Neurones - Seneca Flashcards
How does the nervous system protect organisms?
The nervous system protects organisms from harm by responding to changes in the environment. It does this by coordinating communication between different parts of organisms.
How does the central nervous system co-ordinate effectors ?
The CNS coordinates the response of effectors.
Effectors are muscles or glands that act in response to a change in the internal or external environment
Spinal cord use in coordinating effectors
It is also important in coordinating the response of effectors to changes in the environment.
Where do neurones operate / send impulses through
Neurones (nerve cells) carry electrical impulses (signals) between receptors, the central nervous system (CNS) and effectors.
Describe how an impulse is carried across the synapse ? (6marks)
Synapses are gaps between neurones.
Nerve impulses must travel across these gaps:
The electrical impulse reaches the end of the neurone before the synapse.This triggers the release of chemicals called neurotransmitters.The neurotransmitters diffuse (move down a concentration gradient) across the synapse.
The neurotransmitters bind to receptors on the next neurone.The presence of the neurotransmitter causes the production of a new electrical impulse in the next neurone.
What is the axon insulated by ?
Axons are covered in a layer called a myelin sheath. This insulates the neurone, so electrical impulses travel down it more quickly.
How to remember impulse travel In an axon
A
xons carry nerve impulses
A
way from the cell body
Axons carry nerve impulsesAway from the cell body
So dendrites towards
What is the function of effectors
Effectorsbring about actions in response to a change in the internal or externalenvironment. Such actions include muscles contracting and glands secreting hormones.
What are neurones made up of ?
Nerve cells
What are neurones in terms of nerve cell ?
Neurones are types of nerve cell (bundles of nerve cell)
