Motor Unit

Question 1

Lower motor neurons

Answer 1

efferent

Question 2

alpha motor neurons

Answer 2

The motor neurons that are attached to muscle cells

Question 3

Motor unit

Answer 3

One alpha motor neuron with all of the skeletal muscle cells it attaches to. Basically how many axon terminals it has influences how many muscles cells it attaches to and they all receive the same response and move the same.

Question 4

The size of the motor neuron correlates with

Answer 4

the function of it. For example, muscles involved in fine motor movement like fingers have small, 3-5 axon terminal neurons whereas muscles in out legs and back can have thousands of muscle fibers per unit.

Question 5

Muscle twitch

Answer 5

The contraction generated by a single action potential

Question 6

Three components of a muscle twitch

Answer 6

Latent period, contraction phase, and relaxation phase

Question 7

Latent period

Answer 7

muscle cell has relieved action potential, the time it takes for calcium to diffuse out of the SR to bind to troponin. Tension is present

Question 8

Contraction phase

Answer 8

associated with cycling of cross bridges

Question 9

Relaxation phase

Answer 9

when the muscle comes to it normal length again

Question 10

How does the muscle move so smoothly?

Answer 10

The motor units contract asynchronously meaning they do not all fire at once

Question 11

Muscle tone

Answer 11

the random, sporadic firing of motor units when at rest. It keeps the muscle a little bit contracted at all times.
-The benefits of muscle tone is it takes up the slack for when the muscle is to contract and it deters atrophy

Question 12

What happens when a motor neuron is cut?

Answer 12

The muscle cells do not receive signals and they get flaccid paralysis

Question 13

Isometric contraction

Answer 13

Tension is increased but length is not, same length, maintaining posture

Question 14

Isotonic contraction

Answer 14

muscle length increases but muscle tension does not. Tonic = tension.

Question 15

Concentric contraction

Answer 15

type of isotonic contraction, muscle generates tension and the whole muscle contracts. Curling a weight from your waist to your shoulder. Cause more damage, tearing, of muscle than eccentric contractions

Question 16

Eccentric contraction

Answer 16

type of isotonic contraction, The tension remains but the muscle is lengthening. Weight going from the shoulder down to the waist. Can generate more force than concentric contractions can.

Question 17

Muscle size is determined by what

Answer 17

the number of myofibrils present and thus more myofilament proteins. Strength training produces more proteins

Question 18

Heterotrophy

Answer 18

The increasing of size of muscle through the extra production of myofilament protein. This happens because micro-tears happen to the myofibrils. Muscle soreness. an increase in muscle size is often accompanied by more connective tissue building up

Question 19

How do you increase the force of a muscle?

Answer 19

By increasing the number of motor units that fire at one time. This is called recruitment

Question 20

Wave summation

Answer 20

When action potentials are received at a rapid and increasing rate. There is no refractory period with muscle tissue so they can be stimulated at any time.

Question 21

The four ways that our bodies get ATP

Answer 21

cytosolic, creatine phosphate, glycolysis, aerobic or oxidative respiration

Question 22

Cytosolic

Answer 22

anaerobic, freely floating in the cytoplasm, can be used to fuel 3-4 seconds

Question 23

Creatine phosphate

Answer 23

gives away its phosphate freely to ADP, also anaerobic , requires enzyme. Extends muscle contraction to 10 seconds just from ATP from the pool

Question 24

Central fatigue

Answer 24

The feeling of being tired in the brain. Training helps us get over this physiological fatigue, to recognize the feeling and continue to perform even when it is uncomfortable

Question 25

Peripheral fatigue

Answer 25

low frequency and high frequency