Explain how the three different skeletal system types can be used to create locomotion in animals. Can all three skeletal systems be used for locomotion in each environment (water, land, air)? Why or why not?

A new experimental drug is tested in muscle fibers and it is concluded that it blocks the calcium channels in the sarcoplasmic reticulum. Which of the following are expected consequences of the injection of this drug in skeletal muscles?

What happens when the muscular action potential spreads through transverse (T) tubules of the sarcolemma?    The action potential in T tubules triggers the release of acetylcholine from the axon terminals of the motor neuron.   The action potential in T tubules triggers closing of sodium channels and opening of potassium channels, which enables myosin cross bridges to form.   The action potential in T tubules opens voltage-sensitive calcium channels in the T tubules, allowing calcium to flow into the sarcoplasm.   The action potential in T tubules causes a shape change in voltage-sensitive proteins that pull open calcium channels in the sarcoplasmic reticulum.

In what type of muscle would the structure illustrated in the image at right be found? A. The flight muscle of a bumblebee B. The longitudinal muscles underlying the cuticle in C. elegans C. The longitudinal muscles of the vertebrate intestine D. The cardiac muscle of mammals E. None of the above actin filament Dense body Relaxed myosin filament Contracted

What are the steps of the sliding filament model? Select all that apply. Sarcomeres are in a relaxed state, in which myosin-binding sites on actin are blocked. When a nervous signal excites the muscle, myosin-binding sites on actin open up and myosin binds to actin. The myosin heads hydrolyze ATP to ADP and P. The binding of myosin to actin releases phosphate and triggers a power stroke. ATP binds to myosin, and the myosin releases its grip on actin, returning to a relaxed state.

When an action potential arrives at the neuromuscular junction, acetylcholine is released into the synaptic cleft and binds to receptors in the postsynaptic membrane. Which of the following represents the correct order of the next series of events?   A. An action potential travels down the T tubules, depolarization spreads through the T tubules, Ca2+ is released from the sarcoplasmic reticulum, and myosin binds to actin.   B. Ca2+ is released from the sarcoplasmic reticulum, an action potential travels down the T tubules, depolarization spreads through the T tubules, and myosin binds to actin.   C. An action potential travels down the T tubules, depolarization spreads through the T tubules, Ca2+ is taken up by the sarcoplasmic reticulum, and myosin binds to actin.   D. T tubules are depolarized, Ca2+ is released from the sarcoplasmic reticulum, an action potential is created in the muscle cell, and myosin bonds to actin.   E. An action potential travels…

Which of the following statements is true of the chameleon tongue but not of the human tongue? A. It is a muscular hydrostat. B. Force generation reflects the binding of myosin crossbridges to actin thin filaments. C. The organization of the actin and myosin filaments produces a regular pattern of bands, or striations. D. Gaps or holes in the Z-discs allow supercontraction (shortening beyond the normal limit). E. All of the above statements are true of both the chameleon tongue and the human tongue.

Why are opposing curves important when drawing the legs of a character carrying heavy weight on their back? Explain your answer with an image from the web make sure to cite it.

On the molecular level, why does lifting weights consume energy? A. To contract a muscle, acetylcholine binds and pulls calcium ions. ATP binding and hydrolysis are required in the cycle of acetylcholine and calcium-binding and unbinding. B. To contract a muscle, myosin and actin filaments shorten, requiring ATP binding and hydrolysis. O C. To contract a muscle, myosin binds and pulls actin, ATP binding and hydrolysis are required in the cycle of myosin and actin-binding and unbinding. D. To contract a muscle, acetylcholine and calcium filaments shorten, requiring ATP binding and hydrolysis.

Which of the following statements relating to the developmental aspects of muscles is false? a. All muscle tissue types arise from myoblasts b. Skeletal muscles become amitotic while smooth muscles regenerate throughout life c. Sarcopenia begins by age 30 and is irreversible d. Body strength per unit muscle mass is the same in both sexes  e. none of the above   Which of the following structures is located in the head region of the thick filament myosin? a. actin binding site b. ATP binding site c. ATPase enzyme d. all of the above e. none of the above