Lab 8 Flashcards
Central Nervous System (CNS)
which includes the brain and spinal cord occupying the dorsal body cavity.
Peripheral Nervous System (PNS)
which consists mainly of the nerves which extend from
the brain and spinal cord, the cranial and spinal nerves.
3 basic functions of NS
Sensory
- Sensory receptors detect internal and external stimuli
- sensory information is carried to the brain and spinal cord through cranial and spinal nerves.
Integrative
-The brain and spinal cord process, integrate and coordinate this incoming sensory information to formulate an appropriate response
Motor
-motor response is initiated by activating effector organs (muscles and glands) through cranial and spinal nerves.
CNS 3 main protective structures
- Skull/Vertebral Column: a bony outer covering
- Meninges: three layers of membrane called
- Cerebrospinal fluid: watery fluid
Skull and Vertebral Column
• sutures: immovable joints that join together bone
- All the bones of the adult skull
- except the mandible (lower jaw) & three small bones of the middle ear
•cerebrum is divided up into various regions or lobes
•lobes are named after the bones of the skull which overlie the brain
• Foramina - small holes
• Foramen magnum - large hole at its base
• vertebral column is composed of 33 vertebrae
• Vertebral foramen: each vertebra has a large hole, the vertebral foramen, through which the spinal cord passes.
several small holes in skull through which many of the cranial nerves exit
foramina
large hole at skull base through which the spinal cord passes as it enters the vertebral column
foramen magnum
each vertebra has a large hole through which the spinal cord passes.
vertebral foramen
3 layers of connective tissue in brain
Called meninges (singular: meninx):
- dura mater
- periosteal dura mater
- meningeal dura mater
- arachnoid mater
- pia mater
dura mater
- outermost meninx
- 2 layers: periosteal dura mater, meningeal dura mater
- The dural layers are fused together except where they separate under the cranium to form dural venous sinuses (eg. superior sagittal sinus) that collect venous blood from the brain and transfer it into the internal jugular veins.
- The spinal cord does not have a periosteal dura mater layer.
- epidural space: between the wall of the bony vertebral foramen and the spinal dura mater, filled with fatty tissue for cushioning.
periosteal dura mater,
-closely attached to the inner surface of the bones of the skull
meningeal dura mater
- forms the actual external covering over the brain
- sends one extension down between the cerebrum and cerebellum, and another between the two cerebral hemispheres (FN: anchor the brain inside the cranial cavity)
arachnoid mater
- middle layer of the meninges
- filmy, cobweb like material with spider-like extension
- Beneath the arachnoid mater is a wide separation called the subarachnoid space
pia mater
- innermost meninx
- very delicate
- highly vascularized membrane composed of areolar connective tissue
- adheres closely to the surface contours of the brain and spinal cord and dips deeply into the grooves
- not possible to separate the pia mater from the surface of the brain and spinal cord.
- anchor the spinal cord to the dura mater at regular intervals, limiting sideways movement of the cord.
epidural space
between the wall of the bony vertebral foramen and the spinal dura mater, filled with fatty tissue for cushioning.