Download Ch. 36-2 Muscular System presentation.pps

Vocabulary!
Muscular System!
Ch. 36-2!
I. Muscle Functions!
1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
9. 
skeletal muscle
smooth muscle
cardiac muscle
myosin
actin
sarcomere
Z-line
cross-bridges
cramps
II. Three Types of Muscle Tissue!
A.  Work with bones to produce movements!
B.  Stabilize body position (e.g. posture)!
C.  Movement of materials inside the body!
1.  Urine, blood, lymph, sperm, solid waste, food!
A.  Skeletal!
1.  Attaches to tendons!
a. tendon = tissue that attaches skeletal muscle to
bone!
2.  Control voluntary movements!
3.  Fatigue (get tired)!
D.  Produce heat!
1.  Involuntary contractions (shivering)!
4.  Large and multinucleated!
5.  Striated (striped)!
6.  Work by contracting (shortening)!
7.  Always work in pairs; one contracts and the
other relaxes (bicep and triceps)!
Figure 36-11 Opposing Muscle Pairs
B. Smooth!
1.  Found in stomach, intestines, and blood
vessels!
Section 36-2
2.  Non-striated!
Movement
Movement
Biceps (relaxed)
Biceps (contracted)
3.  Involuntary!
4.  Never get tired; slowly contract and relax!
5.  Single nucleus!
Triceps (contracted)
Triceps (relaxed)
Smooth muscle!
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C. Cardiac!
III. Skeletal Muscle Contraction!
A.  Structure!
1.  Found only in the heart!
2.  Properties of both skeletal and smooth!
1. Composed of myofibrils, which are composed
of smaller structures called filaments!
3.  Striated!
4.  Involuntary and autorhythmic; never get tired!
DRAW 36-7, pg 927 Skeletal Muscle Structure!
5.  Contracts about 70 times/minute your entire
life!
6.  Has a lot of mitochondria. Why?!
2. Two types of filaments:!
a.  Thick – contain a protein called myosin!
b.  Thin – contain actin!
c.  Filaments are arranged in sarcomeres, which
are separated by Z lines!
B. Muscle Contraction!
1.  Occurs when the thin filaments in the muscle
fiber slide over thick filaments!
C.  Sliding Filament Model!
Relaxed Muscle
Z line
Myosin
Actin
Z line
Movement of Actin Filament
Actin
Sarcomere
Binding
sites
Contracted Muscle
Cross-bridges
Z line
Crossbridge
Myosin
During muscle
contraction, the
knoblike head of a
myosin filament
attaches to a binding
site on actin, forming
a cross-bridge.
Powered by ATP,
the myosin crossbridge changes
shape and pulls
the actin filament
toward the center
of the sarcomere.
The cross-bridge is
broken, the myosin
binds to another
site on the actin
filament, and the
cycle begins again.
1.  Myosin cross bridges"
pull on thin filaments!
2.  Thin filaments slide "
inward!
3.  Z disc come toward "
each other!
4.  Sarcomeres shorten,
muscle fiber shortens,
and the muscle shortens!
5.  Note: Thick & thin
filaments do not change
in length!
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D. Contraction Graphic Organizer
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Myosin forms
cross-bridge
with actin
5
2
Myosin returns
to original
shape
4
Cross-bridge
changes
shape
3
Cross-bridge
releases actin
Actin pulled
IV.  Common Muscle Problems!
A.  Cramps – involuntary contractions of the muscle (from
hyperexciteable nerves) that do not relax, often painful!
1.  Caused by vigorous activity, dehydration, low
calcium, magnesium, or potassium levels!
a.  Resting cramps – cause not known!
2.  Most cramps can be stopped if the muscle can be
stretched and/or massaged!
3.  Prevention – good hydration, stretching before and
after exercise, replacement of lost electrolytes like
sodium & potassium lost in sweating)!
B.  Muscle twitches - uncontrollable twitching of a muscle
group from a single motor nerve!
1.  Causes - stress, too much caffeine, a poor diet,
exercise, or as a side effect of some medications!
2.  Common in the eyelid, thumb, or calf muscles,
often related to stress or anxiety!
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