Questions and Answers
In anatomy, a muscle cell is referred to as a muscle _____
fiber
The _____ filament theory explains how muscle fibers shorten during contraction.
sliding
The muscle fibers in a circular muscle are _____ arranged around an opening or recess.
concentrically
What are the functions of muscle fibers?
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What is the function of the sarcolemma?
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What is the function of the sarcoplasm?
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What is the function of sarcoplasmic?
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What are T-tubules responsible for?
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What are the 3 main types of muscle in the body?
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The epimysium of a muscle surrounds the _____.
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After stimulation of ACh receptors, a muscle impulse spreads quickly along the _____ and into the muscle fiber along the T-tubules.
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Minimus refers to the _____ muscle.
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Medius refers to the _____ muscle.
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Maximus refers to the _____ muscle.
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Vastus refers to a muscle that is _____ than others.
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Major refers to the _____ of two muscles.
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The plasma membrane of a skeletal muscle fiber is called the _____.
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What are fascicles?
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What is a muscle fiber?
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What are myofibrils?
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What are myofilaments?
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The process of shortening of muscle cells is called _____.
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What are the three main types of skeletal muscle actions?
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The less mobile attachment of a muscle is called its _____.
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What influences the speed, range, and force of movement?
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Muscle contraction begins when a _____ impulse stimulates an impulse in a muscle fiber.
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The cytoplasm of a skeletal muscle cell is referred to as a _____.
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Two types of muscle contraction are: a.____ contraction (when a muscle contracts but does NOT change length) and b._____ contraction (when muscle contracts and does change length).
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Each _____ shortens as the muscle fiber contracts.
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A single motor neuron typically controls numerous _____ _____ in a muscle.
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What does a large muscle such as the biceps brachii have?
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Although muscle fibers obey the all-or-none principle, the force and precision of muscle movement can be varied, depending on how many _____ and motor units are _____.
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The functional contractile unit of a skeletal muscle fiber is known as a _____.
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Thick filaments are assembled from bundles of the protein called _____.
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What does the M-line serve as?
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What are myofibrils responsible for?
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What is the function of thick filaments?
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What is the function of thin filaments?
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Study Notes
Muscle Cells and Contraction
- A muscle cell is known as a muscle fiber.
- The sliding filament theory explains how muscle fibers shorten during contraction.
- Muscle fibers in circular muscles are arranged concentrically around openings.
Functions of Muscle Components
- Muscle fibers are responsible for metabolic activities and contraction.
- The sarcolemma regulates the entry and exit of materials in muscle cells.
- Sarcoplasm is the site of metabolic processes essential for muscle fiber activities.
- Sarcoplasmic reticulum stores calcium ions necessary for muscle contraction.
Structural Components
- T-tubules transport muscle impulses from the sarcolemma throughout the entire muscle fiber.
- The three main types of muscles in the body are skeletal, cardiac, and smooth.
- The epimysium surrounds the entire skeletal muscle.
- The sarcolemma is the plasma membrane of a skeletal muscle fiber.
- Fascicles refer to bundles of muscle fibers within a muscle.
Muscle Fiber Characteristics
- Muscle fibers are elongated, multinucleated, and cylindrical cells.
- Myofibrils are long, cylindrical contractile elements found within muscle cells.
- There are two types of myofilaments: thick and thin, responsible for contraction.
Muscle Contraction Process
- The process of muscle fibers shortening is called contraction.
- Muscle actions occur through three types: agonists, antagonists, and synergists.
- Muscle contraction begins with a nerve impulse stimulating the muscle fiber.
Muscle Attachments and Mechanics
- The origin of a muscle is its less mobile attachment.
- The attachment's location affects the speed, range, and force of movement.
- Muscle contraction can vary depending on the number of muscle fibers and motor units activated.
Motor Units and Force Generation
- A single motor neuron typically controls numerous muscle fibers.
- Larger muscles, like the biceps brachii, have many motor units, each controlling various fibers.
- Muscle fibers follow the all-or-none principle, where movement force and precision depend on the number of activated fibers and motor units.
Contractile Units and Filaments
- The sarcomere is the functional contractile unit of a skeletal muscle fiber.
- Thick filaments are made from bundles of the protein myosin.
- The M-line serves as an attachment site for thick filaments, keeping them aligned during contraction and relaxation.
- Myofibrils contain myofilaments that are essential for muscle contraction.
- Thick filaments bind to thin filaments to initiate contraction, while thin filaments bind to thick filaments to facilitate the process.
Muscle Contraction Types
- Two types of muscle contraction include:
- Isometric contraction: Muscle contracts but does not change length.
- Isotonic contraction: Muscle contracts and changes length.
Additional Terminology
- Terms such as minimus (smallest), medius (intermediate), maximus (largest), vastus (even larger), and major (largest of two muscles) help classify muscle sizes and characteristics.
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Description
Test your knowledge on muscle cells, their structure, and the mechanisms of contraction. This quiz will cover the sliding filament theory, the role of various muscle components, and the different types of muscle fibers. Perfect for students studying biology or anatomy.
