Term
| parts of the central nervous system |
|
Definition
|
|
Term
| parts of the peripheral nervous system |
|
Definition
cranial nerves
peripheral nerves |
|
|
Term
|
Definition
cell body/soma
axon
dendrites
synapse
myelin
nodes of ranvier |
|
|
Term
| what is a cell body/soma? |
|
Definition
| part of neuron containing the nucleus |
|
|
Term
|
Definition
| convey stimulus away from cell body |
|
|
Term
|
Definition
| convey stimulus toward cell body |
|
|
Term
|
Definition
| junction between axon and dendrite or cell body |
|
|
Term
|
Definition
| fatty insulator of axons for quick conduction |
|
|
Term
| what are nodes of ranvier? |
|
Definition
| gaps in myelination to allow saltatory conduction |
|
|
Term
|
Definition
multipolar
bipolar
unipolar/monopolar/pseudounipolar |
|
|
Term
| components of multipolar neurons and function |
|
Definition
| one axon, multiple dendrites (motor cells, many interneurons) |
|
|
Term
| components of bipolar neurons and function |
|
Definition
| one axon, one dendrite (special sensory cells) |
|
|
Term
| components of unipolar neurons and function |
|
Definition
| one process acting as a dendrite and an axon (sensory cells) |
|
|
Term
| where are unipolar neurons found? |
|
Definition
| dorsal root ganglion (peripheral ganglion associated with spinal cord) |
|
|
Term
| what are branching patterns of dendrites called? |
|
Definition
|
|
Term
| what are glial cells? where found? |
|
Definition
supportive cells in the central and peripheral nervous systems
white matter (CNS) and gray matter (PNS) |
|
|
Term
| types of glial cells in the central nervous system |
|
Definition
astrocytes
oligodendrocytes
microglia
ependymal cells |
|
|
Term
| types of glial cells in the peripheral nervous system |
|
Definition
schwann cells
satellite cells |
|
|
Term
|
Definition
proliferate in response to damage, form blood-brain barrier in CNS
(star-shaped) |
|
|
Term
|
Definition
|
|
Term
|
Definition
| scavengers of dead neurons and their debris in CNS |
|
|
Term
|
Definition
| line ventricles/hollow cavities in brain and spinal cord, make CSF in CSF |
|
|
Term
|
Definition
|
|
Term
|
Definition
| collection of nerve cell bodies/somas in CNS-packed in a defined area |
|
|
Term
|
Definition
| collection of nerve cell bodies in PNS |
|
|
Term
|
Definition
|
|
Term
|
Definition
| bundle of myelinated nerve fibers following a pathway to the brain |
|
|
Term
|
Definition
| toward the brain or spinal cord (sensory reception) |
|
|
Term
|
Definition
| away from the brain or spinal cord (motor function) |
|
|
Term
|
Definition
white matter
gray matter
dorsal root
dorsal root ganglion
ventral root
spinal nerve
dorsal ramus
ventral ramus |
|
|
Term
| why is white matter white? what's in it? |
|
Definition
| myelin, collections of axon tracts (on "outside" of spinal cord) |
|
|
Term
|
Definition
cell-rich, full of unmyelinated neurons--dorsal and ventral horns
found on ("inside" of spinal cord) |
|
|
Term
| what's found in the ventral horn of the spinal cord? |
|
Definition
| MOTOR neurons for skeletal muscle |
|
|
Term
| what's found in the dorsal horn of the spinal cord? |
|
Definition
| SENSORY relay neurons and axons |
|
|
Term
| function of dorsal root ganglion |
|
Definition
axons enter dorsal root and ascend to brain or synapse on interneurons or motor neurons
central processes/axons
lateral processes/dendrites |
|
|
Term
|
Definition
both types of axons=mixed spinal nerve
-impulses go in and out |
|
|
Term
| what does the dorsal ramus project to? |
|
Definition
| posterior surfaces-muscles of back, neck, vertebral column |
|
|
Term
| what does the ventral ramus project to? |
|
Definition
| anterior surfaces-muscles of extremities |
|
|
Term
| if someone survives a stroke, what cells work to remove dead cells and debris in the brain? what happens to the body? |
|
Definition
microglia cells remove debris
extremeties on opposite side shrink over time from disuse |
|
|
Term
| how many spinal nerves are there? what are the segments? |
|
Definition
31 pairs:
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal |
|
|
Term
| how are the spinal nerves assigned a number? |
|
Definition
C1-C8 exit ABOVE corresponding vertebrae
rest exit below corresponding vertebrae |
|
|
Term
| what happens during development, regarding relationship of spinal nerves with vertebrae? |
|
Definition
| column outgrows spinal nerves= spinal cord ends at L1 or L2 |
|
|
Term
| another name for forebrain? components? |
|
Definition
prosencephalon:
telencephalon and diencephalon |
|
|
Term
| another name for telencephalon? components? |
|
Definition
cerebrum:
2 cerebral hemispheres
gray matter
white matter
5 cerebral lobes
basal ganglia
sulci/fissures
gyri
basal forebrain/subcortical regions |
|
|
Term
| what connects the two cerebral hemispheres? |
|
Definition
|
|
Term
| what's the gray matter in the telencephalon/cerebrum? |
|
Definition
| cerebral cortex (superficial layer)-composed of nerve cells |
|
|
Term
| what's the white matter in the telencephalon/cerebrum? |
|
Definition
| (deep) has axons/fiber pathways |
|
|
Term
| what are the cerebral lobes? |
|
Definition
frontal
parietal
temporal
occipital
insular |
|
|
Term
| components/function of frontal lobe in cerebrum/telencephalon |
|
Definition
| motor (precentral gyrus) and premotor areas |
|
|
Term
| components/function of parietal lobe in cerebrum/telencephalon |
|
Definition
| sensory (postcentral gyrus) and association areas |
|
|
Term
| components/function of occipital lobe in cerebrum/telencephalon |
|
Definition
| visual and association areas |
|
|
Term
| components/function of temporal lobe in cerebrum/telencephalon |
|
Definition
|
|
Term
| components/function of insular lobe in cerebrum/telencephalon and where is it found? |
|
Definition
functionally mysterious
found in depths of lateral fissure |
|
|
Term
| components of basal ganglia |
|
Definition
subcortical nuclei:
caudate
putamen
globus pallidus
subthalamic nucleus
substantia nigra |
|
|
Term
| major sulci/fissures of cerebrum/telencephalon |
|
Definition
central sulcus
lateral fissure
parieto-occipital sulcus
calcarine fissure |
|
|
Term
| what is location of the primary visual area? |
|
Definition
|
|
Term
| major gyri of cerebrum/telencephalon |
|
Definition
precentral gyrus
postcentral gyrus
temporal gyri (superior, middle, inferior)
cingulate gyrus
parahippocampal gyrus |
|
|
Term
| location of primary sensory area? |
|
Definition
|
|
Term
| location of primary motor area? |
|
Definition
|
|
Term
| what separates the precentral and postcentral gyri? |
|
Definition
|
|
Term
| subcortical regions in basal forebrain |
|
Definition
amygdala
septum
hippocampus (and fimbria/fornix system)
nucleus basalis (of Meynert)
bed nucleus of stria terminalis |
|
|
Term
| what comprises the diencephalon? |
|
Definition
| thalamus and hypothalamus |
|
|
Term
|
Definition
major relay center for sensory functions (except olfaction)
interconnected to all areas/all 5 lobes of cerebral cortex |
|
|
Term
|
Definition
-involved in maintenance of homeostasis/equilibrium and motivated behaviors
-works with autonomic and endocrine systems |
|
|
Term
| what is the hypothalamus connected to? |
|
Definition
|
|
Term
| another name for midbrain |
|
Definition
|
|
Term
|
Definition
cerebral peduncles
substantia nigra
red nucleus
nuclei of origin of cranial nerves 3 and 4
mesencephalic central gray
tectum |
|
|
Term
| what are the cerebral peduncles? |
|
Definition
| motor fiber tracts, white matter with myelinated axons-descending travel from cerebral cortex to midbrain or spinal cord |
|
|
Term
| substantia nigra function |
|
Definition
| make dopamine and melanin |
|
|
Term
| what dies in Parkinson's disease? |
|
Definition
| cells of substantia nigra=loss of melanin expression, loss of smoothness of motor function from loss of dopamine |
|
|
Term
|
Definition
| origin of spinal tract to the rubrosopinal tract |
|
|
Term
| function of nuclei of origin in cranial nerves 3 and 4 |
|
Definition
| motor function (occulomotor and trochlear) |
|
|
Term
| what's in the tectum? function? |
|
Definition
| superior and inferior colliculi (sup=visual relay areal and inf=auditory relay area) |
|
|
Term
| another name for hindbrain? what does it include? |
|
Definition
rhombencephalon-includes everything but forebrain (=everything but cerebrum, hypothalamus, and thalamus)
*metencephalon and myencephalon |
|
|
Term
| what is in the metencephalon? |
|
Definition
|
|
Term
| what is the pons? what is it interconnected with? origin of what? |
|
Definition
origin and conduit of many ascending and descending fiber tracts
interconnected with cerebellum via cerebellar peduncles
origin of cranial nerves 5, 6, 7 |
|
|
Term
|
Definition
| process proprioceptive info from muscles, tendons, joints to coordinate motor activity |
|
|
Term
|
Definition
folia
anterior, posterior, and flocconodular lobes
primary and posterolateral fissures
superior, middle, and inferior cerebellar peduncles |
|
|
Term
| what are folia in cerebellum analogous to? |
|
Definition
|
|
Term
| what separates anterior, posterior, and flocconodular lobes? |
|
Definition
| primary and posterolateral fissures |
|
|
Term
| another name for myencephalon |
|
Definition
|
|
Term
| components of medulla/myencephalon |
|
Definition
cells of origin of many fiber tracts
sensory relay nuclei (nucleus cuneatus and gracilis)
origins of cranial nerves 8, 9, 10, 11, 12
pyramidal decussation
reticular formation and associated projection systems |
|
|
Term
| what does pyramidal decussation in medulla/myencephalon represent? |
|
Definition
| crossover point for corticospinal fibers at spinomedullary junction |
|
|
Term
| what does "brainstem" refer to? |
|
Definition
| midbrain/mesencephalon, pons, and medulla (NOT cerebellum) |
|
|
Term
| components of ventricular system |
|
Definition
| choroid plexus and several cavities |
|
|
Term
| what is the choroid plexus? function? |
|
Definition
highly vascularized (rich in blood supply) connective tissue (originated from mesoderm) covered with an ependymal layer
supplies/makes 60% of CSF in ventricular system via ependymal cells |
|
|
Term
| where is the choroid plexus found? |
|
Definition
| in lateral ventricle, roof of 3rd ventricle, and roof of 4th ventricle |
|
|
Term
| cavities of the ventricular system |
|
Definition
lateral ventricles (2)
3rd ventricle with interventricular foramen of Monro
4th ventricle wth cerebral aqueduct of Sylvius
Foramen of Magendie
Foramen of Luschka
central canal |
|
|
Term
| where are 3rd ventricle and interventriclular foramen of Monro found? |
|
Definition
midline= interventricular foramen
cavity of diencephalon/(thalamus and hypothalamus)=3rd ventricle |
|
|
Term
| where is 4th ventricle and cerebral aqueduct of Sylvius found? |
|
Definition
cavity of mesencephalon and hidbrain/rhombencephalon=cerebral aqueduct
cavity of metencephalon, and myelencephalon/medulla |
|
|
Term
| what is the posterior exit for CSF in the ventricular system? |
|
Definition
|
|
Term
| lateral exit for CSF in ventricular system? |
|
Definition
|
|
Term
| what are the foramina of Magendie and Luschka continuous with? |
|
Definition
|
|
Term
| what is the cavity of the spinal cord called? |
|
Definition
|
|
Term
| function of subarachnoid space |
|
Definition
makes 40% of CSF
surrounds entire brain, filled with CSF for buoyancy/protection, chemical communication, physical buffer
=protection from gravity because holds structures in space=no pinching of structures |
|
|
Term
| where are lateral ventricles found? components? |
|
Definition
cavity of telencephalon/cerebrum--extends to all lobes
each has 3 horns (frontal/anterior, temporal/inferior, and occipital/posterior horns) |
|
|
Term
| what happens if you have blockage of foramen in ventricular system? |
|
Definition
| swelling in brain=life-threatening |
|
|
Term
|
Definition
|
|
Term
| list the meninges of the brain? |
|
Definition
dura mater
arachnoid
pia mater
arachnoid specializations
dura specializations |
|
|
Term
| what is the dura mater? components? |
|
Definition
tough, superficial brain covering
double layer in skull (periosteal and meningeal)
single layer around spinal cord |
|
|
Term
|
Definition
| more delicate, spider-like, transparent, middle layer of brain coverings |
|
|
Term
| what is between the pia mater and arachnoid? |
|
Definition
| subarachnoid space filled with CSF--surrounds entire brain for protection |
|
|
Term
|
Definition
deep, very thin and delicate layer of brain coverings that adheres to brain surface
can't be seen with naked eye
invaginates into sulci and fissures |
|
|
Term
| list the arachnoid specializations |
|
Definition
subarachnoid space
arachnoid granulations
subarachnoid cisterns |
|
|
Term
| what are arachnoid granulations? function? |
|
Definition
| extensions of arachnoid through the dura mater into the venous sinus (superior sagittal sinus) that permit CSF to enter venous circulations |
|
|
Term
| list the arachnoid cisterns |
|
Definition
cerebellomedullary
pontine
interpeduncular
superior
cisterna ambiens
cistern of the lateral fissure
chiasmatic |
|
|
Term
| list the dura specializations |
|
Definition
falx cerebri
falx cerebelli
tentorum cerebelli
diaphragma sellae
dural venous sinuses |
|
|
Term
| list the dural venous sinuses: most important one? |
|
Definition
superior sagittal sinus -most important
inferior sagittal sinus
straight sinus
transverse sinus
sigmoid sinus |
|
|
Term
| where is the superior sagittal sinus of the dura found? what does it help with? |
|
Definition
b/t hemispheres
assists blood flow out of brain |
|
|
Term
| what is the falx cerebri? |
|
Definition
| dividing curtain b/t 2 cerebral hemispheres |
|
|
Term
| what is the falx cerebelli? |
|
Definition
| dividing curtain b/t 2 cerebellar hemispheres |
|
|
Term
| what is the tentorum cerebelli? |
|
Definition
| "tent over cerebellum"--over cerebellum, under occipital lobe of telencephalon/cerebrum |
|
|
Term
| function of diaphragma sellae |
|
Definition
| anchor pituitary gland in sella turcica |
|
|
Term
| structure combining main arteries of brain |
|
Definition
|
|
Term
|
Definition
internal carotid
basilar
vertebral |
|
|
Term
| branches of internal carotid artery |
|
Definition
| anterior cerebral middle cerebral posterior communicating |
|
|
Term
| main branch of anterior carotid |
|
Definition
| anterior communicating artery |
|
|
Term
| branches of basilar artery |
|
Definition
posterior cerebral
superior cerebellar
pontine
internal auditory
anterior inferior cerebellar (AICA) |
|
|
Term
| branches of vertebral artery |
|
Definition
posterior inferior cerebellar (PICA)
anterior spinal
posterior spinal |
|
|
Term
| what accounts for venous drainage in the brain? |
|
Definition
dural venous sinuses:
superior sagittal sinus
inferior sagittal sinus
straight sinus
transverse sinus
sigmoid sinus |
|
|
Term
| where does the internal carotid branch from? |
|
Definition
| common carotid through carotid canal |
|
|
Term
| where does the anterior cerebral artery run? |
|
Definition
| over corpus callosum and medial surface of cerebrum |
|
|
Term
| what connects the anterior cerebral arteries? |
|
Definition
| anterior communicating artery |
|
|
Term
| what is the middle cerebral artery? |
|
Definition
| continuation of internal carotid |
|
|
Term
| where does the posterior communicating artery run? |
|
Definition
|
|
Term
| where does the basilar artery run? what is it? what does it supply? |
|
Definition
top of pons
merging of vertebral arteries
supplies cerebral cortex via posterior cerebral arteries |
|
|
Term
| what arteries supply the cerebellum? |
|
Definition
superior cerebellar
anterior inferior cerebellar
posterior inferior cerebellar |
|
|
Term
| what does the posterior cerebral artery supply? |
|
Definition
| posterior, inferior, medial surface of temporal and occipital lobes |
|
|
Term
| what does the pontine artery supply? |
|
Definition
|
|
Term
| where does the vertebral artery branch from? what protects it? where does it run? what does it supply? |
|
Definition
from subclavian artery
protected by transverse foramen in vertebrae
goes through foramen magnum and merges at base of pons
supplies undersurface of cerebrum and most of brainstem and cerebellum |
|
|
Term
| where is the posterior inferior cerebellar artery directed to? what is it merging from? |
|
Definition
spinal cord
merging of vertebral arteries |
|
|
Term
| list the meninges of the spinal cord |
|
Definition
dura mater
arachnoid mater
pia mater |
|
|
Term
| where is the spinal cord located in the vertebral column? |
|
Definition
| within the vertebral canal from foramen magnum to vertebrae L1/L2 |
|
|
Term
| where are spinal cord enlargements? why? |
|
Definition
| in cervical and lumbar areas for the extremities which require more neurons |
|
|
Term
| what is the conus medullaris? |
|
Definition
| location where spinal cord ends |
|
|
Term
| what is the filum terminal? |
|
Definition
| specialized pia mater that attaches spinal cord to sacral wall |
|
|
Term
| what is the cauda equina? |
|
Definition
| "horse tail" of spinal nerves after cord ends |
|
|
Term
| why does a person who has a spinal tap done get a massive head ache? |
|
Definition
|
|
Term
| where are spinal taps done? why |
|
Definition
| by cauda equina because nerves will move away from needle=less likely to be damaged |
|
|
Term
| list and give number of spinal nerves |
|
Definition
31 pairs total:
8 cervical
12 thoracic
5 lumbar
5 saccral
1 coccygeal |
|
|
Term
| 3 main spinal cord tracts; |
|
Definition
dorsal column/medial lemniscus pathway
lateral spinothalamic tract
dorsal spinocerebellar tract |
|
|
Term
| what does the dorsal column/medial lemniscus pathway convey? |
|
Definition
| general sensory info: touch, pressure, tactile discrimination and kinesthesis (joint movement),--conscious proprioception |
|
|
Term
| ascending pathways of the medial lemniscus pathway |
|
Definition
fasciculus gacilis
fasciculus cuneatus |
|
|
Term
| location of fasciculus gracilis pathway |
|
Definition
| from lower limbs/trunk (more medial) found throughout entire dorsal spinal cord |
|
|
Term
| location of fasciculus cuneatus pathway |
|
Definition
| from upper limbs/upper trunk (more lateral) above T6 and gets larger as it ascends |
|
|
Term
| how many neurons does it take to relay information via the medial lemniscus pathways of the dorsal column? what is the pathway? |
|
Definition
3 neuron chain:
1)primary neuron in dorsal root ganglion
2)secondary neuron in fasciculus gracilis/cuneatus--to thalamus
(crossover in brain --medulla)
3)tertiary neuron in thalamus projects to somatosensory (CEREBRAL) cortex/postcentral gyrus |
|
|
Term
| what does the lateral spinothalamic tract convey? |
|
Definition
| pain and temperature info |
|
|
Term
| how many neurons does it take to relay info via the spinothalamic tract? what is the pathway? |
|
Definition
3 neuron chain:
1)primary neuron in dorsal root ganglion
2)secondary neuron in nucleus gracili/cuneatus
(fibers crossover in spinal cord on way to thalamus)
3)tertiary neuron in thalamus projects to CEREBRAL cortex/postcentral gyrus |
|
|
Term
| what does the dorsal spinocerebellar tract convey? to where? |
|
Definition
| unconcious proprioceptive info to the CEREBELLUM |
|
|
Term
| how many neurons does it take to relay info via the dorsal spinocerebellar tract? what is the pathway? |
|
Definition
2 neuron chain:
1)primary neuron in dorsal root ganglion
2)secondary neuron in dorsal horn (nucleus dorsalis) which projects to the cerebellum on the SAME SIDE
=(NO CROSSOVER) |
|
|
Term
| what is the most heavily myelinated tract in the spinal cord? what does this mean in terms of its speed? |
|
Definition
dorsal spinocerebellar tract (2 neurons is faster than 3 because it takes time to cross synapses)
highest rate of impulses |
|
|
Term
| names of the neurons involved in the medial lemniscus pathway |
|
Definition
1=dorsal root ganglion cell
2=internal arcuate fibers to nucleus gracilis and cuneatus
3=ventral posterolateral (VPL) nucleus of thalamus |
|
|
Term
| names of the neurons involved in the lateral spinothalamic tract |
|
Definition
1=dorsal root ganglion cell
2=(in dorsal horn of spinal cord)
3=VPL |
|
|
Term
| names of neurons involved in the dorsal spinocerebellar tract |
|
Definition
1=dorsal root ganglion cell
2=nucleus dorsalis (in dorsal horn) |
|
|
Term
| where does the thalamus give and receive input to/from? |
|
Definition
| all parts of cerebral cortex--reciprocal projection with overstimulation by VPL |
|
|
Term
|
Definition
ventral tier:
ventral anterior
ventral lateral
ventral posterior (medial and lateral)
medial geniculate
lateral geniculate
--also anterior nucleus and centromedian nucleus |
|
|
Term
| function of ventral anterior nucleus/VA |
|
Definition
|
|
Term
| function of ventral lateral nucleus/VL |
|
Definition
|
|
Term
| function of ventral posterior nuclei |
|
Definition
VPM=face sensation
VPL=body sensation |
|
|
Term
| function of medial geniculate/MGN |
|
Definition
|
|
Term
| function of lateral geniculate/LGN |
|
Definition
|
|
Term
| function of anterior nucleus |
|
Definition
| in limbic system--affect and emotion |
|
|
Term
| function of centromedian nucleus |
|
Definition
|
|
Term
| if someone has a spinal cord lesion on the RIGHT side at T6, what are the symptoms in terms of pain and temp sensation, conscious proprioception, and unconscious proprioception? |
|
Definition
everything about T6 is fine.
Below T6:
-lose pain and temperature sensation on the LEFT
-lose conscious proprioception on RIGHT
-lose unconscious proprioception on RIGHT |
|
|
Term
what pathway conducts pain and temperature sensation? and where is info sent to? crossover? (if so, where?)
how many neurons in chain? |
|
Definition
lateral spinothalamic tract of dorsal column--to postcentral gyrus of cerebral cortex
crossover in spinal cord within 1-2 vertebrae
3 neuron chain |
|
|
Term
what pathway conducts unconscious proprioception? where is the info sent? crossover? (if so, where?)
how many neurons in chain? |
|
Definition
dorsal spinocerebellar tract to cerebellum
no crossover
3 neuron chain |
|
|
Term
what pathway conducts conscious proprioception? where is the info sent? crossover? (if so, where?)
how many neurons in chain? |
|
Definition
medial lemniscus pathway of dorsal column to somatosensory area in postcentral gyrus of cerebral cortex
crossover in brain
3 neuron chain |
|
|
Term
| features of cerebral cortex |
|
Definition
2-4 mm thick
highly convoluted gray substance
over half=hidden in depths of various sulci and gyri
comprises almost half of brain's volume |
|
|
Term
| divisions of cerebral cortex |
|
Definition
isocortex/neocortex
allocortex |
|
|
Term
how many layers are in the isocortex/neocortex of the cerebrum? how much of the cortex is due to iso/neocortex?
how are the layers numbered? |
|
Definition
6 layers
95% of cortex
layer 1=to outside--most superficial
layer 6=to white matter--deepest |
|
|
Term
|
Definition
|
|
Term
| how many layers are in the allocortex? features? |
|
Definition
| 3-5 layers with a more variable lamination pattern |
|
|
Term
|
Definition
|
|
Term
| function of archicortex: how many layers? |
|
Definition
hippocampal formation
3 layers |
|
|
Term
| types of cells in iso/neocortex |
|
Definition
neurons (pyramidal, stellate, basket cells)
glia (oligodendrocytes, microglia, astrocytes)--white matter |
|
|
Term
| lamination pattern of iso/neocortex of cerebrum: |
|
Definition
1=molecular layer
2=external granular layer
3=external pyramidal layer
4=internal granular layer
5=intermal pyramidal layer
6=multiform layer |
|
|
Term
| characteristics of layer 1/molecular layer in iso/neocortex of cerebrum |
|
Definition
superficial layer
rich in fibers (horizontally oriented axons and dendrites) few neurons |
|
|
Term
| characteristics of layer 2/external granular layer in iso/neocortex of cerebrum |
|
Definition
mostly small neurons
few pyramidal neurons
RECEPTIVE LAYER--receives input from layer 3 |
|
|
Term
| characteristics of layer 3/external pyramidal layer in iso/neocortex of cerebrum |
|
Definition
medium-sized pyramidal cells with one apical dendrite and many basal dendrites
*give rise to association and commissural fibers
-projects to layer 2 |
|
|
Term
| characteristics of layer 4/internal granular layer in iso/neocortex of cerebrum |
|
Definition
mainly stellate (star-shaped) neurons
some pyramidal neurons
RECEPTIVE LAYER of THALAMIC INPUT (esp. in the primary somatosensory cortex) |
|
|
Term
| characteristics of layer 5/internal pyramidal layer in iso/neocortex of cerebrum |
|
Definition
medium and large pyramidal cells
giant (Betz) pyramidal cells
give rise to PROJECTIONS in subcortical areas (to deep forebrain, brainstem, spinal cord) |
|
|
Term
| where do projections from layer 5 of iso/neocortex go to? |
|
Definition
brainstem
spinal cord
deep forebrain |
|
|
Term
| characteristics of layer 6/multiform layer in iso/neocortex of cerebrum |
|
Definition
variety of cell types (inc. stellate and pyramidal neurons)
pyramidal neurons PROJECT to THALAMUS |
|
|
Term
| where do projection fibers from layer 6 of iso/neocortex to go? |
|
Definition
|
|
Term
| what are cortical connections? |
|
Definition
| highly organized myelinated axons |
|
|
Term
function of association fibers
-where are the axons of these neurons located? |
|
Definition
interconnect portions of cortex in the SAME hemisphere
(can be short (arcuate fibers) or long (to connect different lobes w/in a hemisphere on the same side))
cell bodies for these fibers arise in layer 3 and axons terminate in layer 2 |
|
|
Term
|
Definition
association fibers
specifically, short fiber system that connects adjacent gyri |
|
|
Term
function of commissural fibers
-where are these found? |
|
Definition
interconnect hemispheres
-most found in corpus callosum (over 300 million axons), some in ant. and post. commissures
-originate in layer 3, cross the midline and terminate in layer 2 |
|
|
Term
function of projection fibers
-where do they arise from? |
|
Definition
from layer 6=project downstream to thalamus
from layer 5= project downstream to deep forebrain, brainstem, spinal cord |
|
|
Term
| names of projection fibers |
|
Definition
-corticothalamic
-corticosubcortical (re-entrant circuits like corticostriatalpallidothalamocortical loopts)
-corticorubral (to red nucleus of midbrain that projects to spinal cord as rubrospinal tract)
-corticopontine (to pons of cerebellum)
-corticoreticular (to spinal cord)
-corticospinal
-corticobulbar (5,7,9,10,11,12)(input to motor nuclei of 3, 4, and 6 via superior colliculus and brainstem reticular formation for coordination of eye movements) --bulb=brainstem |
|
|
Term
| pathway for projection of thalamocortical fibers |
|
Definition
| originate in thalamus and project to layer 6 |
|
|
Term
| pathway for projection of corticothalamic fibers |
|
Definition
| originate in layer 6 and project to thalamus |
|
|
Term
| pathway for projection of association fibers |
|
Definition
| originate in layer 3 and project to layer 2 |
|
|
Term
| pathway for projection of commissural fibers |
|
Definition
| originate in layer 3, cross midline, and project to layer 2 |
|
|
Term
| pathway for projection fibers |
|
Definition
originate in layer 5 and project to subcortex
originate in layer 6 if going to thalamus, where they terminate in layer 4 |
|
|
Term
| discuss size of layers in association cortex |
|
Definition
| large layers 2 and 3 b/c project to same or opposite side FROM LAYER 2 TO LAYER 3 |
|
|
Term
| discuss size of layers in motor cortex |
|
Definition
large layer 5 b/c projecting lots of motor output
small layer 4 b/c not getting sensory input |
|
|
Term
| discuss size of layers in visual cortex |
|
Definition
-large layer 4 b/c receiving lots of sensory input from thalamus
-small layer 5 b/c not projecting motor output |
|
|
Term
| what affects sizes of layers in iso/neocortex? |
|
Definition
|
|
Term
| why does the thalamus project AND receive input w/cortex? |
|
Definition
|
|
Term
| discuss the lateral corticospinal tract |
|
Definition
-axons from layer 5 neurons in the PRECENTRAL gyrus of the cerebral motor cortex descend as projection fibers through the internal capsule, bypassing the thalamus, through the cerebral peduncles of the midbrain, pons, and pyramids of the medulla.--affect distal motor neurons/distal body segments
-90% cross to contralateral side and descend as the lateral corticospinal tract
(other 10% descend on same side as the anterior corticospinal tract--these axons eventually cross in the spinal cord to innervate motor neurons on contralateral side too, but to more proximal/medial structures of body) |
|
|
Term
| discuss the rubrospinal tract |
|
Definition
(anterior to lateral corticospinal tract)
-originates in the red nucleus of the midbrain, driven by above motor cortex on the same side, but projects to opposite side due to crossover in brainstem (ventral tegmental decussation) |
|
|
Term
| location of crossover in lateral corticospinal tract |
|
Definition
| pyramidal decussation in medulla |
|
|
Term
| location of crossover in anterior corticospinal tract |
|
Definition
| spinal cord near region of destination |
|
|
Term
| what happens if you have damage to the internal capsule? |
|
Definition
| likely to have large level of paralysis due to motor projection pathways crossing through this area |
|
|
Term
| what provides blood to the spinal cord? what is supplied? what happens if you lose blood supply to the spinal cord |
|
Definition
anterior spinal artery=anterior 2/3 of cord--supplies motor neurons of lateral corticospinal tract, rubrospinal tract, lateral spinothalamic tract.
posterior spinal artery=dorsal 1/3
blood loss=paralysis, loss of pain and temp sensation, lose motor function, etc. |
|
|
Term
| other names for a stretch reflex |
|
Definition
MONOSYNAPTIC reflex
myotactic reflex |
|
|
Term
| what monitors stretch reflexes? |
|
Definition
| receptive muscle spindle fibers |
|
|
Term
| where are muscle spindles found? |
|
Definition
|
|
Term
| what is activated with stretch of a muscle spindle? |
|
Definition
| specific sensory nerve fibers called 1a afferent nerve fibers |
|
|
Term
| where are the cell bodies of 1a afferent sensory fibers found? direction of projection? |
|
Definition
dorsal root ganglia of spinal cord... projection into the spinal cord through the dorsal root, synapse on alpha motor neurons that innervate the same muscle
(activation of 1a afferent fibers=monosynaptic activation of alpha motor neurons to make that muscle contract) |
|
|
Term
| what does a reflex test do? |
|
Definition
determine integrity of:
axon
dorsal root ganglion
dorsal root
ventral motor neurons
peripheral nerve of that skeletal muscle |
|
|
Term
| discuss the stretch reflex |
|
Definition
-regulation of muscle length is monitored by muscle spindles
-1a afferent sensory nerve fibers are activated with stretch
-projections sent to spinal cord through dorsal root
-synapse on alpha motor neurons in same muscle
-contraction |
|
|
Term
| function of golgi tendon reflex |
|
Definition
| prevent excessive tension within muscles to prevent damage |
|
|
Term
| what happens in golgi tendon reflexes? |
|
Definition
-golgi tendon organs/GTOs (muscle tendon receptors) respond to excessive tension (from stretch or contraction)
-GTOs are contacted by 1b afferent sensory nerve fibers that project to spinal cord through the dorsal root
-synapse in inhibitory interneurons
-inhibition/relaxation of alpha motor neurons that innervate the same muscle (autogenic inhibition)
-at the same time, excitatory interneurons are contacted to excite antagonist muscle groups=contraction of antagonist muscles |
|
|
Term
| what two reflex systems coordinate their actions? |
|
Definition
flexor withdrawal reflex
crossed extension reflex? |
|
|
Term
| function of flexor withdrawal reflex |
|
Definition
| withdraw affected limb from noxious stimuli |
|
|
Term
| what type of fibers are utilized in the flexor withdrawal reflex? |
|
Definition
|
|
Term
| how does the flexor withdrawal reflex work? |
|
Definition
1)pain receptors stimulate class 3 afferent receptors
2)projections sent into spinal cord
3)these axons stimulate EXCITATORY interneurons to contact alpha motor neurons of FLEXORS
4) simultaneously, the axons synapse on INHIBITORY interneurons of EXTENSOR muscles
5)withdrawal of limb to minimize damage/trauma |
|
|
Term
| where do class 3 afferent receptors have their cell bodies? |
|
Definition
|
|
Term
| function of crossed extension reflex |
|
Definition
| assist flexor withdrawal reflex to minimize damage while maintaining balance and posture because accounts for opposite side of body as well |
|
|
Term
| how does the crossed extension reflex work? |
|
Definition
1) pain receptors stimulate class 3 afferent receptors
2) projections sent into spinal cord
3) innervation of IPSILATERAL interneurons sends an axon collateral ACROSS MIDLINE to CONTRALATERAL spinal cord
4) EXCITATORY interneurons are stimulated to contact alpha motor neurons of EXTENSOR muscles of opposite limb affected by painful stimulus
5) simultaneously, INHIBITORY interneurons are stimulated to contact alpha motor neurons to FLEXOR muscles of opposite limb affected by stimulus
6) balance and posture are maintained to pull affected limb from stimuli and balance on opposite limb |
|
|
Term
| function of basal ganglia |
|
Definition
motor programming and function on opposite side of body
(channel info through a series of subcortical nuclei and back to a motor strip in precise timing to perform motor acts)
(organized via 2 major pathways through a series of 5 nuclei, with relays back to motor-related cortical areas via the thalamus. exerts influence over descending motor pathways--esp. the corticospinal tract) |
|
|
Term
| what is interesting about the term basal "ganglia" |
|
Definition
| it is actually a nucleus, not a ganglion because it is inside the CNS |
|
|
Term
| what are the 5 interconnected subcortical nuclei of the basal ganglia? |
|
Definition
caudate
putamen
globus pallidus
subthalamic nucleus
substantia nigra |
|
|
Term
| what is the striatum? why this name? |
|
Definition
caudate + putamen
both have striations due to myelinated fascicles that penetrate them |
|
|
Term
| what is the lentiform nucleus? |
|
Definition
| putamen + globus pallidus |
|
|
Term
| what is the corpus striatum? |
|
Definition
| caudate + putamen + globus pallidus |
|
|
Term
| if there's a small area of cell death in the putamen, what are the affects? |
|
Definition
| may have no affects because putamen is large and redundant |
|
|
Term
| what are the striatal afferents/inputs of the basal ganglia? |
|
Definition
iso/neocortex
intralaminar thalamus
substantia nigra compacta (direct and indirect pathways) |
|
|
Term
| discuss the iso/neocortex use in motor function |
|
Definition
-virtually entire cortical mantle projects to striatum (caudate and putamen)
-primary motor and somatosensory areas project mainly to putamen, and input is funneled through the basal ganglia to the motor portions of the thalamus, then back to the motor, premotor, and supplementary motor cortices
-association cortical areas project to caudate and follow a similar route through basal ganglia and thalamus, back to premotor cortices |
|
|
Term
| what are the motor parts of the thalamus? |
|
Definition
|
|
Term
| in the intralaminar thalamus, what is an important source of input to the striatum? |
|
Definition
|
|
Term
| what is the intralaminar thalamus? |
|
Definition
(not part of VA/VL)
zone of white matter that bisects thalamus and divides it into 3 segments
-has embedded clusters of neurons (one is the centromedian nucleus) |
|
|
Term
| location, make-up, and function of substantia nigra |
|
Definition
in midbrain
-has compact and reticular parts
cells in the compact area make and project dopamine as a neurotransmitter to the striatum
(melanin is also made here) |
|
|
Term
| how many neurons are involved in the direct/excitatory pathway for motor function? |
|
Definition
|
|
Term
| how many neurons are involved in the indirect/inhibitory pathway for motor function? |
|
Definition
|
|
Term
| steps of direct pathway for motor function |
|
Definition
1)cortex (all areas) -->
2)striatum -->
3)globus pallidus, internus (GPi) -->
4)thalamus (VA/VL) -->
5)back to cortex (supplementary and premotor) |
|
|
Term
| steps of indirect pathway for motor function |
|
Definition
1)cortex (all areas) -->
2)striatum -->
3)globus pallidus, externus (GPe) -->
4)subthalamic nucleus -->
5)globus pallidus, internus (GPi) -->
6)thalamus (VA/VL) -->
7)back to cortex (supplementary and premotor) |
|
|
Term
| what happens if cells in substantia nigra, compacta (SNC) stop producing dopamine? |
|
Definition
input from cortex upon striatum is choked off and striatal neurons can't drive globus pallidus properly
=pathway breaks down, get slowness of motion and rigidity |
|
|
Term
| function of substantia nigra, reticula (SNR) |
|
Definition
acts like a "transplanted globus pallidus internal segment" in the midbrain
-receives input from striatum (not from subthalamic nucleus though)
-projects to thalamus (projection continues to cortex) |
|
|
Term
| why is the direct pathway for motor function considered a re-entrance ciruit? |
|
Definition
| starts and ends in cortex to drive the corticospinal tract |
|
|
Term
| what is happening in Parkinson's disease? |
|
Definition
slowness of motion and rigidity due to lack of dopamine from the substantia nigra, compacta to the striatum because cells of the substantia nigra, compacta died
(also lose the normal dark strip that's seen in this area because melanin won't be produced either from dying of cells) |
|
|
Term
| what are the striatal efferents in the motor pathways? |
|
Definition
1)globus pallidus, internal (GPi)/substantia nigra, reticulata (SNr)
2)globus pallidus, external (GPe) |
|
|
Term
| what are the globus pallidus afferents? |
|
Definition
1) GPi=striatum and subthalamic nucleus
2) GPe=striatum |
|
|
Term
| what are the globus pallidus efferents? |
|
Definition
1) GPi/SNr= thalamus (VA/VL)
2) GPe= subthalamic nucleus |
|
|
Term
| subthalamic nucleus efferents? |
|
Definition
|
|
Term
| what are the thalamic (VA/VL) projections? |
|
Definition
1)primary motor cortex
2)premotor cortex
3)supplementary motor area |
|
|
Term
| what happens if you have a lesion in the motor cortex of the cerebrum? |
|
Definition
| reduced strength and speed of movement and inability to contract individual muscles |
|
|
Term
| what happens if you have a cerebellar lesion? |
|
Definition
| deficit in coordination of limb and eye movements, balance, and muscle tone |
|
|
Term
|
Definition
receive projections from sensory and motor systems, modulate output of descending motor systems
-has repetitive processing modules that perform similar functions
-complementary role to basal ganglia |
|
|
Term
| how much of the brain weight is due to the cerebellum? how many of the brains neurons are in the cerebellum |
|
Definition
10% of weight
50% of neurons |
|
|
Term
|
Definition
folia (analogous to gyri)
anterior (top 1/3) and posterior lobes divided by primary fissure
(post. lobe is also divided by a horizontal fissure) |
|
|
Term
| components and locations in cerebellum |
|
Definition
-flocculus (2) and nodulus (1) form flocconodular lobe =vestibular function
-vermis in midline (part of spinocerebellum)
-paravermis (intermediate part, part of spinocerebellum)
-lateral parts of ant. and post. cerebellar hemispheres (part of cerebrocerebellum) |
|
|
Term
function of vestibulocerebellum
-where is it mediated? |
|
Definition
| coordinates balance and eye movements (mediated in the flocconodular lobe) |
|
|
Term
| function of spinocerebellum |
|
Definition
error detection and correction
-receives afferent info about motor planning (internal feedback) from brain areas responsible for programming and executing motor function.
-also receives afferent sensory info from periphery during course of movement (external feedback)
-compares intended motor program with actual motor response=error detection and sends correction signal
(compares motor intention versus performance) |
|
|
Term
| function of cerebrocerebellum |
|
Definition
function similar to basal ganglia-involved in motor planning and programming
-receives cortical input (indirectly through pontine nuclei)
-sends output back to motor-related areas of cerebral cortex via thalamus (VL)
*from pons, to dentate, VL, premotor motor cortex, corticospinal tract |
|
|
Term
| importance of deep cerebellar nuclei |
|
Definition
| no info leaves cerebellum without communication with deep cerebellar nuclei (=output of cerebellum) |
|
|
Term
| input pathways for cerebellum |
|
Definition
|
|
Term
| output pathway for cerebellum |
|
Definition
| midbrain--everything leaving goes through here, usually to thalamus or midbrain, and from there to cortex |
|
|
Term
| where are deep cerebellar nuclei found? |
|
Definition
| deep in white matter of cerebellum |
|
|
Term
| where are inputs/afferents of cerebellum from? |
|
Definition
| cerebellar cortex (purkinje cells) and axon collaterals from all systems that enter the cerebellum |
|
|
Term
| where do outputs/efferents of cerebellum originate? |
|
Definition
in one of 4 deep cerebellar nuclei
(not flocconodular lobe or vestibulocerebellum--which send axonal projections directly to vestibular nuclei in the brainstem responsible for maintaining balance and eye movements) |
|
|
Term
| what are the deep cerebellar nuclei? |
|
Definition
1) fastigial
2) globose
3) emboliform
4) dentate |
|
|
Term
| characteristics of fastigial nuclei |
|
Definition
-most medial of deep cerebellar nuclei
-output to vestibular nuclei and brainstem reticular formation
-origins of medial descending motor pathways that control axial musculature
-functionally part of spinocerebellum |
|
|
Term
| location of globose nuclei |
|
Definition
|
|
Term
| characteristics of emboliform nuclei |
|
Definition
-lateral to globose
(globose + emboliform =interposed nuclei b/c between fastigial and dentate)
-output is to brainstem nuclei associated with lateral descending systems (particularly red nucleus)--origin of the rubrospinal tract
-functionally part of spinocerebellum |
|
|
Term
| characteristics of dentate nuclei |
|
Definition
-most lateral of deep cerebellar nuclei
-output is to VL nucleus of thalamus, which projects to premotor and motor cortex
-functionally part of cerebrocerebellum |
|
|
Term
| important cell type of cerebellum and characteristics of them |
|
Definition
purkinje--modify output of all deep cerebellar nuclei
=allow detection and correction of errors and plan/program motor info in lateral part of cerebral cerebellum
-dendrites stay in one plane that's perpendicular to folia, so cells can stack |
|
|
Term
| layers of cerebellar cortex |
|
Definition
granular layer
purkinje cell layer
molecular layer |
|
|
Term
| characteristics of granular layer in cerebellar cortex |
|
Definition
| has small relay neurons/granule cells and a few golgi cells/interneurons |
|
|
Term
| characteristics of purkinje cell layer in cerebellar cortex |
|
Definition
| sheet of highly branched purkinje cells, with flattened dendritic trees, oriented perpendicular to folia of the cerebellar cortex |
|
|
Term
| characteristics of molecular layer of the cerebellar cortex |
|
Definition
| has stellate and basket cell interneurons, as well as purkinje and golgi cell dendrite arbors, and axons of granule cells |
|
|
Term
| how do the basal ganglia and cerebellum have complementary roles in motor function? |
|
Definition
1) basal ganglia and cerebrocerebellum (lat. hemis.) project to premotor cortical areas
2) precentral gyrus/motor cortex executes movement and simultaneously projects to spinocerebellum (vermis and int. hemis.) to get feedback via dorsospinocerebellar tract, allowing projection for movement with smooth function
3) spinocerebellum (vermis and int. hemis.) gets peripheral feedback as well |
|
|
Term
function of limbic system
-what happens if damage to limbic system occurs? |
|
Definition
process emotional stimuli (fear, affect, emotion, anxiety, aggression) and induce appropriate behavioral responses
damage=changes in emotional responsiveness |
|
|
Term
| location and formation of limbic system |
|
Definition
most anterior part of thalamus
many structures surround medial border of telencephalon and diencephalon |
|
|
Term
|
Definition
cingulate gyrus
hippocampus
mammillary bodies
anterior thalamic nucleus
hypothalamus
amygdala
prefrontal cortex |
|
|
Term
| location and function of cingulate gyrus |
|
Definition
| a cortical structure overlying the corpus callosum that's implicated in multiple aspects of cognition |
|
|
Term
| location and function of hippocampus |
|
Definition
| structure within the medial temporal cortex (temporal horn of lateral ventricle) that's known for its role in the formation of associations or memories |
|
|
Term
| what is the hippocampus susceptible to? |
|
Definition
depression and stress affect size
antidepressants increase cell birth
susceptible to hypoxia, damage from epilepsy, degenerative diseases |
|
|
Term
| what can damage to the hippocampus lead to? |
|
Definition
| short-term memory defects |
|
|
Term
| location and function of mamillary bodies |
|
Definition
| structure in posterior of hypothalamus that receive a massive input from the hippocampus |
|
|
Term
| what does damage to mamillary bodies lead to? |
|
Definition
|
|
Term
| location and function of anterior thalamic nucleus |
|
Definition
| structure within the anterior thalamus that relays info from mamillary bodies to the cingulate gyrus |
|
|
Term
| relay of info in Papez Circuit |
|
Definition
| cingulate gyrus--(cingulate bundle)--> hippocampus--(fornix)--> mamillary bodies--(mammilothalamic tract)--> anterior thalamic nuclei--(superior thalamic peduncle)-->back to cingulate gyrus |
|
|
Term
| what TYPE of pathway is projected in the fornix? |
|
Definition
| commissural pathway ( as well as associative pathway) |
|
|
Term
| connection from the cingulate gyrus to the hippocampus |
|
Definition
|
|
Term
| connection from the hippocampus to the mamillary body |
|
Definition
|
|
Term
| connection from the mamillary body to the anterior thalamic nucei |
|
Definition
|
|
Term
| connection from the antertior thalamic nuclei to the cingulate gyrus |
|
Definition
| superior thalamic radiation/peduncle |
|
|
Term
| major limbic system fiber pathways |
|
Definition
fornix
cingulum
mammillothalamic tract
superior thalamic tract |
|
|
Term
|
Definition
| mainly of axons in pyramidal/layer 3 cells in the hippocampus (subiculum) |
|
|
Term
| what TYPE of pathways are the major limbic system fiber pathways? |
|
Definition
| association pathways in white matter |
|
|
Term
location of cingulum
-what is it connected with? |
|
Definition
deep within cingulate and parahippocampal gyri, adjacent to hippocampus
-connects all areas of cerebral cortex (carries info to hippocampus) |
|
|
Term
| function of prefrontal cortex in limbic system |
|
Definition
| executive function and decision-making, memory, impulse control |
|
|
Term
| function of amygdala in limbic system |
|
Definition
| fear, anxiety, aggression, emotional memory |
|
|
Term
|
Definition
primarily=homeostasis
involved in:
1) autonomic nervous system
2) endocrine system
3) *output/effector of limbic system
-forms walls of and floor of interior part of the 3rd ventricle |
|
|
Term
| what separates the hypothalamus from the thalamus? |
|
Definition
|
|
Term
| borders of the hypothalamus |
|
Definition
anterior=optic chiasm and lamina terminalis
posterior=mamillary bodies
medial=3rd ventricle
lateral=optic tract |
|
|
Term
| what are the important hypothalamic nuclei? |
|
Definition
lateral zone: lateral tuberal (tuberomamillary) nucleus
medial zone:
- suprachiasmatic nucleus
-anterior hypothalamic nucleus
-paraventricular nucleus
-supraoptic nucleus
-posterior nucleus
-mamillary nucleus |
|
|
Term
| composition of lateral zone in hypothalamus |
|
Definition
loosely arranged neuronal cell groups
-traveled by fibers of medial forebrain bundle |
|
|
Term
| location of lateral tuberal/tuberomamillary nucleus and its components |
|
Definition
ventrolateral surface of medial zone
-contains large neurons that release histamine as a neurotransmitter via axonal projections to widespread portions of forebrain |
|
|
Term
| function of tuberomamillary/lateral tuberal nucleus |
|
Definition
| role in attention and arousal processes--inhibited during sleep |
|
|
Term
|
Definition
| group of neurons turn on and inhibit histamine-containing cells in the lateral tuberal/tuberomamillary nucleus so that less histamine is released in brain=sleep |
|
|
Term
| affects of antihistamines on body via lateral tuberal/tuberomamillary nucleus |
|
Definition
| get tired because histamine action is blocked, so it's hard to maintain alertness |
|
|
Term
| location and role of suprachiasmatic nucleus |
|
Definition
located dorsal to optic chiasm
-receives direct input from retina and plays role in control of circadian rhythm (responds to light to train circadian rhythm) |
|
|
Term
| location and role of anterior hypothalamic nucleus |
|
Definition
between suprachiasmatic and paraventricular nuclei
-involved in temp. regulation (has neurons to sense WARMTH and initiate responses to DISSIPATE excessive HEAT (sweat, increase respiration)
-stimulatory drive of parasympathetic nervous system |
|
|
Term
| what happens if you have bilateral lesions in anterior hypothalamic nuclei? |
|
Definition
|
|
Term
| role of paraventricular nucleus |
|
Definition
neurons release neuropeptides in posterior pituitary (neurohypophysis) that are release to systemic circulation and regulate many functions:
-arginine vasopressin/AVP for water conservation
-oxytocin for milk let-down and release
-corticotropin-releasing hormone/CRH for stress responsiveness
other neurons also project to the intermediolateral cell column of the spinal cord between T1 and L2 to excite sypathetic preganglionic neurons |
|
|
Term
| role of supraopic nucleus |
|
Definition
neurons here synthesize AVP/arginine vasopressin and oxytocin
-these cells project to the neurohypophysis, where they release hormones to the sytemic circulation |
|
|
Term
| affect of alcohol in medial zone of hypthalamus |
|
Definition
| alcohol "paralyzes" the paraventricular nucleus=AVP isn't released=kidney doesn't absorb water=diuresis |
|
|
Term
| function of corticotropin-releasing hormone/CRH |
|
Definition
drive release of ACTH/adrenocorticotropic hormone to stimulate release of cortisol from adrenal cortex
-cortisol shifts metabolic priorities to liberate energy or help us cope |
|
|
Term
| role of posterior nucleus in the hypothalamus |
|
Definition
helps in thermoregulation--neurons sense COLD
-initiate heat conservation and production responses (shivering, vasoconstriction, release thyroid hormone) |
|
|
Term
| what results from bilateral lesions of posterior nuclei in the hypothalamus? |
|
Definition
inability to thermoregulate (poikilothermia)
*damage to this area also knocks out anterior nucleus function--body can't regulate temperature at all so body temp. fluctuates with the external environment |
|
|
Term
| what is the mamillary nucleus in the hypothalamus? |
|
Definition
| series of nuclei within the mamillary bodies that are functionally considered to be part of the limbic system |
|
|
Term
| role of mamillary nucleus in the hypothalamus? |
|
Definition
neurons here receive major input from hippocampus via the fornix (memory and learning)
-the mamillary nuclei project this input to the anterior nucleus of the thalamus via the mamillothalamic tract
(also connected with parts of midbrain tegmentum that convey sensory info to them) |
|
|
Term
| result of damage to mammillary nuclei of hypothalamus |
|
Definition
| memory loss due to interconnectivity with the hippocampus |
|
|
Term
| how does the hypothalamus regulate temp., feeding and energy metabolism, reproductive function, stress responsiveness, BP/electrolyte levels? |
|
Definition
1) it can access sensory info from the entire body (visual info is relayed here to the suprachiasmotic nucleus, pain info from spinal cord and trigeminal nerve, there's internal sensory nerurons responsive to changes in temp., osmality, glucose, and sodium conc., circulating hormones act on neurons here
2) it establishes biological set points for temp, blood osmality, glucose, sodium, hormone levels
3) deviation from set points are detected by the hypothalamus and responded to by adjustments in autonomic, endocrine, behavioral systems to restore homeostasis
(hypothalamus is connected with autonomic, endocrine, and limbic areas to coordinate regulation) |
|
|
Term
| how does the anterior hypothalamic nucleus trigger heat dissipation through multiple mechanisms? |
|
Definition
-activating parts of PARAsympathetic nervous system
-inflammatory cytokines and pyrogens act here also to alter set points to initiate disease-associated fevers |
|
|
Term
| how does the posterior hypothalamic nucleus trigger heat conservation? |
|
Definition
-SYMPATHETIC outflow
-activation of some endocrine responses (thyroid) to alter metabolic rate |
|
|
Term
| what are the anterior and posterior hypothalamic nuclei interconnected with? |
|
Definition
| under influence from forebrain, but also connected with brainstem and spinal cord regions that mediate desired effects (as well as behavioral responses to move to a better temperature location) |
|
|
Term
| why does bilateral destruction of ant. hypothalamic nuclei cause hyperthermia, while bilateral destruction of post. hypothalamic nuclei causes loss of both cold AND warm-sensing neurons and an inability to thermoregulate at all (poikilothermia)? |
|
Definition
| descending projections from the anterior hypothalamic nuclei pass through the posterior hypothalamic area on the way to the brainstem |
|
|
Term
| how does the hypothalamus play a role in coordinating the fight-or-flight response? |
|
Definition
-neuroendocrine control to release stress hormones from adrenal cortex, as well as epinephrine and norepinephrine from the adrenal medulla
-sypathetic connections with viscera initiate physiological changes (diversion of blood from viscera to skin and muscles, increased cardiac output, pupillary dilation, bronchodilation, decreased GI motility, renal activity)
-inhibition of parasympathetic neurons of brainstem |
|
|
Term
| what controls the hypothalamus? by what mechanism? |
|
Definition
| through AFFERENT regulatory control by the pre-frontal cortex, limbic forebrain, and brainstem |
|
|
Term
| what prominent components of the limbic system are extensively interconnected with the hypothalamus? |
|
Definition
|
|
Term
| how does the hypothalamus work with the pre-frontal cortex, limbic forebrain, and brainstem to initiate stress response? |
|
Definition
| it integrates signalling from these areas, takes the input from the stressor and stimulates production of a coordinated set of responses by outflow or autonomic, endocrine, etc. |
|
|
Term
| responsibilities of cerebrum/telencephalon |
|
Definition
higher brain functions:
-perception of sensory impulses
-instigation of voluntary movement
-memory storage
-thought processes
-reasoning ability
-limbic (affect & emotion) functions |
|
|
Term
| what is the largest structure of the brain? what percent of the mass of the brain does it account for? |
|
Definition
cerebrum/telencephalon
80% |
|
|
Term
| what separates the right and left hemispheres of the cerebrum/telencephalon? |
|
Definition
| longitudinal cerebral fissure |
|
|
Term
| what connects the two hemispheres of the cerebrum/telencephalon? |
|
Definition
corpus callosum*
anterior commissure
posterior commissure
hippocampal commissure |
|
|
Term
| a portion of the meninges, called the __________ extends into the longitudinal fissure |
|
Definition
|
|
Term
| each cerebral hemisphere contains a central cavity, _____________, that's filled with cerebrospinal fluid |
|
Definition
|
|
Term
| divisions of the lateral ventricle of the cerebrum/telencephalon--where do these extend? |
|
Definition
anterior
posterior
inferior
these extend to different portions of the hemisphere |
|
|
Term
| function of left hemisphere of cerebrum/telencephalon |
|
Definition
| analytical and verbal skills (reading, writing, speech, mathematics) |
|
|
Term
| function of right hemisphere in cerebrum/telencephalon |
|
Definition
| spatial and artistic ability |
|
|
Term
| function of the corpus callosum, in relation to the left and right hemispheres of the cerebrum/telencephalon |
|
Definition
unify attention and awareness
(and other processes) |
|
|
Term
| what are the 2 major areas of the cerebrum/telencephalon? |
|
Definition
cerebral cortex/surface area--gray matter, 6 layers of nerve cell bodies
white matter (association, commissural, projection fibers--myelinated axons) |
|
|
Term
why is the brain convoluted?--what are these folds called? what are the depressions called?
how does this folding affect the area of gray matter? |
|
Definition
during early development, brain size increases rapidly and the cortex enlarges out of proportion to the underlying white matter
folds=gyri
depressed grooves=sulci
triples that area of gray matter |
|
|
Term
| what separates the frontal and parietal lobes? |
|
Definition
|
|
Term
| what separates the frontal and temporal lobes? where does it extend |
|
Definition
| lateral fissure-laterally from the inferior surface of the cerebrum |
|
|
Term
| what is the important primary motor area in the cerebrum/telencephalon? where is it positioned? what lobe is it in? |
|
Definition
precentral gyrus--immediately in front of the central sulcus
frontal lobe |
|
|
Term
| where is the parietal lobe? |
|
Definition
| posterior to the central sulcus of the frontal lobe |
|
|
Term
| what is the important primary somatosensory area in the cerebrum/telencephalon? where is it positioned? what lobe is it in? |
|
Definition
postcentral gyrus--immediately behind that central sulcus
parietal lobe |
|
|
Term
| why is the postcentral gyrus designated as a somesthetic area? |
|
Definition
| it responds to stimuli from cutaneous and muscular sensory receptors throughout the body |
|
|
Term
| other than somesthetic stimuli, what does the parietal lobe function in? |
|
Definition
understanding speech
articulating thoughts and emotions
interpret texture and shapes of objects as they're handled |
|
|
Term
| what separates the temporal lobe from the frontal and parietal lobes? |
|
Definition
|
|
Term
| components/function of temporal lobe in cerebrum |
|
Definition
| has auditory centers that receive sensory fibers from the cochlea of the inner ear |
|
|
Term
| how is the occipital lobe separated from the temporal and parietal lobes of the cerebrum? |
|
Definition
| it's not distinctly separated |
|
|
Term
| what separates the occipital lobe from the cerebellum? |
|
Definition
|
|
Term
| main function of occipital lobe |
|
Definition
|
|
Term
| location of insular lobe of cerebrum |
|
Definition
| deep to the lateral fissure, not seen on surface--covered by parts of frontal, parietal, temporal lobes |
|
|
Term
|
Definition
| little is know about this lobe, but it integrates other cerebral activities and may assist with memory functions |
|
|
Term
| composition of white matter in the cerebrum |
|
Definition
myelinated axons and associated glial cells (mostly oligodendrocytes)
has 3 types of fiber tracts |
|
|
Term
| how are fiber tracts in the white matter of the cerebrum named? |
|
Definition
| according to location and direction in which they conduct impulses |
|
|
Term
| what are the 3 fiber tracts in the white matter of the cerebrum? |
|
Definition
association
commissural
projection |
|
|
Term
| characteristics of association fibers |
|
Definition
| conduct impulses between neurons WITHIN a hemisphere |
|
|
Term
| characteristics of commissural fibers--examples? |
|
Definition
connect neurons and gyri ACROSS hemispheres
-corpus callosum
-anterior commissure |
|
|
Term
| where are the neurons whose axons become commissural fibers found? |
|
Definition
| cortical layer 3/external pyramidal cell layer |
|
|
Term
| characteristics of projection fibers |
|
Definition
form ascending and descending tracts that transmit impulses from:
1) cerebrum to other parts of brain and spinal cord
2) spinal cord and other parts of brain to the cerebrum |
|
|
Term
| where are the neurons whose axons become projection fibers found? |
|
Definition
| cortical layer 5/internal pyramidal cell layer |
|
|
Term
| principle components of the limbic system |
|
Definition
cingulate gyrus
hippocampus
mammillary bodies
anterior portion of the thalamus |
|
|
Term
| where is the cingulate gyrus found? |
|
Definition
| above the corpus callosum |
|
|
Term
| where is the hippocampus found? |
|
Definition
| in the medial temporal lobe |
|
|
Term
|
Definition
| associative learning and memory formation |
|
|
Term
| where are mammillary bodies found? |
|
Definition
|
|
Term
| what connects the components of the limbic system? |
|
Definition
| series of axonal fiber bundles to form "Papez Circuit" |
|
|
Term
| what structures have been added to the primary components of the limbic system? |
|
Definition
prefrontal/limbic cortex
amygdala
septum
hypothalamus |
|
|
Term
| what is an important output structure to the limbic system? why? |
|
Definition
| hypothalamus--has control over endocrine and autonomic nervous systems |
|
|
Term
| what/where are the basal ganglia? |
|
Definition
| specialized paired masses of gray matter deep within the white matter of the cerebrum |
|
|
Term
| what's the most prominent of the basal nuclei? |
|
Definition
|
|
Term
| components and their locations of the striatum |
|
Definition
caudate nucleus--upper, medially positioned
putamen--below and lateral to caudate |
|
|
Term
| where is the globus pallidus? what are its subdivisions? |
|
Definition
| medial to putamen -internal and external supdivisions |
|
|
Term
| components of basal ganglia |
|
Definition
striatum
subthalamic nucleus
substantia nigra |
|
|
Term
| where is the subthalamic nucleus found? |
|
Definition
| within the diencephalon (thalamus + hypthalamus) |
|
|
Term
| where is the substantia nigra found? |
|
Definition
| within the mesencephalon/midbrain |
|
|
Term
| what is the collective function of the basal ganglia? how? |
|
Definition
control motor programming and planning through direct and indirect circuits:
1)the entire cortical mantle provides input to the striatum
2)processing within channels of the globus pallidus and other basal ganglia components
3)info sent to thalamus (VA/VL)
4)info funneled to motor-related cortical areas
5)output of basal ganglia is expressed through descending corticospinal motor pathway |
|
|
Term
| what are the motor-related cortical areas? |
|
Definition
motor cortex
premotor cortex
supplementary cortical area |
|
|
Term
|
Definition
| speech and language disorders caused by damage to specific language areas of the brain |
|
|
Term
| how was knowledge of brain regions involved in language gained? |
|
Definition
|
|
Term
| where are language areas of the brain located? |
|
Definition
| mostly in the cerebral cortex of the left hemisphere |
|
|
Term
| what is the name for the motor speech area of the brain? |
|
Definition
|
|
Term
|
Definition
| in the left inferior gyrus of the frontal lobe |
|
|
Term
| what does neural activity in the motor speech/Broca's area cause? |
|
Definition
selective stimulation of motor impulses to:
1)motor centers of the frontal lobe that cause coordinated skeletal muscle movement in the pharynx and larynx
2)respiratory muscles to regulate air movement across
vocal folds
-these combined muscular contractions produce phonation/speech |
|
|
Term
| where is Wernicke's area? |
|
Definition
| in the superior gyrus of the temporal lobe |
|
|
Term
| how is Wernicke's area connected to Broca's area? |
|
Definition
| a fiber tract, called the arcuate fasciculus |
|
|
Term
| function of Wernicke's area |
|
Definition
| language comprehension --concept of words to be spoken originates here and is communicated to Broca's area through the arcuate fasciculus |
|
|
Term
| components of the diencephalon |
|
Definition
| thalamus and hypothalamus |
|
|
Term
| what surrounds the diencephalon? |
|
Definition
| cerebral hemispheres of the telencephalon |
|
|
Term
| what cavity is a narrow midline cavity within the diencephalon? |
|
Definition
|
|
Term
| proportion of the diencephalon due to the thalamus |
|
Definition
|
|
Term
|
Definition
relay center for all sensory impulses (except smell) to the cerebral cortex
-specialized masses of nuclei relay the incoming impulses to precise locations within the cerebral lobes for interpretation |
|
|
Term
| how is the thalamus a paired structure? |
|
Definition
| each portion is positioned immediately below the lateral ventricle of its respective cerebral hemisphere |
|
|
Term
| all areas of the cerebral cortex are reciprocally connected with ________ |
|
Definition
|
|
Term
| thalamic projections to the cortex terminate in _________ |
|
Definition
| cortical layer 4/internal granular cell layer |
|
|
Term
| cortical projections to the thalamus arise from neurons in ___________ |
|
Definition
| cortical layer 6/multiform layer |
|
|
Term
| what is the hypothalamus named for? |
|
Definition
| its position below the thalamus |
|
|
Term
|
Definition
most inferior part of diencephalon
forms floor and part of the lateral walls of the 3rd ventricle |
|
|
Term
| the hypothalamus contains several nuclei that are interconnected with other parts of _______________ |
|
Definition
|
|
Term
|
Definition
regulation of internal activities:
-maintain body homeostasis
-fluid and electrolyte balance
-stress responsiveness
-reproductive functions
-thermoregulation
-feeding and energy balance
-circadian rhythmicity |
|
|
Term
| location of mesencephalon |
|
Definition
| narrow part of the brainstem between the forebrain/prosencephalon and the hindbrain/rhombencephalon |
|
|
Term
| components of mesencephalon |
|
Definition
superior and inferior colliculi (dorsally)
cerebral peduncles (ventrally)
red nucleus
substantia nigra
cerebral aqueduct
origination of cranial nerves 3 and 4 |
|
|
Term
| cavity of the midbrain/mesencephalon? |
|
Definition
|
|
Term
| what does the cerebral aqueduct connect? |
|
Definition
|
|
Term
| what cranial nerves originate in the mesencephalon/midbrain? |
|
Definition
|
|
Term
| function of superior and inferior colliculi in the mesencephalon/midbrain |
|
Definition
| visual and auditory reflexes |
|
|
Term
| composition of cerebral peduncles |
|
Definition
| descending motor fiber tracts |
|
|
Term
| what is the origin of the rubrospinal tract? |
|
Definition
| red nucleus in the mesencephalon/midbrain |
|
|
Term
| components of metencephalon? |
|
Definition
pons
cerebellum
4th ventricle |
|
|
Term
|
Definition
-many important cell groups
-ascending and descending white matter pathways
-origins of CN 5-12 |
|
|
Term
| cavity of the metencephalon |
|
Definition
|
|
Term
|
Definition
| send motor output to cerebellum |
|
|
Term
|
Definition
| rounded bulge on inferior surface of the brain, between midbrain and medulla oblongata |
|
|
Term
|
Definition
| white fiber tracts that take 2 principle directions |
|
|
Term
| pathway of surface fibers in pons |
|
Definition
| extend transversely through the cerebellar peduncles to connect with cerebellum |
|
|
Term
| pathway of deeper longitudinal fibers in pons |
|
Definition
| connect medulla oblongata with tracts of midbrain |
|
|
Term
|
Definition
|
|
Term
| what are the deep longitudinal fibers of the pons part of? |
|
Definition
|
|
Term
| what cranial nerves have nuclei within the pons? |
|
Definition
trigeminal (5)
abducens (6)
facial (7)
branches of vestibulocochlear (12) |
|
|
Term
| what is the 2nd largest structure of the brain? |
|
Definition
|
|
Term
| where is the cerebellum located? |
|
Definition
| in the metencephalon-occupies inferior and posterior aspect of the cranial cavity |
|
|
Term
|
Definition
cerebellar cortex (thin outer layer of gray matter)
white matter (deeper and thicker) |
|
|
Term
| names for convolutions of cerebellum |
|
Definition
|
|
Term
| name for branching pattern of white matter tracts in cerebellum |
|
Definition
|
|
Term
| in what view can arbor vitae be seen? |
|
Definition
|
|
Term
| 3 paired bundles of nerve fibers called ____________ support the cerebellum and allow it to communicate with the rest of the brain |
|
Definition
|
|
Term
| what are the paired cerebellar peduncles |
|
Definition
1) superior cerebellar peduncles
2) middle cerebellar peduncles
3) inferior cerebellar peduncles |
|
|
Term
| function of superior cerebellar peduncles--where do fibers that run through these peduncles originate? where do they go? |
|
Definition
connect cerebellum to midbrain
fibers originate from neurons of deep cerebellar nuclei and go to red nucleus or thalamus (VL) |
|
|
Term
| function of middle cerebellar peduncles |
|
Definition
| convey inputs to the cerebellum from the pons |
|
|
Term
| where are pontine neurons activated? |
|
Definition
| motor regions in the cerebral cortex |
|
|
Term
| function and components of inferior cerebellar peduncles |
|
Definition
connect cerebellum with the medulla oblongata and spinal cord
contains incoming proprioceptive fibers, 4th ventricle, vital nuclei, ascending and descending tracts |
|
|
Term
| location of medulla oblongata |
|
Definition
| bulbous, 3 cm long, most inferior structure of the brainstem--continuous with the pons superiorly and spinal cord inferiorly |
|
|
Term
| how is the medulla oblongata differentiated from the spinal cord? |
|
Definition
| 2 triangular elevations called PYRAMIDS on the ventral side and an oval enlargement called the OLIVE on each lateral side |
|
|
Term
| what is the space within the medulla? |
|
Definition
|
|
Term
| what is the 4th ventricle continuous with? |
|
Definition
| interiorly with the central canal of the spinal cord |
|
|
Term
| where do ascending and descending tracts going through the medulla travel between? |
|
Definition
| spinal cord and various parts of brain |
|
|
Term
| what is in the gray matter of the medulla oblongata? |
|
Definition
| several important nuclei including origins of CN 9-12 |
|
|
Term
| where are relay nuclei for the ascending dorsal column system (nucleus gracilis and nucleus cuneatus) found? |
|
Definition
| caudal/inferior part of medulla |
|
|
Term
| what is the name for the crossing point for most descending motor fibers that are part of the pyramidal tract in the medulla? |
|
Definition
|
|
Term
| nuclei in the medulla that function as autonomic centers control ___________ |
|
Definition
| vital visceral functions like cardiac and respiratory functions, reflexes like sneezing, coughing, swallowing, vomitting |
|
|
