Module 3: Muscle System

Question 1

Describe the organization of skeletal muscle?

Answer 1

Sarcomere - myofibril - muscle fiber - fasicle - muscle
endomysium covers muscle fibers
perimysium covers fasicles
epimysium covers the muscle

Question 2

What are the areas that can be found in a sacromere?

Answer 2

M-line: mid line
Z-line/disk: end of the sarcomere
H zone: contains only thick filament (myosin)
A band: contains both thick and thin filaments
I band: contains only thin filaments (actin)

Question 3

Describe the recruitment of motor units?

Answer 3

Small motor units are recruited first (provide fine precise movement)
Large motor units recruited second to give large powerful movements

Question 4

Describe the different ways force production is regulated.

Answer 4

by the number of motor units that are recruited ( increased number recruited = more force) and the frequency of recruitment (increased frequency = increased force production because tetanus is acheived)

Question 5

Describe the difference between active and passive tension?

Answer 5

active - muscle in a lengthened or shortened position has a decreased number of cross bridges and therefore a decreased amount of force possible to generate
passive - passive lengthening = increase in muscle tension as the muscle reaches it’s outer limit

Question 6

Describe the prinicples of muscle strengthening and endurance?

Answer 6

Overload: muscle needs to be challenged with more weight than it is used to in order to grow
Specificity: training needs to be specific to the type of activity
Progressive: the training needs to increase over time
Reversibility: gains can be lost if training stops

Question 7

Describe the force velocity relationship?

Answer 7

Concentric contraction = decreased force with increased velocity
Isometric = no velocity
Eccentric = muscle force stays the same with a similar speed of contraction