P2 - 5.2 The Nervous System, Synapses & Reflexes Flashcards
What 2 things do different parts of are body need to be able to communicate to do
- coordinate behaviour
- respond to our surroundings
What 2 organ systems do we rely on to communicate around our body
- nervous system
- endocrine system
What is an individual nerve cell called
A neurone
What are the 3 types of neurones
- relay
- motor
- sensory
Draw and label a neurone
- long
- thin
- dendrites (lots of branch connections either end)
- cell body
- nucleus
- myelin sheath (layers outside the long thin bit)
- ribosomes
- cell membrane
- cytoplasm
- axon (the long thin bit)
What are neurones designed to do
Carry electrical impulses from one end to the other
What feature of a neurone allows to pass messages to other nerve cells
Lots of branch connections at either end
What can we say a neurone is like
A biological version of a wire carrying a small current
What is a synapse
the empty space/gap between each nerve cell
How do electrical impulses travel from one nerve to the other
At the end of a nerve cell, electrical impulses it releases chemicals that diffuse through the gap of the synapse until it reaches the other nerve cell that converts it back into an electrical impulse
How many nerves are in the nervous system
x100 billion
What is the central nervous system
Where all the thinking happen, it takes in sensory information and sends out orders to create a response to something, it is made up of spinal chord and brain
What 2 organs make up the central nervous system
Brain
Spinal chord
How does the central nervous system receive information
Through sensory neurones that have relied an electrical impulse from the receptors all over your body etc in your skin/eyes
What are some examples of what receptors can detect
- changes in temperature
- sharp objects that might harm us
- CO2 in bloodstream
How does the CNS (central nervous system) order our body what to do
When the body has decided on a response it sends electrical impulses from the brain through our motor neurones that will tell our effectors to contract or release hormones etc
What are the 2 types of effectors
- glands (release hormones)
- muscles (contract)
What is a reflex arc
Technical term for the nerve pathway that causes our unconscious reflexes
Etc. moving hand away quickly from hot pan to prevent burns on body
What are 2 benefits of reflexes
- automatic
- rapid
Why does the body have reflexes
To prevent the body from harm/getting hurt
Scenario:
You have accidentally touched the end of a pin.
Describe what your nervous system would do in response to the scenario
1) Your receptors in your skin detect stimuli of pain/ pressure which sends an electrical impulse through sensory neurone
2) sensory neurone takes electrical impulse to relay neurone in brain/ CNS
3) CNS forms a response and sends electrical impulse from relay neurone to motor neurone
4) motor neurone send electrical impulse to effector such as muscle
5) muscle contracts moving your hand away quickly
What is a stimuli
A change in a condition that is detected by receptor
Etc temperature change
Pricking finger on a pin
The pathway of a reflex arc
automatic / response / sensory neurone / stimulus / motor neurone / reflex
_____ ➔ receptor ➔ ________ ➔ relay neurone ➔ ________ ➔ effector ➔ _______
stimulus ➔ receptor ➔ sensory neurone ➔ relay neurone ➔ motor neurone ➔ effector ➔ response
