neurons, neurontransmitters Flashcards
(23 cards)
What is a neuron?
A neuron is a nerve cell, the basic unit of the nervous system.
How many neurons are in the human body?
There are roughly 100 billion neurons in the human body, with 80% found in the brain.
How do neurons transmit information?
Neurons transmit information chemically and electrically.
What is the soma of a neuron?
The soma is the cell body, which includes the nucleus containing the cell’s genetic material.
What are dendrites?
Dendrites stick out from the cell body and carry impulses from neighboring neurons towards the cell body.
What is an axon?
An axon is a tube-like structure that carries impulses away from the cell body down the length of the neuron.
What is the myelin sheath?
The myelin sheath is a fatty layer over the axon that protects it and speeds up electrical transmission of impulses.
What are the Nodes of Ranvier?
Nodes of Ranvier are gaps between the myelin sheath that allow impulses to ‘jump’ across the gaps, increasing speed.
What is the axon terminal?
The axon terminal is the end of the axon, involved in communication across a gap known as the synapse.
What are sensory neurons?
Sensory neurons carry messages from sensory receptors along the peripheral nervous system (PNS) to the CNS.
What are motor neurons?
Motor neurons carry messages from the CNS to effectors in the body.
What are relay neurons?
Relay neurons connect sensory and motor neurons together and are only found in the CNS.
What is resting potential?
Resting potential is when neurons maintain a resting potential of approximately -70mV.
What is depolarization?
Depolarization occurs when sodium channels open, allowing Na+ to flow into the neuron, making the membrane potential more positive.
What is the threshold in action potential?
The threshold is around -55mV, and if reached, an action potential (AP) is triggered.
What happens during repolarization?
During repolarization, potassium channels open, allowing K+ to exit the neuron, restoring the negative internal charge.
What is hyperpolarization?
Hyperpolarization is when the neuron temporarily becomes more negative than the resting potential before returning to normal.
What is the refractory period?
The refractory period is when a neuron cannot fire another AP until it returns to its resting state.
What occurs at the synapse during an action potential?
A neuron releases neurotransmitters at the synaptic gap, which elicits human behavior.
What are neurotransmitters?
Neurotransmitters are fast chemical messengers that transmit signals across synapses in the brain.
What is the function of neurotransmitters?
Each neurotransmitter has a specific molecular structure and fits into a specific type of postsynaptic receptor.
What did Olds and Milner (1954) study?
They studied rats and connected wires to their brains to trigger the pleasure center, observing addictive behavior.
What was the finding of Jones and Stone (1990)?
They found that regular cannabis users could not detect the difference between marijuana and a placebo, suggesting a cognitive element in drug-taking.
