22 - Sensation & Motor Control Flashcards
Muscles are controlled by…
Nerves
Muscles are innervated by…
Alpha motor neurons (lower motor neurons)
Alpha (lower) motor neurones originate in the…
Ventral horn of the spinal cord
Which statement is true?
A) Motor neurons always innervate only 1 muscle fibre
B) Muscle fibres are only ever innervated by 1 motor neuron
C) There is a 1:1 ratio of motor neurons to muscle fibres
B) Muscle fibres are only ever innervated by 1 motor neuron
However, one motor neuron may innervate multiple muscle fibres
Which of the following statements regarding large motor units is false?
A) Generate strong force B) Innervate many muscle fibres C) Low precision D) Involved in finger movement E) Involved in movement of anti-gravity muscles, such as legs
D) Involved in finger movement
Small motor units are involved in finger movement
Movement is generated by coordinated muscle…
Contraction and relaxation
Flexion is contraction of the…
Flexors (and relaxation of extensors)
Extension is the contraction of…
Extensors (and relaxation of flexors)
The only way muscles can produce movement is by pulling on a joint. This is…
Contraction
Muscles that pull in the SAME direction are known as…
Synergistic
Muscles that pull in opposite directions are known as…
Antagonists
Biceps and brachialis muscles are ( synergists / antagonists )
Synergists
Biceps and triceps are (synergists / antagonists)
Antagonists
List the 4 types of muscle contraction
- Twitch (5Hz)
- Summation (10Hz)
- Unfused tetanus (20Hz)
- Fused tetanus (40Hz)
Which 3 input sources feed into motor neurones?
- Upper motor neurones
- Interneurones within spinal cord
- Muscle spindles & Golgi tendon organs
Interneurones within the spinal cord create local circuits involved in…
Spinal movement programs
Control of movement depends on sensory feedback, which comes from…
Muscle receptors (muscle spindles and Golgi tendon organs)
Muscle spindles are positioned in parallel with…
The extrafusal fibres of the surrounding muscle
Muscle spindles are innervated by…
1a afferents (which go to the spinal cord)
Gamma motor neurones are found in
A) Muscle spindles
B) Golgi tendon organs
C) Proprioceptive receptors
D) All of the above
A) Muscle spindles
Golgi tendon organs are (parallel / in series) with the extrafusal muscle fibres…
In series
Golgi tendon organs are innervated by…
1b nerve afferents
Proprioceptive receptors provide information about the…
Position of limbs in space
Muscle spindles signal the degree of (?) in the muscle?
Stretch
