Motor System 1

Question 1

afferent system is what kind of system?

Answer 1

A - arriving ( sensory) message coming into the brain

it travels up the spinal cord where it’s processed in the brain

Question 2

What kind of system is the efferent system?

Answer 2

motor system - e for EWWWWW!

Question 3

the sensory system has how many neurons?

Answer 3

the sensory system has 3 neurons

Question 4

how many neurons does the motor system have?

Answer 4

2 neurons ( motor has two syllables, and sensory has three syllables therefore sensory has 3 neurons)

Question 5

find the following pieces of surface anatomy on the brain

Answer 5

brain stem

spinal cord

cerebellum

two cerebral hemispheres

central sulcus

precentral gyrus

postcentral gyrus

Question 6

Find the following landmarks on the inferior surface of the brain

the cerebral peduncles

midbrain

pons

medulla

olives of medulla

pyramids of medulla

Question 7

find the follwoing landmarks on the midline sagitall section of the brain

• lateral ventricle
• midbrain
• pons
• precentral gyrus
• central sulcus
• post central gyrus
• thalamus
• cerebellum
• corpos collosum

Question 8

identify the follwoing landmarks on the coronal section of the brain

• head of caudate nucleus
• a) putamen
• thalamus
• internal capsule
• b) globus pallidus
• a+b= lentiform nucleus

Answer 8

Question 9

what are always included in the basal nuclei?

Answer 9

lentiform nucleus, caudate nucleus, and substantia nigra

Question 10

are cerebral peduncles part of the brain stem?

Answer 10

the physical connection between the brain and the brain stem are the cerebral peduncles - they are not technically part of the brain stem

Question 11

describe the difference between the pyramidal and the extrapyramidal system

Answer 11

Pyramidal system upper motor neuron starts in the cerebral cortex (pre-central gyrus). They pass through the pyramids of the medulla. Conscious movement.

Extrapyramidal system upper motor neuron starts in other brain center nuclei (e.g., basal ganglia). They do not pass through the pyramids of the medulla. Fine tune movement and stops unwanted movement - you don’t notice this system until things go wrong ( parkinsons)

Question 12

where does the pyramidal system start?

Answer 12

in the pre-central gyrus- they go through the pyramids of medulla

Question 13

what are the two neurons associated with the motor system?

Answer 13

upper motor neuron/lower motor neuron disease

upper motor neuron

corticobulbar tracts (the bulb is an outdated name for the medulla and originally it was through that all those fibers were located in the medulla) - starts in cerebral cortex - to brainstem (supplies cranial nerves)

Corticospinal tracts (lead to the rest of the body through the spinal cord) starts in the cerebral cortex to spinal cord

Lower motor neuron

corticobulbar tracts (from brainstem to cranial nerve motor nucleus)

corticospinal tract (from spinal cord to anterior horn cell)

Question 14

what is the difference between the corticobulbar tracts and the corticospinal tracts?

Answer 14

corticobulbar = besides the different pathway- supplies the facial nerves

corticospinal = besides the different pathway it supplies skeletal muscle

Question 15

describe the pyramidal motor pathay

Answer 15

1. motor area
2. internal capsule (through one of two areas- corticobulbar or corticospinal)
3. midbrain-cerebral peduncles
4. pons
5. medulla - pyramids
6. 85% decussate- lateral corticospinal tracts

Question 16

which artery is most often effected by a stroke?

Answer 16

the middle cerebral artery - which supplies the blood to the section of brain that controsl face, arm and speech

Question 17

the corticobulbar tracts pass through what seciton of the brain?

Answer 17

the Genu

Question 18

what sort of innervation do the cranial nerves have?

Answer 18

the motor nerves all have bilateral innervation except for cranial nerve 7 (below eye) and 12 - where you only have innervation from one side of the brain -

*above the eyes you have bilateral innervation, so if you have a stroke on the left side of your brain, you should still be able to lfit your eyebrows on both sides. however, below the eyes you only have unilateral innervation, so below the eye you’ll have drooping

Question 19

how do you determine if the stroke is an upper/lower motor neuron injury?

Answer 19

ask to raise eyebrows

• if they can raise their eyebrows - upper motor neuron injury
• if they cannot raise eyebrows/only one raises = lower motor neuron injury

Question 20

what is the pyramidal decussation?

Answer 20

the corticolspinal tracts swap sides on the medulla - these are critical b/c if you have an upper motor neuron injury and it comes above the decussation on the right hand side - the injury will be on the left hand side

• if the injury is on the left side below the deccussation, the injury will also be in the left hand side

Question 21

if someone says ‘upper motor neuron injury on the right hand side’ do you know if the damage is on the right or left hand side?

Answer 21

you don’t know - you need to ask if it’s above or below the medulla - if it’s above the medulla and injury is on the left, then the right hand side will be effected,

• if it’s below the medulla on te left side then the damage will present on the left side

Question 22

what do the basal ganglia do?

Answer 22

they are the ‘ go , no go’ system - they decide whether you shake or not - they are the balancers

Question 23

the upper colliculi and the lower colliculi are associated with what?

Answer 23

upper = vision

lower = hearing

Question 24

describe the result of an upper motor neuron lesion

Answer 24

If unilateral damage in cerebral hemisphere – then contralateral

If in spinal cord then…ispsilateral

Initial weakness/ paralysis

Later hypertonicity

Increased resistance to passive stretching of muscles Spasticity

clasp knife initial resistance to muscular stretching followed by relaxation

Hyperreflexia

Clonus - a rhythmic series of muscle contractions induced by stretching the tendon. It most commonly occurs at the ankle, where it is typically elicited by suddenly dorsiflexing the patient’s foot and maintaining light upward pressure on the sole.

Babinski’s sign (extensor response)

Question 25

polio effects what?

Answer 25

it is a lower motor neurons injury - virus that typically affects anterior horn cells causing LMN injury presentation in spinal nerves

Question 26

multiple scelrosis effects what system?

Answer 26

– affects the myelin coating on neurons (UMN and LMN), which damages the conduction of signals along nerves

Question 27

what is a motor homunculus?

Answer 27

It is a map of the regions of the precentral gyrus and which body parts it supplies - this is especially useful when determining the effected regions in a stroke

Question 28

what portion of the face is unilaterally supplied by the 7th nerve?

Answer 28

everything below the eyes is only supplied by the contralateral side facial nerve- the forehead is spared b/c it is innervated by both sides

Question 29

the anterior corticospinal tract controls the movement of what muscles generally?

Answer 29

the axial muscles of the trunk

Question 30

what is the red nucleus in the brain?

Answer 30

it receives inputs from the cerebellum and cerebral cortex - projects to interneurons in the cord and controls tone of flexor muscles in limbs

Question 31

what is the tectospinal tract?

Answer 31

from superior colliculi to cervical cord - reflex movements in response to visual stimuli

Question 32

what is the vestibulospinal tract?

Answer 32

from vestibular nuclei in medulla&pons to the anterior horn cells - control tone and estensor muscles

maintain posture (antigravity)