Control of body movement

Question 1

motor control hierarchy

Answer 1

Higher center - motor and sensory areas, limbic system, frontal cortex (motivation)

Middle: sensorimotor cortex, cerebellum (balance, motor memory), thalamus, basal ganglia

brain stem, spinal cord –> somatic motor neurons + nearby neurons

Question 2

Basal ganglia

Answer 2

planning and monitoring movements,
learn skilled movements, establish motor programs

pathway: substantia nigra to striatum (dopamin pathway)

Question 3

Cerebellum

Answer 3

input to the brainstem and to motor cortex via thalamus

coordinate timing movements (ball player)
planning movements, complex movement memory (riding a bike)
correcting movements

Question 4

Corticospinal pathway (from brain (cortex) to spinal cord)

what parts of the body is controlled?

Answer 4

from sensorimotor cortex to spinal cord - crossover in brainstem (in medulla) - pyramidal system

fine, isolated movements: finger
join corticobulbar pathway (cranial nerves): head/neck movement

Question 5

Brainstem pathway and what parts of body are controlled?

Answer 5

from brainstem to spinal cord, most of them ipsilateral
control large muscle group, posture, balance and walking

Question 6

where to find Stretch receptors and which information does it provide?

Answer 6

Intrafusual muscle fibers,
afferent axon wrapped around them

help the body know how long a muscle is when relaxed or contracted because it contracts and lengthens also with the other fibers

Question 7

when do stretch receptors respond

Answer 7

increasing of frequency of AP, by axons wrapped around intrafusal fibers, signaling (more AP) with lengthening

when the biceps contracts - intrafusal shortens causing decrease of activation of stretching receptors

Question 8

stretch reflex - which muscle is excited and inhibited

Answer 8

hit on knee -> stretch receptor excites and goes back to ventral horn and excites motor neuron of extensor muscle

and excites little interneuron which inhibits motor neuron of flexor muscle

Question 9

Golgi tendon organ

Answer 9

afferent nerve fiber wrapped around collagen fiber on tendon activated more by contraction than stretching

when muscle shortens it pulls tendons and causes firing, when relax no sresponse, weak response when stretched

Question 10

Which muscle is excited/inhibited by Golgi tendon organs

Answer 10

inhibits extensor muscle, and excites flexor muscle

Question 11

nociceptor receptor (pain receptor)

Answer 11

afferent pain signal to spinal cord throug dorsal horn
-> inhibit extensor muscle and excites flexor muscle to get off the source of pain