Ch13 Motor Systems and Movement Pt1

Question 1

What are motor neurons?

Answer 1

Nerve cells that cause muscle to contract

Question 2

What are the 3 types of muscle involving motor neurons?

Answer 2

Skeletal, cardiac, and smooth

Question 3

Which muscle type produces body movement?

Answer 3

Skeletal muscle

Question 4

Motor neurons that innervate skeletal muscle are called what?

Answer 4

Lower motor neurons

Question 5

What is the Motor Point?

Answer 5

Where the lower motor neuron enters the belly of a muscle

Question 6

What is a neuromuscular junction (NMJ)?

Answer 6

The synapse between a lower motor neuron and a muscle fiber

Question 7

What happens during a neuromuscular junction?

Answer 7

The neuron releases the neurotransmitter acetylcholine, which diffuses across the synaptic cleft and stimulates skeletal muscle contraction

Question 8

The motor end plate on muscle cell membrane contains what type of receptors?

Answer 8

Acetylcholine (Ach) receptors

Question 9

In the beginning of a muscle contraction, the lower motor neuron sends an action potential where?

Answer 9

To the neuromuscular junction

Question 10

During a muscle contraction, acetylcholine is released and binds to what?

Answer 10

The motor end plate

Question 11

The binding to the motor end plate allows sodium to flow where?

Answer 11

Into the cell

Question 12

The sodium influx depolarizes what?

Answer 12

The muscle cell

Question 13

Depolarization releases calcium ions from where?

Answer 13

The sarcoplasmic reticulum

Question 14

Calcium ions trigger what?

Answer 14

Muscular contraction

Question 15

What is a motor unit?

Answer 15

A lower motor neuron and all of the muscle fibers it innervates.

Question 16

Small motor units have what type of control?

Answer 16

Fine control

Question 17

Large motor units have what type of control?

Answer 17

Powerful, but poor fine control

Question 18

Upper motor neurons connect the brain with what?

Answer 18

Lower motor neurons

Question 19

Cell bodies of upper motor neurons are located where?

Answer 19

In the cerebral cortex and brainstem

Question 20

Upper motor neurons that originate in the primary motor cortex usually control skeletal muscles on the contralateral side of the body. True or false.

Answer 20

True

Question 21

How many cortical upper motor neurons arise from the primary motor cortex?

Answer 21

About 60%

Question 22

What other areas of the brain do cortical upper motor neurons arise from?

Answer 22

Premotor cortex, supplementary motor area, and primary somatosensory cortex

Question 23

The motor homunculus is the map of proportional representation. True or false.

Answer 23

True

Question 24

What comprises the corticospinal tracts?

Answer 24

Axons that connect the cortex to lower motor neurons in the spinal cord

Question 25

What comprises the corticobulbar tracts?

Answer 25

Axons that connect the cortex to the cranial nerves (LMN)

Question 26

What are the two types of corticospinal tracts?

Answer 26

Lateral and anterior corticospinal tracts

Question 27

The lateral corticospinal tract crosses to where?

Answer 27

To the contralateral side of the body

Question 28

The anterior corticospinal tract remains where?

Answer 28

On the ipsilateral side of the body

Question 29

The lateral and anterior corticospinal tracts contain upper motor neurons that originate in the primary motor cortex and that control lower motor neurons in the spinal cord. True or false.

Answer 29

True

Question 30

What are the extrapyramidal tracts responsible for controlling?

Answer 30

Trunk movement, proximal muscles of extremities, muscle tone, and postural reflexes

Question 31

What are the 3 types of extrapyramidal tracts?

Answer 31

Reticulospinal, vestibulospinal, and tectospinal

Question 32

Where do reticulospinal tracts originate?

Answer 32

In the brainstem and reticular formation

Question 33

What do the reticulospinal tracts control?

Answer 33

Muscles involved with posture and gait

Question 34

Damage to the reticulospinal tracts can result in what?

Answer 34

Spasticity and hypertonicity

Question 35

Where do the vestibulospinal tracts originate?

Answer 35

In the brainstem

Question 36

What do the vestibulospinal tracts innervate?

Answer 36

Neck, trunk, and proximal extremity muscles needed for balance and posture

Question 37

What do vestibulospinal tracts synapse with?

Answer 37

Cranial nerves that control eye movement to help maintain gaze

Question 38

What does the tectospinal tract control?

Answer 38

Reflex motion of the neck, and links visual system with neck movement to allow visual tracking

Question 39

What can result from lower motor neuron lesions?

Answer 39

Hypotonia, hyporeflexia, atrophy, paralysis or paresis

Question 40

What is muscle tone?

Answer 40

The amount of resistance a muscle has to passive stretching

Question 41

What is the mechanical component of muscle tone?

Answer 41

Muscle cell properties and connective tissues

Question 42

What is the neural component of muscle tone?

Answer 42

Lower motor neurons provide signals to maintain tone