The Nervous System Flashcards
What forms the central nervous system (CNS)?
The brain and the spinal chord.
What connects the CNS to the rest of the body?
The Peripheral nervous system.
What is a neurone?
Collections of many nerve cells.
What is the chain of events which information passes along the nervous system?
A receptor detects a change in conditions (a stimulus). This message is carried to the CNS by a sensory neurone. Then an motor neurone caries a message from the CNS to an organ (an effector) which carries out a response.
What is a synapse?
The junction between the end plate of one neurone and the dendrite of the next.
What is the fatty myelin sheath on a nerve for?
It gives electrical insulation between neighbouring cells and makes impulses travel faster.
What is the axon in a nerve cell?
It’s the long fibre which carries the away from the cell body over long distances.
What are differentiating features of a motor neurone?
They carry impulses from the CNS to the effector (organ).
Visually, it has a myelin sheath and a cell body at one end of the axon.
What are differentiating features of a relay neurone?
The carry slow impulses across spinal chord.
Visually, it has no myelin sheath and a cell body at the end of the axon.
What are differentiating features of a sensory neurone?
They carry impulses from the receptor to the CNS.
Visually, they have a myelin sheath and the cell body in the middle of the axon.
What is a reflex action?
A rapid and automatic response to a stimulus.
What is a reflex arc?
The nerve pathway involved in a reflex action.
What is he path taken in a reflex arc?
Receptor -> Sensory neurone -> Relay neurone -> Motor neurone -> Effector
EXTRA- What are antagonistic muscles?
Muscles which work together to create movement. This happens when one muscle contracts and the other relaxes.
