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Nervous System Part V: Interacionts with the Muscular System TEACHER NOTES needs coding
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Nervous System: Part V
Interactions With The Muscular System
Enduring Understanding 4.A.4.b
Interactions among systems
• Interactions and coordination
between systems provide essential
biological activities
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The nervous and muscular system may not be
specifically tested on the AP Biology Exam but
have been chosen as the pair of systems that can
clearly demonstrate functions of the nervous
system which ARE on the Exam. See Learning
Objectives 3.43 through 3.50 and 4.10.
–Illustrative example:
• Nervous and muscular
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• The contraction of a
muscle is a typical
response generated by
the nervous system.
• Muscle contraction
demonstrates the
interdependence of the
nervous and muscle
systems.
Today we will consider a very specific
mechanism for a RESPONSE generated by the
nervous system: Muscle contraction. We will
learn how a muscle contracts when stimulated by
a chemical signal.
organ
tissue
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Describe the system to cell hierarchy.
cell
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Nervous System Part V: Interacionts with the Muscular System TEACHER NOTES needs coding
Arrange These In A Decreasing Hierarchy:
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Muscle
Muscle fiber cell
Actin
Myofibril
Muscle fibers in bundle
Sarcomere
Myosin
Answers follow on next slide…
CORRECTLY Arranged Into a Hierarchy:
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•
•
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Muscle
Muscle fibers in bundle
Muscle fiber cell
Myofibril
Sarcomere
Myosin
Actin
• What noticeable
difference do you see
in the relaxed and
contracted
sarcomere?
What noticeable difference do you see in the
relaxed and contracted sarcomere? (contracted is
shorted) The components don’t change size. Just
their position relative to each other changes.
They stack up like a deck of cards.
In the extended state, the thin and thick filaments
are spread apart from each other.
Nervous System Part V: Interacionts with the Muscular System TEACHER NOTES needs coding
In the contracted state the thin and thick
filaments slide toward each other, stacking up
and shortening the sarcomere.
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Now lets examine
contraction on a
molecular level.
To begin the animation, scroll across the bottom
of the picture and press play.
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The process of contraction requires the input of
ATP to “reset” the myosin head of the thick
filament. This is why muscles consume large
amounts of energy.
Nervous System Part V: Interacionts with the Muscular System TEACHER NOTES needs coding
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Nervous System Part V: Interacionts with the Muscular System TEACHER NOTES needs coding
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Ask them to think about what they would say if
they were narrating this video clip.
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Point out that the contraction requires the
presence of calcium ions to expose the myosin
binding sites.
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• The arrival of
the action
potential
causes the
sarcoplasmic
reticulum to
release calcium
All of this action is stimulated by the arrival of
the action potential from the motor neuron! Take
some time to tie together the nervous system’s
role in stimulating the contraction.
This image shows how you can have a graded
response, contracting a muscle a little or a lot.
The more motor units that receive the stimulus,
the more contracted the muscle will become.
Nervous System Part V: Interacionts with the Muscular System TEACHER NOTES needs coding
Created by:
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Debra Richards
Coordinator of Secondary Science Programs
Bryan ISD
Bryan, TX