Neuronal Physiology Flashcards
(17 cards)
What are the parts of a neuron?
Cell body (soma), dendrites, axon, and axon terminals.
What do dendrites do?
Receive incoming signals from other neurons or sensory cells.
What is the function of the axon?
Conducts action potentials away from the cell body.
What is a graded potential?
A small, local change in membrane potential that varies in strength and decays with distance.
What is an action potential?
A large, rapid, all-or-none depolarization that travels along the axon without loss of strength.
How is an action potential generated?
f a graded potential reaches threshold at the axon hillock, voltage-gated Na+ channels open, causing depolarization
What happens during the falling phase of an action potential?
Voltage-gated K+ channels open and Na+ channels inactivate, repolarizing the membrane.
What causes the hyperpolarization phase?
K+ channels stay open a bit too long, causing the membrane potential to become more negative than resting.
What is the absolute refractory period?
A period when no new action potential can be generated because Na+ channels are still inactivated.
What is the relative refractory period?
A period when a stronger-than-normal stimulus is required to trigger another action potential.
What ensures one-way propagation of action potentials?
The refractory period prevents backward movement of the impulse.
What affects the conduction speed of an action potential?
Axon diameter and myelination (larger, myelinated axons conduct faster).
What is a synapse?
A junction between two neurons or between a neuron and an effector cell.
How is information passed at a chemical synapse?
Neurotransmitters are released from the presynaptic neuron, cross the synaptic cleft, and bind to receptors on the postsynaptic cell.
How is information passed at a chemical synapse?
Neurotransmitters are released from the presynaptic neuron, cross the synaptic cleft, and bind to receptors on the postsynaptic cell.
What triggers neurotransmitter release?
Ca2+ influx into the axon terminal after an action potential opens voltage-gated Ca2+ channels.
What are EPSPs and IPSPs?
EPSPs depolarize the postsynaptic membrane (more likely to fire), while IPSPs hyperpolarize it (less likely to fire).
