L2 - Neurons Flashcards
1
Q
Neurons
A
Neurons are specialised nerve cells that move electrical impulses to and from the CNS
2
Q
Structure of Neurosen (parts)
A
- cell body
- nucleus
- dendrites
- axon
- myelin sheath
- Schwann cells
- nodes of ranvier
3
Q
Cell Body
A
Control centre of the neuron
4
Q
Nucleus
A
Contains genetic material
5
Q
Dendrites
A
Receives an electric impulse (action potential) from other neurons or sensory receptors (eyes, ears, tongue, skin)
6
Q
Axon
A
A long fibre that carries the electrical impulse from the cell body to the axon terminal
7
Q
Myelin Sheath
A
Insulating layer that protects the axon + speeds up the transmission of the electrical impulse
8
Q
Schwann cells
A
Make up the myelin sheath
9
Q
Nodes of Ranvier
A
Gaps in the myelin sheath = speed up the electrical impulse along the axon
10
Q
Three types of neuron
A
- sensory neuron
- motor neuron
- relay neuron
11
Q
Sensory Neurons
A
- found in sensory receptors
- carry electrical impulses from sensory receptors to CNS (brain + spinal cord) via the PNS
- convert info from sensory receptors into electrical impulses
- impulses converted into sensations e.g. heat, pain etc.. when they reach the brain = body can react appropriately
- some sensory impulses terminate @ spinal cord = allows reflexes to occur quickly without the delay of waiting for the brain to respond
12
Q
Motor Neurons
A
- located in the CNS
- project their axons outside of the CNS
- send electrical impulses via long axons to glands + muscles = affect their function
- gland + muscles = effectors
- when stimulated = release neurotransmitters, bind to the receptors on muscles to trigger a response, leads to movement
13
Q
Relay Neurons
A
- found in the CNS
- connect sensory neurons to motor Neurons = communicate with each other
- during a reflect arc (the relay neurons found in spinal cord decide how to respond without waiting for the brain to respond)
