2. Nervouse Communication Flashcards
Function of receptor
Cell or protein on cell surface membranes which detect stimuli
Why are they lots of different types of receptors?
As receptors are specific to one type of stimulus
What are effectors?
cells that bring about a response to stimulus - produce effect.
Example of effectors.
Muscle cells
Cells found in glands
Pancreas
Link between receptors and effectors
They communicate via nervous system or hormonal system
What is nervous system made up of ?
Neurones
3 neurones
Sensory
Motor
Relay
Sensory neurone
Transmit electrical impulses from receptors to CNS
Motor neurones
Transmit electrical impulses from CNS to effector
Relay neurones
Transmit electrical impulses between sensory and motor neurones
What happens after stimulus is detected by the receptor cells ?
Electrical impulse sent along sensory neurone.
When the electrical impulse reaches end of a neurone chemicals called neurotransmitters take information across the synapse to next neurone.
Another electrical impulse is then generated.
CNS processes info and sends impulses along motor neurone to effector.
What is the central nervous system an example of ?
Coordinator
Function of coordinator
Formulate appropriate response to stimulus before sending impulse to effector
Example.
When you see someone waviness at you and you wave back
Stimulus - see friend waving.
Receptor- light receptors (photo receptors) in your eyes detect wave. Electrical impulses carried by sensory neurone to CNS.
CNS - processes information and sends electrical impulse along a motor neurone.
Effector - muscle cells stimulated by motor neurone
Response - muscles contract to wave arm back.
Example of
Receptor
Coordinator
Effector
Receptor - photo receptors.
Coordinator - CNS
Effector - muscle cells
What neurone stimulates the effector ( muscle cell)
Motor neurone.
When an electrical impulse reaches the end of the neurone, chemical messengers called neurotransmitters secreted directly onto cells, what does this mean?
Nervous response is localised.
Why are neurotransmitters quickly removed after found job?
So response is short lived.
To stop response continually occurring.
What are the cells neurotransmitters are released on to ?
Target cells
Specific receptors for neurotransmitters
What is a simple reflex.
Rapid
Involuntary response to stimulus
Automatic
Protective
How are simple reflected involuntary and automatic?
The pathway of communication goes through spinal cord but not thought conscious parts of the brain.
No time to spend deciding how to response.
when are Nervous impulses are voluntary ?
When they involve conscious parts of the brains.
You have time to think.
Example of simple reflect.
Hand withdrawal response.
Stimulus - touch hot surface.
Receptor - thermoreceptors In skin detect heat stimulus. Sensory neurone carried impulse to CNS.
CNS - a relay neurone in spinal cord carries impulse to Motor neurone.
Effector- Motor neurone carries impulse to muscle cells in biceps.
Response - bicep muscle contracts to pull hand away from heat source.
What happens if there is a relay neurone in the simple reflex?
Then it’s possible to override the reflex eg brain could tell your hand to withstand heat
