Neurophysiology: Action Potentials and Synapses

Questions and Answers

What happens to the areas left behind as the action potential spreads down the axon?

They convert into neurotransmitters

They initiate another action potential

They return to their resting state (correct)

They become depolarized

What is the role of the synapse in neuronal communication?

It stores neurotransmitters until needed

It conducts electrical impulses directly

It physically connects neurons

It allows chemical signals to pass between neurons (correct)

Which neuron releases neurotransmitters?

Presynaptic neuron (correct)

Postsynaptic neuron

Sensory neuron

Motor neuron

Which neurotransmitter is primarily associated with muscle action and memory?

Acetylcholine Signup and view all the answers

What effect do inhibitory neurotransmitters have on a neuron?

They decrease the likelihood of firing an action potential Signup and view all the answers

Which neurotransmitter is primarily linked to the reward system and addiction?

Dopamine Signup and view all the answers

What is the function of reuptake in neurotransmission?

It absorbs leftover neurotransmitters for recycling Signup and view all the answers

What is an effect of increased levels of GABA in the central nervous system?

Inhibition of neuron firing Signup and view all the answers

Which neurotransmitter is crucial for emotional arousal and metabolism of glucose?

Epinephrine Signup and view all the answers

What is the primary role of excitatory neurotransmitters?

To increase neuron firing likelihood Signup and view all the answers

Study Notes

Action Potential and Synapses

Action potentials propagate along the axon while areas behind return to resting state.
Synapses are pivotal for neuronal communication, allowing the passing of chemical signals.
Neurons do not physically touch; neurotransmitters traverse the synaptic gap to transmit signals.
Presynaptic neuron initiates the signal, while postsynaptic neuron receives it.

Neurotransmitter Release and Function

Action potentials trigger terminal buttons at the axon’s end to release neurotransmitters into the synapse.
Vesicles fuse with the presynaptic membrane, releasing their contents into the synaptic cleft.
Neurotransmitters bind to receptors on the postsynaptic membrane, potentially eliciting an action in the postsynaptic cell, depending on whether an action potential is achieved.
Unused neurotransmitters are typically reabsorbed by the presynaptic neuron via reuptake.

Types of Neurotransmitters

Excitatory Neurotransmitters
- Increase the probability of a neuron firing an action potential.
Inhibitory Neurotransmitters
- Decrease the likelihood of neuron firing an action potential.
Acetylcholine (ACh)
- Functions: muscle action, learning, attention, memory, REM sleep, emotion.
- Decreased levels associated with Alzheimer’s disease.
Dopamine (DA)
- Functions: movement, attention, memory, learning, emotion.
- Excess linked to schizophrenia; deficit related to Parkinson’s disease; significant role in addiction and reward pathways.
Endorphins
- Functions: mood regulation, pain relief, memory, learning, blood pressure, appetite, sexual activity.
- Therapeutic applications in pain management.
Epinephrine (Adrenaline)
- Functions: emotional arousal, memory storage, metabolism of glucose for energy release.
GABA (Gamma-Aminobutyric Acid)
- Functions: learning, anxiety regulation.
- Major inhibitory neurotransmitter in the central nervous system; tranquilizers like Valium enhance GABA's effects to reduce anxiety.
Glutamate
- Functions: learning, movement, memory.
- Key role in neural excitation within the central nervous system.

Description

This quiz covers key concepts in neurophysiology, focusing on action potentials and synaptic transmission. Learn how neurons communicate through electrical and chemical signals, exploring the role of neurotransmitters in the process. Test your understanding of neuronal structure and function.