Brain / CNS Flashcards
What is the spinal cord
it is a long column of neurones extending down from the base of the brain and branching off to different parts of the body
identify the 3 main parts of the brain
Cerebral cortex
Cerebellum
Medulla / oblongata
Identify the role of the cerebral cortex
it is located on the outer layer of the brain and it controls the conscious activities : movement , intelligence, memory , language and vision
Identify the role of the cerebellum
responsible for muscle co-ordination and balance
identify the role of the medulla oblongata
it controls the unconscious activities such as blinking, heart rate and breathing
Identify the two ways the brain can be visualised without surgery
- Pet scans
- CT scans
How does CT scan view the brain
it uses x-rays to produce a 3D image of the brain showing the physical structures.
how can you identify the cause of the patients symptoms
if the CT scan shows a damaged brain and the patient has lost function you can work out that the function is lost due to the specific area of damage.
How do PET scanners allow u to view the brain
They use radioactive chemicals to show active parts of the brain
How do PET scanners detect damaged part
before the scan blood is added to the tracer so the radioactive chemicals can detect areas of increased blood flow like cancerous tissues that have higher blood flow
are PET scanners detailed or not
yes they are , you can investigate both structures and function of the brain
Identify 3 reasons of why its hard to treat CNS problems
- hard to repair damaged neurones
- accessibility
- accidental damage
why is it hard to repair damage in CNS
because the neurones in the CNS don’t repair as easily as other tissues in body
Why is it hard to access tumours
because they could be located so deep in the brain and it is not possible to surgically remove them in certain parts
Why is accidental damage an issue in CNS
because nerve tissues are so delicate if further damaged cause permanent damage such as personality and speech
What is the (PNS)
all the nerves in your body
how is information sent through the body
through electrical impulses known as neruones
what is the role CNS
it acts as the central co-ordinating centre for the impulses as nerves spread out from the CNS to regions of body / sense organs
what is a sensory receptor
it is a group of cells that detect a change in the environment - a stimulus
what happens when a stimulus is detected by receptors
the stimulus is received by the sensory neurone and converted into electrical impulses and sent towards the CNS then in the CNS the electrical impulses are passed onto the relay neurone where it is linked to the motor neurone where impulses are sent to the effector which respond to the stimulus
describe the adaptation of the neurones
- extensions from the cell body called axons and dendrons
- myelin sheath
- long neurones
explain the role of the axon
the axon is a main long fibre of neurones that carry electrical impulses away from the cell body
explain the role of the myelin sheath
the myelin sheath acts as an electrical insulator that speeds up electrical impulses
explain the role of long neurones
- speed up impulses as being connected to other neurones slow down the impulse so less time wasted
role of dendrons
dendrons carry electrical impulses towards the cell body acting as a network for easy communication
what does the sensory neurone contain
contain long dendron from receptor to cell body that is located in middle of neurone
short axon which carry impulse from cell body to the CNS
what does a relay neurone consist of
- short dendrites that carry impulses from cell CNS to cell body
- long axon that carries electrical impulses from cell body to the motor neurone
what does the motor neurone consist of
- short dendrites that carry impulses from CNS to cell body
- long axon that carries electrical impulses from cell body to effector cells
explain the function of neurotransmitters
Where two neurones meet there is a small gap called a synapse. Here the electrical signal must be converted into a chemical one,
- an electrical impulse travels along the first axon
- this triggers the nerve-ending of a neurone to release chemical messengers called neurotransmitters
- these chemicals diffuse across the synapse (the gap) and bind with receptor molecules on the membrane of the second neurone
- the receptor molecules on the second neurone bind only to the specific neurotransmitters released from the first neurone
- this stimulates the second neurone to transmit the electrical impulse.
how do drugs work in regards to neurotransmission
Drugs (such as heroin, ecstasy and cocaine) can bind to neurotransmitter receptors, triggering impulses in different regions of the brain
how do drugs work in regards to neurotransmission
Drugs (such as heroin, ecstasy and cocaine) can bind to neurotransmitter receptors, triggering impulses in different regions of the brain
what is a reflex response
an automatic rapid response to a stimulus to prevent injuries or damage
what is a reflex arc
pathway of a reflex response
what is the common reflex arc
The pin (the stimulus) is detected by a (pain/pressure/touch) receptor in the skin on the person’s foot
A sensory neurone sends electrical impulses to the spinal cord (the coordinator)
An electrical impulse is passed to a relay neurone in the spinal cord (part of the CNS)
A relay neurone synapses with a motor neurone
A motor neurone carries an impulse to a muscle in the leg (the effector)
When stimulated by the motor neurone, the muscle will contract and pull the foot up and away from the sharp object (the response)
This all occurs within a fraction of a second
