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Ritika Ahmed

The Brain

The Cerebrum
•Largest area
•Divided into two parts; cerebrum
hemispheres
•Thin outer layer = cerebral cortex —>
large surface area —> highly folded
•Vision, learning, thinking and emotions
•Different parts involved in different
functions
Hypothalamus
•Beneath the middle part of the brain
•Maintains body temperature
•Produces hormones that control pituitary
gland

The Medulla
• Base of the brain —> top of spinal cord
• Automatically controls breathing rate and heart rate
Cerebellum
• Underneath the cerebrum —> has folded cortex
• Important for coordinating movement and balance
Scanners are used to visualise the brain:
CT:
• Use X-rays to produce cross section images of the brain
• Dense structures in the brain absorb more radiation than less dense structures —> lighter
colour on the scan
Uses:
• Investigating brain structure
• Investigating brain functions —> if a CT scan shows a diseased or damaged brain structure
and the patient has lost some function, the function of that part of the brain can be worked out
...
Blood has a different density from brain tissue so it shows up as a lighter
colour on a CT scan —> will show extent of bleeding and location in the brain —> work out
what vessels have been damaged and what brain functions are likely to be affected by the
bleeding
MRI:
• Use strong magnetic field and radio waves to produce cross section images of the brain
Uses:
• Investigating brain structure —> more detailed than CT —> clearly see difference between
normal and abnormal brain tissue
• Investigating brain function —> same as CT

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Ritika Ahmed

• Medical diagnosis —> diagnose diseased areas like tumours —> tumour cells respond
differently to a magnetic field than healthy cells, so they show up as a lighter colour on a MRI
scan —> will show exact size and location —> work out what brain functions affected by
tumour
fMRI
• Like MRI —> show changes in brain activity as they actually happen:
more oxygenated blood flows to active area of the brain (to supply glucose and oxygen)
Molecules in oxygenated blood respond different to a magnet field than those in deoxygenated
blood
So more active areas of the brain can be identified of an fMRI scan
Uses:
• Investigating brain structure —> more detailed picture
• Investigating brain function - If a function is carried out whilst in the scanner, the part of the
brain that’s involved with that function will be more active
...
g
...
The areas of the brain involved in moving the
hand will show up on the fMRI scan
• Medical diagnosis - allow you to study conditions caused by abnormal activity in the brain
...
g
...
This can help to
pinpoint which part of the brain’s not working properly and find the cause of the seizure

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