Topic 2 (The CNS) Flashcards
How does the CNS coordinate to response?
Stimulus is detected by receptors which converts the information to nervous electrical impulse impulses along the sensory neurons to the CNS.
The CNS coordinates the response then the impulses travel through the CNS along relay neurone. The CNS sends information to an effector along a motor neurone. The effector then responds, e.g. a muscle contracts or a gland may secrete a hormone.
What is reaction time?
The time that takes you to respond to a stimulus
What do dendrites and denrons do?
They carry nerve impulses towards the cell body
What do axons do?
The nerve impulses away from the cell body
What does the myelin sheath do?
It acts as an electrical insulator with speed of the electrical impulse
What is the structure and function of a sensory neuron?
It has one long dendron which carries nerve impulses from receptor cells to the cell body which is located in the middle of the neurone. It has one short axon which carries nerve impulses from the cell body to the CNS.
What is the structure and function of a Motor neuron?
It has a many short dendrites which carry nerve impulses from the CNS to the cell body. It has one long axon which carries nerve impulses from the cell body to effector cells.
What is the structure of function of a relay neuron?
It has many short dendrites which carries nerve impulses from sensory neurons to the cell body. It has an axon which carries nerve impulses from the cell body to the motor neurons.
What is a synapse?
It is the connection between two neurone
How is the nerve signal transferred?
It is transferred by chemicals called new transmitters which diffuse across the gap western set of a new electrical signal in the next neurone. The transmission of a nervous impulse is very fast but it slows down a bit at the synapse because the diffusion of neurotransmitters across the gap takes time.
What is a reflex?
It is an automated and rapid response to stimuli which reduces a chance of being injured
How does the reflex arc work?
A stimulus is detected by receptors then impulses are sent along sensory neurons to a really neurone in the CNS. When the impulses reach to synapse between the sensory and the relay neurone, they trigger neurotransmitters to be released these cause impulses to be sent along the relay neurone. Then neurotransmitter are released between the relay and the motor neurone which causes an impulse to be sent along to the motor neurone. Then the impulse travels along the motor neurone to the effector. The muscle then contracts and moves away from the danger.
