Name: ___KEY___35 points_____________________________ Period: ____
Date: ______________
148 questions given in notes; each question worth 0.27 points OR total of 4 points
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 175 and complete this section
1. Describe striated. _muscle tissue that has alternating bands of light and dark color_______
2. Fill in the chart below: ¼ each = 3 points
Muscle type
Skeletal
Cardiac
Smooth
Striated (yes/ no)
YES
YES
NO
Voluntary (yes/ no)
YES
NO
NO
Can regenerate
YES; LIMITED
YES; UNDER CERTAIN YES
(yes/ no)
CAPACITY
CONDITIONS
Locations
ATTACHED TO
ONLY IN HEART
WALLS OF HOLLOW
BONES
INTERNAL
STRUCTURES
B. Functions of Muscular Tissue- Read page 175 and complete this section ¼ each = 2.5 points
1. _PRODUCING BODY MOVEMENT BY INTEGRATING FUNCTIONS OF BONES, JOINTS, AND
SKELETAL MUSCLES_
Ex: _WALKING, RUNNING, WRITING, OR NODDING_________________________________
2. _STABILIZING BODY POSITIONS THROUGH SKELETAL MUSCLE CONTRACTIONS____________
Ex: _STANDING, SITTING, HOLDING HEAD UPRIGHT_________________________________
3. _REGULATING ORGAN VOLUME TO PREVENT OUTFLOW OF CONTENTS TO HOLLOW
ORGANS_
Ex: _STORAGE OF FOOD IN STOMACH OR URINE IN URINARY TRACT____________________
4. _MOVING SUBSTANCES WITHIN THE BODY_______________________________________
Ex: _PUMP BLOOD THROUGH VESSELS; MOVE FOOD THROUGH DIGESTIVE TRACT________
5. _PRODUCING HEAT___________________________________________________________
Ex: _MAINTAIN BODY TEMPERATURE____________________________________________
6. Store H2O and glycogen (not in textbook).
C. Characteristics of Muscular Tissue—not in textbook
1. Excitability: _Receive & respond to stimuli; create action potential____________________
2. Contractility: _the ability of muscle tissue to contract when its thick (myosin) and thin (actin)
filaments slide past each other_________________________________________________
3. Extensibility: _The ability to stretch a muscle to its fullest length ; range of motion over
which the limb can be passively moved__________________________________________
4. Elasticity: _The ability to return to original state___________________________________
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 178, Figure 8.2 of your textbook will help you to complete this task and
possibly Figure 8.1, page 176.
Fill in the oval with the colors you used for each structure.
1/3 each picture = 1 point; ¼ each key = 0.75 points
Label the following in the blank boxes: ¼ each = 2 points
(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
Muscle fiber
Details of several myofibrils in a
muscle fiber
Myofibril
Sarcomere
H zone
M line
I band
Filaments
Z disc
A band
2
What are muscle fibers? _hundreds or even thousands of skeletal muscle cells that make up a skeletal
muscle; called fibers because of elongated shape ½ point
A. Connective Tissue Components- pages 175-177
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: _wraps entire muscle____________________________________________
b. Perimysium: _surrounds bundle of fascicles____________________________________
c. Fascicles: _bundles of muscle fibers__________________________________________
d. Endomysium: _wraps each individual muscle fiber______________________________
3. Tendons: _epimysium, perimysium, and endomysium extended beyond muscle__________
B. Organization of Skeletal Muscle—refer to Figure 8.1; page 176
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 177 and complete this section ½ each = 2.5 points
1. What is the chief characteristic of muscles? _CONTRACTION__________________________
2. In order for a skeletal muscle to contract, it must be stimulated by an electrical signal called
a _MUSCLE ACTION POTENTIAL; NOT IN TEXT MUST ASCERTAIN______________________.
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 _MITOCHONDRIA; NOT IN TEXT MUST ASCERTAIN __ in
muscle cells (Figure 8.2 might help with this).
4. List two functions of blood supply:
a. _DELIVER NUTRIENTS AND OXYGEN_________________________________________
b. _REMOVE WASTE________________________________________________________
Worksheet: Electricity From the Brain; obtain a copy, complete it, and hand it in.
3
D. Histology- pages 177- 179
1. Refer to the diagrams above as we discuss the histology of a skeletal muscle and summarize
its components below:
a. Muscle fibers: _elongated, cylindrical cells arranged parallel to one another__________
b. Sarcolemma: _plasma membrane that covers muscle fiber________________________
c. Transverse (T) tubules: _tunnel-like extensions of sarcolemma, pass through muscle
fiber from side to side and conduct action potential to myofibrils___________________
d. Sarcoplasm: _muscle fiber’s cytoplasm; contains many mitochondria (produce ATP
during contractions)_______________________________________________________
e. Sarcoplasmic reticulum: _like ER; stores Ca2+ ions needed for muscle contractions_____
f. Myoglobin: _reddish pigment molecules; stores O2 until needed by mitochondria to
make ATP________________________________________________________________
g. Myofibrils: _extends entire length of muscle fiber, cylindrical structure, consists of two
type of protein filaments___________________________________________________
4
h.
i.
j.
k.
l.
l.
m.
n.
o.
p.
q.
r.
Thin filaments: _one filament of myofibrils; mostly actin (tropomyosin and troponin)___
Thick filaments: _other filament of myofibrils; mostly myosin______________________
Sarcomeres: _compartment formed by filaments; contractile unit of striated muscle___
Z lines/ disks: _zigzag zones of dense material that separate sarcomeres from one
another_________________________________________________________________
A band: _darker area in sarcomere; extends entire length of thick filament (remains
constant) ________________________________________________________________
H zone: _narrow region at center of each A band (can change); thick filaments________
I band: _lighter-colored area either side of A band; thin filaments; extends into two
sarcomeres; Z disks divide it in half___________________________________________
Myosin: _protein found in thick filaments______________________________________
Crossbridges: _myosin heads________________________________________________
Actin: _protein found in thin filaments________________________________________
Tropomyosin: _thin, linear protein in thin filament- runs its length, covers myosin
binding sites_____________________________________________________________
Troponin: _small protein with two bulbs in thin filament__________________________
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 177 of your textbook. ½ each = 2 points
a. Muscular atrophy: _WASTING AWAY OF MUSCLES; LOSS OF MYOFIBRILS_____________
a. Disuse atrophy: _WHEN MUSCLES ARE NOT USED; NUMBER OF NERVE
IMPULSES TO INACTIVE MUSCLE IS GREATLY REDUCED…EX: BEDRIDDEN OR IN A
CAST_____________________________________________________________
b. Denervation atrophy: _NERVE SUPPLY TO A MUSCLE IS DISRUPTED OR CUT…EX:
PARALYSIS_________________________________________________________
b. Muscular hypertrophy: _AN INCREASE IN THE DIAMETER OF MUSCLE FIBERS OWING TO
PRODUCTION OF MORE MYOFIBRILS, MITOCHONDRIA, SARCOPLASMIC RETICULUM,
AND SO FORTH CAUSED BY VERY FORCEFUL, REPETITIVE MUSCULAR ACTIVITY LEADING
TO MORE FORCEFUL CONTRACTIONS…EX: STRENGTH TRAINING____________________
Page 3…5.85
Page 4…3.75
Page 5…4.35
Page 6…1.89
Page 7…5.24
TOTAL…21.08
5
III. CONTRACTION AND RELAXATION OF SKELETAL MUSCLE
OBJ: Explain how skeletal muscle fibers contract and relax.
A. Sliding-Filament Mechanism- pages 179-180
(1) _ Myosin heads pull on thin filaments___________________________________________
(2) _Filaments slide toward center of sarcomere_____________________________________
(3) _I bands & H zones are narrowed______________________________________________
(4) _When muscle fully contracted: I bands & H zones disappear________________________
(5) _Sarcomere shortens BUT not filaments; they overlap______________________________
1. Under what circumstances will this mechanism operate to cause a muscle contraction? _
_SLIDING OF FILAMENTS SHORTENS SARCOMERES THUS SHORTENING MUSCLE
FIBER;OCCURS ONLY WHEN LEVEL OF CALCIUM IONS IS HIGH ENOUGH AND ATP IS
AVAILABLE________________________________________________________________
2. What structure allows the thin filaments to move forward? _ HAPPENS BECAUSE MYOSIN
HEADS MOVE LIKE OARS OF A BOAT, PULLING ON THE ACTIN MOLECULES OF THE THIN
FILAMENTS ________________________________________________________________
B. Neuromuscular Junction- page 180
1. What makes up a neuromuscular junction? _ axon terminal of motor neuron plus the
motor end plate of a muscle fiber_______________________________________________
2. What starts this process? _ Muscle action potential from a motor neuron starts the
contraction_________________________________________________________________
3. Label the drawing below:
Motor neuron
axon
Synaptic cleft
Synaptic vesicles containing
acetylcholine
Sarcolemma
Axon terminal
T tubules
neuron axon
Terminal cristenae
Motor end plate
Sarcomere
4. Motor unit: _single motor neuron and the muscle fibers it stimulates that contract at the
same time__________________________________________________________________
5. Differences between fine and course motor movement:
a. Fine: _one neuron controls fewer muscle fibers (less than 10). Example: muscles that
move eye________________________________________________________________
6
b. Course: _one neuron controls numerous muscle fibers (up to 2000). Example: muscles
that move biceps in arm________________________________________________
6. How it works:
(1) _RELEASE OF ACETYLCHOLINE: Nerve impulse arrives triggers release of ACh
(acetylcholine); ACh diffuses across synaptic cleft between motor neuron and motor
end plate _______________________________________________________________
(2) _ACTIVATION OF ACh RECEPTORS: ACh binds to receptors in motor end plate opening
ion channels that allow small cations (especially Na+) to flow across membrane ______
(3) _GENERATION OF MUSCLE ACTION POTENTIAL: Muscle cell contracts “all-or-none”
action potential that travels along sarcolemma through T tubules; muscles contract by
50-60% of relaxed length; steps 2 and 3 can repeat if more ACh released ___________
(4) BREAKDOWN OF ACh: After about 5 milliseconds acetylcholinesterase (AChE) is released
and breaks down ACh______________________________________________________
C. Physiology of Contraction- pages 180-182; Read page 180 and complete questions 1- 6 &8
¼ each = 2 points
1. What resources are needed for muscle contractions to occur? _Ca2+ and energy, in the form
of ATP_________________________________________________________________
2. When a muscle fiber is relaxed, Ca2+ concentrations are low, in the sarcoplasm. Why? _Low
concentration of Ca2+ in sarcolemma because the membrane of the sarcoplasmic reticulum
contains Ca2+ active transport pump_____________________________________________
3. What happens when a muscle action potential travels along the sarcolemma and into
transverse tubules? _ Ca2+ release channels open, allowing Ca2+ to escape into the
sarcoplasm _________________________________________________________________
4. Ca2+ binds to _troponin_ in thin filaments, causing it to change shape.
5. What is released when this shape change occurs? _troponin-tropomyosin complex from
myosin-binding sites on actin___________________________________________________
6. When do contraction cycles begin? _When the myosin-binding sites are uncovered________
7. The Contraction Cycle:
(1) _ Myosin heads split ATP and become reoriented and energized. Myosin heads contain
ATPase to split ATP to ADP but phosphate remains attached; energy transfers to
myosin head______________________________________________________________
(2) _Myosin heads bind to actin, forming crossbridges. Once crossbridges formed
phosphate released_______________________________________________________
(3) _Myosin heads rotate toward center of the sarcomere (power stroke). Release of
phosphate triggers power stroke; thin filaments slide past thick filaments____________
(4) _As myosin heads bind to ATP, the crossbridges detach from actin. Power stroke ends,
new ATP molecule detaches myosin heads from actin; cycle repeats_______________
(5) _Contraction cycle continues if ATP is available and Ca2+ level in the sarcoplasm is high
8. What cause rigor mortis? _ After a person dies; Ca2+ begins to leak out of the sarcoplasmic
reticulum and binds to troponin, causing the thin filaments to slide. ATP production has
ceased, however, so the myosin heads cannot detach from actin, result is stiffening muscle._
D. Relaxation- pages 182- 183
1. Two changes that permit a muscle fiber to relax after contraction:
a. acetylcholine (ACh): _broken down by AChE, action potential ceased________________
b. Ca2+ levels: _ release ions from sarcoplasm to sarcoplasmic reticulum; myosin binding
sites no longer covered by tropomyosin-troponin_______________________________
E. Contraction and Relaxation: Summary of Events
7
F. Muscle Tone- page 184
1. Definition: _ Small number of motor units involuntary activated, producing a
sustained contraction of their muscle fibers______________________________________
2. How is muscle tone maintained? _ Shifting pattern of activity and inactivity keeps skeletal
muscles firm; Contractions not strong enough to produce movement, enable head to remain
upright, and established by neurons in the brain and spinal cord______________________
3. Define flaccid: _ damaged or cut motor neurons of skeletal muscles results in limpness;
muscle tone lost _____________________________________________________________
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 184-185
1. General Information (not all in textbook)
a. Muscle cells may use _100_ to _1000_ times ATP as other cells during endurance
exercise
b. Amount of ATP stored in a muscle cell lasts about _5_ to _6_ seconds during intense
activity (ex: 50 m dash)
2. What are the three sources that muscles have for ATP production?
(1) _creatine phosphate________________________________
An energy-rich molecule unique to muscle fibers; created excess ATP
(2) _glycolysis—(lactic acid fermentation) _________________
(3) _aerobic cellular respiration_________________________
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 _creatine_, forming
_creatine phosphate_ and _ADP_____.
b. While muscles are contracting:
High-energy phosphate group transferred from _ creatine phosphate _ back to _ ADP _,
quickly forming new _ ATP_.
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c. Energy created during this process while muscle contracting lasts about _15_ seconds
(ex: 100 m dash)
4. Glycolysis-Lactic Acid System (for activity that lasts beyond 15-second mark)
a. Anaerobic (no oxygen needed) production of _2_ molecules of ATP; occurs in the
_sarcoplasm_
b. Resources: _glucose_ or _glycogen_ (from liver or muscles) broken down to glucose
c. _Glucose_ passing from blood into contracting muscle and is broken down into _pyruvic
acid_.
d. Provides enough energy to last about _30_ to _40_ seconds of maximal muscle activity
(ex: 400 m race)
e. Next lactic acid fermentation if insufficient oxygen available. Hydrogen is stripped off
glucose which is normally bound to O2 to form H2O and is taken up by pyruvate to form
_lactic acid_.
f. For each ATP produced this way, a molecule of lactic acid is formed; build-up of lactic
acid produces _oxygen debt_.
5. Cellular Respiration System
a. Aerobic (requires oxygen) and occurs in the _mitochondria_ of muscle fibers.
b. Where does the oxygen come from?
(1) _ O2 diffused into muscle fibers from blood____________________________
(2) _ O2 released by myoglobin in sarcoplasm_____________________________
Oxygen-binding protein found only in muscle fibers
c. Yields _36_ ATP molecules, lasts about _10_ minutes
6. When these reserves depleted fat is burned for energy.
Quiz on Energy for Muscle Contractions on: ______________
B. Muscle Fatigue- page 185
1. Definition: _ Inability of muscle to contract forcefully after prolonged activity____________
2. What role does calcium play in muscle fatigue? _ CAUSE lower release of Ca2+ from
sarcoplasmic reticulum = declining levels of Ca2+ in sarcoplasm_______________________
3. What other factors contribute to muscle fatigue?
_ Depletion of creatine phosphate _____
_ Build-up of lactic acid and ADP _____
_ Insufficient O2____________________
_ Depletion of glycogen and nutrients __
_ Failure of nerve impulses to release sufficient acetylcholine __
C. Oxygen Consumption After Exercise-Read on page 185 and complete the section below
Q 1 & 2 = ¼ each = 0.5 points; Q3 = 1 point
1. Define oxygen debt: _Refers to the added oxygen, over and above the oxygen consumed at
rest that is taken into the body after exercise______________________________________
2. Define recovery oxygen uptake: _better name for oxygen debt; elevated oxygen use after
exercise ends due to metabolic changes that start during exercise and continue after
exercise____________________________________________________________________
3. Look at the graph below and briefly explain what it shows…
_Oxygen Debt & Deficit: These terms refer to a lack of oxygen while training/racing and
after such activity is over. To go into these areas of exercise are normal, but the goal is to
not go too far into either category. Below is a brief description of each and a chart with will
detail the process more clearly than we can explain with words alone.
Oxygen Deficit. While exercising intensely the body is sometimes unable to fulfill all of its
9
energy needs. Specifically, it is unable to intake and absorb enough oxygen to adequately
'feed' the muscles the amounts of energy needed to adequately perform the tasks the
athlete is requesting from the body. In order to make up the difference without sacrificing
the output, the body must tap into its anaerobic metabolism. This where the body goes into
a mix of aerobic and anaerobic energy production. While not hugely detrimental, oxygen
deficits can grow to a level that the anaerobic energy system cannot cover. This can cause
performance to deteriorate.
Oxygen Debt. This term describes how the body pays back its debt incurred above after the
exercise is over. You will notice that even after you are done racing you will continue to
breath hard. At this point your body is still trying to repay the oxygen debt that was created
when you were working hard. Technically, it is excessive post-exercise oxygen
consumption. That's it.____________________________________________________
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- pages 185-186
1. Define twitch contraction: _ Brief contraction of all muscle fibers in a motor unit in
response to a single action potential in its motor neuron____________________________
2. What is a myogram? _ graphic depiction of a muscle contraction____________________
3. Label the periods of a twitch contraction on the myogram below:
4. Latent period: _Brief delay occurring between application of stimulus and beginning of
contraction__________________________________________________________________
Duration: _2-3 milliseconds_______________________________________
Events of latent period:
 _Calcium ions released from sarcoplasmic reticulum
 _Calcium ions bind to troponin
 _Myosin heads start to bind to actin
10
5. Contraction period:_Repetitive powerstrokes occurring, generating tension or force of
contraction__________________________________________________________________
Duration: _20-30 milliseconds______________________________________
Events of contraction period:
 _Filaments slide
 _Sarcomere shortens
6. Relaxation period: _Powerstroke ceases___________________________________________
Duration: _20-30 milliseconds _______________________________________
Events of relaxation period:
 _Calcium ions in sarcoplasm decreasing to resting levels
 _Filaments slide back
 _Sarcomere extends
7. During which of these periods do the sarcomeres shorten? _contraction period_¼ point___
B. Frequency of Simulation - Read page 186 and complete question 6
1. If a second stimulus occurs before a muscle fiber has completely relaxed, the second
contraction will be _stronger than the first_.
2. Wave summation: _phenomena in which stimuli arriving one after another cause larger
contractions_________________________________________________________________
3. Unfused tetanus: _when skeletal muscle stimulated repeatedly, wave summation causes a
sustained but wavering contraction______________________________________________
4. Cause of wave summation and unfused tetanus:
 _release of additional calcium ions from sarcoplasmic reticulum by second and each
successive stimuli______________________________________________________
5. Fused tetanus: _occurs when frequency of stimulation reaches ~ 90 stimuli per second
resulting in sustained contraction that lacks even partial relaxation between stimuli_______
6. Fatigue:
 _Muscle stimulated repeatedly with such rapidity that recovery is not complete_______
 _Responses become weaker until they fail all together____________________________
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. 1/2 point each section = 2 points
C. Motor Unit Recruitment- page 186
1. Motor unit recruitment: _process in which contracting motor units is increased to match
relaxing motor units to delay muscle fatigue_____________________________________
2. Responsible for:
 _producing smooth movements____________
 _ producing precise movements ____________
 _sustaining large tension when needed______
11
D. Types of Skeletal Muscle Fibers- Read pages 187-188 and complete question 2
1. Three types:
_slow oxidative (SO) fibers__ -about half of all skeletal muscle_________
_fast oxidative-glycolytic (FOG) fibers___ -act like accessory __
_fast glycolytic (FG) fibers___ -increase in size, strength, and glycogen content through
repeated use; ____ -used to produce large amounts of tension_____________
2. Fill in the comparison chart below: ¼ each = 5.75 points
CHARACTERISTICS
SLOW OXIDATIVE
(SO) FIBERS
Color
Myoglobin
Speed of Twitch
(contraction cycle)
Mitochondria
Type of ATP production
Red; dark red
lots
slow
Resistance to fatigue
Diameter of fiber
Found in
Many; large
Aerobic cellular
respiration
Very resistant
small
Postural muscles;
neck, back, legs
FAST OXIDATIVEGLYCOLYTIC (FOG)
FIBERS
Dark red
lots
fast
many
Aerobic cellular
respiration & glycolysis
Moderately high
resistance
Intermediate
legs
FAST GLYCOLYTIC (FG)
FIBERS
White
low
Most powerful, most
rapid
few
glycolysis
Fatigue quickly
Largest in diameter
Shoulders, arms
E. Isometric and Isotonic Contractions- page 188
1. Isometric contraction:
a. _ Muscle tenses; BUT does not shorten_______________________________
Example: _ lifting open textbook off of your desk_________________
b. _ Maintain posture and allow us to support objects in a fixed position ______
2. Isotonic contraction:
a. _Muscle shortens; moves skeleton; no change in tension_________________
Concentric motion: _shortening______________________________________
Eccentric motion: _lengthening_______________________________________
VI. EXERCISING AND SKELETAL MUSCLE TISSUE- page 188
OBJ: Describe the effects of exercise on skeletal muscle tissue.
1. Aerobic activity (swimming, running)
a. Increase in _ number of capillaries_______________________________________________
b. Improves _ oxygen delivery through blood to enable endurance _______________________
c. High percentage of SO fibers: _ more ATP production _______________________________
d. Conversion of FG to FOG fibers
2. Weight lifting
a. _ Increases muscle size and strength for short term feats ____________________________
b. Increase in size and strength of _ FG- fast glycolytic _fibers
3. Hypertrophy: _ muscle enlargement; bulging muscles __________________________________
4. Anabolic steroids
a. Taken to:
_ Increase muscle size _______________________________________
_ Increase strength for competition activities ____________________
b. Side effects:
_Liver cancer, mood swings, kidney damage, tendencies toward aggressive behavior, risk of
heart damage, growth problems (stunted)_________________________________________
VII. CARDIAC MUSCLE TISSUE- page 189
OBJ: Describe the structure and function of cardiac muscle tissue.
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1. Interconnectivity between cardiac muscle fibers established by irregularly transverse thickening
of sarcolemma (see picture below) called: _intercalated discs_
2.
3.
4.
5.
Autorhythmicity: _Built in rhythm of heart contractions _
Under normal resting conditions cardiac muscle tissue contracts _75_times per minute.
Mitochondria are _larger_; more energy needs.
Resources for ATP production:
a. _aerobic cellular respiration___________________
b. _Lactic acid from skeletal muscles utilized to make ATP_
VIII. SMOOTH MUSCLE TISSUE
OBJ: Describe the structure and function of smooth muscle tissue
1. Three types of filaments:
_thick_________________
_thin__________________
_intermediate___________
2. Dense bodies: _located between intermediate filaments; similar to Z discs in striated muscle;
some attached to sarcolemma, others dispersed in sarcoplasm; those attached to sarcolemma
cause lengthwise shortening _______________________________________________________
3. Types of smooth muscle tissue:
a. Visceral (single-unit): _most common; wrap around walls of arteries and veins; stomach,
intestines, uterus, and urinary bladder; tissue bound together in continuous network; is
autorhythmic; all fibers contract in unison_________________________________________
b. Multiunit: _individual fibers with own motor nerve endings; each fiber contracts separately;
found in walls of large arteries, airways to lungs, and internal eye muscles_______________
4. Smooth muscle can _shorten_ and _stretch_ more than other muscle types.
5. Comparing types of muscles: fill in the comparison chart below; page 190 Table 8.1 and pages
189-190 might help….¼ each = 5.25 points
CHARACTERISTICS
APPEARANCE/
SHAPE (INCLUDE
DESCRIPTION)
SKELETAL MUSCLE
CARDIAC MUSCLE
SMOOTH MUSCLE
Long, cylindrical fiber
w/ many peripherally
Branched cylindrical fiber;
one centrally located
Thickest in middle;
tapered at ends; one
central nucleus; not
13
located nuclei;
striated, unbranched
nucleus; intercalated discs
join connecting fibers;
striated
Involuntary
striated
Walls of hollow viscera,
airways, blood vessels,
iris and ciliary body of
eye, pili muscles of hair
follicles
One central
Slow
NERVOUS CONTROL
(VOLUNTARY/
INVOLUNTARY)
LOCATION
Voluntary
Attached to bones by
tendons
Heart
NUMBER OF NUCLEI
SPPED OF
CONTRACTION
CAPACITY FOR
REGENERATION
Many
Fast
One central
Moderate
Limited
Limited
SARCOMERES
(YES/NO)
Yes
Yes
Involuntary
Considerable
compared to other
muscle tissue
No
IX. AGING AND MUSCULAR TISSUE-page 191
OBJ: Explain how aging affects skeletal muscle.
1. After birth _number of skeletal muscle fibers does not significantly increase_________________
2. During childhood _increase in size of muscle fibers controlled by hormones_________________
3. Hyperplasia _growth of more muscular fiber__________________________________________
4. After age 30 _progressive loss of muscle mass and slowing of muscular reflexes______________
5. Endurance and strength training _can slow age-related decline of muscles__________________
X. HOW SKELTAL MUSCLES PRODUCE MOVEMENT- pages 191-192
OBJ: Describe how skeletal muscles cooperate to produce movement.
A. Origin and Insertion
1. _Skeletal muscle_ organ composed of several different types of tissue.
Includes: _skeletal muscle tissue, vascular tissue (blood and blood vessels), nervous tissue
(motor neurons), and several types of connective tissue_____________________________
2. Movement produced by: _pulling on tendons then pull on bones______________________
3. Attachment of a muscle (by tendon) to stationary bone called _origin_.
4. Movable bone called _insertion_.
5. Fleshy portion of muscle between tendons and the origin and insertion called _belly_.
B. Group Actions
1. Movement motion caused by _several skeletal muscles acting in groups_.
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2. Muscles arranged in opposing groups to joints, as _flexors_ to _extensors_ or _abductors_ to
_adductors_.
3. Muscle that causes desired action: _prime mover or agonist_.
4. Other muscle, _antagonist_ relaxes.
5. Muscles called _synergists_ help prime mover function more efficiently.
6. _Fixators_ stabilize the origin of the prime mover.
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