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Questions and Answers
What is the primary function of the trapezius muscle?
What is the primary function of the trapezius muscle?
Which of the following movements decreases the angle between two bones?
Which of the following movements decreases the angle between two bones?
Which type of movement involves turning a bone along its own long axis?
Which type of movement involves turning a bone along its own long axis?
What does the term 'plantar' refer to in terms of foot movement?
What does the term 'plantar' refer to in terms of foot movement?
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Which muscle group includes the biceps femoris and the semitendinosus?
Which muscle group includes the biceps femoris and the semitendinosus?
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What is the primary function of muscle tissue in the body?
What is the primary function of muscle tissue in the body?
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Which structure is responsible for the attachment of muscle to bone?
Which structure is responsible for the attachment of muscle to bone?
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What characteristic of muscle tissue refers to its ability to recoil to its original length after being stretched?
What characteristic of muscle tissue refers to its ability to recoil to its original length after being stretched?
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How do skeletal muscles differ from cardiac muscles in terms of contraction?
How do skeletal muscles differ from cardiac muscles in terms of contraction?
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What is the term for the basic contractile unit within a muscle fiber?
What is the term for the basic contractile unit within a muscle fiber?
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Which of the following accurately describes smooth muscle?
Which of the following accurately describes smooth muscle?
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Which muscle characteristic allows it to respond to stimuli, such as reflexes?
Which muscle characteristic allows it to respond to stimuli, such as reflexes?
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What role do myofilaments play in muscle contraction?
What role do myofilaments play in muscle contraction?
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In the sliding filament theory, what happens to the Z lines during muscle contraction?
In the sliding filament theory, what happens to the Z lines during muscle contraction?
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What is unique about cardiac muscle compared to skeletal muscle?
What is unique about cardiac muscle compared to skeletal muscle?
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Study Notes
Muscle Tissue
- Composed of specialized muscle tissues that contract and relax to create movement.
- Latin word "mus" means "mouse."
- Found throughout the body, under skin, within organs, and blood vessels.
- Muscle size and location influence body shape and movement.
- Functions: movement, shape, stabilize position, produce heat, maintain homeostasis.
- Characteristics:
- Contractility: ability to shorten.
- Excitability: capacity to respond to a stimulus (reflexes).
- Extensibility: stretch beyond resting length and still contract.
- Elasticity: recoil to resting length after stretching.
- Types:
- Skeletal Muscle:
- Strong, fast, voluntary contractions.
- Striations, multiple nuclei, attached to skeleton.
- Cardiac Muscle:
- Strong, continuous, involuntary contractions.
- Intercalated disks, single nuclei, heart walls.
- Smooth Muscle:
- Weak, slow, involuntary contractions.
- No striations, single nuclei, walls of hollow organs.
- Tendons: connect muscles to bones.
- Skeletal Muscle:
Anatomy of Skeletal Muscle
- Epimysium: connective tissue surrounding the entire muscle.
- Perimysium: connective tissue surrounding fascicles (bundles of muscle fibers).
- Endomysium: connective tissue surrounding individual muscle cells (fibers).
- Myofibrils: threadlike structures within muscle fibers containing contractile proteins.
- Myosin: thick filaments, bind to ATP and actin. Myosin head is crucial for separation.
- Actin: thin filaments, bound with troponin and tropomyosin. Troponin and tropomyosin cannot bind
- Sarcomere: repeating unit of thick and thin filaments, basic contractile unit.
- Z Line: actin attachment, sarcomere boundary.
- M Line: myosin attachment.
- A Band: Myosin and actin overlap.
- H Zone and I Band: spaces that shorten during contraction.
- Sarcoplasm: muscle cell cytoplasm.
- Sarcoplasmic Reticulum: muscle cell's smooth endoplasmic reticulum.
- Sarcolemma: muscle cell membrane.
Sliding Filament Theory
- Z lines move closer.
- Mechanism by which sarcomeres shorten during contraction.
Posterior Muscle Group
- Trapezius
- Triceps brachii
- Latissimus dorsi
- Gluteus maximus
- Hamstrings (Biceps femoris, Semitendinosus, Semimembranosus)
- Gastrocnemius
- Soleus
- Erector spinae
Types of Motion
- Gliding: one flat bone slides over another.
-
Angular: increase/decrease angle between bones
- Flexion: decrease angle.
- Extension: increase angle.
- Hyperextension: excess extension.
- Dorsiflexion (foot): lift the foot upward.
- Plantarflexion (foot): point the foot downward.
- Abduction: move limb away from body.
- Adduction: move limb towards body.
- Circumduction: limb moves in a circle.
-
Rotation: turning around long axis.
- Lateral: outwards
- Medial: inwards
-
Special:
- Supination: radius rotates around ulna (palm faces up).
- Pronation: radius rotates around ulna (palm faces down).
- Inversion: sole of foot turns inward.
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Description
Explore the fascinating world of muscle tissue, including its composition, functions, and types. Learn about the unique characteristics of skeletal, cardiac, and smooth muscles that enable movement and maintain bodily functions. Understand how muscle structure influences body shape and motion.
