Lecture 7: Skeletal Muscle Contraction

Question 1

Motor Units

Answer 1

somatic motor neuron and the myocytes it stimulates

Question 2

Motor Unit Recruitment

Answer 2

To increase force, more motor units are required to lift object

Question 3

Skeletal Muscle

Answer 3

Contains excitable cells, conduct electricity.

Question 4

Muscle Organs

Answer 4

1. )Myocytes are the cells that can shorten,
2. )Fibrous cells make up connective tissue for structure,
3. )Muscle organs can contract to varying degrees.

Question 5

Myocytes

Answer 5

Myocytes are the individual cells that require a certain amount of stimulus (threshold stimulus) to contract.

AKA MUSCLE FIBER
Long and Multinucleated

Question 6

Increasing Muscle Mass

Answer 6

1. )Build more proteins in muscle,
2. )Increase number of mitochondria (more ATP),
3. )Increase number of enzymes that produce ATP from ‘fuel’ sources.

Question 7

Motor Unit Function

Answer 7

1. )Brain sends action potentials to ventral horn,
2. )Axon of somatic motor neuron which innervates muscle ‘activates’ myocyte,
3. )Myocyte releases Ca+2 internally which causes muscle filaments to slide.

Question 8

Muscle Tone and Posture

Answer 8

1. )Sensors on skin ‘detect’ tension or stretch,
2. )Relay information to the brain (Integrator) and send information to,
3. )Somatic motor neurons (Effectors) to increase muscle contraction (tone).

Question 9

Hypotonia

Answer 9

Hypotonia can be due to abnormalities in the brain, spinal cord, somatic motor neuron or muscle.

Question 10

Flaccid

Answer 10

Muscles with less than normal tone are called flaccid

Question 11

Spastic

Answer 11

Muscles with more than normal tone are called spastic

Question 12

Electromyography

Answer 12

It is a graph of the electrical behavior of muscle (mV)

Question 13

Treppe

Answer 13

Consistent contraction, going up

Question 14

Tetanus

Answer 14

Stimulation continuing

Question 15

Fatigue

Answer 15

Continued contraction until there is a loss in force