Topic 6 & 11: Human Health and
Physiology
11.2 Muscles and Movement
• What do you know?
• What questions do you have?
• How do skeletons and exoskeletons differ?
1 - Anatomy
Read & Consider 11.2.1-11.2.3
Draw, label, & annotate the human
elbow joint:
 Include:
 Bones
 Muscles
 Ligaments
 Synovial joint features
 Tendons
 Cartilage
Synovial Joints
Pubic Symphysis:
Cartilaginous Joint
Skull Suture Joint:
Fibrous Joint
Antagonistic Pairs
 Both bones and
exoskeletons act as
anchors for muscle and
levers for movement
with the use of
antagonistic muscle
pairs.
• What do you know?
• What questions do you have?
• Are all types of muscle the same?
2 – Muscle Cells / Muscle Fibers
Read & Consider 11.2.4-11.2.6
 Muscle fibers (cells) are multinucleated cells that may
shorten to half or one-third of their resting length.
Fibers (cells) are composed of myofibrils contained in a
plasma membrane called the sarcolemma. Cytoplasm
between myofibrils contains mitochondria. Sarcolemma
in-folds to form sarcoplasmic reticulum containing
transverse tubules.
Actin & Myosin
 Myofibrils are composed of interlocking thick and thin
protein filaments.
 Thin filaments – actin – long and about 7nm in diameter. The
are held together by transverse bands called Z lines.
 Thick filaments – myosin – short and about 15nm in diameter.
 Muscles are striped or striated due to the repeating pattern
of actin and myosin filaments.
Draw and label diagrams of
the structure of a sarcomere.
• What do you know?
• What questions do you have?
3 - Contraction
Read & Consider 11.2.7-11.2.9
Sarcomere  Each repeating until of the myofibril (actin and myosin) is
called a sarcomere. From z line to z line.
Contraction:
1.
2.
3.
4.
5.
Action potential arrives at the
neuromuscular junction.
Acetylcholine (neurotransmitter)
released.
Action potential is initiated in the
muscle cell membrane.
T-tubules carry this chemical signal
throughout the muscle.
Signal causes a calcium release
from the sarcoplasmic reticulum
into myofibrils.
Power Stroke
Calcium causes troponin (protein) to remove
tropomyosin exposing cross bridge binding sites.
7. An ATP molecule “charges” the cross bridge
allowing it to react with the neighboring actin
molecule.
8. The use of the ATP molecule triggers a rowing
movement (cross bridge tilts to 45ºn angle)
pushing the actin filament along = power stroke
and shortening the myofibril.
9. The cross bridge then returns to resting position,
is blocked by tropomyosin, and a new ATP
molecule recharges in preparation for the next
contraction.
6.
Diagram
Muscle Contraction
Analysis
Works Cited
 Contracting Muscles. Digital image. Quick 3D Motion. Gizmag, n.d.
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
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Web. 03 Jan. 2015.
Hip Joint. Digital image. WiseGEEK. Conjecture Corporation, n.d.
Web. 03 Jan. 2015.
Human Skeleton. Digital image. Learn: (by Xinixazi). N.p., n.d.
Web. 15 Dec. 2014.
Pubic Symphysis. Digital image. Pix For Pubic Symphysis. Disqus,
n.d.Web. 03 Jan. 2015.
Water Beetle - Exoskeleton. Digital image. Insect Exoskeleton Viewing Gallery. N.p., n.d.Web. 15 Dec. 2014.
Zygote Media Group Inc. Synovial Joint. Digital image. 3D Science
Clip Art. N.p., n.d.Web. 03 Jan. 2015.