Meninges are the three layer providing
protection to the CNS in addition to the
Bones protecting the brain and spinal cord.
The three layers are:
-Dura mater- the outer layer attached to the
-Arachnoid- the middle layer containing
blood vessels looking like a spider web;
The space between the arachnoid and pia
mater is called subarachnoid space and it is
full of cerebrospinal fluid (for minimizing
damages to the brain).
-Pia mater- the internal membrane covering
the brain
It’s a protective barrier that keeps the environment of the brain as
stable as possible.
It controls the passage of materials from the blood to the brain and
spinal cord:
- It allows some materials such as O2, glucose and amino acids to
enter and CO2 and other waste products to get out.
- It prevents other materials such as foreign substances( drugs,
alcohol), hormones and neurotransmitters to enter the brain
The BBB can be broken by:
-High blood pressure
-High concentration of substances in blood
-Exposure to microwaves for a long time
-Trauma (injury of the brain)
The main parts of the brain are:
-Cerebrum- The largest part of the brain controlling:
- all conscious thoughts
- experience
- actions
It is divided into left and right hemispheres joined by
a bundle of nerve fibers.
-Cerebellum- It is the second largest part of the brain
- the coordination of movements
- posture
- balance
-Brain stem- The part of the brain connecting the
cerebrum to the spinal cord. It controls life functions
basic for survival:
- heartbeat
- breathing
- sleep
- digestion
1. EEG (electroencephalography)- recording the electric activities
of the brain neurons.
2. Medical imaging:
a/ CT-scan- A computerized tomography (CT) scan that uses Xrays and a computer to create detailed images of the inside of
your body.
b/ MRI (magnetic resonance imaging)- giving images of the
brain by using signals produced by protons in our body when the
head is placed in a strong magnetic field.
3. Radio-isotopic techniques – by using low doses of radioactive
substances which can fix on the brain. The radioactive emission is
captured by special sensor instruments.
a/ Scintigraphy- for studying the blood flow inside the brain
b/ PET ( positron emission tomography)- for studying the
cellular metabolism in the brain
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