Skeleteal Muscle part 3

Question 1

Describe skeletal muscle energy stores.

Answer 1

Glycogen and creatine phosphate.

Question 2

Describe the creatine kinase reaction

Answer 2

Substrates: ADP, phosphocreatine
Products: ATP creatinine
Enzyme: Creatine kinase

Question 3

What are the muscles other two energy pathways?

Answer 3

Glycolysis and oxidative phosphorylation; Supplies most of the energy for contraction.

Question 4

Relate the frequency of an action potential to the force of contraction.

Answer 4

Direct relationship

Question 5

Discuss Tetanus

Answer 5

Muscle producing a sustained contraction rather than individual twitches; Does not recruit additional skeletal muscle.

Question 6

Describe spatial summation

Answer 6

Increasing the total force of contraction by increasing the number of active motor units.

Question 7

Relate neuron cell body size to depolarization thresholds

Answer 7

Direct relationship; Smaller cell bodies lead to lower depolarization thresholds. Smaller neurons are recruited before larger ones.

Question 8

Which neurons are recruited first?

Answer 8

Type 1 motor units are first, then Type 2.

Question 9

Describe the 3 types of contractions.

Answer 9

1. Isometric: Muscle develops tension but cant shorten.
2. Concentric: Muscle develops force and shortens.
3. Eccentric: Muscle develops force and lengthens.

Question 10

What is an isotonic component?

Answer 10

An aspect of concentric and eccentric contractions that allows muscle to shorten or lengthen but maintain a constant force.

Question 11

Discuss isometric contractions

Answer 11

Myosin heads rotate and pull actin but the sarcomere doesnt shorten; Force produced matches external load.

Question 12

Discuss concentric contractions

Answer 12

Myosin head pulls actin and sarcomeres shorten; Force produced exceeds external load.

Question 13

Discuss eccentric contractions

Answer 13

Myosin heads pull actin and sarcomere lengthens; Muscle strenghtening is enhanced during this exercise. Can lead to muscle damage.

Question 14

What is a first class lever?

Answer 14

Fulcrum is between the resistance and effort; Atlanto-occipital joint. See-saw

Question 15

What is a second class lever?

Answer 15

The resistance is between the fulcrum and the effort; foot.

Question 16

What is a third class lever?

Answer 16

The effort is between the fulcrum and the resistance; Elbow

Question 17

Define the maximal force as well as the optimal length.

Answer 17

Maximal Force: All the myosin are overlapped with thin filaments
Optimal Length: The muscle length that allows for maximal force.

Question 18

Define Total force

Answer 18

Total force = Passive + Active force

Question 19

Describe the Force-velocity relationship

Answer 19

Muscle can shorten at different rates depending on the load; The heavier the load, the slower the shortening.

Question 20

Define Vmax

Answer 20

The maximum possible shortening velocity for a muscle; Occurs in the absence of a load

Question 21

Define Fmax

Answer 21

Maximum force which can be generated by a muscle; Equals the isometric force

Question 22

Relate eccentric muscle force to Fmax

Answer 22

Force produced by eccentric muscle contractions is greater than or equal to Fmax

Question 23

Relate the muscle fiber length to the speed of contraction.

Answer 23

Direct relationship