Quiz 1.6

Question 1

Summation

Answer 1

The overall effect of added stimuli; before you get back to baseline you stimulate again

Question 2

Tetanus

Answer 2

Sustained maximal tension due to high frequency stimulation

Question 3

Motor unit

Answer 3

Single motor neuron and all of the muscle fibers it innervates (3- 2000)
Smallest functional unit of muscle contraction

Question 4

Motor unit recruitment

Answer 4

Muscle force is proportional to # of MUs recruited (CB foundations)
and proportional to rate of stimulation (only to an extent- Tetanus)
Synchronization of firing impulses may increase force (multiple muscles working vs. just one)

Question 5

Fiber type affects…

Answer 5

muscle force, rate of force production, and recruitment order

Question 6

Type I

Answer 6

Slow shortening speed, small, low force, low fatiguability

Question 7

Type IIa

Answer 7

Fast shortening speed, Large, high force, medium fatigue

Question 8

Type IIb

Answer 8

Fast shortening speed, larger, high force, high fatigue (withstand force for short amount of time)

Question 9

Fast vs. Slow peak force

Answer 9

Fast twitch peak force > slow twitch peak force

Question 10

Fast vs. slow rate of production

Answer 10

takes more time for slow twitch to generate peak force
AKA smaller rate of force production

Question 11

Muscle’s fiber comp.

Answer 11

All fibers within a MU are the SAME, but within a muscle there are a mixture of fibers

Question 12

Henneman’s size principal

Answer 12

Order of recruitment
1. Type I first (hold force for longer, takes more time to get to max force)
2. Type IIa second
3. Type IIb last (most force but can’t withstand)
Reduce force goes other way –> controlled smooth gradation of force

Question 13

Changing fibers

Answer 13

Some is genetic but you can modify between type IIa and IIb with training

Question 14

Arrangement of sarcomeres affects

Answer 14

force production, excursion (length), and velocity

Question 15

Types of fiber arrangements

Answer 15

parallel: side to side, greater force
Series: end to end, greater shortening velocity
See example on slide

Question 16

Muscle fiber architecture

Answer 16

Arrangement of contractile components affects force production

Question 17

Muscle shapes

Answer 17

Longitudinal (esophagus)
Unipennate (Lumbricals)
Bipennate (Gastroc.)
Fusiform (Biceps brachii)

Question 18

Sarcomeres in series

Answer 18

Muscle excursion and velocity are proportional to number of crossbridges/fibers in series
total change in length = sum of change of length of series fibers
IF you increase the change in length you increase velocity (aka shorten more in same amount of time)

Question 19

Sarcomeres in parallel

Answer 19

Muscle FORCE is proportional to number of crossbridges/fibers active in parallel
Muscle force = sum of force of parallel fibers
muscle force = avg force of series fibers

Question 20

Angle of pennation

Answer 20

See slides