1. Gross brain, brainstem & spinal cord Flashcards
What is white matter? & What are other names for white matter?
- collection of axons, many covered w/ myelin
- Fasciculus, funiculus, lemniscus, peduncle & tract
(tracts: 2 part names: 1: location of cell bodies & 2: where they end up = tracts talk about multiple options of white matter)
(fasciculus & funiculus: referred to when talking about parts of along the tract)
What is grey matter?
area w/ neuronal/glial cells & dendrites
- Nuclei: embedded combined cell bodies w/ similar fxn
- Cortex: layers of grey matter over CNS (like cerebral & cerebellar cortices)
what are components of grey matter?
Nuclei: collection of cell bodies w/ common fxn
Cortex: layers of grey matter over other parts of the CNS
What are the different types of folds on the cerebral hemispheres cortical surface
- Gyrus: ridge of cortical tissue
- Sulcus: groove located btn gyri
- Fissures: deep sulci
fxn: increase total cortical area & number of cortical neurons
what are the 4 sulci that divide the cerebral hemisphere into 5 lobes
Central sulcus: divide frontal & parietal (used to help find motor and somatosensory cortex)
Lateral sulcus: divide frontal, parietal & temporal lobes
Parietooccipital sulcus: medial sulcus; divides parietal & occipital lobe
Cingulate sulcus: medial, along cingulate lobe
what are the two hemispheres joined by?
corpus callosum
What are the boundaries of the frontal lobe
Laterally: lateral sulcus aka sylvian fissure (seperate from temporal lobe)
Medially: extend to cingulate sulcus
Posteriorly: top of central sulcus to cingulate sulcus
Inferiorly: continue as orbital part of frontal lobe
(overall: extend from frontal pole –> central sulcus)
What are the boundaries of the temporal lobe
Superiorly: extend to lateral sulcus and line of inferior boundary of parietal lobe (collateral sulcus)
Posteriorly: line connecting top of parietooccipital sulcus and preoccipital notch (extend preoccipital notch toward corpus callosum)
Medially:
What are the boundaries of the parietal lobe
Inferiorly: bound by lateral sulcus (imaginary continuation to posterior border)
- bounded by subparietal & calcarine sulci (medially, inferiorly)
Anterior: frontal lobe
Posterior: parietooccipital sulcus
what are the boundaries of the occipital lobe?
Anterior: parietal & temporal lobe (lateral and medial sides)
What are the boundaries of the limbic lobe
- interposed btn corpus callosum & frontal, parietal & occipital lobe
- curve around to medial surface
=strip of cortex that encircles the telencephalon-diencephalon jxn
frontal lobe contains —-
motor areas
primary motor cortex, premotor and supplementary motor areas
What is the precentral gyrus
lateral surface of frontal lobe (ant. to central sulcus)
= contains primary motor cortex
also contain: premotor & supplementary motor areas (make up part of frontal gyri too) ==> planning & initiating voluntary movements
what makes up the lateral surface of the frontal lobe
precentral gyrus
superior, middle & inferior frontal gyri
What fxn is the broca’s area important for & where is it located?
Motor aspects of written & spoken language
(on one hemisphere usually left, on inferior frontal gyrus; part of opercular and triangular parts)
What does the prefrontal cortex do
executive fxns; personality, decision making, insight & foresight
Which lobe contains somatosensory areas
parietal lobe (post-central gyrus & superior/inferior parietal lobules)
post. to central sulcus
Which gyrus is related to the primary somatosensory cortex? & what does this cortex do
postcentral gyrus
control processing tactile & proprioception fxn info, sensory localization
What is involved in language comprehension
inferior parietal lobule
(usually in only 1 hemisphere, likely left)
pariatel lobe contains——
sensory info
primary somatosensory cortex
What does the parietal cortex outside of the gyrus and lobules do?
spatial orientation & directing attn
How is the homunculus mapped?
= spatially distorted & reflects the amount of innervation involved in given area of the body
= somatotopic map = contralateral half of body mapped in postcentral gyurus
-applies to primary motor & somatosensory cortices
Which gyri make up the temporal lobe
superior, middle & infeiror temporal gyri
& inferior surface = occipitotemporal (fusiform) gyrus
temporal lobe contains—-
auditory areas
What 4 fxns are associated with the temporal lobe
- superior: continuation of superior temporal gyrus = primary auditory cortex
- posterior (usually one hemisphere, likely left) : Wernicke’s area: comprehnsion of language
- inferior: higher order processing of visual info
- medial: learning & memory
where is Wernike’s area located
post. part of superior temporal gyrus; including supramarginal & angular gyri
What are the limbic lobe fxns
made of cingulate & parahippocampal gyri (learning & memory)
hippocampus (learning & memory)
amygdala (fear & emotion)
=imp for emotional response, drive-related behavior & memory
what is the uncus? what are possible complications that can occur with the uncus?
formed when the anterior end of the parahippocampal gyrus hooks backwards on itself (makes a medial bump)
-get stuck under dura & cause compression (esp in & around brainstem)
what are the limbic structures
hippocampus: folded into temporal lobe at the hippcampal sulcus
amygdala: underneath the uncus
uncus: medial portion, end of parahippocampal gyrus that wraps around itself
also: cingulate & parahippocampalgyri
Where can you locate the insula & what is its function?
pry open the lateral sulcus or remove the opercula - underneath frontal, parietal and temporal
outlined by the circular sulcus
taste
what are the components of the occipital lobe
lateral: lateral occipital gyri
cuneus: wedge shaped btn parietooccipital and calcarine sulci
primary visual cortex: in the walls of the calcarine sulcus
remainder = visual association cortex (higher order processing of visual info)
what does the diencephalon contain
thalamus (above hypothalamus = gateway for sensory info, except olfaction)
hypothalamus (behind optic chiasm = auntomoic controsl and direct “talk” to pituitary gland)
epithalamus
subthalamus
where can you find the hypothalamus? & what are its fxns
behind optic chiasm; inrelation to pituitary gland (connect via infundibular stalk)
autonomic controls & direct interaxn with pituitary
What does the basal nuclei contain & what is its fxn
= group of nuclei deep to cerebral cortex
Caudate Nucleus & Lentricular nucleus (subdivided into putamen & globus pallidus) & subthalamus
=control movement & moderation of movement
what divides the lentricular nuclei & what does it contain
internal capsule: seperate lentricular nuclei from thalamus and caudate
=thick sheet of fibers - contain most of the fibers conntecting the cerebral cortex and deep structrues (thalamus, basal nuclei and brain stem)
name the central white matter structures & list what they do
- arcuate fibers: connect cortical areas w/i sulci/gyri (close conections)
- longitudinal/association fasciculi: connect cortical area w/i same hemisphere (ie lobe to lobe)
- projection tracts: connect cortical area w/i other body region (ie corticospinal tract)
- corpus callosum: interconnect 2 cerebral hemisphere lobes - frontal, parietal and occipital (~ 250 mil axons)
- anterior commissure: comissural fibers to/from temporal lobe (esp inferior part)
what are the limbs that white matter is divided into
how are these clinically relevent
anterior limb
genu
posterior limb
sublenticular limb
retrolenticular limb
- contain vasculature: damage to blood supply can damage tract and cause adverse effects
what are the parts of the brainstem & what is the overall fxn
midbrain, pons, medulla
cranial nerve fxn; convery info to/from forebrain
describe the parts of the midbrain
houses the tectum of the midbrain
superior and inferior colliculi = paired bumps posterior to cerebral aqueduct
paired cerebral peduncles
what are the parts of the pons
protuding basal pons
pontine tegmentum (part of floor of 4th ventricle)
what are the parts of the medulla
rostral = open portion (has part of 4th ventricle)
caudal = closed portion (continous with sp. cord) - blends in w/ sp. cord
what is the fxn of the cerebellum? & what are its components?
= sensory info processing & influences motor neurons (fine & fluid movements)
surface = transverse ridges, folia
lobes and lobules divided by fissures
white matter in medullary center: made of afferent/efferent fibers
what are the parts of the post. horn of the sp. cord
substantia gelatinosa: region of grey matter that caps the horn
body: interneurons & projection neurons that transmit somatic & visceral sensory info
Lissauer’s tract - white matter btn substantia gelatinosa & surface of sp. cord
Clark’s nucleus (poterior thoracic nucleus)
what is the path of the roots/rootlets of the spinal cord?
posterior rootlets enter via posteriolateral sulcus
& anterior rootlets leave via anterolateral sulcus
what is Clark’s nucleus
= aka = posterior thoracic nucleus
cells on medial surface of base of post. horn (T1-L2)
-sensory & posture processing
= cerebellar feedback
what is the fxn of the cells from the anterior horn
contain cell bodies of lower MNs (supply skeletal Ms)
-provide CNS control for voluntary/involuntary body movements
what is the intermediate grey matter
= collection of various projection neurson, sensory interneurons & interneurons
- Presynaptic sym neurons (T1-L3) in intermediolateral cell column = lateral horn (axon leave via ventral roots)
sacral parasym nucleus - S2-S4 (DOESNT form distinct lateral horn)
Lamina I (marginal zone)
nucleus: Marginal zone
levels: All
some spinothalamic tract cells
(thin layer covering substantia gelatinosa)
Lamina II
nucleus: substantia gelatinosa
all levels
modulate transmission of pain/temp info
Lamina III - VI
Nucleus: body of post horn
all levels
sensory processing
Lamina VII
Clark’s nucleus (intermediate gray matter & extensions into anterior horn) -> T1-L2
posterior spinocerebellar tract cells
intermediolateral column -> T1-L3 = preganglionic sym neurons
Sacral parasym nucleus: -> S2-S4 - preganglionic parasym neurons - pelvic viscera
Lamina VIII
some of the interneuron zone of anterior horn
lamina IX
Acessory nucleus: -> medulla - C5 - MNs to SCM & trapezius M
Phrenic nucleus: -> C3-C5 - MNs to diaphragm
lamina X
zone of grey matter surrounding central canal
how is information conveyed to CNS
primary afferents & lower MNs
primary afferents terminate in CNS on second-order neurons (sensory primary afferent = ipsilateral w/ few exceptions)
(lower MNs: info from CNS to skeletal M)
what do second order neruons & third order neurons do?
2nd order: relay signal from primary afferent in spinal cord to thalamus (can cross midline of body) -
3rd order: relay signal to final target in cortical area = thalamus to upper corical areas (then cortex decides on given output)
Name the ascending tracts & their fxn
- Posterior columns: ipsilat proprioceptive, tactile & vibratory info from body (NOT FACE)
- Spinocerebellar tracts: info to cerebellum, thalamus & motor cortex –> influence efficiency of motor activity
- Anterolateral system (ALS): pain, temp and nondiscriminative touch from body (NOT FACE)
what are the results of cerebellar damage
abnormalitites of equalibrium, postural control & coorindation of voluntary movements
Name the descending tacts & their fxn
- Corticospinal tract: controls voluntary, fine movement of Ms
- Vestibulospinal tract: influence MNs innervating primary axial & neck Ms
- Rubrospinal fibers: excite flexor MNs and inhibit extensor MNs
what happens if you have damage in the postcentral gyrus/sulcus
problems with percieving sensations & proprioception
what will happen if you have damage to the calcarine sulcus, cuneus &/or lingual gyrus?
some sort of vision impairment
-primary visual cortex in walls of calcarine sulcus & associated with cuneus, lingual gyrus
What happens if you damage the basal nuclei or associated structures?
some sort of motor disorder
-Parkinsons, Huntingtons, dystonia, tremors, etc
what may occur if you damage the cerebellum
abnormal equilibrium, postural control and coordination of voluntary movements
-decreased/lacking fine/fluid movements
(rmr it gets input from vestibular system for balance and posture)
