Neurons Flashcards
What is a neuron?
A neuron is a type of cell specialised to receive, transmit and process information.
Define cell body (soma)
The part of a cell that contains the nucleus; controls the maintenance and metabolic function of the cell.
Define dendrites
Fine branches that stretch from the cell body; they receive incoming information from other neurons and transmit it to the cell body
Define axon
Part of a nerve cell that transmits information from the cell body to other neurons or to cells in glands and muscles
Define Myelin sheath
A layer that protects the axon and assists with a speedy transmission of nerve impulses
Location and function of sensory neurons
Located primarily in PNS; detect energy from environment and carry info about it to CNS
Define afferent information
sensory information detected by sensory neurons, carried towards the CNS
Location and role of motor neurons
Located primarily in PNS; Carry commands from brain to muscles, organs and glands to enable movement
What happens when sensory info reaches brain?
Sensory info interpreted, decisions made about appropriate response. Usually this response involves some kind of movement, info about which is carried by motor neurons
Location and role of interneurons
CNS; carry info directly between sensory & motor neurons, involved in reflex arc
Define reflex arc
AKA Spinal reflex; coordinated by interneurons
When involvement of brain has been bypassed so body can respond instantly in a manner that enhances our survival
When are interneurons activated? What happens?
When sensory neurons receive intense sensation. When this happens, it is important for our survival that we react quickly. In order for an automatic response, interneurons in spinal cord relay information from sensory neurons directly to motor neurons.
Define synaptic gap
a chemical connection that bridges the gap between 2 neurons
neurotransmitters carry chemical messages across synapse to dendrite of receiving neuron
Define and describe axon terminal
Branches at end of axon; points at which chemical substance can be released to enable communication between 2 neurons
How do neurons communicate?
They communicate using electrochemical energy. While waiting for message, neuron has resting potential. Action potential is fired when neurotransmitter is received- races don axon to axon terminal, causing synaptic vesicles to open.
Synaptic vesicles contain neurotransmitters which are released across synaptic gap and received by receptor site of next neuron’s dendrite. This fires action potential in next neuron, process repeats until message reaches its destination.
