Chapter 2: Neuronal Structure and Function

Neuronal Structure and Function

What is the name of the fatty substance the covers axons to improve their ability to conduct action potentials?

A. Adipose tissue

B. Extracellular matrix

C. Myelin

D. Neurolemma

C. Myelin

For the type of axon noted above, what is the name of the gap not covered by fatty substance?

A. Internode

B. Voltage-gated sodium channel

C. Axon hillock

D. Node of Ranvier

D. Node of Ranvier

What is the name of the force that determines which way ions will flow across the neural cell membrane when a certain ion pore opens?

A. Electrical gradient

B. Electromechanical gradient

C. Electrochemical gradient

D. Concentration gradient

C. Electrochemical gradient

What kind of ion channel must be opened to initiate an action potential at the axon hillock of a projection interneuron?

A. Voltage-gated potassium channel

B. Voltage-gated sodium channel

C. Voltage-gated calcium channel

D. Metabotropic receptors

B. Voltage-gated sodium channel

Assuming other characteristics are equal, the neuron with the fastest conduction velocity would be the one with the …

A. Largest diameter axon

B. Longest axon

C. Highest number of voltage-gated sodium channels

D. Smallest number of inhibitory synapses

A. Largest diameter axon

What is different about the axon membrane at the nodes of Ranvier than in the axon where it is wrapped with the substance produced by Schwann cells?

A. There is a high degree of membrane resistance

B. There is a high concentration of voltage-gated sodium channels

C. There is no passive decay of the membrane potential

D. Ligand-gated receptors are present to respond to neurotransmitters

B. There is a high concentration of voltage-gated sodium channels

Which one of these processes can NOT contribute ...