Unit 3.1 - Neurons Flashcards
What are glial cells?
They are support cells that help the nervous system become more efficient.
What are dendrites?
They branches with neuro-receptors, they receive imputes information by having chemicals and neurotransmitters bond to it. They mean “tree” in Greek. They relay information.
What is the soma?
It is the cell body, it contains the nucleus and other organelles. They also convert noise to impulse.
What is an axon?
It carries neural impulses by depolarizing and repolarizing, which creates a wave.
What are the terminal buttons?
They contain synaptic vesicles which package and distribute neurotransmitters to the extracellular space; therefore, it is an output system.
What is a resting potential?
It is the state of readiness in a membrane, it is usually -70 mV. The K+ ions are inside and Na+ ions are outside. Inside is negative while outside is positive.
What is an action potential?
An action potential is electrical signal that moves down the axon to the terminal buttons, as it moves down, there is an influx of Na + each time.
What is happens when a cell receives a signal?
The signal opens Na+ gates open, which allows them to enter the cell and make the membrane’s charge become positive. It has to cross the threshold of excitement (-55 mV), which causes more Na+ to come out and depolarization to occur.
What occurs at repolarization?
At the peak (+30 mV), the Na+ gates close and the K+ gates open. The membrane starts to become negative again.
What is hyperpolarization?
The K+ gates close too slowly, so more K+ leaves the membrane, making it become more negative than resting potential. The sodium-potassium pump eventually returns it to its original voltage.
What is the refractory period?
It is the rest period, where it cannot fire again or go in the wrong direction. The gates cannot open again until the membrane is at resting potential.
What do action potentials have to be like (binary signals)?
They have to be all or nothing. They may differentiations in frequency, but they cannot stop halfway.
What are the myelin sheath?
They are white matter that insulate the axon. This improves the speed and efficient of the action potential.
What occurs at the nodes of ranvier?
It is where ion exchange occurs, saltatory conduction is the leap from one node to another.
What is a synapse?
It is where communication between two different neutrons occur via the release of neurotransmitters, where they bind to receptors.
