Motor Systems

Question 1

describe the sensory reflex arc

Answer 1

• Sensory input from the skin travels via the afferent nerve through the spinal cord via an interneuron, and leaves the spinal cord to travel to the muscle (effector) via the efferent nerve.

Question 2

in terms of reflex arcs, all movements contain what?

Answer 2

• All movements include 1 or more reflex arc.

Question 3

what do spinal reflex arcs avoid?

Answer 3

the brain

Question 4

where is the primary motor cortex?

Answer 4

(Brodman area 4) in the posterior frontal cortex.

Question 5

what can be found in the primary motor cortex?

Answer 5

o The motor homunculus is here (more fine motor movements are bigger on the homunculus)

Question 6

role of premotor cortex

Answer 6

processes external environment

Question 6

what is at brodmann area 4?

Answer 6

primary motor cortex

Question 7

what is found at the outer area of brodman 6?

Answer 7

premotor cortex

Question 8

where is the premotor cortex?

Answer 8

outer area of brodman 6

Question 9

role of supplementary motor area

Answer 9

prepares plan

Question 10

where is the supplementary motor area?

Answer 10

medial area of brodman 6

Question 11

what is at medial brodman 6?

Answer 11

supplementary motor area

Question 12

role of basal ganglia

Answer 12

initiates movement and suppresses unwanted movement

Question 13

name a condition the basal ganglia is important in

Answer 13

parkinsons

Question 14

role of cerebellum

Answer 14

coordinates ingoing movement

Question 15

two types of spinal tracts

Answer 15

ascending and descending

Question 16

descending spinal tract

Answer 16

corticospinal tract

Question 17

is the corticospinal tract ascending or descending

Answer 17

descending

Question 18

where is the corticospinal tract?

Answer 18

from cerebellum to spinal cord

Question 19

role of corticospinal tract

Answer 19

Corticospinal tract (from cerebellum - decussation of the pyramids in the medulla – conveys motor commands to the muscles)

Question 20

which spinal tract is is responsible for:

decussation of the pyramids in the medulla and conveying motor commands to the muscles?

Answer 20

corticospinal tract

Question 21

ascending spinal tracts

Answer 21

spinocerebellar tract
dorsal columns
spinothalamic tract

Question 22

is the spinocerebellar tract ascending or descending?

Answer 22

ascending

Question 23

is the spinothalamic tract ascending or descending?

Answer 23

ascending

Question 24

are the dorsal columns ascending or descending?

Answer 24

ascending

Question 25

role of spinocerebellar tract

Answer 25

to cerebellum – provides sensory feedback to motor structures allowing for real-time error correction)

Question 26

which tract is this? to cerebellum – provides sensory feedback to motor structures allowing for real-time error correction

Answer 26

spinocerebellar

Question 27

role of dorsal columns

Answer 27

(proprioception of fine motor movements)

Question 28

which tract is this? (proprioception of fine motor movements)

Answer 28

dorsal columns

Question 29

role of spinothalamic tract

Answer 29

gross movements

Question 30

what tract is this? gross movements

Answer 30

spinothalamic tract

Question 31

example reflex - tapping a ligament

Answer 31

- Tap a ligament - Stretches muscle and muscle spindle - Mechanosesnsitive strcutre - Fires AP when stretched to a certain point - Travels along 1a (alpha) afferent neuron to the spinal cord etc. (interneuron/relay neuron) connecting to efferent neuron to muscle for a response (e.g. pull away) - Alpha motor neuron: makes the muscle contract - Gamma motor neuron: causes contraction of the muscle spindle Sensitive to stretch

Question 32

describe lower motor neurons

Answer 32

- In reflex arc - Out of ventral route - All movements follow this wiring

Question 33

describe upper motor neurons

Answer 33

- Allow exertion of voluntary control - Originate in the brainstem and cortex - Synapse with lower motor neurons rather than lower motor neurons directly (usually)

Question 34

where are lower motor neurons?

Answer 34

in reflex arc out of ventral route

Question 35

where are upper motor neurons?

Answer 35

originate in brainstem and cortex

Question 36

what do upper motor neurons allow?

Answer 36

exertion of voluntary control

Question 37

what do upper motor neurons synapse with?

Answer 37

- Synapse with lower motor neurons rather than lower motor neurons directly (usually)

Question 38

example sensorimotor pathway - nociceptors

Answer 38

1. Nociceptor 2. Dorsal root ganglion 3. Posterior horn 4. Interneuron 5. Anterior horn 6. Alpha motor neurons 7. Muscles

Question 39

order of spinal cord segments from head to toe

Answer 39

1. Cervical 2. Thoracic 3. Lumbar 4. sacral