Signal Transmission in the Brain

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Questions and Answers

How do signals travel in the brain?

Signals travel electrically and chemically through neurotransmitters.

Electrical signals in the brain travel through non-excitable membranes.

False

What is the role of calcium in neurons?

Calcium is important for neurotransmitter transmission.

Which two ions are the most important in the neuronal membrane?

Sodium and potassium Signup and view all the answers

How is the resting potential of a neuron maintained?

Resting potential is maintained by ion equilibrium, especially potassium and sodium. Signup and view all the answers

The neuronal membrane is 40 times more permeable to sodium than potassium.

False Signup and view all the answers

What is the approximate resting membrane potential of a neuron?

-65 millivolts Signup and view all the answers

What causes electrical excitability in cells?

Electrical excitability occurs when sodium enters the cell, changing polarity. Signup and view all the answers

What is the function of the sodium-potassium pump?

It exchanges internal sodium for external potassium to maintain resting potential. Signup and view all the answers

Electrical excitability in neurons does not require any energy expenditure.

False Signup and view all the answers

What percentage of the body's total ATP is produced by the brain?

70% of the body's total ATP Signup and view all the answers

What factors contribute to the resting membrane potential?

Ion channels and the sodium-potassium pump Signup and view all the answers

What is an action potential?

An action potential is a signal that conveys information over long distances. Signup and view all the answers

What causes the depolarization of a membrane?

A generator potential causes membrane depolarisation. Signup and view all the answers

What is the threshold for generating an action potential?

A certain threshold must be reached to generate an action potential. Signup and view all the answers

The all-or-none law states that an action potential can occur partially if the threshold is not met.

False Signup and view all the answers

An action potential will be generated even if the membrane does not reach the threshold.

False Signup and view all the answers

A higher depolarising current will decrease the firing rate of action potentials.

False Signup and view all the answers

What is the maximum firing rate of action potentials?

The maximum firing rate is 1000 action potentials per second. Signup and view all the answers

How does frequency coding represent stimulus strength?

Frequency coding represents stimulus strength by firing rate. Signup and view all the answers

What is the absolute refractory period?

The absolute refractory period is when another action potential can't be generated. Signup and view all the answers

What is the relative refractory period?

The relative refractory period requires more current to generate an action potential. Signup and view all the answers

How does synaptic input affect membrane potential?

Synaptic input makes the membrane potential less negative. Signup and view all the answers

Describe the properties of sodium channels.

Sodium channels open quickly and stay open for about 1 millisecond. Signup and view all the answers

What is the range of propagation speeds for action potentials?

Action potentials propagate from 0.1 to 100 meters per second. Signup and view all the answers

Larger axons have a slower propagation speed for action potentials.

False Signup and view all the answers

What is saltatory conduction?

Saltatory conduction occurs when action potentials jump from node to node. Signup and view all the answers

What is the speed of action potential propagation in myelinated axons?

Myelinated axons can transmit signals up to 100 meters per second. Signup and view all the answers

Study Notes

Signal Transmission in the Brain

Signals travel electrically and chemically via neurotransmitters.
Electrical signals travel along excitable membranes conducting nerve impulses.
Calcium is crucial for neurotransmitter release.
Potassium and sodium are the main ions in neuronal membranes.
Resting potential is maintained by ion equilibrium (mainly potassium and sodium).
The membrane is significantly more permeable to potassium (about 40 times).
The typical resting membrane potential is around -65 millivolts.
Excitability arises when sodium enters the cell, altering polarity.
The sodium-potassium pump maintains resting potential by exchanging internal sodium for external potassium.
Brain activity requires significant ATP (about 70% of the body's total).
Resting membrane potential is impacted by ion channels and the sodium-potassium pump.
An action potential is a signal for long-distance transmission.
Depolarization of a membrane is triggered by a generator potential.
Action potentials only occur if a threshold is reached.
The "all-or-none" law states that an action potential occurs fully or not at all.
A higher depolarizing current increases the rate of action potentials.
The maximum firing rate of action potentials is approximately 1000 per second.
Stimulus strength is often represented by firing frequency (frequency coding).
During the absolute refractory period, another action potential cannot be generated.
The relative refractory period requires a stronger stimulus for another action potential.
Synaptic input typically makes the membrane potential less negative.
Sodium channels open quickly and stay open for around 1 millisecond.
Action potential propagation speed ranges from 0.1 to 100 milliseconds.
Larger axon diameters increase propagation speed.
Saltatory conduction, action potentials jumping between nodes, occurs in myelinated axons.
Myelinated axons can transmit signals at speeds up to 100 meters per second.

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Description

This quiz explores the mechanisms of signal transmission within the brain, focusing on the role of neurotransmitters and ion movement. It covers topics such as resting membrane potential, action potentials, and the importance of the sodium-potassium pump in maintaining ion balance. Test your knowledge on how these processes contribute to neuronal excitability and brain function.