Central Nervous System Flashcards
What do the cerebral hemispheres do?
Controls voluntary movement, interpret sensory info learning and memory.
What does the medulla oblongata do?
Regulates the heart beat and breathing rate.
What does the cerebellum do?
Controls precise smooth movement.
How does a CT scan work?
- patient is given a radioactive tracer which allows certain parts of the brain to show up.
- a CT scan is carried out, taking different X-rays of the skull and brain from different angles.
- a computer puts all these images together to give a 3-dimensional image.
How does a PET scan work?
- patient is give a small amount of a radioactive form of glucose.
- this travels to parts where respiration is happening rapidly.
- shows changes to the body such as brain which will indicate damage or disease.
- scanner detects radioactivity and builds up images showing where the tracer is most concentrated.
How are the brain + spinal cord protected?
- brain is protected by skull.
- spinal cord is protected by spine.
- capillaries that supply the brain are not as leaky as normal. This is called the ‘blood-brain barrier’. This makes it difficult to get medicines into the brain.
- the brain + spinal cord are protected by bone which makes it hard to access them during surgery.
- the spinal cord is made of nerves.
- if them spinal cord broke then this would stop nerve impulses passing to parts of the body below the break. The person would be unable to control or move parts of the body below the break, causing paralysis.
What are neurones?
Specialised cells that carry nervous impulses.
What do the 3 main neurones do?
Sensory=
carry impulses to the CNS.
Relay=
found only in the CNS.
Motor=
carry impulses from the CNS to effector organs.
Name the parts of a sensory neurone and the functions:
- skin receptor cells.
- dendrites collect impulses from receptor cells.
- dendron carries impulses towards cell body.
- axon carries impulses away from cell body.
- fatty myelin sheath insulates the neurone.
- axon endings pass impulses to other neurones.
Name the parts of a motor neurone and the functions:
- the axon carries the electrical impulse over long distances through the body.
- the electrical impulse cannot cross the fatty myelin sheath.
- the impulse jumps from one gap in the myelin sheath to the next, speeding up the rate of transmission.
- the nerve ending transmits the impulse to an effector, such as a muscle or gland.
What is a synapse?
A point where 2 neurones meet and its a small gap between neurones. The electrical nerve impulse cannot cross this gap so is carried by neurotransmitters.
What’s the role of a neurotransmitter?
Its a chemical released from one neurone that carries the impulse across the synaptic gap to another neurone.
What re reflex arcs like?
- immediate
- involuntary
- innate
- invariable
What is the reflex arc?
- Stimulus
- Receptor
- Sensory
- Relay
- Motor
- Effector muscle or gland
