UNIT 2: Brain Stems and Supporting Systems Flashcards

1
Q

what does the diencephalon include

A

thalamus, epithalamus, subthalamus, hypothalamus, plus mammillary bodies

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2
Q

describe the thalamus

A
  • contains multiple nuclei that are part of motor, sensory, and associative pathways
  • receives ALL sensory feedback (except olfactory), and relays to the cortex (i.e. thalamus decides whether the info is worthwhile - like a gate keeper/amplifier … decides what is worthwhile and also whether the the dial needs to be turned up or down)
  • motor contribution –> transmits info from cerebellum and BG to primary motor cortex (involved in motor planing and initiation of speech)
  • axons that connect thalamus and cerebral cortex pass thru the internal capsule
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3
Q

what is the thalamus made up of

A

many nuclei - each do something specific and talk to specific systems (ex. vision)

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4
Q

Connection bw limbic sys and thalamus

A

limbic sys will tell the thalamus whether it needs to focus on something in relation to memories associated w a sensory or motor signal

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5
Q

hypothalamus functions

A
  • controls many body activities - major regulator of homeostasis
  • sensory input related to somatic, visceral, and special (taste, smell, vision) senses arrive here
  • important connections w pituitary gland; produces a variety of hormones
  • controls and integrate activities of the ANS - major regulator of visceral activities (contraction of smooth and cardiac muscle, gland secretion)
  • regulates emotion + behaviour, eating and drinking, body temp, circadian rhythms, and consciousness
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6
Q

describe the composition of the cerebellum

A
  • external portion is gray matter (cortex)
  • internal core is comprised of white matter (tracts) and deep nuclei (subcortical nuclei)
  • communicates w pons via cerebellar peduncles (afferent and efferent tracts)
  • each hemisphere has 3 lobes: anterior, posterior, flocculonodular
  • vermis = central cortex that connects the 2 cerebellar hemispheres (analogous to corpus callosum)
  • more neurons than cortex!
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7
Q

function of cerebellum

A
  • primary structure responsible for coordination of fine movement: integrates somatic info related to vestibular function (balance), muscle and joint sense, and perception of the body in space
  • works w cerebrum to fine tune the motor plan for optimal execution
  • i.e. helps us compare what I thought i was gonna do to what I actually did (motor learning ) - whereas the BG helps us select a motor plan
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8
Q

what are the 3 functional divisions of the cerebellum?

A
  • vestibulocerebellum (flocculonodular lobe)
  • spinocerebellum (anterior lobe and posterior lobe)
  • cerebrocerebellum (posterior lobe)
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9
Q

vestibulocerebellum (flocculonodular lobe) of cerebellum

A

integrates vestibular info about body position w motor plan

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10
Q

spinocerebellum (anterior lobe and posterior lobe) of cerebellum

A

integrates proprioceptive info (body sense of position and movement in space) and controls gait and stance

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11
Q

cerebrocerebellum (posterior lobe) of cerebellum

A

execution of voluntary motor plans initiated by cerebral cortex - feedback to smooth movements, correct errors, coordinate complex sequences of muscle contraction

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12
Q

3 anatomic divisions of the brainstem

A

mesencephalon = midbrain
metencephalon = pons (minus cerebellum)
myelencephalon = medulla oblongata

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13
Q

all pathways to and from cerebrum pass through…

A

the brainstem (afferent and efferent)

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14
Q

the brainstem contains what types of nuclei

A
  • many autonomic regulatory nuclei
  • nuclei associated w cranial nerves II thru XII
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15
Q

what does the midbrain contain

A

aqueduct, fibre tracts, nuclei

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16
Q

the midbrain’s aqueduct connects to…

A

the 3rd ventricle above w the 4th ventricle below

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17
Q

the fibre tracts of the midbrain are also called “___” and contain “___” and “____”

A
  • cerebral peduncles (pair of vertical fibre tracts)
  • corticopsinal, corticobular, and corticopontine motor neuros (refer to where they go)
  • sensory neurons from medualla to thalamus
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18
Q

what are the 4 nuclei of the midbrain

A

superior colliculi, inferior colliculi, substantia nigra, red nuclei

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19
Q

superior colliculi

A
  • nuclei in the midbrain
  • central visual pathway nuclei
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20
Q

inferior colliculi

A
  • nuclei in the midbrain
  • central auditory pathway nuclei
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21
Q

substantia nigra

A
  • nuclei in the midbrain
  • subconscious muscle activity (functionally part of the basal ganglia)
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22
Q

red nuclei

A
  • nuclei in the midbrain
  • minor role in motor function (i.e. limb flection) in association w cerebellum
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23
Q

which cranial nerves are associated w the midbrain

A

oculimotor nerve (III) (motor), trochlear nerve (IV) (motor), mesencephalic nerve of trigeminal tract (V) (sensory)

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24
Q

what and where is the pons

A
  • enlarged section of the brainstem bw the midbrain (above) and medulla (below)
  • bridge to the cerebellum (anterior to it)
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25
Q

the pons contains

A
  • fibre tracts
  • CN nuclei
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26
Q

on the ventral side of the pons you can see what type of fibre tracts?

A
  • cerebral peduncles –> horizontal fibre tracts allowing communication bw cerebrum, brainstem, and cerebellum (maximizes efficiency of voluntary motor control)
  • basilar sulcus –> cradles the basilar artery (a depression)
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27
Q

on the dorsal side of the pons there are fibre tracts similar to the…

A

medulla - carry both sensory and motor info - corticobular and corticospinal tracts

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27
Q

which cranial nuclei are in the pons

A
  • trigeminal motor nuclei
  • principal sensory nuclei of the trigeminal tract
    -abducent nuclei (motor)
  • facial motor nuclei
  • superior salivatory nuclei (motor)
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28
Q

the pons also has the emergence of which critical cranial nerves

A
  • CN V - trigeminal
  • CN VI - abducens
  • CN VII - facial
  • CN VIII - Vestibulocochlear
29
Q

medulla’s location/function/contents

A
  • most caudal portion of the brainstem; in bw the pons (above) and spinal cord (below)
  • 2.5 cm in length, 1 cm in diameter
  • extremely vital for life functions (ex. respiratory drive, cardiac function)
  • contains fibre tracts and CN nuclei
30
Q

What are the pyramids of the medulla

A

a structure where all motor fibres from the cerebrum to spinal cord travel through

31
Q

pyramidal decussation of the medulla

A

location where corticospinal tracts decussate (where fibers cross) (contralateral innervation)

32
Q

list the CN nuclei of the medulla

A

-vestibular nuclei (sensory)
-cochlear nuclei (sensory)
- N of the spinal tract (sensory)
- N tractus solitarius (sensory)
- N ambiguus (motor)
- Dorsal motor n.
- spinal n. of the accessory nerve (motor)

33
Q

what critical cranial nerves emerge from the medulla

A
  • CN VIII (vestibulocohlear)
  • CN IX (gloffopharyngeal)
  • CN X (vagus)
  • CN XI (accessory)
  • CN XII (hypoglossal)
34
Q

3 supporting systems of NS

A

meninges, ventricular system, vascular system

35
Q

meninges function

A

protection of the brain (and spinal cord) and its vasculature

36
Q

ventricular system functions

A

nutrient supply and protection

37
Q

vascular systems functions for NS

A

oxygen and glucose supply

38
Q

3 types of meninges

A

dura mater, arachnoid mater, pia mater

39
Q

Dura matter is

A
  • the most superficial meninge
  • 2 layers thick (bilaminar) w epidural space bw
  • limits excessive movement of brain
40
Q

3 extensions of the dura mater

A

falx cerebri, falx cerebelli, tentorlum cerebelli

41
Q

the arachnoid mater is

A
  • the meninge deep to the dura mater
  • thinner, more elastic
  • follows brain convultions more closely
  • has blood vessels and CSF
42
Q

the space bw the dura mater and arachnoid mater is

A

subdural space

43
Q

pia mater is

A
  • the deepest meninge
  • very thin
    -clings to surfaces, follows fissures and sulci
  • surrounds blood vessels that pierce the cortex
44
Q

space bw the arachnoid mater and pia mater

A

subarachnoid space (CSF and cerebral arteries/veins)

45
Q

3 components of the ventricular system

A
  • lateral ventricle
  • 3rd ventricle
  • 4th ventricle
46
Q

lateral ventricles

A
  • bilateral
  • deep in both hemispheres
  • where most CSF is produced (choroid plexi)
47
Q

3rd ventricle

A

slit like cleft bw the R and L thalamus

48
Q

4th ventricle

A

bw cerebellum and brainstem

49
Q

explain flow of CSF thru ventricles

A

mostly produced in lateral ventricle, then flows to third vent thru the interventricular foramen, then thru cerebral aqueduct to 4th ventricle, and then eventually into venus draining system

50
Q

ventricular system communicates via

A
  • inter-ventricular foramen
  • cerebral aqueduct
51
Q

cerebrospinal fluid

A
  • cushions the CNS and delivers nutrients, removes waste
  • replenished every 7 hours
  • absorbed by venous system
52
Q

if the brain swells what part of the ventricular system is vulnerable

A

cerebral aqueduct

53
Q

where is CSF produced

A

choroid plexus of each ventricle, particularly in the lateral ventricles

54
Q

describe the vascular system of the NS (why is it special in terms of demand)

A
  • nervous tissue has the highest metabolic rate of any human tissue… cannot store nutrients and therefore needs a constant supply of oxygen
55
Q

10 sec oxygen disruption leads to

A

loss of consciousness

56
Q

3-4 min oxygen disruption leads to

A

brain damage

57
Q

how many pathways can blood get to the brain

A

2

58
Q

describe the path of blood flow from the aorta through the subclavian arteries to the brain

A
  1. blood from aorta enters subclavian arteries (L + R)
  2. To verterbral arteries (R + L) which ascend thru transverse formina of 6 C vertebrae
  3. enter cranial vault thru foramen magnum
  4. L and R join (anastamose) to form the basilar artery
59
Q

describe the path of blood flow from the aorta through the common carotid artery to the brain

A
  1. blood from aorta goes thru the common carotid artery (R + L)
  2. Goes into internal carotid artery (R and L)
  3. enters temporal bone thru carotid canal (L and R)
  4. exits tempora bone thru foramen lacerum
  5. Joins the basilar artery at the circle of willis
60
Q

interal carotides course in the

A

anterior lateral neck

61
Q

external carotids supply…

A

structures of the head outside the skull

62
Q

the circle of willis is formed by

A
  • basilar artery
  • internal carotid arteries
  • middle cerebral arteries
  • anterior cerebral arteries
  • posterior cerebral arteries
  • anterior communicating artery
  • posterior communicating arteries
63
Q

middle cerebral arteries, anterior cerebral arteries, and posterior cerebral arteries take blood from circle of willis and move it to…

A

the brain

64
Q

damage to which cerebral artery would produce the worst stroke symptoms on speech/swallowing

A

middle cerebral artery, bc it feeds this area of the brain

65
Q

middle cerebral artery is the most direct continuation of the _____ important for ____and supplys ____

A
  • internal carotid artery
  • speech, swallowing, hearing, language
  • lateral cortex (including operculum and insula), internal capsule, basal ganglia, and thalamus
66
Q

the anterior cerebral artery supplies

A

medical and superior surfaces of frontal and parietal lobes

67
Q

posterior cerebral artery supplies

A

occipital lobe and the inferior and medial parts of the temporal lobe

68
Q

Branches of the vertebral/basilar system supply 3 things

A

cerebellum, brainstem, spinal cord

69
Q

the venus return system does what

A

where blood drains to so that it can be directed back to the heart