SB2g Nervous System Flashcards
What is the central nervous system (CNS) made up of?
the brain and the spinal cord.
What do the nerves (neurones) make up?
the rest of the nervous system.
What does the structure of the CNS and nerves allow?
different parts of our body to communicate with each other via electrical signals called impulses.
What is neurotransmission?
impulses travelling around our body.
What are the three different types of neurone?
.sensory
.relay
.motor
Explain what our senses do.
.they make us aware of changes in our surroundings and in our bodies
.we have sense cells which respond to stimuli (stimulus)
What is a stimulus?
a change in light, temperature, pressure, etc, which produces a reaction in a living organism.
What are structures that respond to stimuli called?
receptors.
Where are receptors found?
in the skin or concentrated in special organs e.g. tongue, ear.
Where do sensory neurons send impulses from and to?
from receptors to the CNS.
Where do relay neurons send impulses from and across?
from sensory neurones, across the CNS.
Where do motor neurons send impulses from and to?
from the CNS to effector muscles to stimulate a response.
Describe dendrites.
dendrites extend from the cell body and connect with other neurones, allowing electrical impulses to pass from one to the other, they then travel along the dendron to the axon.
What are the axons of most neurones wrapped in?
an insulating lipid layer called the myelin sheath.
Why are dendrons and axons very long?
to allow fast neurotransmission.
Why is the myelin sheath important?
it insulates the neurone, preventing the signal losing energy. This speeds up the rate of neurotransmission.
