L3 Neuroanatomy 2

Question 1

gyrus (pl. gyri)

Answer 1

folds in the brain

Question 2

sulcus (pl. sulci)

Answer 2

grooves in the brain

Question 3

central sulcus

Answer 3

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

Question 4

parieto-occipital sulcus

Answer 4

separates parietal and occipital lobes

Question 5

folium (pl. folia)

Answer 5

folds in the cerebellum (like gyri)

Question 6

lateral fissure

Answer 6

separates frontal and parietal lobes with the temporal lobe

Question 7

insula lobe

Answer 7

folded deep behind the frontal and temporal lobes, functions: emotions and limbic-system

Question 8

Brodmann Areas

Answer 8

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)

Question 9

Brodmann Area #4

Answer 9

primary motor cortex

Question 10

Brodmann Area #17

Answer 10

primary visual cortex

Question 11

corpus callosum

Answer 11

major fibre tract that connects the left and right brain

Question 12

brain ventricles

Answer 12

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

Question 13

function of brainstem in motor pathways

Answer 13

location of motor pathways for postural control (extrapyramidal systems)

Question 14

grey matter deep in the brain (i.e. not on the outer edges)

Answer 14

basal ganglia, parkinson’s is based on problems with them, they are important for motor control

Question 15

size of grey matter in spinal cord

Answer 15

depends on the number of neurons, which depends on the number of motor units (i.e. the need for movement)

Question 16

size of spinal cord

Answer 16

depends on the function, more function equates to larger spinal cord (cervical and lumbar enlargements)

Question 17

funiculus

Answer 17

columns/tracts of white matter/axons in the spinal cord

Question 18

conus medullaris

Answer 18

ends at L2 (spinal end proper)

Question 19

cauda equina

Answer 19

extends beyond the conus medullaris (looks like a horse tail)

Question 20

primary motor cortex

Answer 20

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)

Question 21

motor homunculus

Answer 21

the size of cortical surface responsible for part of body is proportional to degree of motor control needed for part

Question 22

internal capsule

Answer 22

white matter tract that goes between the basal ganglia

Question 23

location of secondary cortices to primary cortices

Answer 23

primary cortices are surrounded by secondary cortices and secondary cortices are surrounded by tertiary ones

Question 24

Brodmann Area #6

Answer 24

supplementary motor cortex (SMC) and premotor cortex (PMC)

Question 25

hierarchical organisation of motor cortices

Answer 25

prefrontal cortex (highest order association cortex) –> SMC and PMC –> Primary motor cortex (M1) –> spinal cord –> somatomotor output

Question 26

Function of SMC and PMC

Answer 26

contributes to learning sequence of movements, stored skills, sensory integration and bilateral coordination (esp. of upper limbs)

Question 27

where can motor pathway lesion occur?

Answer 27

LMN, UMN and PMC/SMC/other motor planning areas

Question 28

result of lesion/damage in LMN

Answer 28

flaccid paresis or paralysis (hypotonia/atonia)

Question 29

result of lesion/damage in UMN

Answer 29

spastic paresis or paralysis (hypertonia) - because LMN is responsible for reflex, therefore reflex actions still exist, UMN acts to inhibit uninitiated reflex actions

Question 30

result of lesion/damage in PMS/SMC/other motor planning areas

Answer 30

apraxia (a-lack of, praxia-practice) = can’t execute voluntary motor movement despite having normal muscle function, inhibits ability to imitate a move

Question 31

what two main types of motor systems are there?

Answer 31

lateral and anterior motor systems

Question 32

what are the two corticospinal tracts in the pyramidal system

Answer 32

ventral (anterior) corticospinal tract and lateral

corticospinal tract

Question 33

lateral cortical spinal tract

Answer 33

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

Question 34

anterior (ventral) cortical spinal tract

Answer 34

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

Question 35

decussation of pyramids

Answer 35

the part inferior to the pyramids where they are joined together, this marks the midline crossing of the lateral cortical spinal tracts