Exam 7: The Nervous System and Neuronal Excitability

Movement of ions through channels occurs as a result of gradients. If left alone, these gradients would eventually run down (ie reach equilibrium). How do active transporters (pumps) like the Na⁺/K⁺ ATPase maintain the gradients?

You have accidentally given a patient a dose of atropine rather than acetylcholine. What symptoms do you expect to see in the patient?

Identify the true statement about presynaptic modulation.

You have been given an unknown neurotransmitter to identify. What characteristics would indicate that it is more likely a small-molecule neurotransmitter?

Electrical synapses are different from chemical synapses because

Place the following events of the action potential in the correct order. 1) Voltage-gated Na+ channels open, and Na+ flows in 2) Voltage-gated K+ channels close, membrane potential returns to rest 3) Membrane is depolarized to threshold 4) Voltage-gated Na⁺ channels close 5) Voltage-gated K⁺ channels open, membrane rapidly repolarizes 6) Membrane rapidly depolarizes

Regeneration is more likely to occur in the peripheral nervous system because the oligodendrocytes form a regeneration tube.

While some channels can have open states regulated by stimuli, others are random. What common term among those that are opened by a stimulus?

In myelinated axons, the channels found in the nodes of Ranvier are

A scientist wants to study the effects of summation on graded potentials. Her assistant applies the stimuli, but there is no apparent result. Compose a situation that would explain these results.

Information is sent from the dendrites to the ________, where an action potential may be generated.

Regrowth of neurons in injured areas of the central nervous system does not generally occur because