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Questions and Answers
What type of muscle tissue is primarily responsible for producing body movements and is under voluntary control?
What type of muscle tissue is primarily responsible for producing body movements and is under voluntary control?
- Connective muscle tissue
- Skeletal muscle tissue (correct)
- Smooth muscle tissue
- Cardiac muscle tissue
Which muscle tissue is found only in the heart and is not under voluntary control?
Which muscle tissue is found only in the heart and is not under voluntary control?
- Cardiac muscle tissue (correct)
- Striated muscle tissue
- Skeletal muscle tissue
- Smooth muscle tissue
Which characteristic distinguishes smooth muscle tissue from the other types of muscle tissues?
Which characteristic distinguishes smooth muscle tissue from the other types of muscle tissues?
- It has multiple nuclei.
- It is voluntary.
- It is non-striated. (correct)
- It is striated.
Which of the following statements accurately describes skeletal muscle fibers?
Which of the following statements accurately describes skeletal muscle fibers?
What is the primary function of the muscular system related to internal body activities?
What is the primary function of the muscular system related to internal body activities?
Identify a function of smooth muscle tissue.
Identify a function of smooth muscle tissue.
Which component is NOT found in skeletal muscle tissue?
Which component is NOT found in skeletal muscle tissue?
What characteristic of cardiac muscle cells contributes to their involuntary function?
What characteristic of cardiac muscle cells contributes to their involuntary function?
What initiates the muscle action potential at the motor end plate?
What initiates the muscle action potential at the motor end plate?
What role does acetylcholinesterase play in muscle contraction?
What role does acetylcholinesterase play in muscle contraction?
What happens after calcium ions enter the sarcoplasm?
What happens after calcium ions enter the sarcoplasm?
What is the final result of calcium release and muscle contraction?
What is the final result of calcium release and muscle contraction?
Which process occurs to ensure calcium levels return to a resting state after contraction?
Which process occurs to ensure calcium levels return to a resting state after contraction?
What is the role of the transverse tubule in muscle contraction?
What is the role of the transverse tubule in muscle contraction?
Which ion is crucial for exposing the binding sites on actin during muscle contraction?
Which ion is crucial for exposing the binding sites on actin during muscle contraction?
What prevents muscle contraction from continuing indefinitely?
What prevents muscle contraction from continuing indefinitely?
What primarily determines the amount of tension produced by muscle fibers?
What primarily determines the amount of tension produced by muscle fibers?
Which phase is NOT part of a muscle twitch?
Which phase is NOT part of a muscle twitch?
What is the result of incomplete tetanus?
What is the result of incomplete tetanus?
How does the size of motor units affect muscle contraction?
How does the size of motor units affect muscle contraction?
What primarily causes muscle fatigue during intense activity?
What primarily causes muscle fatigue during intense activity?
Which type of muscle contraction results in the muscle length remaining constant?
Which type of muscle contraction results in the muscle length remaining constant?
What speeds up the contraction time of muscle fibers?
What speeds up the contraction time of muscle fibers?
What is one characteristic of slow fibers compared to fast fibers?
What is one characteristic of slow fibers compared to fast fibers?
Which type of muscle is characterized as 'white muscle'?
Which type of muscle is characterized as 'white muscle'?
What physiological change does training induce in muscle fibers?
What physiological change does training induce in muscle fibers?
What initiates the series of steps for muscle contraction?
What initiates the series of steps for muscle contraction?
What happens after calcium binds to troponin during muscle contraction?
What happens after calcium binds to troponin during muscle contraction?
Which component is essential for the recovery stroke in muscle contraction?
Which component is essential for the recovery stroke in muscle contraction?
What is the primary role of acetylcholinesterase in muscle contraction?
What is the primary role of acetylcholinesterase in muscle contraction?
Which sequence correctly represents the steps in muscle contraction after an action potential?
Which sequence correctly represents the steps in muscle contraction after an action potential?
What happens during the power stroke of muscle contraction?
What happens during the power stroke of muscle contraction?
How does ATP relate to the muscle contraction cycle?
How does ATP relate to the muscle contraction cycle?
Which part of the muscle fiber contains the thick and thin filaments involved in contraction?
Which part of the muscle fiber contains the thick and thin filaments involved in contraction?
What is the role of calcium in the sliding filament theory?
What is the role of calcium in the sliding filament theory?
What is the primary function of the T-tubule in muscle contraction?
What is the primary function of the T-tubule in muscle contraction?
What is the primary function of pacemaker cells in the heart?
What is the primary function of pacemaker cells in the heart?
Which type of muscle tissue is under involuntary control?
Which type of muscle tissue is under involuntary control?
What surrounds individual muscle fibers in skeletal muscle?
What surrounds individual muscle fibers in skeletal muscle?
The thick and thin filaments in muscle fibers are primarily made up of which proteins?
The thick and thin filaments in muscle fibers are primarily made up of which proteins?
What initiates the muscle fiber contraction process?
What initiates the muscle fiber contraction process?
What is the role of calcium ions in muscle contraction?
What is the role of calcium ions in muscle contraction?
Which structure serves as the attachment point for muscles to bones?
Which structure serves as the attachment point for muscles to bones?
What is the main role of skeletal muscle in the body?
What is the main role of skeletal muscle in the body?
What is the sarcolemma identified as?
What is the sarcolemma identified as?
Which structure is responsible for the storage of calcium in muscle cells?
Which structure is responsible for the storage of calcium in muscle cells?
What happens to acetylcholine after it has stimulated a muscle action potential?
What happens to acetylcholine after it has stimulated a muscle action potential?
Which muscle tissue type is not striated?
Which muscle tissue type is not striated?
Which of the following best describes the primary function of smooth muscle?
Which of the following best describes the primary function of smooth muscle?
Flashcards
Skeletal muscle tissue
Skeletal muscle tissue
The most abundant tissue in the human body, responsible for movement, it is under our conscious control.
Cardiac muscle tissue
Cardiac muscle tissue
Found only in the heart, this muscle tissue is responsible for pumping blood throughout the body.
Smooth muscle tissue
Smooth muscle tissue
Found in internal organs like the stomach and intestines, this muscle tissue helps move substances through the body.
Skeletal muscle fiber
Skeletal muscle fiber
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Neuromuscular junction
Neuromuscular junction
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Muscle contraction
Muscle contraction
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Muscle relaxation
Muscle relaxation
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Neuron
Neuron
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Pacemaker Cells
Pacemaker Cells
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Smooth Muscle
Smooth Muscle
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Cardiac Muscle
Cardiac Muscle
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Skeletal Muscle
Skeletal Muscle
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Epimysium
Epimysium
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Perimysium
Perimysium
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Endomysium
Endomysium
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Sarcolemma
Sarcolemma
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Sarcoplasm
Sarcoplasm
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Sarcoplasmic Reticulum
Sarcoplasmic Reticulum
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Sarcomere
Sarcomere
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Thin Filament
Thin Filament
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Thick Filament
Thick Filament
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Acetylcholine (ACh)
Acetylcholine (ACh)
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Motor end plate
Motor end plate
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Action potential (AP)
Action potential (AP)
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Troponin
Troponin
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Tropomyosin
Tropomyosin
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Transverse tubule (T-tubule)
Transverse tubule (T-tubule)
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Sliding Filament Theory
Sliding Filament Theory
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Myosin
Myosin
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Actin
Actin
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Tension production
Tension production
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Twitch
Twitch
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Summation
Summation
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Motor Unit
Motor Unit
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Recruitment
Recruitment
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Muscle Fatigue
Muscle Fatigue
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Isometric Contraction
Isometric Contraction
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Isotonic Contraction
Isotonic Contraction
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Fast Fibers (Type II Myosin)
Fast Fibers (Type II Myosin)
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Slow Fibers (Type I Myosin)
Slow Fibers (Type I Myosin)
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Study Notes
Musculoskeletal System (Part 2)
- Learning Outcomes: Students will be able to list muscle types and characteristics, understand action potential mechanisms, identify components of neuromuscular junctions, and learn about muscle contraction/relaxation.
- Functions of the Muscular System:
- Produce body movements.
- Stabilize body positions.
- Move substances within the body.
- Produce heat.
- Support soft tissue.
- Guard body entrances and exits.
- Provide nutrient reserves.
- Types of Muscle Tissues:
- Skeletal muscle tissue: Primarily attached to bones, striated, and voluntary.
- Cardiac muscle tissue: Forms the heart walls, striated, and involuntary.
- Smooth muscle tissue: Located primarily in internal organs, non-striated (smooth), and involuntary.
- Skeletal Muscle Tissue Details:
- The most abundant tissue in the human body.
- Under voluntary control.
- Contains skeletal muscle cells, connective tissues, blood vessels, and nerves.
- Each skeletal muscle cell is called a skeletal muscle fiber.
- Each skeletal muscle fiber is long, cylindrical, contains many nuclei, and is striated (alternating light and dark bands).
- Skeletal muscle fibers bind together with connective tissue, nerves, and blood vessels to form bundles.
- These bundles form muscles.
- Cardiac Muscle Tissue Details:
- Only found in the heart.
- Composed of cardiac muscle cells (cardiocytes).
- Striated.
- Usually contains a single, centrally located nucleus.
- Not under voluntary control.
- A bundle of specialized cells (pacemaker cells) in the upper heart sends electrical signals, causing rhythmic contraction and blood pumping.
- Smooth Muscle Tissue Details:
- Found in many internal organs (abdomen, intestines) and blood vessel walls
- Spindle-shaped with a single nucleus.
- Not striated.
- Not under voluntary control.
- Its contractions move food through the digestive tract, control blood flow, and change pupil size in response to light.
Skeletal Muscle Tissue Organization
- Epimysium: Surrounds the entire muscle.
- Perimysium: Sheathes bundles of muscle fibers (fascicles).
- Perimysium and epimysium contain blood vessels and nerves.
- Endomysium: Covers individual muscle fibers.
- Tendons: Attach muscles to bones or other muscles.
Skeletal Muscle Fiber Structure
- Sarcolemma (cell membrane).
- Sarcoplasm (muscle cell cytoplasm).
- Sarcoplasmic Reticulum (modified ER) with high calcium concentration.
- T-tubules and myofibrils aid in contraction.
- Sarcomeres: Regular arrangement of myofibrils.
Muscle Fiber Components
- Myofibrils: Bundles of protein filaments (actin and myosin).
- Actin: Thin filaments.
- Tropomyosin: Covers active sites on actin.
- Troponin: Binds to G-actin and holds tropomyosin in place.
- Myosin: Thick filaments.
- Myosin heads form cross-bridges during contraction.
- Interactions between actin and myosin prevented by tropomyosin when not contracting.
Muscle Contraction Mechanics
- Created when muscles contract.
- Series of steps starting with excitation at the neuromuscular junction..
- Action potential triggers calcium release from the sarcoplasmic reticulum.
- Thick/thin filament interaction causing muscle fiber contraction.
Sliding Filament Theory
- Thick and thin filaments slide past each other during contraction.
- Cyclic process begins with calcium release from the sarcoplasmic reticulum.
- Calcium binds to troponin.
- Troponin moves, exposing actin active site.
- Myosin head forms cross-bridge and bends toward H zone.
- ATP allows release of cross-bridge.
Muscle Relaxation
- Acetylcholinesterase breaks down acetylcholine (ACh).
- Limits the duration of contraction.
Tension Production by Muscle Fibers
- Amount of tension depends on the number of cross-bridges formed.
- Skeletal muscle contracts most forcefully over a narrow range of resting lengths.
- Twitch: Contraction and relaxation of muscle in response to a stimulus (lag, contraction, relaxation phases).
Summation
- Repeated stimulation before the relaxation phase has been completed results in wave summation (one twitch added to another.)
- Incomplete tetanus = muscle never relaxes completely.
- Complete tetanus = relaxation phase entirely eliminated.
Motor Units and Recruitment
- Motor units consist of a motor neuron and the muscle fibres it stimulates.
- A motor neuron usually makes contact with about 150 muscle fibers.
- Control of precise movements consists of many small motor units.
- Muscles that control voice production have few muscle fibers per motor unit, while those for eye movements have more, and limbs have the largest (2000-3000).
Muscle Fatigue
- Muscle fibers use ATP faster than they produce it, resulting in weaker contractions.
- New ATP binding is needed to break the cross-bridge.
- Examples: Muscle cramps, Rigor mortis (muscle stiffness after death).
Types of Muscle Contractions
- Isometric: Tension rises, length remains constant.
- Isotonic: Tension rises, length changes (concentric & eccentric).
Muscle Performance
- Fast fibers (II myosin): large, powerful, fast contractions, fatigue quickly, abundant myofibrils & glycogen (white muscle)
- Slow fibers (I myosin): endurance, half the diameter of fast fibers, take longer to contract but resist fatigue, greater capillary & mitochondrial density (red muscle)
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Description
Test your knowledge of the muscular system with this quiz covering muscle types, functions, and characteristics. From skeletal to smooth and cardiac muscle, assess your understanding of how these tissues contribute to body movements and internal functions.
