The Nervous System Flashcards
What does the nervous system enable humans to do?
Enables humans to react to their surroundings and coordinate their behavior
What is it made out of?
A network of nerves
What do nerves do?
Transmit electrical impulses between the brain, spinal cord, and the rest of the body.
What is the role of nerves?
to transmit electrical impulses
What is the CNS (central nervous system) made up of?
The brain and the spinal cord
What helps the CNS carry out its responses?
Coordinates responses via:
- receptors
- sensory neurones
- motor neurones
- effectors
What does the PERIPHERAL nervous system consist of?
Consists of neurones that travel to and from the CNS.
What is the peripheral nervous system’s role?
Connects the CNS to the body
What is a nerve?
A bundle of many neurones
What is a neurone?
An individual nerve cell
What do neurones do?
Neurones carry electrical impulses between receptors, the CNS and effectors
What do nerves do?
Nerves carry electrical impulses from the CNS to the rest of the body
What do receptors do?
detect change/ stimuli
What does the CNS do?
Coordinate a response
What do effectors do?
Carry out a response
What are effectors and why are they called that?
Often glands or muscles
Called that because they go into action when they recieve nerve impulses of hormones.
What are nerve impulses from sense organs to the CNS called?
sensory impulses
What are nerve impulses from the CNS to the effectors called?
motor impulses
How does the nervous system act as a COORDINATOR?
Acts as a coordinator by directing responses to stimuli such as changes in body conditions
How do sensory receptors help to coordinate a response?
Sensory receptors, located in sense organs, stimulate sensory neurones.
What do relay neurones do?
Relay neurones in CNS stimulate motor neurones
What are examples of responses that effectors can carry out?
- muscle contraction
- hormone secretion
What is the junction between 2 neurones called?
A synapse / synaptic cleft
How do electrical impulses pass between neurones?
When an electrical impulse reaches the end of the first neurone, it triggers the release of a chemical. This chemical is called NEUROTRANSIMITTER
How does the neurotransmitter travel?
Diffuses across the gap
Does the process of the electrical impulse travelling over the synapse slow down the speed of nerve impulses?
Yes
Do synapses control the direction of impulses? If so, how?
Yes
- neurotransmitter substances are synthesised on only one side of the nerve impulse, while receptor molecules are only present on one side
How does heroin interact with receptor molecules at synapses?
Stimulates receptor molecules in synapses in the brain, triggering the release of dopamine
How do spider toxin and the toxin released by tetanus affect the nervous system?
Breaks down vesicles, releasing mass amounts of transmitter substance and disrupting normal synaptic function.
What is a reflex?
A very fast, automatic response to a stimulus that does not involve direct coordination by the concious part of the brain. They are INVOLUNTARY.