The Nervous System Flashcards
What should all control systems include?
Receptors, coordination centre and effectors
What do receptors do?
Detect stimuli(touch)
What does the ‘coordination centre’ do?
Receives and processes information from receptors around the body
Give an example of the coordination centre
Brain, spinal cord or pancrease
What do effectors do?
Bring about responses which restores optimum levels( body temp, blood sugar levels)
Give an example of effectors
Muscles and glands ( they include muscle contradictions or hormone release)
What are nerve cells called?
‘Neurones’
What are neurones function?
To carry electrical impulses from one place to another
What are a bundle of neurones called?
A nerve
What are the 3 types of neurone?
Sensory
Motor
Relay
Name some features of the nerve cells
Axon( long fibre), myeline sheath
Dendrons
What’s the function of the axon?
Long so they can carry messages up and down the body
What’s the function of the myeline sheath?
Insulates the axon
What’s the functions of dendrons?
Branch further as dendrites at each end- receive incoming impulses from other neurones
What’s a synapse?
The gap between 2 neurones when they meet
State what happens when an electrical impulse moves from one neurone to another
1) electrical impulse travels along the first axon
2) this trigger the nerve-ending of a neurone to release chemical messengers caused neurotransmitters
3) these chemicals diffuse across the synapse+bind with receptor molecules on the membrane of the 2nd neurone
4)receptor molecules on the 2nd neurone bind to specific neurotransmitters released from 1st neurone
5)this stimulates the 2nd neurone to transmit the electrical impulse
What do receptor cells detect?
A change in the environment( stimulus) and start electrical signals along neurones- this moves to central nervous system -CNS.
What happens after the receptor cell moves the electrical signals to the CNS?
The relay neurone coordinates the responses, sending messages back along different neurones to the muscles
What do the effectors do after the CNS sent the response?
Muscles contract/relax
Glands secrete hormones
Give what happens receptors to response
Stimulus
Receptor(sensory neurone)
CNS/relay neurones
Motor neurones
Effectors
Response
What’re receptors?
Groups of specialised cells-detect a change in the environment and stimulate electrical impulse in response
Give the pathway of a reflex
Stimulus
Receptor
Sensory neurone
Relay neurone
Motor neurone
Effector
Response
Give the steps in the reflex arc in more detail
1) skin detects a stimulus
2)sensory neurones send electrical impulses to relay neurones- located in the spinal chord. They connect sensory neurones to motor neurones
3) motor neurones send electrical impulses to an effector
4) the effector produces a response
Give the aim of the practical to investigate human reaction time
To determine whether a factor such as caffeine or background noises affects reaction time
What do sensory neurones do?
Transmit signals from receptors
What do relay neurones do?
Transmit signals between neurones
What do motor neurones do?
Transmit signals to effectors
Give the sequence of events for a voluntary response
-Stimulated receptor— sensory neurones
-Sensory neurone send a signal to the spinal chord then to the brain
-The brain processes then sends a signal via a motor neurone to the effector
- effector carried out the response
Give the sequence of an involuntary action (reflex)
-stimulated receptor send a signal to a sensory neurone
-the sensory neurone sends a signal to a relay neurone in the spinal chord
-relay neurone connects to a motor neurone
-Response travels from the motor neurone to the effector
-effector carries out the response
