Neurological System - Test Bank

Flashcards based on Neurological System Test Bank questions, focusing on key concepts and definitions.

What best defines 'flow down gradients' in physiology?

A. Substances require energy to move from low to high concentration

B. Substances move passively from high to low concentration, influenced by energy gradients

C. Substances are moved across membranes only via vesicular transport

D. Substances flow randomly across membranes regardless of resistance

Substances move passively from high to low concentration, influenced by energy gradients

Which event directly triggers neurotransmitter release at a chemical synapse?

A. Sodium influx through ligand-gated channels

B. Potassium efflux at the axon hillock

C. Calcium influx through voltage-gated calcium channels

D. ATP release from mitochondria in the synaptic terminal

Calcium influx through voltage-gated calcium channels

What is the absolute refractory period?

A. The time when no new action potential can be generated regardless of stimulus strength

B. The time when a stronger-than-normal stimulus is required to trigger an action potential

C. The interval during which voltage-gated K⁺ channels are open

D. The interval when the Na⁺/K⁺ pump is inactive

The time when no new action potential can be generated regardless of stimulus strength

Which structure in a neuron is primarily responsible for receiving incoming signals?

A. Axon

B. Myelin sheath

C. Dendrite

D. Synaptic terminal

Dendrite

What is the main purpose of the sodium-potassium pump in neurons?

A. To propagate action potentials

B. To maintain ion gradients necessary for resting membrane potential

C. To directly open voltage-gated channels

D. To produce neurotransmitters

To maintain ion gradients necessary for resting membrane potential

Which of the following describes a typical action potential propagation?

A. It travels in both directions along the axon

B. It decreases in strength as it travels

C. It requires continuous external stimulation

D. It is unidirectional due to the refractory period

It is unidirectional due to the refractory period

What is the expected result if voltage-gated Na+ channels fail to inactivate?

A. The cell becomes permanently hyperpolarized

B. Repolarization is delayed or does not occur

C. Neurotransmitter release increases

D. The resting membrane potential becomes more negative

Repolarization is delayed or does not occur

Which mechanism allows ions to move against their concentration gradients?

A. Passive diffusion

B. Facilitated diffusion

C. Osmosis

D. Active transport via ATP-powered pumps

Active transport via ATP-powered pumps

Guillain-Barré Syndrome most directly disrupts which part of the neuron?

A. Axon terminal

B. Myelin sheath

C. Synaptic cleft

D. Dendritic spine

Myelin sheath

Why do myelinated axons conduct impulses faster than unmyelinated ones?

A. Myelin increases the strength of action potentials

B. Myelin allows impulses to skip internodal regions via saltatory conduction

C. Myelinated axons have more voltage-gated channels per micrometer

D. Myelin directly stimulates neurotransmitter release

Myelin allows impulses to skip internodal regions via saltatory conduction

1. What is the primary function of a neuron?

A. To transport oxygen
B. To store glycogen
C. To receive, integrate, and transmit information
D. To regulate hormonal secretion

C. To receive, integrate, and transmit information

2. Which statement best describes the structure of the cell membrane?
A. A single layer of proteins and lipids
B. A rigid wall made of cellulose
C. A lipoprotein bilayer with embedded proteins
D. A layer of cholesterol and sugar molecules

C. A lipoprotein bilayer with embedded proteins

3. What type of ion movement initiates depolarization in an action potential?
A. K⁺ moves out of the cell
B. Ca²⁺ moves into the cell
C. Na⁺ moves into the cell
D. Cl⁻ moves out of the cell

C. Na⁺ moves into the cell

4. What is the function of the Na⁺/K⁺ pump in the resting membrane potential?
A. Moves glucose into the cell
B. Transports Ca²⁺ out of the cell
C. Generates neurotransmitters

D. Moves 3 Na⁺ out and 2 K⁺ in, maintaining the resting potential

D. Moves 3 Na⁺ out and 2 K⁺ in, maintaining the resting potential

5. What occurs during the absolute refractory period of a neuron?
A. The membrane can respond to any stimulus
B. Another action potential can occur only with a stronger stimulus
C. No action potential can be initiated, regardless of stimulus strength
D. The membrane becomes hyperpolarized

C. No action potential can be initiated, regardless of stimulus strength

6. What is saltatory conduction?
A. Conduction across a chemical synapse

B. Rapid conduction by jumping between nodes of Ranvier in a myelinated axon
C. Continuous conduction in an unmyelinated axon
D. Slowed conduction due to depolarization

B. Rapid conduction by jumping between nodes of Ranvier in a myelinated axon

7. What type of transport moves substances down an electrochemical gradient without energy use?
A. Primary active transport
B. Endocytosis
C. Passive diffusion
D. Exocytosis

C. Passive diffusion

8. Which component initiates neurotransmitter release at the synapse?
A. Na⁺ influx
B. Ca²⁺ influx
C. K⁺ outflow
D. Cl⁻ influx

B. Ca²⁺ influx

9. What distinguishes an excitatory postsynaptic potential (EPSP)?
A. It results in membrane hyperpolarization
B. It leads to depolarization of the postsynaptic membrane
C. It permanently alters the cell’s DNA
D. It activates the Na⁺/K⁺ pump

B. It leads to depolarization of the postsynaptic membrane

10. Which pathophysiological mechanism underlies Guillain-Barré Syndrome?
A. Hormonal imbalance
B. Autoimmune-mediated demyelination
C. Synaptic overgrowth
D. Dopamine deficiency

B. Autoimmune-mediated demyelination