Nerves Flashcards
What is a stimulus?
A change in the animals surroundings
What is a receptor?
The organ which detects the change
What is the effector?
Muscles are the effectors which contract in response to the stimulus.
How is the response made?
By the endocrine or nervous system.
What are the examples of a receptor?
Sense organs: eye, ear, tongue, nose, skin
What does the central nervous system consist of?
The brain and the spinal cord.
What does the Central nervous system do?
Coordinates all of the nervous responses such as moving or reflexes.
What is the peripheral nervous system?
It contains all of the other nerves which send impulses to all the effectors.
What are the three types of neurone?
Relay, motor, sensory
Describe the path of impulses in terms of neurones.
Impulses from receptors pass along sensory neurones until they reach the brain and spinal cord. Impulses pass to relay neurones in the CNS. The impulse is then passed to effectors along motor neurones.
What is the dendrite?
Tree like projections which connect to different neurones. One neurone can connect to many other neurones.
What is the axon?
The long section - electrical impulses travel long distances through the axon.
What is the myelin sheath?
Insulates the axon and speeds up the transmission of the impulse.
What are reflexes?
Automated actions which do not involve the brain.
What is the movement of the impulse from receptor to effector called?
The reflex arc
Describe the steps involved in the reflex arc.
The receptors detect the stimulus and send an impulse along the sensory neurone.
The sensory neurone passes the impulse to the spinal cord to a relay neurone. The relay neurone then passes the impulse through the spinal cord to a motor neurone.
The motor neurone causes the effector to contract and move the arm away from the stimulus.
What is the small gap between two neurones called?
The synapse
What happens at the synapse?
An electrical impulse travels along an axon.
This triggers the nerve ending of a neuron to release chemical messengers called neurotransmitters.
These chemicals diffuse across the synapse and bind with the receptor molecules on the membrane of the next neuron.
The receptor molecules on the second neuron bind only to the specific chemicals released for the first neuron. This stimulates the second neurons to transmit the electrical impulse.
What can be an effector?
Muscles or glands
What is a neurotransmitter?
A chemical that transmits the impulse across the synapse.
