Physiology LE 1: Nerve

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What is the function of the Peripheral Nervous System (PNS)?

Responsible for homeostasis

Associated with involuntary control of the body

Provides an interface between the environment and the CNS (correct)

Processing center of the nervous system

What is the Autonomic Nervous System responsible for?

Relaying information between the CNS and visceral organs

Processing center of the nervous system

Voluntary control of the body

Homeostasis (correct)

What is the concentration of potassium inside the cell?

0.0001 mM

5 mM

2 mM

140 mM (correct)

What is the function of the Central Nervous System (CNS)?

Processing center of the nervous system Signup and view all the answers

What is the direction of the chemical gradient for potassium?

Out of the cell Signup and view all the answers

What is the Somatic Nervous System associated with?

Voluntary control of the body Signup and view all the answers

Why does potassium not move far outside the cell?

It returns to its resting potential Signup and view all the answers

What is the Visceral Nervous System responsible for?

Relaying information between the CNS and visceral organs Signup and view all the answers

What is the concentration of calcium outside the cell?

2 mM Signup and view all the answers

What are the two main divisions of the Peripheral Nervous System?

Somatic and Autonomic Signup and view all the answers

What happens when voltage-gated calcium channels open?

Calcium moves into the cell Signup and view all the answers

What is the effect of calcium influx on the membrane?

It depolarizes the membrane locally Signup and view all the answers

What is the function of the cranial nerves?

Part of the Peripheral Nervous System Signup and view all the answers

Why is the membrane not permeable to calcium?

Because the membrane is not permeable to it Signup and view all the answers

What is the function of the spinal nerves?

Part of the Peripheral Nervous System Signup and view all the answers

What is the direction of the electrical gradient for potassium?

Into the cell Signup and view all the answers

What is the resting membrane potential in millivolts?

-65 Signup and view all the answers

What happens to the sodium gates during depolarization?

They open Signup and view all the answers

What is the term for the rapid change in membrane potential across the nerve fiber membrane?

Action potential Signup and view all the answers

What happens to the potassium during repolarization?

It gets out of the cell Signup and view all the answers

What is the term for the state where the membrane potential is lower than the resting membrane potential?

Hyperpolarization Signup and view all the answers

What is the property of action potential that means it will not change its amplitude from the start to the end of the neuron?

Decrementless Signup and view all the answers

What is the purpose of the active sodium/potassium ATPase pump?

To bring back the resting membrane potential Signup and view all the answers

What is the term for the rapid changes in membrane potential that spread rapidly along the nerve fiber membrane?

Propagating Signup and view all the answers

What is the minimum amount of stimulus strength required to elicit a response?

Threshold stimulus Signup and view all the answers

What is a characteristic of the action potential?

All or none Signup and view all the answers

What is the period of rest for neurons?

Period of refractoriness Signup and view all the answers

During which period can no amount of stimulus strength re-excite the neuron?

Absolute refractory period Signup and view all the answers

What is the importance of the refractory period?

Renders neurons indefatigable Signup and view all the answers

What do nerve conduction velocity studies measure?

How fast an electrical impulse travels through the length of the nerve Signup and view all the answers

What is a use of nerve conduction velocity studies?

Diagnosing nerve disorders Signup and view all the answers

What symptoms may indicate the need for nerve conduction velocity studies?

Tingling sensation in the fingers or legs Signup and view all the answers

What determines the nerve conduction velocity?

Degree of myelination and axon diameter Signup and view all the answers

What is the function of neuroglial cells?

To support and maintain nerve cells Signup and view all the answers

What type of refractory period follows an absolute refractory period?

Relative refractory period Signup and view all the answers

Why does myelination increase the velocity of action potential?

Because myelination increases the distance between nodes of Ranvier Signup and view all the answers

What is the primary ion responsible for the negative membrane potential in most cells?

Potassium Signup and view all the answers

What equation is used to calculate the resting potential of a cell?

Goldman equation Signup and view all the answers

In which type of neurons does myelination increase the velocity of action potential?

Myelinated neurons Signup and view all the answers

What is the main factor that affects the velocity of action potential in unmyelinated axons?

Axon diameter Signup and view all the answers

Which of the following has the highest velocity of conduction?

Large myelinated axon Signup and view all the answers