Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Human physiology > Lecture 10: Spinal Cord and Brainstem Control of Motor Function II > Flashcards

Lecture 10: Spinal Cord and Brainstem Control of Motor Function II Flashcards

1
Q

Pyramidal system definition

A

Tracts that pass through the medullary pyramids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Components of pyramidal system

A

Corticospinal tract

Corticobulbar tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Upper motor neurons of pyramidal system decussate where and form what

A

75-85% decussate in pyramids and form the lateral corticospinal tracts
Remainder decussate near synapse with LMN and form anterior corticospinal tracts
Most synapse with association neurons in SC central gray

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Origins of corticospinal tract

A

Primary motor cortex
Premotor cortex
Somatosensory area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Pathway of corticospinal tract

A

Site of origin–> internal capule–> medullary pyramids–> X in lower medulla (most fibers)–> lateral columns of spinal cord (lateral corticospinal tract)

Some fibers do not cross but continue down ipsilaterally in ventral corticospinal tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Lateral corticospinal tract made up of and supply what

A

Corticospinal fibers that have crossed in the medulla

Supply all levels of spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Anterior corticospinal track made up of and supply what

A

Uncrossed corticospinal fibers that cross near level of synapse with LMN
Supply neck and upper limbs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Functions of corticospinal tract divisions

A

Add speed and agility to conscious movements (especially in hand)
Provide high degree of motor control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Giant pyramidal (Bertz) cells

A

Located in motor cortex
Large fibers
Send collaterals back to cortex
Synapse directly on LMNs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Symptoms of cortical spinal tract lesions

A

Reduced muscle tone
Clumsiness
Weakness
Complete paralysis only occurs if both pyramidal and extrapyramidal systems are involved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Corticobulbar tract

A

Upper motor neurons of the cranial nerves, innervating face, head and neck

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Corticobulbar tract fibers terminate where

A

In reticular formation near cranial nerve nuclei

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Association neurons of corticobulbar tract synapse where

A

Cranial nerve nuclei with lower motor neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Corticobulbar tract lesions

A

Can affect hypoglossal nerve (CN XII)

Can affect facial nerve (CN VII)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Extrapyramidal system

A

Descending motor tracts that do not pass through medullary pyramids or corticobulbar tracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Extrapyramidal system includes what tracts

A

Rubrospinal
Vestibulospinal
Reticulospinal
Olivospinal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Extrapyramidal subcortical nuclei (taylor)

A 
Thalamus
Red nucleus
Subthalamic nucleus
Caudate
Substantia niagra
Globus pallidus
Putamen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Red nucleus description

A

Fibers from primary motor cortex (corticorubral pathways) and branches from corticospinal tract synapse in magnocellular portion of red nucleus

19
Q

Large neurons from magnocellular region of red nucleus give rise to

A

Rubrospinal tract which decussates in lower brain stem

20
Q

Magnocellular region has a ________ of all muscles of the body

A

Somatotopic representation

21
Q

Stimulation of red nucleus results in

A

Stimulation of flexors

Inhibition of extensors

22
Q

Red nucleus relays info from x to y (what are x/y?)

A

From motor cortex to cerebellum

23
Q

Rubrospinal tract originates, decussates, descends where

A

Originates in red nucleus
Decussates in midbrain
Descends in lateral funiculus
Function is closely related to cerebellum

24
Q

Rubrospinal tract responsible for

A

Large muscle movement and some fine motor of UE

25
Q

Lesions of rubrospinal tract cause

A

Impairment of distal arm/hand movement
Intention tremors
May take over for injured corticospinal tract in some animals

26
Q

Vestibulospinal tract originates, descends, synapses where

A

Originates in vestibular nuclei
Descends in anterior funiculus
Synapses with LMNs to extensor muscles (maintains upright posture)

27
Q

Vestibulospinal tract receives input from

A 
Vestibular nerve (CN VIII) about changes in head position
Helps maintain balance
28
Q

Lateral vestibulospinal tract characteristics

A

Major part of tract
Ipsilateral
To lumbar region of SC
Upright posture/balance (extensors of LE/trunk)

29
Q

Medial vestibulospinal tract characteristics

A

Projects bilaterally

30
Q

Reticulospinal tract originates/descends

A

In reticular formation

Descends in lateral funiculus (column)

31
Q

Functions of reticulospinal tract

A 
Mediates larger movement of trunk/limbs
Excites axial extensors when standing
Controls alpha/gamma motor neurons
Mediates autonomic functions (breathing)
Can modulate pain
32
Q

Pontine reticular nuclei

A

Make up anterior column

Stimulatory effect on both extensors/flexors but mostly extensors

33
Q

Medullary reticular nuclei

A

Make up lateral column

Inhibitory effect on both extensors/flexors but mostly extensors

34
Q

Semicircular canals detect ___ while utricle and saccule detect

A

Semicircular canals detect angular acceleration of head

Utricle and saccule detect linear acceleration of head

35
Q

Utricle and saccule each contain

A

Macula which contains hair cells

36
Q

Semicircular canal contains

A

Enlargement at one end called ampulla which has hair cells

37
Q

Function and plane of macula of utricle

A

Horizontal plane

Determining orientation of head when head is upright

38
Q

Function and plane of macula of saccule

A

Vertical plane

Signals head orientation when person is lying down

39
Q

Statoconia

A

Calcium carbonate crystals in macula

The weight of these crystals bend cilia in direction of gravitational pull

40
Q

Bending of stereocilia towards kinocilium does what

A

Opens hundreds of cation channels causing receptor membrane depolarization/excitation

41
Q

Bending of cilia in opposite direction of kinocilium does what

A

Closes channels and hyperpolarizes receptor membrane

42
Q

Semicircular canal fluid function

A

Fluid flows through the ampulla and causes cupula to bend to one side
Hair cells within cupula detect bending and send signals via vestibular nerve

43
Q

Ampulla characteristics

A

Filled with endolymph
Contains crista ampullaris
Contains cupula above the crista

44
Q

Response of hair cell in semicircular canal with head rotation

A

At onset of rotation, cupula is dragged through endolymph and cilia are bent-depolarization
When head stops, endolymph continues moving and cilia are bent in opposite direction causing hyperpolarization

Human physiology (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions