motor control 1&2

Question 1

what does a motor unit consist of

Answer 1

composed of the motor neuron and all the muscle cells (fibres) that it innervates

Question 2

what is muscle force increased by

Answer 2

1. recruitment of more motor neurons
2. increase in activity of motor neurons

Question 3

what motor neuron innervates extrafusal muscle fibre

Answer 3

Alpha motor neuron innervates extrafusal muscle fibers

Question 4

what innervates intrafusal fibre

Answer 4

gamma motor neurorsns

Question 5

what is 1a sensory neurons function

Answer 5

send information about muscle stretch to the spinal cord

Question 6

what is 1b sensory neuron function

Answer 6

1b is a Golgi tendon organ receptor

Question 7

what happens if a alpha neuron fires without gamma

Answer 7

• alpha (extrafusal fibres)
• gamma (intrafusal fibers)

-if only the alpha motor neurons contract, that is only contracting the extrafusal fibers of the muscle

• the intrafusal fibers will become slack
• therefor no action potential will be able to generate
• and unable to signal length change

Question 8

what happens to action potential when muscle shortens/ lengthens

Answer 8

when muscle shortens
- less action potential

• if get short enough lose potential all together
• brain won’t receive any input all together (stop firing)

lengthens
- increase of action potential
- more length= more action potential

Question 9

what DIFFERS golgi tendon vs muscle spindles during a STRETCH VS CONTRACTION of the muscle

Answer 9

PASSIVELEY STRETCHED
- increased firing of muscle fibers
- increased firing of gogi tendon

CONTRACT
- decrease of firing of muscle fibers
- increased firing of gogli tendon

Question 10

why is it important that both alpha and gamma contract at the same time

Answer 10

so intrafusal and extrafusal contract

tension is maintained and muscle spindles can detect change in length

Question 11

what are the steps to the stretch reflex

Answer 11

• stretch activates the muscle
  intrafusal muscle fiber

cause a response- afferent nerve (away from the muscle) to the spinal cord

contraction initiated by muscle stretch, as a protective mechanism so muscle doesn’t overstretch and cause damage

Than- another nerve pathway to agantiogist muscle to inhibit signal

(hamstring- signal inhibited to allow the leg to kick out)

Question 12

frequency vs amplitude

Answer 12

frequency is the pitch of the sound
- as the fluid waves travel against the basal ganglia , location of fluid wave determines frequency

amplitude is the sound intensity ( how loud)

Question 13

what determines the frequency of sound we hear

Answer 13

the way fluid travels across the basal membrane

narrow and thick part— high frequencies

wide, thin- low frequencies

Question 14

how is receptor potential created in hair cells

Answer 14

bending of the STEREOCILIUM opens mechanically linked ion channels, depolarizing the cell

increases the release of neurotransmitters causing an action potential on the afferent nerve

Question 15

what parts of the brain are required for movement (three stages)

Answer 15

planning movement
- cerebellum
- cortical association areas
- basal ganglia

initiating movement
- motor cortex

executing movement
- cerebellum

Question 16

what’s the cerebellum function

Answer 16

evaluates differences between intended action and actual action while movement is in progress

receives input Fromm cortex cortex, and spinal cord, which sends projections back to them- forming a vast loop

this loop can be modified which is important for motor adaption and learning

Question 17

auditory pathway in the CNS

Answer 17

• from the ears
• medulla
• midbrain
• thalamus
• auditory cortex

Question 18

what are effects of cerebellum disease

Answer 18

wide gait
instability of trunk
irregular staggering steps

Question 19

what is proprioception

Question 20

spinal cord- where does sensory and motor info travel

Answer 20

sensory info- leave dorsal root
motor info- leave ventricular root

medial- controls posture

Question 21

how is the spinal cord organized

Answer 21

medial parts (grey matter)- involved primary in the control of posture

lateral parts- involved in fine control of distal extremities
(

Question 22

what is the corticospinal tract

Answer 22

is the path that LEAVES the motor cortex to innervate motor neurons in the spinal cord

• right side of body mainly controlled by the left

Question 23

what are the two input neurons for the cerebellular circuit

Answer 23

mossy fibres and granule cells-
form parallel fibers which synapse on purkinje cells

climbing fibers
- synapse directly onto purkinjke fibers
- can only receive input one climbing fibre

Question 24

what would happen if the inferior olive wasn’t present in the cerelebellum

Question 25

what is the role of the inferior olive and locus corereleus

Answer 25

- send inputs for learning and memory

Question 26

dysemtria

Answer 26

causes a person to overshoot, under shoot a target

Question 27

what's the purpose of the basal ganglia

Answer 27

involved in regulating and planning movements - projects back to the cortex

Question 28

what is cerebellar lesions

Answer 28

defects of cerebellar diseases include dysemtrica and decomposition of movements

Question 29

explain basal ganglia pathway

Question 30

Parkinson's disease symptoms

Answer 30

- tremor at rest -slowness of movement -rigity extremities -minimal facial expression - rigid gait -slooped foward -slow movement initation -slow shuffling step -hypikinsea

Question 31

what are the 3 divisions of ANS

Answer 31

things that happen without your control sympathetic nervous system - fight or flight parasympathetic nervous system - rest and digest entering nervous system - ENS the gut

Question 32

What helps with the idea of muscle memory

Answer 32

inferior olive and locus coeruleus

Question 33

what is the role of inferioir olive and locus

Answer 33

uses knowldege from past experiences to adjust your movements muscle memory