Download Chapter 6 Worksheet#1 KEY - Mr. Lesiuk

Chapter 6 : The Muscular System – Introductory
Worksheet
Intro:
1. Approximately what percent of a 120 pound
person is skeletal muscle?
42%
A) Muscle Tissue
1. What is another name for a muscle cell? Muscle
Fiber
2. What are the three different names given to the
type of muscle tissue that attaches to bones?
a) Skeletal
b) Voluntary
c) Striated
3. For the three different types of muscle tissues,
fill in the correct spaces in the table below.
A
Muscle
Type
Cardiac
B
Skeletal
C
Smooth
Location and Function
HEART – Branched striated fibers
connected with intercalated discs
to allow them to beat in unison
SKELETON – Long
multinucleated cylindrical cells
with striations that contract to
move joints
Short tapered non-striated fibers
that slowly contract to change the
diameter of blood vessels and gut
organ shapes
3. In the diagram above identify and label the nuclei, striations and intercalated
disks when present. (use a ruler and write names of those structures)
4. What term is given for the shortening of muscle
cells?
CONTRACTION
B) Structure of Skeletal Muscle
5. What name is given to the strong fibrous
connective tissue that connect muscles to bones?
TENDONS
6. What are the two points of attachment of a
muscle called, and describe the location of each
site in comparison with the two bones and the
joint.
The tendons that fasten onto the more stationary
bone is called the ORIGIN. The other attached
tendon onto the more mobile bone is called the
INSERTION. These tendons are generally found
on the opposite sides of a joint.
7. Use the word bank to correctly label the
diagram below.
1. SCAPULA
A\\\
2. TRICEP ORIGIN
3. PROXIMAL
TRICEP TENDON
4.TRICEPS MUSCLE
BODY
9. Biceps Origin
10. Ball + Socket
11. PROXIMAL BICEP
TENDON
12. HUMERUS
13. BICEP MUSCLE
BODY
5. DISTAL
TRICEP TENDON
6. TRICEP
INSERTION on ULNA
7. HINGE JOINT
8. ULNA
WORD BANK
- Humerus
- Triceps Muscle Body
- Radius
- Distal Tricep Tendon
- Ulna
- Distal Bicep Tendon
- Proximal Tricep Tendon - Tricep Origin
- Scapula
- Tricep Insertion
- Hinge Joint
14. Distal Bicep Tendon
15. BICEP INSERTION
16. RADIUS
- Proximal Bicep Tendon
- Bicep Origin
- Bicep Insertion
- Biceps Muscle Body
- Ball and Socket Joint
8. Describe the structure and function of a bursa. A
Small fluid-filled sac that lies between bones and the
tendons that rides over those bones. They act to
cushion and reduce friction around the tendon.
9. Use the glossary in the back of the book (pp 529 ) to
define the following terms:
A) Actin: The contractile protein found in the THIN
myofilaments of skeletal muscle
B) Myosin : The contractile protein found in the
THICK myofilaments of skeletal muscle
C) Sarcomere: Contractile unit of muscle; length of a
myofibril between to Z-Lines.
D) Myofilament: Ultramicroscopic thread-like
structures found in myofibrils.
10. Label the diagram below.
1. Sarcomere
2. Actin
3. Myosin
4. Z-Line
11. A muscle is made up of many contractile cells called
muscle fibers. Use the diagram below to study the
microscopic anatomy of a muscle. Use the picture to
answer the following questions?
a) What is a muscle bundle? A bundle is a bundle of
muscle fibers that are wrapped up with perimysium.
Many bundles run together to form the Muscle Body.
b) What is the difference between a muscle fiber and a
myofibril? A muscle fiber is a muscle cell, myofibrils
consists of 100’s of arranged packages of myosin and
actin.
c) What happens to the amount of overlapping between
the bands of myosin and actin as a muscle contracts?
As the myosin pulls actin under its arms, the amount of
overlap increases.
12. What element must be present to form the bridges
between actin and myosin?
CALCIUM (Ca ++)
C) Function Of Skeletal Muscle
13. List the three primary functions of the muscular
system.
a) MOVEMENT
b) HEAT PRODUCTION
c) POSTURE / MUSCLE TONE
*** Also some protection
14. Which bone tends to move the origin or the
insertion?
INSERTION bone
15. When using the arms to curl weights in the
gym, which of the following muscles (Brachialis,
Triceps brachii, and Biceps brachii) fits each of
the categories below. See pp. 143-144.
a) Prime Mover: BICEPS Brachii
b) Antagonists: TRICEPS Brachii
c) Synergists : BRACHIALIS
16. What is tonic contraction and what is its
purpose?
Tonic contraction is when enough muscle fibers
are contracting to steady the position of parts of
the body to oppose gravity. This helps maintain
posture and tone, without creating any significant
movement.
17. When ATP is broken down to ADP, during
muscle activity, what two things happen to the
energy that is released?
a) Most of the energy goes into contraction of
Myosin heads pulling or locking onto actin.
b) Some of this energy is just wasted as heat.
D) Fatigue
18. What is produced when muscles switch from
aerobic (oxygen) respiration to anaerobic (without
oxygen) respiration?
Lactic Acid is produced along with O2 debt.
E) Motor Unit
19. Define the following:
a) Motor Neuron: The type of nerve cells that
innervate and stimulate muscles and glands.
b) Neuromuscular Junction: The point of contact
between the nerve fiber ending and the actual
muscle fiber.
c) Motor Unit: The combination of a single motor
neuron and all of the muscle fibers it innervates.
F) Muscle Stimulus
20. A muscle fiber will only contract once a
certain level of stimulation has been reached, what
is this called?
This is called the THRESHOLD STIMULUS
LEVEL or “All or None Law”
21. If muscle cells are said to respond in an “all or
none” mechanism, why is it that you can gently
curl both a 1-pound weight and a 25-pound
weight?
When you gently lift something, you only recruit
and activate a few motor units (5) that call on
their muscle fibers (10 each = total of 50). When
you lift something heavy you activate way more
motor units (500) that each call on their muscle
fibers (10 each = total of 5000).
G) Types Of Muscle Contraction
22. Other than Tonic Contraction, list the four other
types of muscle contractions.
Type Of
Description Of Contraction
Contraction
(Give Example For last two types)
TWITCH A single stimulation of a muscle fiber,
causing it to quickly jerk and then relax.
TETANIC When the muscle fiber is stimulated
multiple times over a very short period
the muscle fiber has a much smoother
contraction as the stimuli blend together
ISOTONIC Any type of contraction of muscle that
results in fluid movement of the joint.
Example : Normal Exercise.
ISOMETRIC When muscle contracts to increase
tension but movement does not occur.
Example: Holding a curled barbell
steady.
H) Effects of Exercise
23. The pictures below represent hypertrophy and atrophy, correctly label each.
ATROPHY
HYPERTROPHY
24. How does aerobic training increase muscle
endurance?
Aerobic training increases stamina in two ways,
firstly, the muscle tissue develops better
vascularization with capillaries. Secondly, the
actual muscle fibers develop more mitochondria
(sarcosomes)