Biology Flashcards
Sequence of Stimulating the Next Neuron
Neurotransmitter –> Synapse –> Dendrite
What is a neuron?
The basic cell that makes up the nervous system and is responsible for receiving and sending messages within that system.
What is the function of the myelin sheath?
It acts like insulation for the neuron, helping to speed up the transmission of electrical signals along the axon.
What are the three main parts of a neuron?
Dendrites, axon, and cell body (soma).
What is the function of dendrites?
To receive messages from other neurons and send them toward the cell body.
What is the function of the axon?
To carry electrical impulses away from the cell body toward other neurons, muscles, or glands.
What is the synapse?
The gap between two neurons where neurotransmitters are released to transmit messages.
What are axon terminals?
Rounded areas at the ends of branches at the end of the axon, responsible for communicating with other nerve cells by releasing neurotransmitters.
What are synaptic vesicles and their function inside the axon terminal?
Synaptic vesicles are sack-like structures inside the axon terminal that contain neurotransmitters. When released, these neurotransmitters have an effect on the next cell, facilitating communication between neurons.
What is the all-or-none principle in neural impulses?
The all-or-none principle states that a neuron either fires completely or does not fire at all. After firing, the neuron returns to its resting potential.
What is the role of the synapse in neuron communication?
The synapse (gap), is a fluid-filled space between the axon terminals of the pre-synaptic neuron and the dendrites or surface of the post-synaptic neuron, where neurotransmitters are released to communicate between cells.
What are receptor sites on the post-synaptic neuron?
Receptor sites are holes in the surface of the dendrites, shaped to fit specific neurotransmitters, functioning like a “lock and key” mechanism.
How do neurons communicate through neurotransmitters?
Neurons communicate by using excitatory and inhibitory neurotransmitters:
Excitatory neurotransmitters
activate the receiving cell, causing it to fire.
Inhibitory neurotransmitters
deactivate the receiving cell, causing it to stop firing.
What are agonists in the context of neurotransmitter effects?
Chemical substances (e.g., drugs) that mimic or enhance the effects of a neurotransmitter on receptor sites, increasing or decreasing receptor activity.
What are antagonists in the context of neurotransmitter effects?
Chemical substances that block or reduce the action of neurotransmitters, inhibiting the cell’s response.
Acetylcholine (ACh)
Excitatory/Inhibitory; arousal, attention, memory, controlling muscle contractions
Norepinephrine (NE)
Mainly excitatory; arousal + mood
Dopamine (DA)
Excitatory/Inhibitory; sleep, mood, anxiety, appetite; control of movement and sensing pleasure
Serotonin (5-HT)
Excitatory/Inhibitory; sleep, mood, anxiety, appetite
Gaba-aminobutric Acid (GABA)
MAJOR INHIBITORY NEUROTRANSMITTER; sleep and movement
Glutamate
MAJOR excitatory neurotransmitter; learning, memory formation, nervous system development, and synaptic plasticity
Endorphins
Inhibitory neural regulators; pain relief