Neurons Flashcards
Types of neurons
- sensory
- motor
- interneurons
Sensory neurons
Conduct information towards the central nervous system
Motor neurons
carry information from central nervous system to an effector (muscle or gland)
Interneurons
Interpret sensory signals and initiate a response
Cell body of a neuron
Processes signal received
Dendrites
Receive signals
Axon
Single long extension down which a signal travels
Axon endings
Transmit a signal to next cell
Myelin sheath
Insulating outer layer of axon
Neuroglial cells
Schwann cells; support and protect neurons
Action potential
Nerve impulse; sudden reversal in the charge difference across membrane, followed by the restoration of original charge difference
During rest, how do the charges of a neuron differ?
The inner surface of membrane is more negatively charged that the outer surface
What ion has a high concentration on the inside of a neuron?
Potassium
What ion has a high concentration on the outside of a neuron?
Sodium
Resting potential
Charge differences across membrane of a neuron which results from the unequal distribution of ions
Depolarization
Signal causes sodium ion gates to open and sodium rushes into a nerve cell
Repolarization
Potassium ion gates open and potassium ions rush out; pumps redistribute ions
Refractory period
Brief instant immediately after an action potential occurs in which a neuron cannot be stimulated again for a short period
Synapse
Junction between a neuron and another neuron
Neurotransmitters
Chemicals that carry signals between neurons
Excitatory synapse
Causes increase in activity of postsynaptic cell (increased likelihood of action potential)
Inhibitory synapse
Causes decrease in activity of postsynaptic cell (decreases likelihood of action potential)
Once neurotransmitters are used, they are removed by…
- enzymes
- protein pumps (return to presynaptic neuron for reuse)
Neuron
Nerve cell; generates and transmits information
