Neurons , Nerves and The Nervous system Flashcards
What is a neuron ?
a nerve cell; the basic building block of the nervous system
What are the 3 types of nerve cells ?
Motor neurons
Sensory neurons
Interneuron
What is the nerve pathway ?
Stimulus , receptor , sensory neuron , brain , relay neuron , effector , response
What is a glial cell ?
glial cells support the nervous system by carrying out functions such as :
Maintaining homeostasis
Formation of myelin
Providing support
Providing protection
Removing debris and old neurons
What is resting potential?
The difference in electric charge between the inside and outside of a neuron’s cell membrane
-70 mv
How does a neuron maintain a resting potential ?
Movement of charged atoms (ions) into and out of the cell using ion pumps / channels.
When ATP is present 3 positive sodium ions are pumped out of the cell.
Two positive potassium ions are pumped into the cell.
Therefore there is a net movement of positive ions out of the cell making the inside negative charged compared to the outside of the cell
What are the main components of a nerve cell ?
Dendrite , Cell body , Axon ,Axon terminal ,Schwann cells ,Myelin sheath, Nodes of ravinder, Nucleus
Which ions are found within nerve cells ?
Na - sodium +
CL - chloride -
K - Potassium +
What are the 3 stages of an action potential ?
Depolarisation , Repolarisation , refractory period
What happens during depolarization ?
Sodium channels open within the membrane of the axon
Na+ ions are made more concentrated outside the neuron
Na+ channels open causing a passive influx of sodium , making the membrane potential positive
What happens during Repolarization ?
Due to the influx of Na+ , K + channels will open within the membrane of the axon .
K+ ions are more concentrated inside the neuron , opening potassium channels causes an efflux of potassium.
The efflux of potassium causes the membrane potential to return to a negative internal difference
What happens during the refractory period ?
the sodium ions are pumped back out of the cell and the axon returns to the original state of polarity, called the resting potential, prepare to fire again
What is saltatory conduction?
saltatory conduction is the “jumping” of an action potential between the unmyelinated nodes of ranvier
