#7. Brain stem Flashcards Preview

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Flashcards in #7. Brain stem Deck (59):
1

What makes up the brain stem?

1. medulla oblongata
2. pons
3. midbrain

2

Where is the medulla oblongata located?

it goes from the foramen magnum and goes to the pons

3

What is the medulla oblongata made of?

sensory (ascending) tracts and motor (descending) tracts

4

What are the pyramids?

-bulges of white matter on the anterior part of the medulla.
-formed by the corticospinal tracts

5

What is the crossing of axons in the pyramids called?

decussation of pyramids

6

What is the importance of the decussation of pyramids?

it explains why each side of the brain controls the opposite side of the body.

7

What percentage of axons cross at the decussation of pyramids?

90%

8

What does the cardiovascular center in the medulla do?

regulates the rate and force of the heartbeat and the diameter of BV's

9

What does the medullary rhythmicity area of the respiratory center do?

adjusts the basic rhythm of breathing (along with areas in the pons)

10

What is the olive?

a oval-shaped swelling located lateral to each pyramid.

11

Which nucleus is located in the olive?

the inferior olivary nucleus

12

What does the inferior olivary nucleus receive input from?

-receives input from the cerebral cortex, the red nucleus (midbrain) and the spinal cord.

13

What does the olive deal with?

it mainly has to do with movement

14

Where do the neurons from the inferior olivary nucleus go?

- they extend into the cerebellum, where they regulate the activity of the cerebellar neurons

15

What does the inferior olivary nucleus do?

-it provides instructions that the cerebellum uses to make adjustments to mm activity as you learn new motor skills

16

What are the gracile nucleus and cuneate nucleus involved with?

-they are associated with sensations of touch, pressure, vibration and conscious proprioception

17

What is the gustatory nucleus for?

-receiving gustatory input from the taste buds of the tongue.
-relays from the tongue to the brain

18

What is the cochlear nuclei for?

-it is part of the auditory pathway from the inner ear to the brain
- receives auditory input from cochlea of the inner ear

19

What is the vestibular nuclei for?

-equilibrium pathway from inner ear to brain

20

Which cranial nerves have their nuclei located in the medulla?

VIII - vestibularcochlear nerve
IX - glossopharyngeal nerves
X - vagus nerve
XI - accessory nerve
XII - hypoglossal nerve

21

What are the nuclei located in the medulla?

- gracile nucleus
-cuneate nucleus
-gustatory nucleus
-cochlear nucleus
-vestibular nuclei
-CN VII, IX, X, XI, XII
-inferior olivary nucleus
-cardiovascular center
-medullary rhythmicity area of respiratory center
-vomiting center
-deglutition center

22

How can you injure the medulla?

a hard blow to the back of the head/upper neck

23

What does an alcohol overdose affect in the medulla?

the medullary rhythmicity area.
can result in death

24

What is the pons?

the bridge that connects parts of the brain with each other

25

What is the pons made of?

nuclei and tracts

26

What the pontine nucleus do?

-relays signals for voluntary movements from cerebral cortex to the cerebellum

27

Which nuclei are in the pons?

-pontine nucleus
-neclei for: pneumotaxic area and apneustic area
- CN V, VI, VII, VIII

28

what is the pneumotaxic area responsible for?

rhythm of breathing

29

What is the apneustic area responsible for?

inhale/exhale

30

Which cranial nerve has nuclei in both the pons and the medulla?

VIII - vestibulocochlear nerve

31

Where are the cerebral peduncles located?

anterior part of the midbrain

32

What are the cerebral peduncles?

-paired bundles of axons
-axons from corticospinal tracts, corticobulbar tracts, and corticopontine tracts.

33

Are the tracts in the cerebral peduncles efferent or afferent?

efferent

34

what is the corticospinal tract for?

the motor area in the cerebral cortex to the spinal cord

35

What is the corticobulbar tract for?

the motor areas in the cerebral cortex to the medulla

36

What is the corticopontine tract for?

motor areas in the cerebral cortex to the pons.

37

Where is the tectum?

the posterior part of the midbrain

38

What does the tectum contain?

superior colliculi and inferior colliculi

39

What does the superior colliculi do?

-nuclei in 2 superior elevations that coordinate movement of head, eyes, trunk in response to a visual stimulus
(ie. you see something in the corner of your eye and you turn towards it)

40

What does the inferior colliculi do?

-coordinates movements of the head, eyes, trunk in response to auditory stimuli
(ie. you hear something and you turn)

41

what is the startle reflex?

sudden movements of the head, eyes, and trunk that occur when surprised by a loud noise

42

What is the substantia nigra?

-neurons that release dopamine and help control the subconscious muscles activities

43

What is loss of the substantia nigra associated with?

Parkinson's disease

44

What does the red nuclei do?

involved with voluntary muscle movements

45

Why is the red nuclei red?

it has a rich blood supply and iron-containing pigment

46

What nuclei are in the midbrain?

-substantia nigra
-red nuclei
- CN III and IV

47

What is the reticular formation?

a net like arrangment of grey and white matter that is located throughout the brain stem

48

What is the importance of the RAS?

-system that wakes you up.

49

What does RAS stand for?

reticular activating system

50

What makes up the RAS?

sensory axons that project to the cerebral cortex and motor axons connecting to the cerebellum and spinal cord

51

What activates the RAS?

-visual stimuli
-auditory stimuli
-mental activites
-pain, touch, pressure stimuli
-proprioceptive receptors

52

What does the RAS do?

-it is involved in consciousness
-active during arousal
-helps maintain attention and alertness
-prevents sensory overload

53

How does the RAS prevent sensory overload?

by filtering out insignificant information so the it does not reach consciouness (ie. pants, pants, pants.)

54

What does inactivation of RAS do?

produces sleep.

55

Define sleep

a stat of partial consciousness from which an individual can be aroused

56

What happens if the RAS is damaged?

-coma

57

Define muscle tone

the slight degree of involuntary contraction in normal resting skeletal muscles

58

What is the RAS involved in?

-regulating muscle tone
-regulation of heart rate
-regulation of BP
-regulation of respiratory rate

59

What sense does the RAS not receive sensory input from?

olfactory