Neuron structure
Largest part of the neuron; contains the nucleus.
What is the soma (cell body)?
Receive information and travel via the afferent pathway to the control (integration) center.
What is a sensory neuron?
Charge difference across a membrane measured in mV.
What is the membrane potential?
Phase where voltage-gated Na2+ & voltage-gated K+ channels are closed. Leak channels are open.
Bonus: Where an action potential is first produced in a neuron.
What is the resting potential?
Bonus: What is the initial segment?
Next cell that an neuron will propagate its signal to via a synapse.
What is the post-synaptic cell?
Extensions of the neuron that receive signals.
What are dendrites?
Issues a motor command via the efferent pathway from the control (integration) center to the effector.
What is a motor neuron?
-70 mV in most human cells.
Bonus: explain what the -70 mV means.
Bonus: What is the charge difference is more negative inside the cell compared to outside by a measured value of 70 mV.
Phase where voltage-gated Na2+ channels are open; voltage-gated K+ channels are closed. Leak channels are open.
Bonus: direction where Na2+ will move.
What is depolarization?
Bonus: What is into the cell?
Unmyelinated axons use this method to propagate APs.
What is continuous propagation?
Single long extension that transmits signals to other cells.
What is an axon?
Most common neuron in the brain; connect neural pathways. Make up the control (integration center).
What are interneurons?
Local stimulus than can be a depolarization or a hyperpolarization. Signal strength decreases with distance.
What is a graded potential?
Phase where voltage-gated Na2+ channels close; voltage-gated K+ channels open. Leak channels are open.
Bonus: direction where K+ will move.
What is repolarization?
Bonus: Out of the cell
Myelinated axons use this method to propagate APs
What is saltatory propagation?
Location where signals in the neuron are integrated together; is cone-shaped.
What is the axon hillock?
The brain and spinal cord.
What is the CNS?
Stimulus that is always a depolarization. Signal strength remains constant with distance. Is the language of the brain. All or nothing principle.
What is an action potential?
Phase where voltage-gated Na2+ channels are closed; voltage-gated K+ channels remain open. Leak channels are open.
Bonus: direction where K+ will move.
What is hyperpolarization? (extra negative)
Bonus: Continue to move out of the cell
During depolarization, all of the voltage-gated Na2+ channels are already open. During repolarization, the voltage-gated Na2+ channels are closed & inactivated. This period is when the neuron cannot respond to another incoming stimulus, regardless of its strength.
What is the absolute refractory period?
Location at the end of an axon that is bulb-shaped and forms part of the synapse.
What is a synaptic terminal?
All nerves in the body except the brain & spinal cord.
What is the PNS?
Value that must be reached to generate an action potential.
Bonus: these channels open if this value is reached
What is threshold?
Bonus: what are voltage-gated Na2+ channels. Na2+ will rush into the cell, depolarizing it.
Phase where voltage-gated Na2+ channels are closed; voltage-gated K+ channels close. Leak channels are open. But the cell is still extra negative. Mechanisms used to return the cell to its resting potential (2 answers).
What are: 1. Na2+/K+ ATPase (pump)
2. Na2+ & K+ leak channels
Later during repolarization, the voltage-gated Na2+ channels are closed, but released from inactivation. Voltage-gated K+ channels are open/remain open. This period is when the neuron can respond to another incoming stimulus, but only if it is sufficiently strong to reach threshold.
What is the relative refractory period?