CHAPTER 47 Effectors: Making Animals Move
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Transcript of CHAPTER 47 Effectors: Making Animals Move
Chapter 47: Effectors: Making Animals Move
CHAPTER 47Effectors: Making
Animals Move
Chapter 47: Effectors: Making Animals Move
Chapter 47: Effectors: Making Animals MoveEffectorsEffectors
Cilia, Flagella, and Cell MovementCilia, Flagella, and Cell Movement
Muscle ContractionMuscle Contraction
Skeletal Systems Provide Support for Skeletal Systems Provide Support for MusclesMuscles
Other EffectorsOther Effectors
Chapter 47: Effectors: Making Animals Move
Effectors• Effectors enable animals to respond to Effectors enable animals to respond to
information from their internal and information from their internal and external environments. external environments.
• Most effector mechanisms generate Most effector mechanisms generate mechanical forces and cause mechanical forces and cause movement.movement.
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Cilia, Flagella, and Cell Movement• Cell movement is generated by two Cell movement is generated by two
structures, microtubules and structures, microtubules and microfilaments. microfilaments.
• Both consist of long protein molecules Both consist of long protein molecules that can change length or shape.that can change length or shape.
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Cilia, Flagella, and Cell Movement • The movements of cilia and flagella The movements of cilia and flagella
depend on microtubules. depend on microtubules.
Review Figures 47.1, 47.3, 47.4Review Figures 47.1, 47.3, 47.455
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Figure 47.1
Figure 47.1Figure 47.1
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Figure 47.3
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Figure 47.4
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Cilia, Flagella, and Cell Movement • Microfilaments allow animal cells to Microfilaments allow animal cells to
change their shape and move.change their shape and move.99
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Muscle Contraction• The three types of vertebrate muscle The three types of vertebrate muscle
are smooth, cardiac, and skeletal.are smooth, cardiac, and skeletal.1010
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Muscle Contraction • Smooth muscle provides contractile Smooth muscle provides contractile
force for internal organs. force for internal organs. • Smooth muscle cells are electrically Smooth muscle cells are electrically
coupled through gap junctions, so coupled through gap junctions, so action potentials causing contraction action potentials causing contraction spread rapidly throughout the tissue. spread rapidly throughout the tissue.
• Autonomic neurotransmitters alter the Autonomic neurotransmitters alter the membrane potential of smooth muscle membrane potential of smooth muscle cells. cells.
Review Figure 47.6Review Figure 47.61111
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Figure 47.6 – Part 1
Figure 47.6 – Part 1Figure 47.6 – Part 1
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Figure 47.6 – Part 2
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Chapter 47: Effectors: Making Animals Move
Muscle Contraction • The walls of the heart consist of sheets The walls of the heart consist of sheets
of branching cardiac muscle cells. of branching cardiac muscle cells. • The cells are electrically coupled The cells are electrically coupled
through gap junctions, so action through gap junctions, so action potentials spread rapidly throughout potentials spread rapidly throughout sheets of cardiac muscle and cause sheets of cardiac muscle and cause coordinated contractions. coordinated contractions.
• Some are pacemaker cells that Some are pacemaker cells that generate heartbeatgenerate heartbeat
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Muscle Contraction • Skeletal, or striated, muscle consists of Skeletal, or striated, muscle consists of
muscle fiber bundles. muscle fiber bundles. • Each muscle fiber is a huge cell Each muscle fiber is a huge cell
containing multiple nuclei and containing multiple nuclei and numerous myofibrils, which are bundles numerous myofibrils, which are bundles of actin and myosin filaments. of actin and myosin filaments.
• The regular, overlapping arrangement The regular, overlapping arrangement of the filaments into sarcomeres gives of the filaments into sarcomeres gives the muscle a striated appearance. the muscle a striated appearance.
• During contraction, filaments slide past During contraction, filaments slide past each other in a telescoping fashion. each other in a telescoping fashion.
Review Figure 47.7Review Figure 47.71515
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Figure 47.7 – Part 1
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Figure 47.7 – Part 2
Figure 47.7 – Part 2Figure 47.7 – Part 2
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Muscle Contraction • The molecular mechanism of muscle The molecular mechanism of muscle
contraction involves binding of the globular contraction involves binding of the globular heads of myosin molecules to actin. heads of myosin molecules to actin.
• Upon binding, the myosin head changes Upon binding, the myosin head changes conformation, causing the two filaments to conformation, causing the two filaments to move relative to each other. move relative to each other.
• Release of the myosin heads from actin Release of the myosin heads from actin and return to original conformation and return to original conformation requires ATP. requires ATP.
Review Figure 47.8Review Figure 47.81818
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Figure 47.8
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Muscle Contraction • The plasma membrane of the muscle The plasma membrane of the muscle
fiber is continuous with a system of T fiber is continuous with a system of T tubules that extends deep into the tubules that extends deep into the sarcoplasm. sarcoplasm.
Review Figure 47.9Review Figure 47.92020
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Figure 47.9
Figure 47.9Figure 47.9
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Muscle Contraction • When an action potential spreads across the When an action potential spreads across the
plasma membrane and through the T tubules, plasma membrane and through the T tubules, it causes Cait causes Ca2+2+ ions to be released from the ions to be released from the sarcoplasmic reticulum. sarcoplasmic reticulum.
• CaCa2+2+ ions bind to troponin and change its ions bind to troponin and change its conformation, pulling the tropomyosin strands conformation, pulling the tropomyosin strands away from the myosin binding sites on the away from the myosin binding sites on the actin filament. actin filament.
• Cycles of actin–myosin binding and release Cycles of actin–myosin binding and release occur, and the muscle fiber contracts until occur, and the muscle fiber contracts until CaCa2+2+ is returned to the sarcoplasmic is returned to the sarcoplasmic reticulum. reticulum.
Review Figure 47.10Review Figure 47.102222
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Figure 47.10
Figure 47.10Figure 47.10
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Muscle Contraction • In striated muscle, a single action In striated muscle, a single action
potential causes a minimum unit of potential causes a minimum unit of contraction, a twitch. contraction, a twitch.
• Twitches occurring in rapid succession Twitches occurring in rapid succession can be summed, increasing the can be summed, increasing the strength of contraction. strength of contraction.
Review Figure 47.11Review Figure 47.112424
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Figure 47.11
Figure 47.11Figure 47.11
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Muscle Contraction • Slow-twitch muscle fibers are adapted Slow-twitch muscle fibers are adapted
for extended, aerobic work; fast-twitch for extended, aerobic work; fast-twitch fibers for generating maximum forces fibers for generating maximum forces for short periods. for short periods.
• The ratio of slow- to fast-twitch fibers The ratio of slow- to fast-twitch fibers in an individual’s muscle is genetically in an individual’s muscle is genetically determined. determined.
Review Figure 47.12Review Figure 47.122626
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Figure 47.12
Figure 47.12Figure 47.12
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Skeletal Systems Provide Support for Muscles• Skeletal systems provide rigid Skeletal systems provide rigid
supports against which muscles can supports against which muscles can pull.pull.
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Skeletal Systems Provide Support for Muscles • Hydrostatic skeletons are fluid-filled Hydrostatic skeletons are fluid-filled
cavities that can be squeezed by cavities that can be squeezed by muscles. muscles.
Review Figure 47.13Review Figure 47.132929
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Figure 47.13 – Part 1
Figure 47.13 – Part 1Figure 47.13 – Part 1
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Skeletal Systems Provide Support for Muscles• Exoskeletons are hardened outer Exoskeletons are hardened outer
surfaces to which internal muscles are surfaces to which internal muscles are attached. attached.
Review Figure 47.14Review Figure 47.143232
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Figure 47.14
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Skeletal Systems Provide Support for Muscles • Endoskeletons are internal, articulated Endoskeletons are internal, articulated
systems systems • They are composed of rigid rod, plate, They are composed of rigid rod, plate,
and tubelike supports and tubelike supports • These consisting of bone and cartilage These consisting of bone and cartilage
to which muscles are attached. to which muscles are attached.
Review Figure 47.15Review Figure 47.153434
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Figure 47.15
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Skeletal Systems Provide Support for Muscles • Bone is continually being remodeled Bone is continually being remodeled
by osteoblasts, which lay down new by osteoblasts, which lay down new bone, and osteoclasts, which erode bone, and osteoclasts, which erode bone. bone.
Review Figure 47.16Review Figure 47.163636
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Figure 47.16
Figure 47.16Figure 47.16
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Skeletal Systems Provide Support for Muscles • Bones develop from connective tissue Bones develop from connective tissue
membranes or from cartilage through membranes or from cartilage through ossification. ossification.
• Cartilage bone can grow until centers Cartilage bone can grow until centers of ossification meet. of ossification meet.
Review Figure 47.17Review Figure 47.173838
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Figure 47.17
Figure 47.17Figure 47.17
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Skeletal Systems Provide Support for Muscles • Bone can be solid and hard, or it can Bone can be solid and hard, or it can
contain numerous internal spaces.contain numerous internal spaces.4040
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Skeletal Systems Provide Support for Muscles • Tendons connect muscles to bones.Tendons connect muscles to bones.• Ligaments connect bones to each Ligaments connect bones to each
other and help direct forces generated other and help direct forces generated by muscles by holding tendons in by muscles by holding tendons in place. place.
Review Figure Review Figure 47.1947.194141
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Figure 47.19
Figure 47.19Figure 47.19
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Skeletal Systems Provide Support for Muscles • Muscles and bones work together Muscles and bones work together
around joints as systems of levers. around joints as systems of levers.
Review Figures 47.20, 47.21Review Figures 47.20, 47.214343
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Figure 47.20
Figure 47.20Figure 47.20
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Figure 47.21
Figure 47.21Figure 47.21
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Other Effectors• Effector organs other than muscles Effector organs other than muscles
nematocysts nematocysts chromatophores chromatophores glandsglands electric pulses electric pulses
Review Figure Review Figure 47.224646