Protecting the brain
The human brain is located inside of the cranial cavity or skull and is protected by its curved bones. Three membranes called meninges protect the brain further by acting as a barrier and providing physical support. Meninges are sheet like layers that wrap around the brain. They act as filters to allow necessary substances to pass through to the brain and keep harmful substances that may be in the blood out. The outer meninges is the dura mater and is the tough fibrous tissue clinging to the inside of the skull. Below the dura mater is the arachnoid membrane, a delicate and web like layer. Underneath the arachnoid membrane is the innermost membrane that snugly wraps the outer surface of the brain, the pia mater. The pia mater contains tiny blood vessels. Between the pia mater and the arachnoid membrane is a layer of cerebrospinal fluid (CSF). CSF flows in all areas of the brain and fills the spaces. The brain floats in CSF and together with the meninges cushion the brain from shaking and jarring, acting like a shock absorber. The fluid and meninges also extend down the entire length of the spinal cord to cover and protect is from damage as well (Farley et al., 2014) (Roca & Serrano, 1996) (Olesky, 2001) (Parker, 1997) (Walker & Wood, 2003).
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