motor system

Question 1

4 systems for the control of movement

Answer 1

local spinal cord and brain stem circuits
descending modulator pathway
basal ganglia
the cerebellum

Question 2

alpha motor neurons what do they do and where are they found

Answer 2

ventral horn of spinal cord
direct innervation of muscles
different levels drive different muscles

Question 3

motor units what are they made of

Answer 3

1 alpha motor neurone and muscle fibres

Question 4

muscles fibres are innervated by

Answer 4

only 1 alpha motor neurone

Question 5

1 alpha motor neurone can innervate

Answer 5

many muscle fibres

Question 6

when stimulating a muscle once a stimulation is achieved another straight after will cause

Answer 6

the strength to rise

memory effect of muscles

Question 7

slower motor neurones provide

Answer 7

tension required for standing

Question 8

fast fatigue resistant neurons provide

Answer 8

the additional force needed for walking

Question 9

fast fatigue units provide

Answer 9

force for the most strenuous activities

Question 10

motor neurons are recruited at a

Answer 10

low frequency of firing

the rate of firing for each unit increases, generating more and more force

Question 11

where are the senosry and motor neurones found

Answer 11

on the same level of the spinal cord which can induce stereotypical spinal reflex activity

Question 12

what is the main mechanosensory pathway

Answer 12

the dorsal column-
medial lemniscus pathway carries maachanosensory info from the posterior third of the head and the rest of the body
the trigeminal portion carries similar info from the face

Question 13

muscle feedback,
Ia afferent what fibres does it contain
what are they sensitive too

Answer 13

bag and chain fibres

sensitive too velocity and position (tonic response)

Question 14

muscle feeback,
II afferent what fibres does it contain
what are they sensitive too

Answer 14

chain fibre

sensitive to position

Question 15

muscle feedback,
IB afferent what fibres does it contain
what is its activity

Answer 15

from golgi tendon organ

changes because of the external force acting on the tendon during passive stretch is small

Question 16

gamma afferent what does it control

Answer 16

control sensitivity

Question 17

knee jerk reflex is

Answer 17

myotactic

stimulation of peripheral sensors triggers AP

Question 18

knee jerk,
this info stimulates
which then does what

Answer 18

spinal motor neurons via
synaptic contact
riving rise to muscle contractions and behavioural responses

Question 19

negative feedback - clasp knife reflex
what happens to excess muscle contractions
how is this activated

Answer 19

sudden inhibition to reduce damage to muscle

golgi tendon organ located in tendons at the end of muscles

Question 20

locomotion in lamprey

different patterns of electrical activity in lamprey spinal neurons corresponds to

Answer 20

distinct periods in the sequence of muscles contraction related to the swim cycle

Question 21

locomotion

what is the central pattern generator

Answer 21

an oscillatory spinal cord local circuit

which alters flexing and extension of the limb during locomotion

Question 22

central control of movement
corticospinal tract what happens to axons
what does it mainly control

Answer 22

most terminate among pools of local circuit neurons
few direct to lower motor neurons
main control is distal limb muscles

Question 23

central control of movement

what do the upper neurones in the brain stem contol

Answer 23

they control axial and proximal muscles

controlling posture and behaviour

Question 24

what is the pathway that controls axial and proximal muscles controlling posture and behaviour

Answer 24

reticulospinal pathway

Question 25

cortical neurons have a

what do they control and dont

Answer 25

limited direct affect on lower motor neuron activity
thus muscle activity
but control intentional activity

Question 26

brain stem activity is

Answer 26

dynamically modulated by basal ganglia and cerebellum