Somatomotor System

Question 1

Where are UMN located?

Answer 1

Within the brain and spinal cord

Question 2

Function of UMN

Answer 2

To initiate or modulate a voluntary movement

- sends signal to LMN whether to start or stop contracting

Question 3

Where are a large proportion of LMN cell bodies located?

Answer 3

Ventral horn of spinal cord

Question 4

What is the function of LMN ?

Answer 4

Messenger to muscle to tell it to contract

Question 5

LMNs innervating flexors are distal/medial to those supplying extensors ?

Answer 5

Flexors - distal

Extensors - proximal

Question 6

What forms the final point of communication to initiate a muscle contraction?

Answer 6

LMN

Question 7

Name 2 types of LMN

Answer 7

Alpha MN

Gamma MN

Question 8

Alpha MN/Gamma MN innervates the bulk of skeletal muscle fibres that generate force.

Answer 8

Alpha MN

Question 9

Alpha MN/Gamma MN - innervates a sensory organ within the muscle.

Answer 9

Gamma MN

Question 10

Axons of LMNs exit the spinal cord in the dorsal/ventral roots?

Answer 10

Ventral

Question 11

Motor neurones are distributed equally within the spinal cord. True or false?

Answer 11

False

- greater number in the cervical and lumbar enlargement as these are supplying the limbs

Question 12

Muscle contraction results from the individual and combined actions of ____ ?

Answer 12

Motor units

Question 13

Small motor units are for fine movements. True or false? q

Answer 13

True

Question 14

Type 1 motor unit fibres

Answer 14

Slow oxidating

Question 15

Type IIa motor unit fibres

Answer 15

Fast

- ATP derived from oxidative phosphorylation

Question 16

Type IIb motor unit fibres

Answer 16

Fast

- ATP derived from glycolysis

Question 17

Fast fatiguing motor units are which type?

Answer 17

Type IIb

Question 18

Fatigue resistant motor units are which type?

Answer 18

Type IIa

Question 19

Slow motor units are which type

Answer 19

Type I

Question 20

The myotatic reflex is a monosynaptic reflex arc. True of false?

Answer 20

True

Question 21

The knee jerk is underpinned by which type of reflex?

Answer 21

Myotatic

Question 22

Name 2 types of intrafusal muscle fibres

Answer 22

Nuclear bag fibres
- bag 1 and 2
Chain fibres

Question 23

what are Intrafusal muscle fibres innervated by?

Answer 23

Gamma-MNs

Question 24

Where are golgi tendon organs located?

Answer 24

At the junction of muscle and tendon

Question 25

Function of golgi tendon organs ?

Answer 25

Monitor changes in muscle tension

Question 26

Where are proprioceptive axons located?

Answer 26

In connective tissue of joints

Question 27

Function of proprioceptive axons?

Answer 27

Respond to changes in angle, direction and velocity of movement of a joint.

Question 28

What are the function of Renshaw cells?

Answer 28

Stop motor neurones from firing

Question 29

Interneurones can be excitatory or inhibitory. True or false?

Answer 29

True