Download Chapter 8: THE MUSCULAR SYSTEM

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Chp 8: THE MUSCULAR SYSTEM
This chapter deals with the physiological characteristics of muscular tissue and the classification
of muscular tissue into skeletal, cardiac, and smooth muscle. The blood and nerve supplies of muscle are
also considered. Attention is then directed to the ultrastructure of skeletal muscle and the physiology of
muscle contraction. Emphasis is placed on the Sliding-Filament Theory, neuromuscular junctions, and
the physiology of con traction. There is considerable discussion given to the energy for contraction and
the maintenance of muscle homeostasis. The discussion continues with the types of skeletal muscle
contractions including muscle twitch, isotonic and isometric contractions.
The relationship between bones and muscles is established. Movement by skeletal muscles is
related to their origins, insertions, lever systems and group actions. The chapter concludes with a brief
discussion of cardiac and smooth muscle, common muscular disorders, and a list of medical terms.
OBJECTIVES
1. Describe the connective tissue components, blood and nerve supply, and histology of skeletal
muscle tissue.
2. Explain the factors involved in the contraction and relaxation of skeletal muscle.
3. Discuss the metabolism of skeletal muscle tissue.
4. Describe the various kinds of muscle contraction.
5. Define muscle tone.
6. Describe the structure and function of cardiac muscle tissue.
7. Describe the structure and function of smooth muscle tissue.
8. Describe how skeletal muscles produce movement.
ASSIGNMENTS
1. Read Chapter 8; pages 197- 215 and 245-246.
2. Complete this packet as you read and listen to classroom lectures or discussions; it will be
collected for a grade.
3. Complete all activities, Checkpoint Questions and Critical Thinking Applications when directed to
do so.
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Chapter 8: THE MUSCULAR SYSTEM
I. OVERVIEW OF MUSCULAR TISSUE
OBJ: Describe the types and functions of muscular tissue.
A. Types of Muscular Tissue- Read page 198 and complete this section
1. Describe striated.
___________________________________________________________________________
2. Fill in the chart below:
Muscle type
Striated (yes/ no)
Voluntary (yes/ no)
Can regenerate
(yes/ no)
Locations
Skeletal
Cardiac
Smooth
B. Functions of Muscular Tissue- Read page 198 and complete this section
1. ___________________________________________________________________________
Ex: ________________________________________________________________________
2. ___________________________________________________________________________
Ex: ________________________________________________________________________
3. ___________________________________________________________________________
Ex: ________________________________________________________________________
4. ___________________________________________________________________________
Ex: ________________________________________________________________________
5. ___________________________________________________________________________
Ex: ________________________________________________________________________
6. Store H2O and glycogen (not in textbook).
C. Characteristics of Muscular Tissue—not in textbook
1. Excitability: _________________________________________________________________
2. Contractility: _______________________________________________________________
3. Extensibility: ________________________________________________________________
4. Elasticity: ___________________________________________________________________
II. SKELETAL MUSCLE TISSUE
OBJ: Explain the relation of connective tissue components, blood vessels, and nerves to skeletal
muscle.
Describe the histology of a skeletal muscle cell.
Color, label and study the diagram of skeletal muscle on the next page of this
packet. Page 199, Figure 8.1 of your textbook will help you to complete this task and
possibly Figure 8.2, page 201.
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Fill in the oval with the colors you used for each structure.
Label the following in the blank boxes:
(1) Fascicle (done for you)
(5) Z disc
(2) Sarcomere
(6) A band
(3) M line (done for you)
(7) I band
(4) H zone
(8) Muscle fiber
Fascicle
Details of several myofibrils in a
muscle fiber
Myofibril
M line
Filaments
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What are muscle fibers?
__________________________________________________________________________________
__________________________________________________________________________________
A. Connective Tissue Components- pages 198-200
1. Muscle tissue is held together by deep fascia; a sheet or broad band of fibrous connective
tissue that surrounds muscles; it holds muscles together and separates them into functional
groups.
2. Types of connective tissue coverings extending from deep fascia:
a. Epimysium: ______________________________________________________________
b. Perimysium: _____________________________________________________________
c. Fascicles: ________________________________________________________________
d. Endomysium: ____________________________________________________________
3. Tendons:
___________________________________________________________________________
___________________________________________________________________________
B. Organization of Skeletal Muscle—refer to Figure 8.1; page 199
1. Muscle: bundle of fascicles
2. Fascicle: bundle of fibers
3. Muscle fiber: single muscle cell
4. Myofibrils: contractile units of cells
5. Myofilaments: protein strands (thin and thick)
C. Nerve and Blood Supply- Read page 200 and complete this section
1. What is the chief characteristic of muscles? _______________________________________
2. In order for a skeletal muscle to contract, it must be stimulated by an electrical signal called
a ________________________________________________________________________.
3. A great deal of energy is required in the form of ATP for muscle contractions. An indication
of this would be an abundance of __________________________________ in muscle cells
(Figure 8.2 might help with this).
4. List two functions of blood supply:
a. ________________________________________________________________________
b. ________________________________________________________________________
Worksheet: Electricity From the Brain; obtain a copy, complete it, and hand it in.
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D. Histology- pages 200- 202
1. Refer to the diagrams above as we discuss the histology of a skeletal muscle and summarize
its components below:
a. Muscle fibers: ____________________________________________________________
________________________________________________________________________
b. Sarcolemma: _____________________________________________________________
c. Transverse (T) tubules: _____________________________________________________
________________________________________________________________________
d. Sarcoplasm: _____________________________________________________________
________________________________________________________________________
e. Sarcoplasmic reticulum: ____________________________________________________
________________________________________________________________________
f.
Myoglobin: ______________________________________________________________
________________________________________________________________________
g. Myofibrils: _______________________________________________________________
________________________________________________________________________
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h. Thin filaments: ___________________________________________________________
________________________________________________________________________
i.
Thick filaments: __________________________________________________________
________________________________________________________________________
j.
Sarcomeres: _____________________________________________________________
________________________________________________________________________
k. Z lines/ disks: ____________________________________________________________
________________________________________________________________________
l.
A band: _________________________________________________________________
________________________________________________________________________
m. H zone: _________________________________________________________________
n. I band: __________________________________________________________________
________________________________________________________________________
o. Myosin: _________________________________________________________________
p. Crossbridges: ____________________________________________________________
q. Actin: ___________________________________________________________________
r.
Tropomyosin: ____________________________________________________________
________________________________________________________________________
s. Troponin: _______________________________________________________________
Quiz on Sarcomere structure on: _____________________
2. Muscle nourishment- Once a person reaches physical maturity; they do not grow new
muscles, as a rule. The size of skeletal muscles can change due to the shrinking or
enlargement of muscle fibers as myofibrils are lost or created. Fill in the information below,
using page 202 of your textbook.
a. Muscular atrophy:
________________________________________________________________________
a. Disuse atrophy:
_________________________________________________________________
_________________________________________________________________
b. Denervation atrophy:
_________________________________________________________________
b. Muscular hypertrophy:
________________________________________________________________________
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III. CONTRACTION AND RELAXATION OF SKELETAL MUSCLE
OBJ: Explain how skeletal muscle fibers contract and relax.
A. Neuromuscular Junction- pages 202-204
1. What makes up a neuromuscular junction?
__________________________________________________________________________
2. What starts this process?
___________________________________________________________________________
3. Label the drawing below:
4. Motor unit:
___________________________________________________________________________
5. Differences between fine and course motor movement:
a. Fine:
________________________________________________________________________
b. Course:
________________________________________________________________________
6. How it works:
(1) ________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
(2) ________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
(3) ________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
(4) ________________________________________________________________________
________________________________________________________________________
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B. Sliding-Filament Mechanism- page 204
(1) ___________________________________________________________________________
(2) ___________________________________________________________________________
(3) ___________________________________________________________________________
(4) ___________________________________________________________________________
(5) ___________________________________________________________________________
1. Under what circumstances will this mechanism operate to cause a muscle contraction?
___________________________________________________________________________
2. What structure allows the thin filaments to move forward?
___________________________________________________________________________
C. Physiology of Contraction- pages 204-205
1. What resources are needed for muscle contractions to occur?
___________________________________________________________________________
2. When a muscle fiber is relaxed, Ca2+ concentrations are low, in the sarcoplasm. Why?
___________________________________________________________________________
3. What happens when a muscle action potential travels along the sarcolemma and into
transverse tubules?
___________________________________________________________________________
___________________________________________________________________________
4. Ca2+ binds to _________________________ in thin filaments, causing it to change shape.
5. What is released when this shape change occurs?
___________________________________________________________________________
6. When do contraction cycles begin?
___________________________________________________________________________
7. The Contraction Cycle:
(1) ________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
(2) ________________________________________________________________________
________________________________________________________________________
(3) ________________________________________________________________________
________________________________________________________________________
(4) ________________________________________________________________________
________________________________________________________________________
(5) ________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
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8. What cause rigor mortis?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
D. Relaxation- page 205
1. Two changes that permit a muscle fiber to relax after contraction:
a. acetylcholine (ACh):
________________________________________________________________________
b. Ca2+ levels:
________________________________________________________________________
________________________________________________________________________
E. Contraction and Relaxation: Summary of Events
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F. Muscle Tone- pages 205- 207
1. Definition:
___________________________________________________________________________
___________________________________________________________________________
2. How is muscle tone maintained?
___________________________________________________________________________
___________________________________________________________________________
3. Define flaccid:
___________________________________________________________________________
___________________________________________________________________________
IV. METABOLISM OF SKELETAL MUSCLE TISSUE
OBJ: Describe the sources of ATP and oxygen for muscle contraction.
Define muscle fatigue and list its possible causes.
List the reasons that oxygen consumption is higher after exercise than at rest.
A. Energy for Contraction- pages 207-208
1. General Information (not all in textbook)
a. Muscle cells may use _______ to _______ times ATP as other cells during endurance
exercise
b. Amount of ATP stored in a muscle cell lasts about ____ to ____ seconds during intense
activity (ex: 50 m dash)
2. What are the three sources that muscles have for ATP production?
(1) _________________________________________________
An energy-rich molecule unique to muscle fibers; created excess ATP
(2) _________________________________________________
(3) _________________________________________________
3. Creatine Phosphate System
a. While muscles are at rest:
Muscle fibers produce more ATP than needed, creating an excess.
One of ATP’s high-energy phosphate groups is transferred to _____________________,
forming _______________________________ and ______.
b. While muscles are contracting:
High-energy phosphate group transferred from _________________________________
back to ______, quickly forming new ______.
c. Energy created during this process while muscle contracting lasts about _____ seconds
(ex: 100 m dash)
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4. Glycolysis-Lactic Acid System (for activity that lasts beyond 15-second mark)
a. Anaerobic (no oxygen needed) production of _______ molecules of ATP; occurs in the
_____________________________
b. Resources: __________________ or ____________________ (from liver or muscles)
broken down to glucose
c. ______________________________ passing from blood into contracting muscle and is
broken down into _____________________________.
d. Provides enough energy to last about _____ to _____ seconds of maximal muscle
activity (ex: 400 m race)
e. Next lactic acid fermentation if insufficient oxygen available. Hydrogen is stripped off
glucose which are normally bound to O2 to form H2O and are taken up by pyruvate to
form _____________________________.
f. For each ATP produced this way, a molecule of lactic acid is formed; build-up of lactic
acid produces ________________________________.
5. Cellular Respiration System
a. Aerobic (requires oxygen) and occurs in the ___________________________ of muscle
fibers.
b. Where does the oxygen come from?
(1) ____________________________________________________________________
(2) ____________________________________________________________________
Oxygen-binding protein found only in muscle fibers
c. Yields _____ ATP molecules, lasts about ____ minutes
6. When these reserves depleted fat is burned for energy.
Quiz on Energy for Muscle Contractions on: ______________
B. Muscle Fatigue- page 208
1. Definition:
___________________________________________________________________________
___________________________________________________________________________
2. What role does calcium play in muscle fatigue?
___________________________________________________________________________
___________________________________________________________________________
3. What other factors contribute to muscle fatigue?
__________________________________
__________________________________
__________________________________
__________________________________
__________________________________
C. Oxygen Consumption After Exercise-Read on pages 208- 209 and complete the section below
1. Define oxygen debt:
___________________________________________________________________________
___________________________________________________________________________
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2. Define recovery oxygen uptake:
___________________________________________________________________________
___________________________________________________________________________
3. Look at the graph below and briefly explain what it shows…
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
V. CONTROL OF MUSCLE TENSION
OBJ: Explain the three phases of a twitch contraction.
Describe how frequency of stimulation and motor unit recruitment affect muscle tension.
Compare the three types of skeletal muscle fiber.
Distinguish between isotonic and isometric contractions.
A twitch is a single muscle action potential, which produces very little force. How strong a twitch
is depends upon its frequency of stimulation (number of impulses per second).
Total tension produced is dependent upon number of muscle fibers contracting in unison.
A. Twitch Contraction-page 209
1. Define twitch contraction:
___________________________________________________________________________
___________________________________________________________________________
2. What is a myogram?
___________________________________________________________________________
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3. Label the periods of a twitch contraction on the myogram below:
4. Latent period:
___________________________________________________________________________
___________________________________________________________________________
Duration: ________________________________________
Events of latent period:
 ________________________________________________________________________

________________________________________________________________________

________________________________________________________________________
5. Contraction period:
___________________________________________________________________________
___________________________________________________________________________
Duration: _______________________________________
Events of contraction period:

_______________________________________________________________________

_______________________________________________________________________
6. Relaxation period:
___________________________________________________________________________
___________________________________________________________________________
Duration: ________________________________________
Events of relaxation period:

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________
7. During which of these periods do the sarcomeres shorten? ___________________________
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B. Frequency of Simulation- Read pages 209-210
1. If a second stimulus occurs before a muscle fiber has completely relaxed, the second
contraction will be __________________________________________________________.
2. Wave summation:
___________________________________________________________________________
___________________________________________________________________________
3. Unfused tetanus:
___________________________________________________________________________
___________________________________________________________________________
4. Cause of wave summation and unfused tetanus:
 ________________________________________________________________________
________________________________________________________________________
5. Fused tetanus:
___________________________________________________________________________
___________________________________________________________________________
6. Fatigue:

________________________________________________________________________
________________________________________________________________________

________________________________________________________________________
7. Fill in the graph below to depict a myogram showing the effects of different frequencies of
stimulation. Your graph should show (1) a single twitch, (2) a second stimulus before the
muscle has relaxed (wave summation), and a second contraction stronger than the first, (3)
an unfused tetanus, and (4) a fused tetanus.
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C. Motor Unit Recruitment- page 210
1. Motor unit recruitment:
___________________________________________________________________________
___________________________________________________________________________
2. Responsible for:
 _______________________________________

_______________________________________

_______________________________________
D. Types of Skeletal Muscle Fibers- Read pages 210-211
1. Three types:
(1) ________________________________________________________________________
________________________________________________________________________
(2) ________________________________________________________________________
________________________________________________________________________
(3) ________________________________________________________________________
________________________________________________________________________
2. Fill in the comparison chart below:
CHARACTERISTICS
SLOW OXIDATIVE
(SO) FIBERS
FAST OXIDATIVEGLYCOLYTIC (FOG)
FIBERS
FAST GLYCOLYTIC
(FG) FIBERS
Color
Myoglobin
Speed of Twitch
(contraction cycle)
Many
Mitochondria
Type of ATP
production
Resistance to fatigue
Diameter of fiber
Found in
E. Isometric and Isotonic Contractions
1. Isometric contraction:
a. ________________________________________________________________________
Example: ________________________________________________________________
b. ________________________________________________________________________
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2. Isotonic contraction:
a. ________________________________________________________________________
Concentric motion: _______________________________________
Eccentric motion: ________________________________________
VI. EXERCISING AND SKELETAL MUSCLE TISSUE- page 211
OBJ: Describe the effects of exercise on skeletal muscle tissue.
1. Aerobic activity (swimming, running)
a. Increase in __________________________________________________________________
b. Improves ___________________________________________________________________
c. High percentage of SO fibers: ___________________________________________________
d. Conversion of FG to FOG fibers
2. Weight lifting
a. ___________________________________________________________________________
b. Increase in size and strength of ________________fibers
3. Hypertrophy: ___________________________________________________________________
4. Anabolic steroids
a. Taken to:
__________________________________________________________
__________________________________________________________
b. Side effects:
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
VII. CARDIAC MUSCLE TISSUE- pages 211-212
OBJ: Describe the structure and function of cardiac muscle tissue.
1. Interconnectivity between cardiac muscle fibers established by irregularly transverse thickening
of sarcolemma (see picture below) called: ____________________________________________
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2. Autorhythmicity:
______________________________________________________________________________
3. Under normal resting conditions cardiac muscle tissue contracts _______times per minute.
4. Mitochondria are ___________________________; more energy needs.
5. Resources for ATP production:
a. ___________________________________________
b. ___________________________________________
VIII. SMOOTH MUSCLE TISSUE- pages 212- 213
OBJ: Describe the structure and function of smooth muscle tissue
1. Three types of filaments:
_______________________
_______________________
_______________________
2. Dense bodies:
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
3. Types of smooth muscle tissue:
a. Visceral (single-unit):
___________________________________________________________________________
___________________________________________________________________________
b. Multiunit:
___________________________________________________________________________
___________________________________________________________________________
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4. Smooth muscle can ______________________ and ____________________ more than other
muscle types.
5. Comparing types of muscles: fill in the comparison chart below; page 214 Table 8.1 and pages
211-213 might help….
CHARACTERISTICS
SKELETAL MUSCLE
CARDIAC MUSCLE
SMOOTH MUSCLE
APPEARANCE/ SHAPE
(INCLUDE
DESCRIPTION)
NERVOUS CONTROL
(VOLUNTARY/
INVOLUNTARY)
LOCATION
NUMBER OF NUCLEI
SPPED OF
CONTRACTION
CAPACITY FOR
REGENERATION
SARCOMERES (YES/NO)
IX. AGING AND MUSCULAR TISSUE- pages 213- 214
OBJ: Explain how aging affects skeletal muscle.
1. After birth
______________________________________________________________________________
2. During childhood
______________________________________________________________________________
3. Hyperplasia
______________________________________________________________________________
4. After age 30
______________________________________________________________________________
______________________________________________________________________________
5. Endurance and strength training ___________________________________________________
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X. HOW SKELTAL MUSCLES PRODUCE MOVEMENT- pages 214- 215
OBJ: Describe how skeletal muscles cooperate to produce movement.
A. Origin and Insertion
1. _________________________ organ composed of several different types of tissue.
Includes: ___________________________________________________________________
___________________________________________________________________________
2. Movement produced by: ______________________________________________________
3. Attachment of a muscle (by tendon) to stationary bone called _______________________.
4. Movable bone called ______________________________.
5. Fleshy portion of muscle between tendons and the origin and insertion called __________.
B. Group Actions
1. Movement motion caused by ___________________________________________________
__________________________________________________________________________.
2. Muscles arranged in opposing groups to joints, as ________________________to
______________________________ or _____________________________ to
________________________.
3. Muscle that causes desired action: ______________________________________________.
4. Other muscle, __________________________ relaxes.
5. Muscles called _____________________________ help prime mover function more
efficiently.
6. ___________________________ stabilize the origin of the prime mover.
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