Week 20 Flashcards
(28 cards)
What are the three main parts of a neuron?
Cell body, dendrites, axon
What is the primary function of a neuron?
Responsible for communications in the CNS and PNS by generating and conducting impulses
What is the role of dendrites in a neuron?
Provide large surface area to receive communications from other neurons
What is the axon responsible for?
Sends impulses away from the cell body to other neurons and cells
What are nodes of Ranvier?
Gaps in the myelin sheath of axons
What is neuroglia?
Collective term for 6 types of cells that support neurons
List the four types of neuroglia in the CNS.
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal
List the two types of neuroglia in the PNS.
- Schwann cells
- Satellite cells
What is the resting membrane potential of a neuron?
-70mV
What ions are primarily found extracellularly?
- Na+
- Cl-
What ions are primarily found intracellularly?
- K+
- PO4- (attached to ATP molecules)
What is the all-or-none principle in action potentials?
The action potential is always the same; a stronger stimulus does not cause a larger impulse
What is an action potential?
A nerve impulse involving a change in the charge of the membrane
What happens during depolarization?
The charge changes from negative to positive
What is repolarization?
Return to the resting membrane potential after an action potential
What is hyperpolarization?
A temporary dip lower than -70mV after repolarization
What role do neurotransmitters play in synaptic transmission?
They carry signals across synapses between neurons
What occurs at the synaptic cleft?
Neurotransmitters diffuse across to interact with receptors on the post-synaptic neuron
True or False: Neurotransmitters can only be excitatory.
False
Name an important excitatory neurotransmitter.
Acetylcholine
What is the function of the sodium-potassium pump?
Active transport that maintains the resting membrane potential
What is the difference between continuous conduction and saltatory conduction?
Continuous conduction flows uninterrupted along unmyelinated axons; saltatory conduction jumps from node to node in myelinated axons
What is the threshold potential for action potential initiation?
-55mV
What happens when the threshold potential is reached?
Voltage-gated Na+ channels open, causing rapid depolarization
