s) is/are False?

When an action potential depolarizes a terminal button, Ca2+:

Presynaptic facilitation (i.e. increased transmitter release) occurs when:

Myelination:

In the CNS, a severed or injured axon undergoes Wallerian degeneration but virtually no regeneration takes place because:

Which of the following comparisons between neurons and muscle tissue is incorrect?

How would the ventricular muscle action potential be affected if calcium channels were blocked?

The generation of an action potential occurs when the following the main steps take place: a. sodium channels are inactivated b. voltage-regulated potassium channels open and potassium moves out of the cell initiating repolarization c. sodium channels regain their normal properties d. a graded depolarization brings an area of an excitable membrane to threshold e. a temporary hyperpolarization occurs f. sodium channel activation occurs g. sodium ions enter the cell and depolarization occurs, the proper sequence of event is:

Lysosomes are stabilized by:

Action potential is recorded from a length of squid axon that has a conduction velocity of 100 m/sec; the latent period is 1 msec and the amplitude of the action potential is 100mV. With this information in hand the length of the axon must be:

synaptic transmission decreases when:

About Receptors:

The All-or-nothing rule applies to:

IPSPs:

When a second EPSP arrives at a single synapse before the effects of the first have disappeared, what occurs is:

Exocytosis is involved in:

Which of the following is not normally embedded in the plasma membrane?

The resting potential is due, in part, to the:

Threshold for an action potential:

The amplitude of action potential in an axon is dependent on: