Membrane-0.3 Flashcards
What does the Action Potential do during impulse conduction?
Action potential (AP) moves across the membrane, depolarizing adjacent areas.
What is the component of a cell membrane that makes a cell excitable?
Presence of voltage-gated Na+ channels.
What is the job of an axon?
Carries action potentials away from the cell body.
What is the job of dendrites?
Receive input signals for the neuron.
What is the axon hillock?
Initial segment where the action potential starts.
Why can’t action potentials turn back?
Refractory period inactivates Na+ channels.
What wraps around axons during myelination and why?
Glial cells wrap around axons, reducing current leakage.
What is the length constant (λ) represent?
Distance where voltage drops to 37% of original value.
What does the myelin sheath do? (2)
Insulates the axon
increases conduction speed.
What happens during saltatory conduction?
Action potentials jump between nodes of Ranvier in myelinated axons.
what is needed to increase conduction velocity? (2)
Increase axon diameter
Increase membrane resistance (e.g., myelination)
What happens during an electrical synapse?
Direct ion flow through gap junctions.
What happens during a chemical synapse?
Neurotransmitters released into the synaptic cleft.
