Medulla oblongata

Question 1

ventral grooves

Answer 1

fissura mediana anterior : pyramis medullae oblongatae on both sides (contains tractus corticospinalis), decussatio pyramidum (75-90%) of fibers pass to the other side

sulcus anterolateralis: CN 12 nervus hypoglossus emerges

sulcus retroolivaris: CN10 nervus vagus CN9 nervus accessorius and CN11 nervus glossopharyngeus emerge

Question 2

dorsal grooves + structures

Answer 2

fossa rhomboidea in upper part

sulcus medianus posterior

fasciculus gracilis + tuberculum gracilis

fasciculus cuneatus + tuberculum cuneatum

pedunculus cerebellaris inferior laterally in the upper part of medulla to cerebellum

Question 3

grey substance

Answer 3

nuclei craniales
nucleus gracilis
nucleus cuneatus
nucleus cuneatus accessorius
nuclei olivares inferiores
nucleus olivaris superior (mostly in pons though)
formatio reticularis
nucleus arcuatus

Question 4

nuclei craniales

Answer 4

CN 12, CN 11, CN10, CN9, partly CN5 and CN8 (in fossa rhomboidea)

Question 5

nucleus gracilis

Answer 5

in tuberculum gracilis

2nd neuron of conscious proprioception and fine touch sensation, from lower part of the body (below T7)

Question 6

nucleus cuneatus

Answer 6

in tuberculum cuneatum

2nd neuron of conscious proprioception and fine touch sensation, from upper part of the body

Question 7

nuclei olivares inferiores

Answer 7

coordination of movement, cerebellar motor learning

afferents from tractus rubroolivaris (nucleus ruber) and tractus spinoolivaris (unconscious proprioceptive information)

axons form tractus olivospinalis and tractus olivocerebellaris (balance regulation, via pedunculus cerebellaris inferior to cortex cerebellii)

Question 8

nucleus olivaris superior

Answer 8

mainly in pons

part of auditory system

Question 9

nucleus cuneatus accessorius

Answer 9

functionally homologus to Clarke’s column

also 2nd order neurons of subconscious proprioceptive pathway (fibrae cuneocerebellares)

Question 10

nucleus arcuatus

Answer 10

in the pyramids

axons form striae medullares ventriculi quatri (border between medulla and pons, in the middle of fossa rhomboidea)
–> cross to the other side in the middle of fossa rhomboidea and reach cerebellum through pedunculi cerebellares inferiores

Question 11

white substance: ascending tracts

Answer 11

fasciculus gracilis
fasciculus cuneatus
fibrae cuneocerebellares
tractus spinothalamicus lateralis
tractus spinothalamixus anterior
tractus spinocerebellaris posterior
tractus spinocerebellaris anterior
tractus spinoolivaris

Question 12

fasciculus gracilis

Answer 12

conscious proprioceptive sense and fine touch sensation

composed of axons of pseudounipolar neurons of the spinal ganglion –> synapse with 2nd neuron in nucleus gracilis –> axons form fibrae arcuatae internae –> fibers cross at decussatio lemnisci medialis –> ascend as lemniscus medialis

lemniscus medialis travels to thalamus and synapses with 3rd order neurons

Question 13

fasciculus cuneatus

Answer 13

conscious proprioceptive sense and fine touch sensation

composed of axons of pseudounipolar neurons of the spinal ganglion –> synapse with 2nd neuron in nucleus cuneatus –> axons form fibrae arcuatae internae –> fibers cross at decussatio lemnisci medialis –> ascend as lemniscus medialis

lemniscus medialis travels to thalamus and synapses with 3rd order neurons

Question 14

fibrae cuneocerebellares

Answer 14

axons of nucleus cuneatus accessorius

subconscious proprioceptive impulses from lower limbs to cerebellum via inferior cerebellar peduncule

Question 15

tractus spinothalamicus lateralis

Answer 15

pain and temperature sensation

ascend as spinal lemniscus to synapse at the thalamus

Question 16

spinal lemniscus

Answer 16

tractus spinothalamicus lateralis & anterior

Question 17

tractus spinothalamicus anterior

Answer 17

light touch sensation

ascend as spinal lemniscus to synapse at the thalamus

Question 18

tractus spinocerebellaris posterior

Answer 18

to cerebellum via pedunculus cerebellaris inferioris

Question 19

tractus spinocerebellaris anterior

Answer 19

to cerebellum via pedunculus cerebellaris superioris

Question 20

white substance: descending tracts

Answer 20

1. tractus corticospinalis
2. tractus corticonuclearis
3. tractus rubrospinalis
4. tractus tectospinalis
5. fasciculus longitudinalis medialis
6. tractus vestibulospinalis lateralis
7. tractus vestibulocerebellaris
8. tractus olivospinalis
9. tractus olivocerebellaris
10. tractus reticulospinalis
11. fibrae hypothalamospinales

Question 21

tractus corticospinalis

Answer 21

voluntary control of trunk and limb skeletal muscle

axons of pyramidal cells of the cortex

pass through the pyramid, synapse with motor nuclei of the spinal cord

majority of fibers cross at decussatio pyramidalis –> descend in the lateral funiculus of spinal cord as tractus corticospinalis lateralis

10-10% of fibers do not cross –> descend on the anterior funiculus of spinal cord as tractus corticospinalis anterior

Question 22

tractus corticonuclearis

Answer 22

voluntary control of head and neck skeletal muscles

axons of pyramidal cells in cortex

synapse with motor nuclei of cranial nerves
CN9,10,11,12

Question 23

tractus vestibulospinalis lateralis

Answer 23

axons of nucleus vestibularis lateralis (in fossa rhomboidea)

Question 24

tractus vestibulocerebellaris

Answer 24

balance pathway

connects nucleus vestibularis inferior and grey matter of cerebellum

Question 25

tractus olivospinalis

Answer 25

axons of nuclei olivares inferiores

Question 26

tractus olivocerebellaris

Answer 26

balance regulation

axons of nuclei olivares inferiores to cortex cerebellii via pedunculus cerebellaris inferior

Question 27

fibrae hypothalamospinales

Answer 27

connect hypothalamic nuclei with sympathetic & parasympathetic nuclei of autonomic nervous system in the spinal cord