CNS1 Flashcards
what are the two major types of cells in the central nervous system
neurons and glial cells
what are the effectors or sensors
neurons
what do glial cells do
play an important role in protection and support
what is the grey matter
neurons
what are the types of glial cells
oligodendrocytes
astrocytes
microglia
ependymal cells
schwann cells
satelite cells
what glial cells are in the CNS
oligodendrocytes
astrocytes
microglia
ependymal cells
what glial cells are in PNS
schwann cells
satelite cells
What are mylenated tracts in the CNS: white matter
glial cells
what lies enirely within the CNS
interneurons
what are interneurons a part of
intrinsic circuits
what are nerves
long bundles of sensory and motor acons in the PNS
what protects and nourishes the brain
glia, meninges, CSF, and BBB
what are half of the cells in the brain
glial cells
what serves as the connective tissues of the brain
glial cells
what do glia do
maintains the homeostatic composition of the extracellular enviroment surrounding neurons
physically support neurons in proper spacial relationships
induce formation of BBB
serve as a scaffold during fetal brain development
astrocyte
form neural scar tissue
astrocyte
take up and degrade released neurotransmitters into raw materials for synthesis of more neurotransmitters by neurons
astrocytes
take up exess k to help maintain proper brain ECF concentration and normal neural excitability
astrocytes
enhance synapse formation and strengthen synaptic transmission via chemical signallling with neurons
astrocyte
form myelin sheath in CNS
oligodendrocytes
play a role in defense of brain as phagocytic scavengers
microglia
line internal cavities of brain and spinal chord
ependymal cells
contribute to formation of cerebrospinal fluid
ependymal cells
serve as neural stem cells with potential to form new neurons and glial cells
ependymal cells
what seperates the two hemispheres
the longitudinal fissure
what are the layers of the meminges
PAD
pia mater
arachnoid mater
dura mater
what protects the brain and spinal chord
3 layer sheath of the meninges
most fragile inner most layer
pia mater
middle meninges membrane
arachnoid mater
tough outer most layer
dura mater
where is the subarachnoid space
the space bw the arachnoid mater and pia mater
what does the subarachnoid space contain
filled with csf and contains the blood vessesl that supply the brain
what does the brain and spinal chord fload in
fluid filled space called cerebrospinal fluid
how many ventricles are in the brain
four
what produces the CSF
choroid plexus inside vernticles
where does the CSF circulate
through the ventricles and exits the fourth ventricle and flows in the subarachnoid space and is reabsorbed from subarachnoid space into venous blood via the arachnoid vili
what are the 2 purposes of the CSF
physical and chemical
bouyancy reduces weight of the brain makes it 30x lighter less pressure on vessels and nerves
provides protective padding, fluid absorbs some of the shock
creates regulated extracellular enviroment for the neurons, not same as plasma, lower k, ca, hco3, and glucose: na is similar
contains little proteins and no blood vessels
spinal tap
when samples of CSF test positive for the presence of protien or blood cells and it suggest infection
volume of csf
125-150
how many times is the csf volume replaced
3x a day
what does problems with csf formation and reabsorption lead to
hydrocephalus
functional barrier between interstitial fluid and blood
BBB
what does the BBB limit the passage of
blood borne agents into CNS
what does the selective permeability of brain capilaries protect the brain from
toxins, flucutations in hormones, ions, and neuroactive substances in the blood
what cells make up the BBB
endothelial cells of the brain capilaries
what forms tight junctions in the BBB
endothelial cells
what is a way that things can possible exchange though in the BBB
the endothelial cells themselves
what can cross through the endothelial cells
lipid soluble substances such as oxygen, co2, steroid hormonse, and alcohol
how do water soluble molecules cross the BBB
cannot unless via specific carrier
where is the BBB leaky
curcumbentricular organs such as neurohypophysis of the pituitary
what percentage of blood pumped by the heart goes to the brain
15%
what can the brain no do without oxygen
produce ATP
how long can the brain last without oxygen
5 min leads to brain damage
how much of the bodies glucose consumption does the brain use
1/2
what moves gucose from the plasma into the brain interstitial fluid
membrane transporters
what does hypoglycemia lead to
confusion, unconsciousnesss, and death
how long can the brain last wihthout glucoe before there is damage
more than 15 min
what is in the brainstem
midbrain, pons, and medulla
functions of the cerebral cortex
sensory perception
voluntary control of movement
language
personality traits
sophisticated mental events such as thinking, memory, decision making, creativity, and self consciousness
basal nuclei major functions
inhibition of muscle tone
coordinatino of slow sustained movement
supression of useless patterns of movement
thalamus major funcions
relay station for all synaptic input
crude awareness of sensation
some degree of consciousness
role in motor control
hypothalamus major functions
regulation of many homeostatic functions such as temp control, thirst, urine output, and food intake
important link bw nervous and endocrine system
extensive involvement with emotion and basic behaviourla patterns
sleep wake cycle
cerebellum major fucntions
maintenance of balance
enhancement of muscle tone
coordination and planning of skilled voluntary muscle activity
brain stem functions
origin of majority of peripheral cranial nerves
cardiovascular respiratory and digestive control centres
regualtion of muscle reglexes involved with equilibrium and posture
reception and integration of all synaptic inuput from spinal chord, arousal and activation of cebreal cortex
role in sleep wake cycle
gyrus
the bulges of the grey matter
sulcus
the inside of the buldgse of the grey mattter
what is on the outside of the brain, grey or white matter
grey
what colour is the cerebral cortex and the core
cerebral cortex is grey, core is white
what is grey matter composed of
neuronal cells, dendrites and glial cells
whre does integration of neural input and initiation of neural ouptut take place
grey matter
what does the white matter consist of
bunbdles of myelinated nerve fibres that interconnect with brain areas
what is the cerebral cortex orginaixed into
six well defined layers also organized into vertically organized columns of cells
lobes in the cerebral cortex
occipital lobe
temportal lobe
parietal lobe
frontal lobe
what lobe recieves and processes visual inputs
occipital lobe
what lobe receives and processes auditory inupts
temportal lobes
what lobes receive and process somatoesnsory input
parietal lobe
what lobe has voluntary motor activity, speaking, and elaboration of thought
frontal lobes
what detects magnitude of blood flow in the brain
PET
what does the pirmary auditory cortex receive
topographic sensory fibres from the cochlea of each each mapped by pitch
what are associative strutcures in the temporal lobe involved in
higher order processing of auditory and visual information such as language comprehension and object perception (ventral stream)
where are the hippocampus and amygdala
temporal lobe
what ar the hippocampus and amugladal important for
episodic memory formation of recent events
where isthe limbic association cortex
temportal lobe
where is the primaty visual cortex
occipital lobe
what does each hemisphere of the occipital lobe receive info from eye wise
from both eyes in one hemifield via optic nevre and thalamus (LGN)
whre does the visual hemi field project onto
primary visual cortex upside down and reversed
area in front of the central sulcus
PRIMARY MOTOR CORTEX
plan and execute movements in coordination with pre motor cortex
primary motor cortex
controls muscle movement on opposite sides of the body
primary motor cortex
depicts the location and relative amount of motor cortex devouted to ouptut to the muscles of each body part
motor homonculus
higher motor areas
supplementary motor crotex
muscles of each body part are represented topographically
motor humoncylus
what is adjascent in motor humonculus
motor areas are adjacent to sensory areas for the same body regions facilitation communication
this is called tactile exploration
where does the primary motor cortex project to
motor neurons that directly innervate the skeletal muscle
executes muscel movements by coordinated activation of multiple muscle groups
frontal lobe- primary motor cortex
low level info
neurons incode force, direction, and speed of movemnt
motor cortex controls what on what side
on each side controls the opposite side of the body
tracts originating in the cortex cross before continuing downthe spinal chord
signals preparation for movement, informed of bodys position in relation to target, codes behavioural context/ goals, correct and inccorect actions
premotor cortex
plays a preparatory role in programming complex sequences of moveemnt, responds to remembered movement, active during action and imagination of action
supplementary motor area
planning and organixation of goal directed behaviour, working memory and decision making
prefrontal cortex
where is somaesthetic sensation projected to
primary somatorsensory cortex
site for processing touch inputs and features of the object you are holding
primary somatosensory cortex
whre is the somatosensory cortex
in the parietal lobe
area posterior to central sulcus
somatosensory cortex
where is info acquired by PNS processing relayed to
CNS and somatosensory cortex
integrates touch, vision and audition information in spacial context and is PART OF THE DORSAL STREAM
associative parietal cortex
where does the primary sensory cortex recieve info from
the opposite side of the body
what are the association cortexes
prefrontal association cortex
parietal temporal occipital association cortex
limbic association cortex
how much space in the cerebral cortex do association areas take up
one half
