- Notes used to achieve EDEXCEL GCSE biology grade 9
- all the information needed for these chapters
- covers chapter SB2e (the brain) to SB2i (neurotransmission speeds)
- Cornell note-taking method (extremely effective!!)
Spinal Chord 1. long column of neurones, run from base of brain down the spine
2. several places down the chord, neurones branch off and connect with
other parts of the body
3. relays information between brain and the rest of the body
Brain Diagram
Function and - largest part of the brain (makes up 80%)
Structure of - divided into two halves called cerebral hemispheres and is highly folded
Cerebrum
- right hemisphere controls muscles on the left side + vice versa
- different parts of the cerebrum are responsible for different things
- eg. most of our senses such as vision, language, memory, behaviour,
intelligence, movement, and consciousness (our inner thoughts and
feelings)
Discovery of the Due to the cerebral cortex's wrinkled surface, Aristotle believed it
function of the acted as a radiator, cooling the body
Cerebral Cortex
however, a railway worker called Phineas Gage was checking that a
stick of dynamite was properly positioned in a hole by prodding it
with a long metal rod
- dynamite exploded, firing rod upwards through his head
only unconscious for a few minutes before being able to walk and
talk normally
before accident, he was hard-working and friendly, afterwards he
became lazy + bad-tempered
his doctor concluded that the front of cerebral cortex where rod
affected is involved in controlling personality
Function and 1. at the base of the brain
Structure of the 2. divided into 2 halves
Cerebellum 3. controls balance + posture
4. coordinates the timing and fine control of muscle activity, making
sure movements are smooth
Function and 1. controls unconscious activities such as heart + breathing rate
Structure of the 2. also responsible for reflexes eg. vomiting sneezing and swallowing
Medulla 3. mass of neurones making up medulla oblongata connect the brain to
Oblongata the spinal chord
Function and Regulates temperature and water balance within the body
Structure of the
Hypothalamus
, SPECIFICATION POINTS 2.10B-2.17B
CT Scanners to Brain tissue can be accessed with surgery however it's quite risky so brain can
Investigate Brain be visualised without surgery using a CT Scanner, non-invasive procedure:
Function
1. uses X-Rays to produce an image of the brain
- an X-ray beam moves in a circle around the head + detectors
measure the absorption of the rays
- a computer uses this information to build up a view of the inside of
the body as a series of "slices"
2. shows the main structures, but doesn't show the functions of them
3. however, if a CT scan shoes a diseased or damaged brain structure
and the patient has lost some function then the function of that part
of the brain can be worked out
eg. if area of brain is damaged and patient can't see then that's the area
involved in vision
PET Scanning to Brain tissue can be accessed with surgery however it's quite risky so brain can
Investigate Brain be visualised without surgery using a PET Scanner, non-invasive procedure:
Function
1. PET Scanners work by injecting a patient with radioactive glucose to
show which parts of the brain are active when the person is inside
the scanner
2. very detailed + can be used to investigate BOTH structure and
function of the brain in real time
3. show if areas in brain are usually active or inactive so are useful for
studying disorders that change the brain's activity
eg. in alzheimer's disease, activity in certain areas of brain = reduced
- more active cells take in more glucose than less active ones (for
respiration)
- radioactive atoms cause gamma rays, which the scanner detects
- more gamma rays come from parts containing more cells
Using Electrical electrodes apple electrical currents to the brain + patients describe
Stimulation to what they feel
Investigate the If the motor area is stimulated, the patient makes an involuntary
Brain movement
If the visual area is stimulated, they may see a flash of colour
EEGs can be created and studied, to observe the electrical activity in
the brain + functions of brain parts to be investigated
Spinal Chord - damage to spinal chord reduces flow of information between the brain and
Damage parts of the body
- Nerve damage in the lower spinal chord can cause loss of feeling in, and use
of legs
- Damage in neck can cause quadriplegia (loss of use of both arms and legs)
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