Nerve Physiology Quiz

<p>Only maximal stimuli produce a nerve impulse. (C)</p> Signup and view all the answers

<p>Resting membrane potential (A)</p> Signup and view all the answers

<p>Fatigue from repeated stimulation (A)</p> Signup and view all the answers

<p>Nerves eventually stop responding to a continuous stimulus. (A)</p> Signup and view all the answers

<p>The difference in charge between two points. (D)</p> Signup and view all the answers

<p>-70 mV (C)</p> Signup and view all the answers

<p>Potassium ions (K+) (A)</p> Signup and view all the answers

<p>Na+/K+-ATPase pump (B)</p> Signup and view all the answers

<p>It reduces negativity toward zero (-60 mV) (B)</p> Signup and view all the answers

<p>It increases in negativity (-90 to -110 mV) (C)</p> Signup and view all the answers

<p>Higher concentrations of K+ inside the cell (C)</p> Signup and view all the answers

<p>Presence of negatively charged proteins inside (D)</p> Signup and view all the answers

<p>It pumps 3 Na+ ions out and 2 K+ ions into the cell (B)</p> Signup and view all the answers

<p>The minimum stimulus required to achieve an action potential. (C)</p> Signup and view all the answers

<p>Sodium ions (Na+) (D)</p> Signup and view all the answers

<p>Potassium ions (K+) exit the cell, returning the membrane potential to a negative value. (C)</p> Signup and view all the answers

<p>An overshoot beyond the resting membrane potential due to prolonged K⁺ channel opening. (A)</p> Signup and view all the answers

<p>A period of complete unresponsiveness to any stimulus, regardless of intensity. (C)</p> Signup and view all the answers

<p>Na⁺-K⁺ pump adjusts excess Na⁺ and K⁺ levels. (A)</p> Signup and view all the answers

<p>Depolarization phase. (A)</p> Signup and view all the answers

<p>It results in an overshoot in the hyperpolarizing direction. (B)</p> Signup and view all the answers

<p>Destruction by acetylcholinesterase (B)</p> Signup and view all the answers

<p>Impulse propagation time (A)</p> Signup and view all the answers

<p>It promotes the rupture of acetylcholine vesicles (A)</p> Signup and view all the answers

<p>Curare (B)</p> Signup and view all the answers

<p>Produces antibodies that block acetylcholine receptors (B)</p> Signup and view all the answers

<p>Irreversible inhibition of acetylcholinesterase (A)</p> Signup and view all the answers

<p>Myasthenia gravis (B)</p> Signup and view all the answers

<p>Neuromuscular transmission fatigue (B)</p> Signup and view all the answers

<p>They are important for short distance signaling. (A)</p> Signup and view all the answers

<p>It increases proportionately to the stimulus strength. (D)</p> Signup and view all the answers

<p>Saltatory conduction. (D)</p> Signup and view all the answers

<p>They are non-propagated and localized. (C)</p> Signup and view all the answers

<p>They can be summated. (B)</p> Signup and view all the answers

<p>Unmyelinated conduction is slower. (A)</p> Signup and view all the answers

<p>Destruction by acetylcholinesterase. (D)</p> Signup and view all the answers

<p>They are responsible for the occurrence of local potentials. (D)</p> Signup and view all the answers

The main cell body of a neuron, containing the nucleus and other organelles.

A long, slender projection that extends from the soma, transmitting nerve impulses away from the cell body.

Branching projections that receive nerve impulses and conduct them toward the cell body.

A fatty substance that wraps around axons, increasing the speed and efficiency of nerve impulse conduction.

Gaps in the myelin sheath on axons, where nerve impulses jump from one node to another.

The ability of a nerve or muscle to respond to stimuli.

The ability of a nerve to conduct a nerve impulse along its length.

The principle stating that a nerve fiber will either produce a maximal action potential or no action potential at all, regardless of the strength of the stimulus.

The difference in electrical charge between the inside and outside of a nerve cell membrane when it's not transmitting signals.

The cell membrane is more permeable (allows things through) to potassium ions (K+) than sodium ions (Na+). This is because there are more K+ leakage channels than Na+ leakage channels.

A pump that moves 3 sodium ions (Na+) out of the cell and 2 potassium ions (K+) into the cell, requiring energy (ATP). This contributes to the negative charge inside the cell.

The state of the membrane potential when it's at rest, typically around -70mV. The inside of the cell is negatively charged compared to the outside.

A reduction in the membrane potential's negativity, becoming less negative. It could reach zero or even become positive.

An increase in the membrane potential's negativity, becoming more negative.

The state of the membrane potential during an action potential when the inside of the cell becomes momentarily positive compared to the outside.

The state of the membrane potential during an action potential when the inside of the cell returns to its negative resting potential.

The minimum stimulus required to generate an action potential in a nerve or muscle cell.

A brief overshoot in the negative direction of the membrane potential, after repolarization is completed.

The resting membrane potential (RMP) is restored by closing voltage-gated potassium channels and the Na⁺-K⁺ pump re-establishes the ion gradients.

A period during which the nerve is absolutely unexcitable to any stimulus, regardless of its strength.

A period where the nerve is partially responsive to stimuli, but requires a stronger than normal stimulus to trigger an action potential.

These changes in excitability during an action potential ensure that the nerve impulse travels in one direction and prevent back propagation.

A local potential is a temporary change in the membrane potential that occurs only at the site of stimulation. It is graded, meaning its amplitude is proportional to the strength of the stimulus.

Local potentials can be either excitatory or inhibitory, depending on the type of stimulus and the receptors involved. An excitatory potential increases the likelihood of an action potential occurring, while an inhibitory potential decreases the likelihood.

A subthreshold stimulus is a stimulus that is not strong enough to trigger an action potential. However, it can still create a local potential.

Saltatory conduction is the rapid conduction of nerve impulses along myelinated axons, where the impulses jump from one node of Ranvier to the next.

Point-to-point conduction is the slower conduction of nerve impulses along unmyelinated axons, where the impulses travel continuously along the entire length of the axon.

Myelin is a fatty substance that surrounds axons, increasing the speed and efficiency of nerve impulse conduction. It acts as an insulator, preventing leakage of the electrical signal.

The nodes of Ranvier are gaps in the myelin sheath on axons. Nerve impulses jump from one node to the next, allowing for faster conduction.

Acetylcholine is a neurotransmitter that is released at the neuromuscular junction, causing muscle contraction.

The rapid removal of acetylcholine from the synaptic cleft prevents continued muscle excitation.

An enzyme that breaks down acetylcholine in the synaptic cleft.

Neuromuscular transmission only goes in one direction: from nerve to muscle.

There's a slight delay between the nerve impulse arriving at the junction and the muscle responding.

Repetitive nerve stimulation can lead to a decrease in signal strength.

Calcium ions enhance neuromuscular transmission by stimulating acetylcholine release. Magnesium inhibits it by stabilizing the vesicles.

Certain drugs mimic acetylcholine and activate its receptors.

Curare blocks acetylcholine receptors, preventing muscle contraction.

Botulinum toxin blocks the release of acetylcholine from nerve terminals.

A condition characterized by muscle weakness due to insufficient acetylcholine transmission.

In Myasthenia Gravis, the body's immune system attacks acetylcholine receptors.

Severe Myasthenia Gravis can lead to paralysis, particularly of the respiratory muscles.