L20. Neurons Flashcards
What do dendrites do?
Receive the signal which activates a neuron
What is the tapered axon area called?
Axon hillock
Name the net overall charge of the intracellular fluid.
Negative
Name the overall net change of the extracellular fluid.
Positive
What is the term given when the membrane potential rises above -70mv?
Depolarised
What is the term given when the membrane potential falls below -70mv?
Hyperpolarised
What type of event is action potential?
All-or-none
Can 2 action potentials fire at the same time?
No, the first one must end before a second can start.
Can action potentials be added together?
No
What is the period called when Na+ channels are inactivated?
Period of inexcitability - refractory period
How does current flow in the ICF and ECF?
From positive to negative
Which length of axon conducts impulses more rapidly?
Large axons
What is the sheath on Schwann cells made of?
Myelin
What is the myelin sheath interrupted by?
Nodes or Ranvier
What happens at the nodes of ranvier?
The axon membrane is exposed to the ECF for ion flow. It appears that the action potential jumps from node to node as conduction speed is increased in the myelinated regions.
