Thursday, November 12, 2015
• Put muscular worksheet in the blue
basket
• Get a textbook
• Get a highlighter
• Get out paper & something to write
with
FYI…
•A muscle cell is also
called a muscle fiber
Read pgs. 182-185
• on your paper answer the
following
1. Describe the similarities and
differences in the structure and
function of the 3 types of muscle
tissue, and indicate where they are
found in the body.
2. Define muscular system.
•Organ system
consisting of skeletal
muscles and their
connective tissue
attachments
3. Define and explain the
role of the following:
endomysium,
perimysium, epimysium,
tendon, and aponeurosis.
Endomysium
• Connective tissue sheath
that encloses each muscle
fiber
perimysium
• Coarse fibrous membrane
that encloses several
sheathed muscle fibers /
surrounds a bundle of
fibers called a fascicle
Epimysium
• Tough, outer covering that
bind together many fascicles;
covers the entire muscles and
blends into the tendons or
aponeuroses; covered with
fascia
Both connect muscles indirectly to
bones, cartilages, or connective tissue
coverings
Tendons
• Cordlike
• Provide
durability
&
conserve
space
Aponeuroses
• sheetlike
A skeletal muscle is composed of a variety of tissues
Muscle
Bone
Fascicles
Tendon
Muscle fibers (cells)
Fascia
(covering muscle)
Myofibrils
Epimysium
Perimysium
Thick and thin filaments
Endomysium
Fascicle
Axon of motor
neuron
Blood vessel
Myofibril
Nucleus
Sarcoplasmic
reticulum
Filaments
Muscle fiber
Sarcolemma
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
4. Describe the
microscopic structure of
skeletal muscle and
explain the role of actinand myosin-containing
myofilaments
• Sarcolemma—specialized plasma membrane
• Myofibrils—long organelles inside muscle cell
• Sarcoplasmic reticulum—specialized smooth
endoplasmic reticulum
• Myofibrils are aligned to give distinct bands
–I band = light band
• Contains only thin filaments
–A band = dark band
• Contains the entire length of the thick
filaments
• Sarcomere—contractile unit of a
muscle fiber
• Organization of the sarcomere
–Myofilaments
•Thick filaments = myosin
filaments
•Thin filaments = actin filaments
• Thick filaments = myosin filaments
–Composed of the protein myosin
–Has ATPase enzymes
–Myosin filaments have heads
(extensions, or cross bridges)
–Myosin and actin overlap somewhat
• Thin filaments = actin filaments
–Composed of the protein actin
–Anchored to the Z disc
• At rest, there is a bare zone that lacks actin
filaments called the H zone
• Sarcoplasmic reticulum (SR)
– Stores and releases calcium
– Surrounds the myofibril
Extra Credit
•
•
•
•
Due Wednesday, November 18, 3015
Make a model of skeletal muscle
Use Figure 6.1 as a guide
Must label
–
–
–
–
–
–
Muscle fiber (cell)
Fascicle
Perimysium
Endomysium
Epimysium
fascia
Homework
•watch 5 videos on the
Sliding Filament Theory
of Muscle Contraction