Motor Systems 2

Question 1

Golgi Muscle Tendon

Answer 1

IT’S A TRAP

Innervated by 1b afferents

Question 2

In parallel with muscle

Answer 2

Muscle spindle

Question 3

In series with muscle

Answer 3

Golgi Tendon Organ

Question 4

Preferentially signals muscle stretch

Answer 4

Muscle spindle

Question 5

Preferentially signals muscle tension

Answer 5

Golgi Tendon Organ

Question 6

Important for stabilizing contractions

Answer 6

Golgi Tendon Organ

Question 7

Composed of muscle fibers

Answer 7

Muscle spindle

Question 8

Signals via Ia afferent fibers

Innervated by gamma motor neurons

Answer 8

Muscle spindle

Question 9

Signals via Ib afferent fibers

Not contractile

Answer 9

Golgi Tendon Organ

Question 10

Feedback system for maintaining muscle force

Answer 10

Golgi Tendon Organ

Question 11

Feedback system for maintaining muscle length

Answer 11

Muscle spindle

Question 12

Muscle spindle

Answer 12

In parallel with muscle
Preferentially signals muscle stretch
Important for maintaining muscle tone
Composed of muscle fibers
Signals via Ia afferent fibers
Innervated by gamma motor neurons
Feedback system for maintaining muscle length

Question 13

In series with muscle
Preferentially signals muscle tension
Important for stabilizing contractions
Composed of collagen fibers and capsule
Signals via Ib afferent fibers
Not contractile
Feedback system for maintaining muscle force

Answer 13

Golgi Tendon Organ

Question 14

Central pattern generation

Answer 14

Definition: neural networks that can produce patterned, rhythmic outputs in the absence of sensory or central input

Question 15

Flexor activated….

Answer 15

NEEDS extensor relaxed

Enforced by inhibitory interneurons

Question 16

central pattern generator. Describe a behavior that uses one and where it resides.

Answer 16

Spontaneous locomotor activity if transected rostral to mammillary bodies

No spontaneous locomotor activity if transected caudal to MB

Mesencephalic locomotor center stimulation necessary for locomotion

Question 17

Lower motor neuron syndrome

Answer 17

Damage to lower motor neuron cell bodies or peripheral axons

Paralysis

Paresis (weakness)

Loss of reflexes

Loss of muscle tone (why?)

Later, muscle atrophy due to denervation of muscle

Spontaneous twitches: changes in excitability of denervated muscle/ abnormal activity of alpha motor neurons

Question 18

Diseases that lead to lower motor neuron syndrome

Answer 18

Syphilis : DRG
Herniated disc: sens nerve root
Polio / ALS: motor neuron
Guillan-Barre: demyelination of peripheral motor nerve
Lambert-Eaton syndrome: peripheral Ca channel attack hits NMJ (mysteninc syndrome)
Myasthenia gravis
Muscular dystrophy: muscle directly.

Question 19

Summary of lower motor neuron system

Answer 19

Motor units and motor unit types

Location of lower motor neurons in ventral horn of spinal cord

Anatomy and function of muscle spindles

Anatomy and function of Golgi tendon organs

Basic concept of the Central Pattern Generator

CPGs in locomotor behavior

Question 20

Location of lower motor neurons in ________ of spinal cord

Answer 20

ventral horn

Question 21

Spinal circuitry mediating simple spinal reflexes –

Answer 21

myotatic reflex, extensor-flexor coupling, crossed extensor-flexor coupling