Podcast
Questions and Answers
For antagonistic muscle groups to move a limb, flexor contraction occurs coincident with:
For antagonistic muscle groups to move a limb, flexor contraction occurs coincident with:
The function of transverse tubules in skeletal muscles is to:
The function of transverse tubules in skeletal muscles is to:
Most of the time, the parallel thick and thin filaments of the myofibrils are connected by ________.
Most of the time, the parallel thick and thin filaments of the myofibrils are connected by ________.
crossbridges
The function of the titin protein is to:
The function of the titin protein is to:
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The brief period of time between the beginning of the action potential in the muscle and the beginning of contraction is referred to as the:
The brief period of time between the beginning of the action potential in the muscle and the beginning of contraction is referred to as the:
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________ is the backup energy molecule that can be rapidly converted to ATP in active skeletal muscle.
________ is the backup energy molecule that can be rapidly converted to ATP in active skeletal muscle.
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During heavy exercise, the ATP requirements of active muscle are likely to be met by metabolism of:
During heavy exercise, the ATP requirements of active muscle are likely to be met by metabolism of:
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Which of the following is a characteristic of slow-twitch oxidative skeletal muscle fibers?
Which of the following is a characteristic of slow-twitch oxidative skeletal muscle fibers?
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Motor units that control skeletal muscles involved with fine motor movements have ________ muscle fibers.
Motor units that control skeletal muscles involved with fine motor movements have ________ muscle fibers.
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Which fibers generate more force?
Which fibers generate more force?
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A contraction that generates enough force to move a load is known as ________, whereas one that generates force that equals the load is known as ________.
A contraction that generates enough force to move a load is known as ________, whereas one that generates force that equals the load is known as ________.
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Compared to skeletal muscle, contraction of smooth muscle cells is:
Compared to skeletal muscle, contraction of smooth muscle cells is:
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Which protein is activated by the Ca2+-calmodulin complex to phosphorylate the myosin light chain protein?
Which protein is activated by the Ca2+-calmodulin complex to phosphorylate the myosin light chain protein?
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After death, when metabolism stops, in which step of the contractile cycle must skeletal muscles remain?
After death, when metabolism stops, in which step of the contractile cycle must skeletal muscles remain?
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The effector in a reflex is the:
The effector in a reflex is the:
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Identify the FALSE statement.
Identify the FALSE statement.
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Which class of movement can be considered a combination of the other two?
Which class of movement can be considered a combination of the other two?
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Match the structures with the accurate description:
Match the structures with the accurate description:
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The T-tubular membrane contains _____________ receptors that are ______________ and therefore respond to action potentials.
The T-tubular membrane contains _____________ receptors that are ______________ and therefore respond to action potentials.
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Calcium, released by the sarcoplasmic reticulum, binds to _________________ to move the _________________, which allows actin to form a __________________ with myosin.
Calcium, released by the sarcoplasmic reticulum, binds to _________________ to move the _________________, which allows actin to form a __________________ with myosin.
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The heavy chain of myosin contains 2 important regions: the first acts as _________ to convert energy into movement whereas the second binds to _________.
The heavy chain of myosin contains 2 important regions: the first acts as _________ to convert energy into movement whereas the second binds to _________.
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Asynchronous activation of motor units is important because it functions to _______________.
Asynchronous activation of motor units is important because it functions to _______________.
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Autonomic reflexes are also called ______________ reflexes.
Autonomic reflexes are also called ______________ reflexes.
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Rhythmic reflexive motor activities, such as breathing or walking, are controlled by networks of neurons in the central nervous system called _____________________________.
Rhythmic reflexive motor activities, such as breathing or walking, are controlled by networks of neurons in the central nervous system called _____________________________.
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____________ reflexes involve skeletal muscles.
____________ reflexes involve skeletal muscles.
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In a _____________ reflex, a sensory neuron synapses directly on a motor neuron.
In a _____________ reflex, a sensory neuron synapses directly on a motor neuron.
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Muscle spindles are ___________ receptors and cause reflex _________, whereas Golgi tendon organs respond primarily to ___________ and cause a _____________ reflex.
Muscle spindles are ___________ receptors and cause reflex _________, whereas Golgi tendon organs respond primarily to ___________ and cause a _____________ reflex.
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Study Notes
Antagonistic Muscle Action
- Flexor contraction happens simultaneously with relaxation of the extensor to move limbs.
Transverse Tubules Function
- Transverse tubules rapidly conduct action potentials to the interior of skeletal muscle fibers.
Myofibril Structure
- Parallel thick and thin filaments in myofibrils are connected by crossbridges that link myosin and actin.
Titin Protein Role
- Titin stabilizes the position of myosin filaments within the sarcomere structure.
Latent Period
- The latent period is the time between the onset of action potential and the start of muscle contraction.
Energy Sources in Muscle
- Phosphocreatine serves as a backup energy source that can be rapidly converted to ATP in active skeletal muscle.
Muscle Metabolism During Exercise
- During intense exercise, active muscles primarily obtain ATP from the metabolism of carbohydrates.
Characteristics of Muscle Fibers
- Slow-twitch oxidative skeletal muscle fibers exhibit long contraction durations and high capillary density.
Motor Unit Composition
- Motor units controlling fine motor movements have fewer muscle fibers compared to those responsible for gross movements.
Force Generation in Muscle Fibers
- Fast-twitch fibers are capable of generating more force than slow-twitch fibers.
Types of Contraction
- Isotonic contractions generate enough force to move a load, while isometric contractions generate force equal to the load without movement.
Smooth Muscle Contraction
- Smooth muscle cells respond more slowly to stimuli and maintain contraction without fatigue compared to skeletal muscle.
Activation of Myosin Light Chain
- The myosin light chain kinase is activated by the calcium-calmodulin complex and phosphorylates the myosin light chain protein.
Rigor State Post-Mortem
- After death, muscles remain in the rigor state if metabolism halts, preventing muscle relaxation.
Reflex Action Components
- The effector in a reflex arc is typically a muscle or gland that executes the reflex action.
False Statement Identification
- Not all reflexes require input from the brain; some can operate independently.
Rhythmic Movements
- Rhythmic movements are a combination of reflexive and voluntary actions.
Muscle Structure Identification
- Muscle structures include T-tubules (inward extensions), sarcomeres (basic contractile unit), muscle fibers (single muscle cells), sarcolemma (muscle membrane), and fascicles (bundles of muscle cells).
Membrane Receptor Functions
- T-tubular membranes contain voltage-sensing dihydropyridine (DHP) receptors connected mechanically to ryanodine receptors in the sarcoplasmic reticulum.
Calcium and Muscle Interaction
- Calcium binds to troponin C, causing movement of tropomyosin and facilitating the formation of high-force crossbridges with actin.
Myosin Heavy Chain Regions
- The myosin heavy chain has an ATPase region for energy conversion and a binding site for actin.
Motor Unit Activation
- Asynchronous motor unit activation helps to prevent muscular fatigue during prolonged activity.
Types of Reflexes
- Autonomic reflexes are also known as visceral reflexes, while somatic reflexes involve skeletal muscles.
Central Pattern Generators
- Rhythmic reflexive actions, such as walking and breathing, are managed by networks of neurons known as central pattern generators.
Monosynaptic Reflex Definition
- Monosynaptic reflexes involve a direct synapse between a sensory neuron and a motor neuron.
Muscle Receptors and Reflexes
- Muscle spindles act as stretch receptors prompting reflex contraction, while Golgi tendon organs detect tension and promote reflex relaxation.
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Description
Test your knowledge on the muscular system with this quiz based on Module 6. The quiz covers key concepts such as muscle groups, flexor and extensor contractions, and the role of transverse tubules in skeletal muscles. Perfect for students studying human anatomy or physiology.
