Download Preface Each action we complete in a given day, from brushing our

LESSON 4.2 MUSCLES KEY TERMS & ESSENTIAL QUESTIONS
Preface
Each action we complete in a given day, from brushing our teeth to walking the dog, comes down to the
organization and action of the amazing human tissue called muscle. We bend. We stretch. We push our
bodies to the limit and although they may get tired, our muscles rarely fail us. These muscles work in
coordinated groups with our bones at joints, allowing us to interact with the world. In this lesson, students
will explore the structure and function of skeletal muscle tissue. Students will expand their knowledge of
joints and movement by investigating just how it is that muscle is able to pull on bone.
In this lesson students will examine the three types of muscle tissue under a microscope and describe key
differences in structure and function. Students will focus on skeletal muscle in this lesson, but will further
investigate smooth and cardiac muscle and their relationship to the movement of blood in the next lesson.
By building a spaghetti muscle and clay muscles on the Maniken®, students will begin to see that how a
muscle is structured is directly related to its particular function in the body. Students will follow instructions
to build the muscles of the chest and then will be asked to independently build another muscle group on
their model. They will begin to relate muscle structure to the exercises we choose to tone and strengthen
particular muscle groups.
Students will then explore the actual process of muscle contraction. They will observe contraction of frog
muscle as they administer various salt and ATP solutions. Students will begin to see the requirements for
contraction and will further explore this idea as they create a working model of sarcomere shortening. They
will explain how the thin filaments of actin, troponin, and tropomyosin, interact with the thick filaments of
myosin, as well as calcium and ATP to shorten a sarcomere and contract a muscle. Students will also use
this model to explain the phenomenon of rigor mortis.
Finally, students will build nerves on their Maniken® and see the connection between the nervous system
and the muscles they have built. They will create the nerves that serve the extensor and flexor muscles of
the forearm. Students will also investigate the repetitive motion disorder, carpal tunnel syndrome, and use
their knowledge of nerves to model this disorder on their Maniken®.
Essential Questions
1.
How do muscles assist with movement of the body and of substances around the body?
2.
How do the structure and function of the three types of muscle tissue compare?
3.
How are muscle fibers and membranes organized to form a whole skeletal muscle?
4.
What do skeletal muscle structure and attachment to bones tell you about function?
5.
How are muscles named?
6.
What are the requirements for muscle contraction?
7.
What role do calcium and ATP play in muscle contraction?
8.
What is a sarcomere?
9.
How does a sarcomere contract and lengthen to cause muscle contraction?
10. How is the condition rigor mortis related to muscle contraction?
11. How do nerves interact with muscles?
12. How can we assess muscle function?
Key Terms
Actin
Afferent neurons
Cardiac muscle
Carpal tunnel
syndrome
Contract
Efferent neurons
Endomysium
Epimysium
Fascicle
Insertion
Muscle
Myofibril
Myosin
Nerve
Origin
Perimysium
Plexus
Rigor mortis
Sarcomere
Skeletal muscle
Sliding filament
mechanism
Smooth muscle
Striation
Tropomyosin
Troponin
A contractile protein that is part of the thin filaments in muscle fibers
Nerve cells that carry impulses towards the central nervous system
Striated muscle fibers (cells) that form the wall of the heart; stimulated by the
intrinsic conduction system and autonomic motor neurons
A condition caused by compression of the median nerve in the carpal tunnel
and characterized especially by weakness, pain, and disturbances of sensation
in the hand and fingers
To shorten and thicken
Nerve cells that conduct impulses away from the central nervous system
The delicate connective tissue surrounding the individual muscular fibers within
the smallest bundles
The external connective-tissue sheath of a muscle
A small bundle or cluster, especially of nerve or muscle fibers
The attachment of a muscle tendon to a moveable bone or the end opposite
the origin
An organ composed of one of the three types of muscular tissue (skeletal,
cardiac, and smooth), specialized for contraction to produce voluntary and
involuntary movements of parts of the body
A threadlike structure, extending longitudinally through a muscle fiber (cell)
consisting mainly of think filaments (myosin) and thin filaments (actin, troponin,
and tropomyosin)
The contractile protein that makes up the thick filaments of muscle fibers
A cordlike bundle of neuronal axons and/or dendrites and associated
connective tissue coursing together outside the central nervous system
The attachment of a muscle tendon to a stationary bone or the end opposite
the insertion
The connective-tissue sheath that surrounds a muscle and forms sheaths for
the bundles of muscle fibers
Network of interlacing blood vessels or nerves
Temporary rigidity of muscles occurring after death
Any of the repeating structural units of striated muscle fibrils
An organ specialized for contraction, composed of striated muscle fibers
(cells), supported by connective tissue, attached to bone by a tendon or
aponeurosis, and stimulated by somatic motor neurons
The explanation of how thick and thin filaments slide relative to one another
during striated muscle contraction to decrease sarcomere length
A tissue specialized for contraction, composed of smooth muscle fibers (cells),
located in the walls of hollow internal organs, and innervated by the autonomic
motor neurons
Any of the alternate dark and light cross bands of a myofibril of striated muscle
A protein of muscle that forms a complex with troponin regulating the
interaction of actin and myosin in muscular contraction
A protein of muscle that together with tropomyosin forms a regulatory protein
complex controlling the interaction of actin and myosin and that when
combined with calcium ions permits muscular contraction