Question | Answer |
2 protective coverings of brain and spinal cord | outer-consist of bone-cranial encases the brain, vertebea encase the spinal cordinner-membranes known as meninges |
Meninges | inner covering of the brain; has 3 distinct layers: Dura mater, arachnoid mater, pia mater |
Dura mater | stong white fibrous tissue, outer later of meninges and inner periosteum of cranial bone |
Extensions of the dura mater | falx cerebri, falx cerebelli, tentorium cerebelli |
Falx cerebri | partition between the 2 cerbral hemispheres |
Falx cerebelli | separates the 2 hemispheres of the cerebellum |
Tentorium cerebelli | separates the cerebellum from the cerebrum |
Arachnoid mater | delicate, cobwebby layer between the dura mater and pia mater |
Pia mater | innermost layer of meninges, transport layer, adheres to the outer surface of the brain and spinal cord, contains blood vessels |
Spaces between and around the the meninges | epidural space, subdural space, subarachnoid space |
Epidural space | located between the dura mater adn inside the bony covering of the spinal cord; contains a supporting cushion of fat and other connective tissues |
Subdural space | located between the dura mater and arachnoid mater; contains lubricating serous fluid |
Subarachnoid space | located between the arachnoid and pia mater; contains a significant amoung of cerebrospinal fluid |
filum terminale | slender filament formed by the pia mater that blends with the dura mater and then the periosteum of teh coccyx |
Functions of the cerbrospinal fluid | provides a supportive, protective cushionreservior of circulating fluid, which is monitored by the brain to detect changes in the internal environment |
Where are the cerbrospinal fluid spaces found | subarachnoid space around the brain adn spinal cord within the cavities and canals of the brain and spinal cord |
Ventricles | 4 fluid-filled spaces within the brain1-2:lateral, one located on each hemisphere3: thin, vertical pocket of fluid below and medial to the lateral ventricles4: tiny, diamond-shaped space where cerebellum attaches to the back of brainstem |
Formation and circulation of cerebrospinal fluid | occurs by separation of fluid from blood in the choroid plexuses |
Choroid plexuses | networks of capillaries that project from the pia mater into the lateral ventricles and into the roofs of the 3rd & 4th ventricles |
Amount of CSF in average adult | 140ml |
Structure of the spinal cord | lies within the spinal cavity and extends form the foramen magnum to the lower border of the 1st lumbar vert, oval cylinder that tapers downward, 2 bulges, anterior median fissure and posterior median sulcus are 2 deep grooves |
Anterior median fissure | deeper and wider of the two grooves |
Nerve roots | two bundles of nerve fibers project from each side of the spinal cord: dorsal nerve root and ventral nerve root |
Fibers of dorsal nerve root | carry sensory information into the spinal canal |
Fibers of ventral nerve root | carry motor information out of the spinal cord |
Spinal nerve | single mixed nerve on each side of spinal cord where the dorsal and ventral roots join together |
Cauda equina | bundle of nerve roots extending form the conus medullaris |
Gray matter | structure of spinal cordcolumns extend the length of the cord; consist predominantly of cell bodies of interneurons and motor neurons; in transverse section looks like an H |
White matter | structure of spinal cordsurrounds the gray matter and is subdivided in each half of cord into 3 funiculi |
Funiculi | anterior, posterior, and lateral white columnsconsist of a large bundle of nerve fibers divided into smaller bundles called spinal tracts |
Spinal tracts | white columns of the spinal cord that provide consuction paths to and from the brainascending tracts carry information to the brain; descending tracts conduct impulses from the brain |
Functions of the spinal cord | provide conduction routes to and from the brain |
Structures of the brain that make up the brainstem | medulla oblongata, pons, midbrain; extends inferiorly from diencephalon to foramen magnum where it meets the spinal cord |
Location of Medulla Oblongata | attaches to the spinal cord, located just above the foramen magnum, composed of white matter and a network of gray and white matter called the reticular formation network |
pyramids | two bulges of white matter located on ventral surface of medulla |
olive | oval projection located lateral to the pyramids on the medulla |
Location of Pons | located above medulla and below the midbrain; composed of white and reticular matter |
Location of Midbrain | forms the midsection of the brain, loacted above the pons adn below the cerebrum |
Cerebral peduncles | roplelike masses of white matter that extend divergently through the midbrain, tracts within conduct impulses between the midbrain and the cerebrum |
Functions of the brainstem | performs sensory, motor, and reflex functions |
Spinothalamic tracts | important sensory tracts that pass through the brainstem |
Funtion of Pons | contains reflex mediated by 5h-8th cranial nerves and pneumotaxic centers that help regulate respiration |
Function of midbrain | integration of numerous cranial nerve reflexes, such as eye movement and ear reflexes |
Structure of cerebellum | roughly spherical structures attached at the posterior of the brainstem; wrinkled gray matter cortex, branched network of white fibers inside, and several small gray nuclei |
sulci | grooves on the surface of the cerebellum and cerebrum |
gyri | raised areas on the surface of the cerecullum and cerbrum |
Dentate nuclei | important pair of cerebellar nuclei; nuclei connected with thalamus and with motor areas of the cerebral cortex by tracts; by means of tracts cerebellar impulses influence the motor cortex and the motor cortex influences the cerebellum |
Functions of cerebellum | coordinates many functions of cerebrum, including planning and control of skilled movements, posture, balance, coordination of sensory information relating to body position and movement |