13.2 Neurones Flashcards
What is the role of the nervous system?
detect, process & respond
to stimuli
What is the structure of a general neurone?
- CELL BODY
- many mitochondria + endoplasmic reticulum for neurotransmitter synthesis
- DENDRON
- nerve fibres transmitting electrical impulses towards cell body.
- divide into smaller dendrites
- AXON
- nerve fibres transmitting electrical impulses away from cell body
What are the 3 types of neurones from longest to shortest?
(longest)
sensory
motor
relay
(shortest)
Where does the sensory neurone transmit electrical impulses to and from?
from receptor ⟶ relay/motor/brain
Where do motor neurones transmit electrical impulses to and from?
from relay/sensory ⟶ effector
Where do relay neurones transmit electrical impulses to and from?
between neurones
What is the general pathway of electrical impulses through neurones?
What is a myelinated neurone?
neurone with myelin sheath around axon
How do Schwann cells increase the rate of electrical impulse transmission along the axon?
- Schwann cells wrap around axon, adding phospholipid bilayer
- wrap around many times, adding many phospholipid bilayers
- High lipid content acts as insulator
- Electrical impulse forced to “jump” between Nodes of Ranvier, (as opposed to continuous transmission)
- increases impulse transmission
- Electrical impulse forced to “jump” between Nodes of Ranvier, (as opposed to continuous transmission)
What is the difference in structure of the 3 types of neurone?
- Sensory:
- 1 long dendron + shorter axon (cell body further along neurone)
- Motor:
- 1 long axon + many short dendrons (cell body @ end)
- Relay:
- many short axons + dendrons
What is this type of neurone?
Sensory neurone
What is this type of neurone?
Relay neurone
What is this type of neurone?
Relay neurone
What makes the myelin sheath a good electrical insulator?
Made from layers of phospholipid bilayer,
so high lipid content,
so good electrical insulator.
What type of neurone is this?
(myelinated) sensory
What type of neurone is this?
(myelinated) motor
What is this part of a neurone?
Node of Ranvier
What is a Node of Ranvier?
Gap in the myelin sheath of a nerve
between adjacent Schwann cells
What is this part of a neurone?
Cell body
(contains nucleus + many mitochondria + endoplasmic reticulum for neurotransmitter synthesis)
How is the cell body of a neurone specialised?
contains many mitochondria + endoplasmic reticulum
for neurotransmitter synthesis
What is this part of a neurone?
Schwann cell/myelin sheath
What is the difference in function between axons and dendrons?
axons carry electrical impulses away from cell body
dendrons carry electrical impulses towards cell body
What is this part of a neurone?
dendrite
What is this part of a neurone?
dendron
What is this part of a neurone?
axon
