UNIT 2: Brain Stems and Supporting Systems Flashcards
1
Q
what does the diencephalon include
A
thalamus, epithalamus, subthalamus, hypothalamus, plus mammillary bodies
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
3
Q
what is the thalamus made up of
A
many nuclei - each do something specific and talk to specific systems (ex. vision)
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
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
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!
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
8
Q
what are the 3 functional divisions of the cerebellum?
A
- vestibulocerebellum (flocculonodular lobe)
- spinocerebellum (anterior lobe and posterior lobe)
- cerebrocerebellum (posterior lobe)
9
Q
vestibulocerebellum (flocculonodular lobe) of cerebellum
A
integrates vestibular info about body position w motor plan
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
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
12
Q
3 anatomic divisions of the brainstem
A
mesencephalon = midbrain
metencephalon = pons (minus cerebellum)
myelencephalon = medulla oblongata
13
Q
all pathways to and from cerebrum pass through…
A
the brainstem (afferent and efferent)
14
Q
the brainstem contains what types of nuclei
A
- many autonomic regulatory nuclei
- nuclei associated w cranial nerves II thru XII
15
Q
what does the midbrain contain
A
aqueduct, fibre tracts, nuclei
16
Q
the midbrain’s aqueduct connects to…
A
the 3rd ventricle above w the 4th ventricle below
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
18
Q
what are the 4 nuclei of the midbrain
A
superior colliculi, inferior colliculi, substantia nigra, red nuclei
19
Q
superior colliculi
A
- nuclei in the midbrain
- central visual pathway nuclei
20
Q
inferior colliculi
A
- nuclei in the midbrain
- central auditory pathway nuclei
21
Q
substantia nigra
A
- nuclei in the midbrain
- subconscious muscle activity (functionally part of the basal ganglia)
22
Q
red nuclei
A
- nuclei in the midbrain
- minor role in motor function (i.e. limb flection) in association w cerebellum
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)
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)
25
the pons contains
- fibre tracts
- CN nuclei
26
on the ventral side of the pons you can see what type of fibre tracts?
- 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)
27
on the dorsal side of the pons there are fibre tracts similar to the...
medulla - carry both sensory and motor info - corticobular and corticospinal tracts
27
which cranial nuclei are in the pons
- trigeminal motor nuclei
- principal sensory nuclei of the trigeminal tract
-abducent nuclei (motor)
- facial motor nuclei
- superior salivatory nuclei (motor)
28
the pons also has the emergence of which critical cranial nerves
- CN V - trigeminal
- CN VI - abducens
- CN VII - facial
- CN VIII - Vestibulocochlear
29
medulla's location/function/contents
- 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
What are the pyramids of the medulla
a structure where all motor fibres from the cerebrum to spinal cord travel through
31
pyramidal decussation of the medulla
location where corticospinal tracts decussate (where fibers cross) (contralateral innervation)
32
list the CN nuclei of the medulla
-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
what critical cranial nerves emerge from the medulla
- CN VIII (vestibulocohlear)
- CN IX (gloffopharyngeal)
- CN X (vagus)
- CN XI (accessory)
- CN XII (hypoglossal)
34
3 supporting systems of NS
meninges, ventricular system, vascular system
35
meninges function
protection of the brain (and spinal cord) and its vasculature
36
ventricular system functions
nutrient supply and protection
37
vascular systems functions for NS
oxygen and glucose supply
38
3 types of meninges
dura mater, arachnoid mater, pia mater
39
Dura matter is
- the most superficial meninge
- 2 layers thick (bilaminar) w epidural space bw
- limits excessive movement of brain
40
3 extensions of the dura mater
falx cerebri, falx cerebelli, tentorlum cerebelli
41
the arachnoid mater is
- the meninge deep to the dura mater
- thinner, more elastic
- follows brain convultions more closely
- has blood vessels and CSF
42
the space bw the dura mater and arachnoid mater is
subdural space
43
pia mater is
- the deepest meninge
- very thin
-clings to surfaces, follows fissures and sulci
- surrounds blood vessels that pierce the cortex
44
space bw the arachnoid mater and pia mater
subarachnoid space (CSF and cerebral arteries/veins)
45
3 components of the ventricular system
- lateral ventricle
- 3rd ventricle
- 4th ventricle
46
lateral ventricles
- bilateral
- deep in both hemispheres
- where most CSF is produced (choroid plexi)
47
3rd ventricle
slit like cleft bw the R and L thalamus
48
4th ventricle
bw cerebellum and brainstem
49
explain flow of CSF thru ventricles
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
ventricular system communicates via
- inter-ventricular foramen
- cerebral aqueduct
51
cerebrospinal fluid
- cushions the CNS and delivers nutrients, removes waste
- replenished every 7 hours
- absorbed by venous system
52
if the brain swells what part of the ventricular system is vulnerable
cerebral aqueduct
53
where is CSF produced
choroid plexus of each ventricle, particularly in the lateral ventricles
54
describe the vascular system of the NS (why is it special in terms of demand)
- nervous tissue has the highest metabolic rate of any human tissue... cannot store nutrients and therefore needs a constant supply of oxygen
55
10 sec oxygen disruption leads to
loss of consciousness
56
3-4 min oxygen disruption leads to
brain damage
57
how many pathways can blood get to the brain
2
58
describe the path of blood flow from the aorta through the subclavian arteries to the brain
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
describe the path of blood flow from the aorta through the common carotid artery to the brain
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
interal carotides course in the
anterior lateral neck
61
external carotids supply...
structures of the head outside the skull
62
the circle of willis is formed by
- basilar artery
- internal carotid arteries
- middle cerebral arteries
- anterior cerebral arteries
- posterior cerebral arteries
- anterior communicating artery
- posterior communicating arteries
63
middle cerebral arteries, anterior cerebral arteries, and posterior cerebral arteries take blood from circle of willis and move it to...
the brain
64
damage to which cerebral artery would produce the worst stroke symptoms on speech/swallowing
middle cerebral artery, bc it feeds this area of the brain
65
middle cerebral artery is the most direct continuation of the _____ important for ____and supplys ____
- internal carotid artery
- speech, swallowing, hearing, language
- lateral cortex (including operculum and insula), internal capsule, basal ganglia, and thalamus
66
the anterior cerebral artery supplies
medical and superior surfaces of frontal and parietal lobes
67
posterior cerebral artery supplies
occipital lobe and the inferior and medial parts of the temporal lobe
68
Branches of the vertebral/basilar system supply 3 things
cerebellum, brainstem, spinal cord
69
the venus return system does what
where blood drains to so that it can be directed back to the heart
