The nervous system Flashcards
What is a neuron?
Basic functional unit of the nervous system (nerve cell)
How many neurons typically exist in the body?
100 billion
What are neuroglia?
The supporting cells of the nervous system
What are the 4 types of supporting cells in the CNS?
Oligodendrocytes
Astrocytes
Microglia
Ependymal cells
What do oligodendrocytes do?
Form and maintain myelin
What do astrocytes do?
Help to form the blood-brain barrier
What do microglia do?
Remove bacteria and damaged tissue
What do ependymal cells do?
Secrete cerebrospinal fluid (CSF)
What type of cells myelinate axons in the CNS and PNS?
CNS - Oligodendrocytes
PNS - Schwann cells
What are the steps of an action potential?
Stimulus received
This changes the voltage such that the threshold is met
Opening of voltage gated sodium channels
Sodium moves into cell
Inside of cell becomes more positive (depolarisation)
Change in voltage triggers opening of voltage gated potassium channels
Potassium leaves the cell
Inside of the cell becomes more negative (repolarisation)
Return to resting membrane potential
What are the stages of synaptic transmission?
Arrival of an action potential
Opens up voltage gated Ca2+ channels
Triggers vesicles to move and fuse with nerve membranes
Neurotransmitters diffuse across synaptic cleft
Act on specific receptors on post synaptic neurone
