Neurons Flashcards
Neurons make up what percentage of cells in the brain?
10%
How many billion neurons are there in the brain?
100 billion neurons;
1,000,000 billion synapses;
101,000,000 possible circuits
Name the three types of Glia or Glial Cells:
- Astrocytes
- Microglia
- Oligodendrocytes
Astrocytes function:
– Supply nutrients from blood to the neurons for energy
– Maintain “blood-brain barrier” (keep substances in bloodstream separated from neurons of brain)
Microglia function:
– brain’s immune system
– Clean up foreign or toxic substances
Oligodendrocytes function:
– Produce a fatty substance called “myelin” which wraps around axons of neurons.
– Essential for transmission of neural signals
Name the parts of a neuron:
– Dendrites – Cell body – Axon – Myelin – Axon terminals / synapses
What is another name for the cell body?
Soma
Function of Axon terminal / Terminal boutons:
– Forms synapses with another neuron
– Sends information to that neuron
– Secretes neurotransmitters when an action potential reaches them
Function of synapses:
Join axon terminals of one neuron to dendrites of another neuron for transmission of signals
Pre-synaptic neural signals go
From cell body to axon terminal
Axon – Axon Terminal – Synapse
Post-synaptic neural signals go
From dendrite to cell body
Synapse – Dendrite – Cell body
Membrane potential is
Difference in the electrical charge (voltage) between inside and outside cell, across cell membrane wall
Resting potential is
– Difference in the electrical charge (voltage) across cell membrane wall when neuron is at rest (no Action Potential)
rest
– resting potential of neuron is -70mv
– more sodium Na+ outside, more potassium K+ inside
Action potential is
Transmission of electrical signal along axon
