Neuronal communication Flashcards
What are neurones?
They are specialised cells that transmit action potentials (impulses).
Structure of a neurone
- Dendron/ite
- Axon
- Myelin sheath
- Axon terminal
- Schwann cell
- Cell body
- Nucleus
- Nodes of ranvier
long to transmit signals over large distances
Dendron
Sends impulses to the cell body (from stimuli direction)
Cell body
neurone
does alot but can release neurotransmitters
Axon
Sends impulses away from the cell body (in the effector direction)
Myelin sheath
layers of plasma membranes (lipids)
insulates the neurone to speed the rate of transmission. produced by Schwann cells.
Schwann cells
Cells that produce the myelin sheath
Nodes of ranvier
Gaps on the neurone not covered by the myelin sheath
Sensory neurone
Structure
Have a long dendron and short axon
Motor neurone
Cell body in the CNS. Long axon and short dendrites.
Relay neurone
Cell body in the middle. Short dendrites and axons
What are myelinated neurons and where are they found?
- Neurones that have a myelin sheath.
- Control muscle movement
- Found in peripheral neurones
What is transmission like in myelinated neurones?
- Fast
- Action potential moves from node-to-node
- Ion movement occurs at Nodes of Ranvier
What are non-myelinated neurons and where are they found?
- Neurones w/o a myelin sheath
- Control breathing and digestive system
- Found in the CNS
What is transmission like in non-myelinated neurones?
- Slow(er)
- Action potentials move as a wave
What are sensory receptors?
Cells that are specialised to detect changes in our environment
* they are energy transducers (generator potential)
* specific to one type of stimulus
Habituation
When receptors don’t respond to constant stimulus
