Lectures 5.2-5.3: Lower and Upper Motor Neurons

Question 1

A motor unit is made up of

Answer 1

a motor neuron and all of the skeletal muscle fibres innervated by that motor neuron’s axonal terminals

Question 2

Smaller neurons have _____ input resistance

Answer 2

higher

Question 3

Increased motor unit size leads to ____ input resistance

Answer 3

decreased

Question 4

The monosynaptic reflex arc

Answer 4

part of a feedback control mechanism that maintains limb and body position. This control is a vital part of our ability to maintain stance and position under changing loads.

Question 5

The ventral / medial tracts (tectospinal, vestibulospinal and reticulospinal) carry information related

Answer 5

maintenance of posture

Question 6

The motor cortex influences the spinal cord and brainstem via the

Answer 6

lateral tracts principally the corticospinal tract

Question 7

Supplementary and premotor cortex encode

Answer 7

more complex movements and more abstract representations of motor goals

Question 8

Damaging the primary motor cortex produces

Answer 8

weakness

Question 9

damage to the supplementary motor

Answer 9

doesn’t affect muscle strength but causes problems in planning & sequencing movements (apraxia).