Neuroscience Quiz: Neuron Structure and Function

Neurons are cells in the nervous system that transmit electrical signals.

Neurons consist of a cell body, axon, and dendrites.

Carries impulses from receptors to the central nervous system (CNS).

Carries impulses from CNS to effectors (muscles or glands).

The electrical potential difference across the neuron membrane when it's not transmitting a signal.

The difference in electrical charge across a cell membrane.

The propagation of an action potential along a nerve fiber.

A rapid change in membrane potential that allows a signal to travel along a nerve fiber.

The process where the inside of a neuron becomes more positive relative to the outside due to the influx of sodium ions through open channels.

The process where the inside of a neuron returns to its negative resting potential after depolarization, caused by the outflow of potassium ions.

A protein pump that actively transports sodium ions out of the neuron and potassium ions into the neuron, maintaining the concentration gradients necessary for action potentials.

The thickness of the axon, which influences the speed of nerve impulse conduction.

A nerve fiber coated in myelin, a fatty substance that acts as an insulator, speeding up nerve impulse conduction.

The jumping of nerve impulses from one node of Ranvier (gap in the myelin sheath) to the next, increasing conduction speed.

The junction between two neurons or between a neuron and an effector cell where information is transmitted.

The narrow gap between the presynaptic and postsynaptic membranes at a synapse.

A muscle or gland that responds to a nerve impulse.

A chemical messenger released from the presynaptic neuron at a synapse, which diffuses across the synaptic cleft and binds to receptors on the postsynaptic membrane.

A neurotransmitter that increases the likelihood of an action potential in the postsynaptic neuron.

A neurotransmitter that decreases the likelihood of an action potential in the postsynaptic neuron.

The minimum level of depolarization required to trigger an action potential in a neuron.

The minimum membrane potential that must be reached for an action potential to be triggered.

Voltage-gated sodium channels open when the membrane potential reaches the threshold potential, allowing sodium ions to flow into the neuron, further increasing the membrane potential.

Voltage-gated potassium channels open as the membrane potential becomes more positive during depolarization, allowing potassium ions to flow out of the neuron, reducing the membrane potential.

A visual representation of the electrical activity of a neuron over time, showing the changes in its membrane potential.

A brief period after an action potential where the neuron is less likely to fire another action potential.

A myelinated nerve fiber has an axon wrapped in myelin, a fatty substance that acts as an insulator, with gaps called nodes of Ranvier.

Myelin prevents the flow of ions across the axon membrane except at the nodes of Ranvier, forcing the action potential to 'jump' from node to node, speeding up the transmission.

Chemicals that come from outside the body, such as drugs or pesticides.

Neonicotinoids bind to acetylcholine receptors, causing sodium channels to remain open, leading to overstimulation and paralysis.

Cocaine blocks dopamine reuptake transporters, causing dopamine to build up in the synapse, leading to increased excitation.

Excitatory neurotransmitters increase the likelihood of a postsynaptic neuron firing by causing depolarization, while inhibitory neurotransmitters decrease the likelihood of firing by causing hyperpolarization.

GABA is an inhibitory neurotransmitter that binds to receptors and opens chloride channels, causing hyperpolarization of the postsynaptic neuron.

The combined effect of multiple excitatory or inhibitory neurotransmitters on a postsynaptic neuron.