Unit 2 Exam

Question 1

Which cortiocospinal tract fibers form the ventral corticospinal tract?

Answer 1

Ipsilateral

Question 2

Which corticospinal tracts form the lateral corticospinal tracts?

Answer 2

Contralateral

Question 3

What percentage of corticospinal tract fibers originate from areas behind the central sulcus, including the primary somatosensory cortex?

Answer 3

40%

Question 4

What percentage of fibers from the corticospinal tract originate in front of the central sulcus?

Answer 4

60%

Question 5

Greater than 1/2 of the primary motor cortex is devoted to control of which areas?

Answer 5

Hands and speech

Question 6

A stroke that lesions the posterior limb of the internal capsule would be associated with?

Answer 6

Loss of voluntary movement

Question 7

A high brain stem lesion gives what clinical finding?

Answer 7

Spacticity

Question 8

A mid brain lesion gives what clinical finding?

Answer 8

Rigidity

Question 9

A low brain stem lesion gives what clinical finding?

Answer 9

Flaccidity

Question 10

What brainstem area receives stimulation from the vestibular nuclei and transmits excitatory signals to stimulate the axial trunk and extensor muscles that support the body against gravity?

Answer 10

Pontine nuclei

Question 11

What brainstem area receives stimulation from the vestibular nuclei and transmits inhibitory signals to allow muscles tones to be increased or decreased depending on need?

Answer 11

Medullary reticular nuclei

Question 12

If descending cortical signals are blocked what is the expected result?

Answer 12

Increased extensor tone

Flexion reflexes suppressed; stretch reflexes are exaggerated

Question 13

What is the function of a dynamic signal from pyramidal cells to alpha motor neurons?

Answer 13

Initiation of skeletal muscle contraction

Question 14

What is the function of a static signal from pyramidal cells to alpha motor neurons?

Answer 14

Maintain muscle contraction after initiation has occurred

Question 15

Explain neck rotation to the right as far as extensor and flexors are concerned.

Answer 15

Flexors are facilitated on the right, and extensor inhibited on the right

Question 16

With clockwise rotation (to the right), what would you expect to happen in the VIII cranial nerve on the left side?

Answer 16

Decrease in firing rate

-stimulation of semicircular canals on side rotation is into (clockwise stimulates canals on that side)

Question 17

After 20 clockwise (to the right) rotations with the eyes closed on a revolving stool, the subject is abruptly stopped, and the eyes are opened. What would be observed?

Answer 17

Lateral nystagmus with the slow component clockwise

Nystagmus occurs when the semicircular canals are being stimulated while the head is not in motion

Question 18

When supine, head tilt is best detected by which of the following?

Answer 18

Saccule

-saccule deals with the vertical plane (important when one is LYING DOWN)

Question 19

When upright, head tilt is best detected by which mechanisms?

Answer 19

Utricle

-utricle deals with the horizontal plane (important when one is UPRIGHT)

Question 20

Signals from the neck propioception typically ______ signals from the vestibular apparatus as the head and neck are rotated and have similar effects on limb flexion and extension.

Answer 20

Oppose

Question 21

In sway, contraction of muscles to maintain balance occurs in?

Answer 21

Distal to proximal sequence

Question 22

What would happen to a reptitive simple stretch reflex, if when the muscle contracts it destabilizes posture?

Answer 22

It would be inhibited

Question 23

Which basal ganglia circuit plays a major role in cognitive control of motor activity?

Answer 23

Caudate circuit

Question 24

Which basal ganglia circuit plays a major role in subconscious execution of learned patterns of movement?

Answer 24

Putamen

Question 25

Ones sense of upright is a combination of what?

Answer 25

Visual and vestibular information

Question 26

Effects of Striatum on substancia negra

Answer 26

Inhibitory (GABA)

Question 27

Effects of substancia nigra on the striatum?

Answer 27

Stimulatory (DOPAMINE)

Question 28

Which area acts as a comparator ?

Answer 28

Inferior olivary nucleus - Comparing intention with performance - effects the cerebellum via climbing fibers - alter cerebellar activity -> alter decending corticalspinal traffic

Question 29

Purkinje fibers

Answer 29

- Major inhibitory in the cerebellar cortex | - inhibit deep cerebellar nuclei

Question 30

Complex AP

Answer 30

- climbing fiber input from inferior olicary nucleus | - 1:1 ratio of climbing fibers to purkinje fibers

Question 31

Simple AP

Answer 31

- mossy fibers input via granule cells - 1 mossy fibers excites 100-1000 of purkinje fibers - found everywhere but inferior olivary nucleus

Question 32

Lesions to the globus pallidus?

Answer 32

Spontaneous and continuous writhing movements

Question 33

Lesion to subthalamus?

Answer 33

Hemiballismus = sudden violent flailing movements of the limbs

Question 34

Lesion to the substantia nigra?

Answer 34

Parkinson’s = rigidity, acinesia, resting tremors

Question 35

Lesion to the putamen?

Answer 35

Chorea = flicking movements in hands, face

Question 36

Cerebellar lesions are demonstrated on which side?

Answer 36

Ipsilateral -(dysmetria, ataxia, past pointing, dysdiadochokinesia, dysarthria, international tremor, nystagmus)

Question 37

Longest pathway name

Answer 37

Corticopontocerebellarubrothalamocorticospinal Impulses from motor cortex ->pontine -> purkinje cells -> dentate nucleus -> red N of midbrain ->thalamus ->motor cortex

Question 38

Superior peduncle

Answer 38

Ventral spinocerebellar | **contains most efferent projections**

Question 39

Middle peduncle

Answer 39

Pontocerebellar

Question 40

Inferior peduncle

Answer 40

Dorsal spinocerebellar

Question 41

Yohimbine

Answer 41

Increases Norepinephrine release NE can regulate its own release release (negative feedback)

Question 42

SNS Preganglionic release?

Answer 42

Release Acetylcholine

Question 43

SNS Postganglionic release?

Answer 43

Release NE - NE binds to alpha or beta receptors which effect G protein - NE has equal affinity for Alpha and Beta receptors - E has a greater affinity for Beta

Question 44

PNS pregnaglionic release?

Answer 44

ACH

Question 45

PNS Postganglionic release?

Answer 45

ACH | -ACH binds to muscarinic receptor, which effect G protein

Question 46

Denervation supersensitivity

Answer 46

Sharp increase of sensitivity of post-synaptic membranes to a chemical transmitter after DENERVATION. It is a compensatory change

Question 47

SNS stimulation effects?

Answer 47

Vascular smooth muscle = constrict Ducts = dilation Blood vessels = constriction

Question 48

Inhibitory motor neurons form the myenteric plexus release what neurotransmitter?

Answer 48

Dynorphin & vaso active intestinal peptide

Question 49

Excitatory motor neurons form the myenteric plexus release what neurotransmitter?

Answer 49

ACH & Substance P

Question 50

What facilitates the release of NE?

Answer 50

ACH, E, Ang II, corticotropin, PACAP

Question 51

Inhibit release of NE?

Answer 51

GABA, adenosine, NPY, somatostatin, opioids, PGE, NO, dopamine

Question 52

Amount of pressure applied to a normal vertebrae eliciting a minimal response?

Answer 52

7Kg.

Question 53

Less than half of the primary motor cortex is devoted to?

Answer 53

Trunk and equilibrium

Question 54

How much pressure can be applied to an abnormal vertebrae eliciting a minimal response?

Answer 54

1-3 Kg