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Flashcards in (6) Brainstem Deck (92)
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1

are divisions of the brainstem clearest anteriorly/posteriorly

anteriorly

2

what is the pyramidal decussation

dividing line between medulla and spinal cord

corticospinal fibres cross one side to another

3

what is the pontomedullary junction/sulcus

where pons are separated from medulla

cranial nerves emerge at side

4

midbrain begins at levels of the ...

cerebral peduncles

5

what are the cerebral peduncles

connect brainstem with white matter of cerebrum

form 2 thick band of fibers

6

brainstem 3 components (top to bottom)

midbrain
pons
medulla

7

medulla ends where?

just above the vagal trigone

8

what is the vagal trigone?

small elevation on the floor of 4th ventricle produced by the underlying dorsal motor nucleus of the vagus

9

pons beings where?

at lower border of the inferior colliculus

10

upper margin of midbrain is extent of..

rostral extent of superior colliculus

11

rostral vs caudal

rostral= upper/above

caudal= lower/below

12

rostral and caudal midbrain divided by

line between superior and inferior colliculi

13

rostral and caudal pons divided by

line where the superior cerebellar peduncle forms the roof of the 4th ventricle (called superior medullary velum)

14

medulla sections open/closed

rostral= open (upper)

caudal= closed (lower)
- no 4th ventricle

15

rostral and caudal medulla divided by

caudal limit of the 4th ventricle called obex

16

above the obex, each level of brainstem is adjacent to ventricular space (name them)

midbrain= anterior and posterior to cerebral aqueduct

pons= anterior and posterior to the 4th ventricle

medulla= anterior to the 4th ventricle

17

what is the obex

caudal limit (lower) of the 4th ventricle

18

3 general areas identified in cross section at any level above obex

1) tectum
2) tegmentum
3) large structures appended to anterior surface of the brainstem

19

what is the tectum

area posterior to the ventricular space (mostly found in midbrain)

- consist of superior and inferior colliculi

20

what is the tegmentum

area anterior to the ventricular space

- consist of reticular formation, cranial nerve nuclei and tracts, ascend/descending pathways

21

large structures appended to anterior surface of the brainstem consist of ...

- most of the pons of tegmentum are appendages
- pyramids and other structures are appendages of tegmentum

22

brainstem is a conduit for... (2)

1) ascending tracts to reach thalamus and cerebellum
2) descending tracts to reach spinal cord

23

cranial nerve nuclei associated with brainstem

- mostly all associated

only one cranial nerve no direct association with brainstem= olfactory (CN1)

24

brainstem intrinsic features (2)

- reticular formation

- associated projections

25

what is reticular formation?

- stuff left over

contains neurons, nucleus fibres, don't for discrete components
- neurons and processes

26

descending motor tracts, brainstem conduits

Corticospinal fibres travel in most ANTERIOR past of the brainstem

cerebral peduncle (basis pedunculi)--> basal pons --> medullary pyramids

27

at highest level if brainstem, corticospinal fibres are found

in basis pedunculi (cerebral peduncles)

located ANTERIOR part of brainstem

28

at any level of the brainstem, where are corticospinal fibers located?

ANTERIOR/ventral part of brainstem

29

cerebral peduncles also carry what type of fibres? (2)

corticobulbar (corticonuclear) fibres

corticopontine fibres

30

what are corticobulbar fibres?

descending, mostly bilateral, motor input to cranial nerve nuclei

- travel to innervate cranial nerve nuclei in brainstem
- come from cortex, innervate lower motor neuron targets in brainstem