What are the three layers of connective tissue and the location of each? correct answers 1. Epimysium: around the entire muscle (outer)
2. Perimysium: surrounding individual bundles of muscle fibers (middle)
3. Endomysium: tissue between individual fibers (inner)
(All wrapped inside the fascia)...
Kin 310 Exam 2 || with Complete Solutions.
What are the three layers of connective tissue and the location of each? correct answers 1.
Epimysium: around the entire muscle (outer)
2. Perimysium: surrounding individual bundles of muscle fibers (middle)
3. Endomysium: tissue between individual fibers (inner)
(All wrapped inside the fascia)
What do muscle fibers contain? correct answers Bundles of muscle fibers (called fascicles)
which contain myofibrils (inside fiber) with the contractile proteins actin and myosin.
Fascia correct answers -Sheath that "wraps" layers of skeletal muscle
-Provides a "sliding and gliding" environment for muscles.
-Suspends organs in their proper place.
-Transmits movements from muscle to the bones they are attached to; and provides a supportive
and mobile "wrapping" for nerves and blood vessels as they pass through and between muscles.
Myofibrils correct answers Contain the contractile proteins actin and myosin.
Actin correct answers Responsible for the contraction and relaxation of a muscle
Myosin correct answers involved in the contraction of muscle fibers
How many capillaries supply an average muscle fiber? How does this change with training?
correct answers - 3-4 avg person
- 5-7 for athletes; increases blood flow, increases O2, and increase energy/ATP.
What is a tendon? Compare it to muscle fiber in terms of strength and elasticity. correct answers
-Stronger/tougher than muscle; small tendon can w/stand tension developed by larger muscle.
-"Less stretchy" fascia; intramuscular connective tissue merges w/ dense connective tissue at
each of the muscle to attach it to the bone.
What type of nerves innervate your muscles? (How do muscles contract?) correct answers
Neuro-muscular system; motor nerve/motor neuron.
What is a motor unit? What determines the fiber:nerve ratio? correct answers - A single motor
nerve and all the fibers it innervates.
- Each motor nerve has a job, single motor nerve innervates a certain # of muscle fibers - from 1-
500+.
All or None Law correct answers A motor unit contracts maximally or not at all, which means
that a muscle fiber contracts maximally or not at all.
What is the principle of "gradation" and how does it affect movement? (The Size Principle)
correct answers Recruited along a gradient, from small to large; size of motor axon supplying the
motor unit determines which fires first.
Small ----> Large
, "Low to High" Principle correct answers Motor nerves activate the low threshold motor units
first, then the higher threshold units.
What two factors determine the force of any given muscular contraction? correct answers -
Number of motor units recruited
-Frequency at which these motor units are recruited
Which motor units are activated first? Do these units typically produce a small or large amount
of force? correct answers -Motor nerves activate the smaller, low threshold motor units first, then
the bigger, higher threshold units.
-Small
What is a low threshold motor unit? correct answers Units that produce small amounts of force
have low threshold of activation --> it doesn't take a lot of input to get them to fire.
-Smaller muscle fiber size
-Lower number of fibers
-Slow twitch type of fibers
What's a high threshold motor unit? correct answers Units that produce greater amounts of force
have a higher threshold of activations --> it takes more to build up to get them to fire.
-Larger muscle fiber size
-Higher number of fibers
-Fast twitch type of fibers
Units that produce greater amounts of force have a ____ threshold of activation and a ____
number of fibers correct answers HIGH
The ramp-like recruitment seen during muscular contraction ensures that the easily fatigued ____
twitch fibers are protected because the slow twitch fibers will always be recruited first. correct
answers FAST
The functional capacity of a motor unit is determined by the type of _____ that make up the unit.
correct answers MUSCLE FIBERS
Slow twitch fibers have a _____ speed of contraction and a _____ force production correct
answers slow; low
Fast twitch fibers have a _____ speed of contraction and a ____ force production correct answers
fast; high
Describe an intermediate fiber in terms of speed of contraction and force production correct
answers Fast speed; Moderate force
How will fiber type vary among individuals? Within the same individual? correct answers -
Dependent of sports they play
-Within the same muscle, between different muscles
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