1. Twenty Questions
-The Muscular Edition-
Movements

2. Twenty Questions
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20

3. 1. How do skeletal muscles provide
movement/heat/posture
Movement: During contraction of the muscles,
bones are tugged and caused to move. With
relaxation, the bones are at rest as well
Heat: During the breakdown of ATP from food,
heat is produced. It being released to maintain
body temp. and warming the
muscles/surrounding tissues.
Posture: Receiving acetelecholine from a motor
nerve triggers an action potential across the
muscle fibers causing a contraction.
-All these functions are unique to muscles due to the chemicals and
self produced heat.-

4. 2. The characteristics of
Excitability are shared with ______
The Nervous System
(1)

5. 3. What has the ability to shorten;
creating body movements?
Contractility
(Packet)

6. 4. What is the ability to elongate and
then return to the primary state?
Extensibility
(Packet)

7. 5. Do they perform a specific
movement?
Agonist muscles
(1)

8. 6. During contraction, they oppose
prime movers?
Antagonist
(1)

9. 7. What are unique to skeletal
muscle fibers?
Slow red fibers, Fast white fibers and
Intermediate fibers. (1)

10. 8) What are different structures that
differentiate contractility and excitability?
Fast fibers are involved in excitability while
slow fibers are involved in contractility.
(1)

11. 9. What are myofilaments?
Four different types of protein molecules;
myosin, actin, tropomyosin and troponin.
Myosin heads are chemically attracted to
actin molecules of nearby thin filaments,
angling toward them. When bridging the gap
between adjacent myofilaments, they’re then
called cross bridges.”
(1)

12. 10. What contributes to the sliding
filament theory in shortening muscle?
When a myofibril changes length, the area
must slide past each other to increase their
area to overlap. The myosin filaments do not
move, but the actin filaments are pulled in.
(Packet)

13. 11. What is the role of Ca++ in
excitation?
Ca++ is released from the SR into the
sarcoplasm; binding to troponin molecules in
the thin myofilaments. Tropomyosin
molecules then shift and expose actin sites
which in response, cross bridges are formed
for pulling thin myofilaments out toward thte
sarcomere. Repeats while the Atp is still
available resulting in contraction.
(1)

14. 12. What is the role of Ca++ in
relaxation of a muscle cell?
The Sr pumps Ca++ back into its sacs. As
Ca++ is stripped from troponin molecules in
thin myofilaments, tropomyosin returns to
blocking the actin sites. The cross bridges
are then prevented from attaching and can’t
sustain the contraction.
(Packet)

15. 13. What occurs within the muscle
during an exercise burn?
The myosin heads are attaching and moving
to actin, causing the heads to be ripped off,
which is the burning sensation. More,
stronger heads grow in return. (Packet)

16. 14. What’s the anatomical
arrangement of a motor unit?
The motor unit consists of motor neurons as
well as the muscle fibers to which it attaches.
The gross motor unit consists of multiple
neurons and muscle fibers, a fine motor unit
consisting of less.
Fine motor unit
Gross motor unit

17. 15. What muscle would a
marathon runner have?
Marathon runner-
80% of their muscles are Slow fibers: produce
atp quickly enough to keep pace with the energy
needs of myosin; avoiding fatigue.
100- yrd dash-
intermediate and fast fibers: contract rapidly and
quickly deliver Ca++, aslo using Atp quickly,
perfect for a short distance runner.
(1)

18. 16. What is a unit of combined
cells?
syncytium being the branching exhibited by
individual cells, that allows cardiac fibers to form
a continuous, electrically coupled mass.
I.e. cardiac muscle due to its low resistance
connections between adjacent cells such as
when an action potential is generated, the
atria and ventricle contract together. (1)

19. 17. What is Rigor Mortis?
Occurring several hours post someone’s
death; the joints of the body stiffen and
become locked in place due to the skeletal
muscles partially contracting and not allowing
the muscles to relax. (27)

20. 18. What four factors describe the
Graded Strength Principle of muscles?
Skeletal muscles contract with varying
degrees of strength at different times.
1) The metabolic conditions of individual fibers
2) The number of fibers contracting simultaneously.
Greater number=stronger contraction
3) The number of motor units recruited
4) The intensity and frequency of the stimulation
(1)

21. 19. What are twitch contractions?
A quick jerk of a muscle as a result of a single,
brief threshold stimulus.
The 3 phases involved are the
– Latent Phase: a nerve impulse traveling to the
sarcoplasmic reticulum, triggering the release of Ca++.
– Contraction Phase: Ca++ binding to troponin and
filaments sliding.
– Relaxation Phase: When the filaments cease to slide
(1)

22. 20. What does the treppe effect
have to do with athletes?
When athletes warm-up, the treppe is
gradually increasing strength of contraction
and relaxation phases will dissapear.
(1)

23. It’s Muscular
Physiology!