L3 Neuroanatomy 2 Flashcards
gyrus (pl. gyri)
folds in the brain
sulcus (pl. sulci)
grooves in the brain
central sulcus
a main sulcus in the brain separating the frontal and parietal lobes
the primary motor cortex sits anterior to it
the primary sensory cortex sits posterior to it
parieto-occipital sulcus
separates parietal and occipital lobes
folium (pl. folia)
folds in the cerebellum (like gyri)
lateral fissure
separates frontal and parietal lobes with the temporal lobe
insula lobe
folded deep behind the frontal and temporal lobes, functions: emotions and limbic-system
Brodmann Areas
map of the brains based on the result of cellular differences in regions of the brain (i.e. they were separated due to histological differences, not functional differences)
Brodmann Area #4
primary motor cortex
Brodmann Area #17
primary visual cortex
corpus callosum
major fibre tract that connects the left and right brain
brain ventricles
two lateral ventricles (one in each hemisphere)
3rd ventricle in diencephalon (interbrain), between the two thalami (sing. thalamus)
4th ventricle between brainstem and cerebellum
filled with CSF
function of brainstem in motor pathways
location of motor pathways for postural control (extrapyramidal systems)
grey matter deep in the brain (i.e. not on the outer edges)
basal ganglia, parkinson’s is based on problems with them, they are important for motor control
size of grey matter in spinal cord
depends on the number of neurons, which depends on the number of motor units (i.e. the need for movement)
size of spinal cord
depends on the function, more function equates to larger spinal cord (cervical and lumbar enlargements)
funiculus
columns/tracts of white matter/axons in the spinal cord
conus medullaris
ends at L2 (spinal end proper)
cauda equina
extends beyond the conus medullaris (looks like a horse tail)
primary motor cortex
located anterior to the central sulcus (precentral gyrus), controls movement; contains upper motor neurons which leads to lower motor neurons (and to the target muscles)
motor homunculus
the size of cortical surface responsible for part of body is proportional to degree of motor control needed for part
internal capsule
white matter tract that goes between the basal ganglia
location of secondary cortices to primary cortices
primary cortices are surrounded by secondary cortices and secondary cortices are surrounded by tertiary ones
Brodmann Area #6
supplementary motor cortex (SMC) and premotor cortex (PMC)
hierarchical organisation of motor cortices
prefrontal cortex (highest order association cortex) –> SMC and PMC –> Primary motor cortex (M1) –> spinal cord –> somatomotor output
Function of SMC and PMC
contributes to learning sequence of movements, stored skills, sensory integration and bilateral coordination (esp. of upper limbs)
where can motor pathway lesion occur?
LMN, UMN and PMC/SMC/other motor planning areas
result of lesion/damage in LMN
flaccid paresis or paralysis (hypotonia/atonia)
result of lesion/damage in UMN
spastic paresis or paralysis (hypertonia) - because LMN is responsible for reflex, therefore reflex actions still exist, UMN acts to inhibit uninitiated reflex actions
result of lesion/damage in PMS/SMC/other motor planning areas
apraxia (a-lack of, praxia-practice) = can’t execute voluntary motor movement despite having normal muscle function, inhibits ability to imitate a move
what two main types of motor systems are there?
lateral and anterior motor systems
what are the two corticospinal tracts in the pyramidal system
ventral (anterior) corticospinal tract and lateral
corticospinal tract
lateral cortical spinal tract
80% of fibers
UMN crosses midline at “decussation in medulla” passes through the lateral funiculi to the LMN and innervates the distal muscles of the body
anterior (ventral) cortical spinal tract
20% of fibers
UMN bypasses the pyramids (w/o crossing the midline) and travels along the anterior funiculus (or travels in the anterior region, not so sure) to their LMN and innervates the proximal muscles of the body
decussation of pyramids
the part inferior to the pyramids where they are joined together, this marks the midline crossing of the lateral cortical spinal tracts
