Unit 3 Study Guide Flashcards
Gray matter
- derives its color from the motor neuron and interneuron cell bodies and their associated capillary beds, as well as the dendrites and some unmyelinated axons
- cortex and cerebral nuclei
cerebral nuclei
- internal clusters of gray matter embedded within masses of white matter
white matter
- derives its color from the myelin on the abundant myelinated axons.
- lies deep to the gray matter of the cortex
- inner white matter, corpus callosum, internal capsule
tracts
- bundles of parallel axons in the CNS
brain protected by and isolated by multiple structures
- cranium
- meninges
- cerebrospinal fluids
- blood-brain barrier
cranium
- provides rigid support
meninges
- surround and partition
- connective tissue membranes unique to CNS
cerebrospinal fluid
- cushions
blood-brain barrier
- prevents entry of harmful products
three cranial meningeal layers
- pia mater
- arachnoid mater
- dura mater
function of the meninges
- separate and support the soft tissue of the brain from the bones of the cranium, enclose and protect some of the blood vessels that supply that brain, and help contain and circulate CSF
pia mater
- innermost layer
- thin layer of delicate areolar connective tissue
- tightly adheres to the brain and follows every contour of the brain surface
arachnoid mater
- external to the pia mater
arachnoid space
- delicate web of collagen and elastic fibers that extend from the arachnoid to the pia mater
subarachnoid space
- contains CSF
subdural space
- becomes an actual space if blood or fluid accumulates there
- between arachnoid mater and dura mater.
dura mater
- strongest of the meninges
- composed of meningeal and periosteal layer
meningeal layer
- immediately superficial to the arachnoid
periosteal layer
- forms the periosteum on the internal surface of cranial bones
dural venous sinuses
- formed when the meningeal and periosteal layers separate to form large, blood-filled spaces
- do not have valves to regulate blood flow.
cranial dura septa
- double layers of dura mater that separate specific parts of the brain and provides additional stabilization and support
structure of ventricles
- cavities or expansions within the brain that are derived from the neural canal.
- all lined with ependymal cells and produce CSF within the choroid plexus.
- largest volume of CSF produced in lateral ventricles.
lateral ventricles
- 2 of them
- located in cerebrum
- separated by the septum pellucidum
third ventricle
- smaller and thinner
- located within the diencephalon
fourth ventricle
- located between the pons, medulla oblongata, and cerebellum
- opens to the subarachnoid space via a single median aperture and paired lateral aperatures
- merges with central canal in the spinal cord
interventricular foramen
- opening that connects the lateral ventricles to the third ventricle.
cerebral aqueduct
- passes through the midbrain and connects the third ventricle with the fourth
CSF formation
- produced by the choroid plexus
choroid plexus
- composed of a layer of glial cells called ependymal cells and the blood capillaries within the pia mater
CSF flow
- flows from lateral ventricles to the third ventricle through the interventricular foramen
- then through the cerebral aqueduct to the fourth ventricle
- passes through the paired lateral apertures and median aperture into the subarachnoid space as well as the central canal of the spinal cord
CSF removal
- excess CSF flows into the arachnoid villi and collected in arachnoid granulations
- CSF forced from the subarachnoid space across the arachnoid villi to return to the blood within the dural venous sinuses
structure of blood-brain barrier
- formed by specialized capillaries composed of endothelial lining resting on a basement membrane
endothelial cells contain
- tight junctions, which passage of materials between cells.
perivascular feet of astrocytes
- wrap capillaries
- form outmost portion of BBB
- act as gatekeepers controlling materials that are unable to cross into or out of blood
What can pass through BBB?
- lipid-soluble substances such as alcohol and nicotine
What damages the BBB?
- drugs such as cocaine or heroin
BBB is missing or partially removed in?
- choroid plexus
- hypothalamus
- pineal gland
function of BBB
- protect nervous tissue by strictly regulating which substances can and cannot enter the interstitial fluid of the brain to help prevent exposure of neurons in the brain to drugs, waste products in the blood, and variations in levels of normal substances.
cerebrum
- location of conscious thought processes and origin of all complex intellectual functions.
- center of intelligence, reasoning, sensory perception, thought, memory, voluntary motor, visual, auditory activities, and judgement
2 hemispheres of cerebrum
- separated by longitudinal fissure
- communication facilitated by white matter tracts
corpus callosum
- connects the hemispheres
- main method for communication between these hemispheres
frontal lobe
- voluntary motor function, concentration, verbal communication, decision making, planning, and personality
- premotor cortex and motor speech area (Brocha’s)
parietal lobe
- general sensory functions such as touch and taste
- somatosensory cortex and association area
temporal lobe
- hearing and smell
occipital lobe
- processes incoming visual information and storing visual memories
insula
- involved in memory and the interpretation of taste
prefrontal cortex
- associated with many higher intellectual functions such as complex thought, judgement, expression of personality, planning future behaviors, and decision making