Question 1

Which property of neurons is primarily responsible for the poor conduction of electrical signals through their cytoplasm?

Accepted Answer

High internal resistance and significant K$^+$ leakage through always-open channels

Question 2

What is the main reason action potential conduction is faster in myelinated neurons compared to unmyelinated neurons?

Accepted Answer

Action potentials 'leap' from node to node in a process called saltatory conduction

Question 3

Which equation best describes the relationship between conduction speed ($v$) and axon diameter ($d$) in neurons?

Accepted Answer

$v \propto d$

Question 4

In the context of synaptic transmission, what is the role of SNARE proteins?

Accepted Answer

They dock vesicles containing neurotransmitters at the plasma membrane

Question 5

Which of the following best describes the function of the Ca$^{2+}$ pump in neurons?

Accepted Answer

It removes Ca$^{2+}$ from the cytoplasm, creating a concentration gradient for rapid Ca$^{2+}$ influx

Question 6

Which type of synapse allows ions and molecules to pass directly from one cell to another via gap junctions?

Accepted Answer

Electrical synapse

Question 7

Otto Loewi’s experiment with the vagus nerve and the heart provided evidence for which concept?

Accepted Answer

Chemical transmission at the neuromuscular junction

Question 8

Which of the following is TRUE regarding ionotropic receptors?

Accepted Answer

They directly form ion channels that open upon neurotransmitter binding

Question 9

What is the primary difference between ionotropic and metabotropic postsynaptic receptors?

Accepted Answer

Ionotropic receptors directly open ion channels; metabotropic receptors activate signaling cascades via G-proteins

Question 10

Which neurotransmitter is released at the neuromuscular junction and binds to nicotinic receptors to produce muscle contraction?

Accepted Answer

Acetylcholine

Question 11

A patient with myasthenia gravis is treated with neostigmine. What is the mechanism of action of this drug?

Accepted Answer

It inhibits acetylcholinesterase, increasing acetylcholine levels in the synaptic cleft

Question 12

Which of the following best explains why the response to acetylcholine can be either excitatory or inhibitory?

Accepted Answer

It depends on the postsynaptic complement of receptors and their associated channels

Question 13

Which process is responsible for the rapid removal of acetylcholine from the synaptic cleft?

Accepted Answer

Degradation by acetylcholinesterase

Question 14

Which of the following is a function of acetylcholine in the central nervous system?

Accepted Answer

Memory, arousal, and attention

Question 15

Which of the following statements about saltatory conduction is correct?

Accepted Answer

Action potentials 'leap' from one node of Ranvier to the next

Question 16

Which of the following best describes the role of synaptotagmin in neurotransmitter release?

Accepted Answer

It acts as a Ca$^{2+}$ sensor and triggers vesicle fusion with the plasma membrane

Question 17

Which of the following is a consequence of blocking nicotinic acetylcholine receptors at the neuromuscular junction?

Accepted Answer

Muscle weakness, as seen in myasthenia gravis

Question 18

Which of the following is TRUE about graded potentials and action potentials in neurons?

Accepted Answer

Action potentials are propagated without decrement along the axon

Question 19

Which of the following is a characteristic of metabotropic receptors?

Accepted Answer

They activate intracellular signaling cascades via G-proteins

Electrical Activity, Synaptic Transmission, and Cholinergic Signaling in Neurons

Study Guide - Practice Questions