NEURO Test 3

cerebral cortex is the

highest level of CNS

cerebral cortex always functions in

association with lower centers

gray matter in cerebral cortex is responsible for (3)

conscious thought

memory

language

cerebral cortex description (2)

very thin

outer few millimeters of cerebrum

cerebral cortex has how many neurons and where are they located

10-14 billion neurons

located in gray matter

how are nerve cells organized in cerebral cortex

type of cell & layer

how many layers in cerebral cortex

6

explain how layers are numbered in cerebral cortex

the higher the number the closer to the center

types of nerve cells in cerebral cortex (5)

pyramidal cells

fusiform cells

stellate cells

martinotti cells

horizontal cells

what are pyramidal cells named after

their shape

in pyramidal cells dendrites project to

cortical surface (up)

explain axons for pyramidal cells

axons form tracts, leave cortex and enter white matter (go down)

fusiform cells dendrites project to

cortical surface

explain axons in fusiform cells

axons form tracts, leave cortex, and enter white matter (go down)

stellate cells description

small (granular) cells with short axon and multiple dendrites

stellate cell communication type

local communication

horizontal cells location

most superficial layers of the cortex

horizontal cells connect

dendrites of pyramidal cells

explain axons for cells of martinotti

axons project to most superficial layer of the cortex (go up)

in the cerebral cortex, each layer has

its distinct pattern of organization and connections

in the cerebral cortex, each layer is grouped by

motor or sensory and function

the motor cortex has many of what layer cells

layer 5 and 6 cells

the motor cortex has what types of cells (3)

pyramidal

fusiform

martinotti

motor cortex sends axons to

other brain areas

sensory cortex has many of what layer cells

layer 4 cells

sensory cortex has many of what kind of cells

stellate cells

sensory organs send info to where (3)

primary sensory cortex: somatosensation

visual cortex: vision

auditory cortex: hearing

association cortex has many of what layer cells

layer 1, 2, and 3 cells

what layer does the association cortex receive input from

layer 4

what types of cells are in the association cortex (4)

horizontal

pyramidal

fusiform

stellate

myelinated fibers function is to

quickly synthesize transport and respond to signals

interconnecting fibers keeps brain

informed about all things going on in the brain

3 things interconnecting fibers inform the brain about

perception and discrimination of sensory stimuli

expression of emotions

regulate behaviors and bodily processes

commissural fibers location

between hemispheres

commissural fibers description

white matter that runs horizontally and connects right and left hemisphere

corpus callosum is the

largest horizontal interhemispheric commissural fiber bundle

parts of corpus callosum (4)

rostrum

genu

body

splenium

what part(s) of the brain does the rostrum connect

two frontal lobes

what part(s) of the brain does the genu connect

frontal lobes

what part(s) of the brain does the body connect

frontal and parietal lobes

what part(s) of the brain does the splenium connect

temporal and occipital lobe

most interior part of the corpus callosum

rostrum

what doesn’t the corpus callosum connect

primary centers for motor, sensory, auditory, and visual functions

association fibers description

white myelinated fibers

association fibers location

confined within one hemisphere

association fibers funciton

process refined and integrated info

corpus callosum is a(n)

commissural fiber

arcuate fasciculus is a(n)

association fiber

arcuate fasciculus connects (lobes of the brain)

frontal, temporal, parietal and occipital lobe

arcuate fasciculus connects what areas of speech

broca’s area and wernicke’s area

arcuate fasciculus is important for

normal acquisition of language

what happens when the arcuate fasciculus is damaged

conduction aphasia

conduction aphasia

auditory comprehension and speech articulation is preserved but it’s hard to repeat heard speech

three subcortical trats associated with language processing

• dorsal pathway

• ventral pathway

• uncinate fasciculus

two structures in the dorsal pathway

superior longitudinal fasciculus

arcuate fasciculus

two structures in ventral pathway

inferior longitudinal fasciculus

connects middle temporal lobe

projection fibers travel

between cortical and subcortical structures

projection fibers function

carry sensory/motor info and travel vertically

corona radiata is a(n)

projection fiber

corona radiata description

white matter sheet contains both descending and ascending axons that carry sensory/motor info from/to cerebral cortex

internal capsule is a(n)

projection fiber

internal capsule location

between basal ganglia and thalamus

internal capsule description

white matter structure contains ascending and descending fibers

three major projection fibers

corticobulbar tract

corticospinal tract

sensory projection fibers

corticobulbar tract is a

white matter pathway

where does corticobulbar tract originate and end

originates from motor cortex

terminates in brainstem

corticobulbar tract aka

pyramidal tract

corticobulbar tract stimulates

muscles of face, tongue, larynx, and pharynx

almost all cranial nerves receive _______ innervation from corticobulbar tract

bilateral

what cranial nerve does not receive bilateral innervation and what kind of innervation does it have

cranial nerve seven

contralateral innervation

what cranial nerve receives more contralateral innervation than bilateral innervation

cranial nerve 12

unilateral corticobulbar tract lesion causes

weakness

explain why unilateral corticobulbar tract lesions result in weakness and not paralysis

almost all cranial nerves would continue to function almost normally as nuclei of each cranial nerve pair still receive messages from at least one motor cortex

bilateral corticobulbar tract lesion leads to (2)

paralysis and serious speech problems

corticospinal tract is a

white matter pathway

corticospinal tract originates and terminates where

originates in primary motor cortex

terminates in spinal cord

corticospinal tract controls

voluntary movements of torso, upper, and lower limbs

corticospinal tract forms

the pyramid at the medulla before crossing the midline and entering the spinal cord

upper motor neurons are

motor neuron cell bodies (pyramidal cells) and their descending axonal processes

upper motor neurons originate in

primary motor cortex

when do upper motor neuron symptoms occur

following brain/spinal cord damage

upper motor neuron symptoms (3)

weakness

decreased control

increase spinal reflexes and Babinski signs

upper motor neurons carry

motor info down to a lower motor neuron

upper motor neurons synapse with

lower motor neurons in the brain stem (motor neurons of cranial nerves) and in spinal cord (motor neurons of spinal nerves)

axons of lower motor neurons innervate

skeletal muscle fibers

sensory projection fibers is a

white matter pathway

pathway for sensory projection fibers

starts in skin/joint

through brainstem (cross), thalamus, internal capsule, and corona radiata

terminates in CNS (primary somatosensory cortex)

sensory projection fibers transmit sensory info to CNS parts (3)

thalamus

cerebral cortex

cerebellum

brainstem parts (3)

midbrain

pons

medulla oblongata

brainstem function

monitor brain output

midbrain connects

diencephalon (thalamus) and pons

midbrain houses

cerebral aqueduct

the 2 superior colliculi house the

visual reflex

the 2 inferior colliculi are the

auditory cortex

midbrain contains what 2 cranial nerves

3 and 4

pons connects (2)

medulla to midbrain

cerebellar hemisphere

the pons have what cranial nerves (4)

V

VI

VII

VIII

pons houses the

4th ventricle

medulla oblongata connects

pons and spinal cord