Muscle Tissue Study Guide
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Muscle tissue is specialized for contraction, enabling movement, posture maintenance, and heat production in the body. The main properties include:
- Excitability: Ability to respond to stimuli, typically from motor neurons.
- Contractility: Ability to shorten forcefully when stimulated.
- Extensibility: Ability to stretch without being damaged.
- Elasticity: Ability to return to original length after stretching or contracting.
Functions:
- Movement: Muscles produce movement of the body (skeletal), pump blood (cardiac), and move contents through hollow organs (smooth).
- Posture and Stability: Muscles help maintain body posture and stabilize joints.
- Heat Production: Muscle contractions generate heat, which helps regulate body temperature.
- Support of Soft Tissues: Muscles in the abdominal wall support visceral organs.
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Type-Location-Function-Nuclei-Striations-Specialized Structures |
Skeletal | Attached to bones | Voluntary movement of skeleton | Multiple, peripheral | Yes | Neuromuscular junction, motor end plate |
Cardiac | Heart | Pump blood involuntarily | One or two, central | Yes | Intercalated discs, H zone |
Smooth | Walls of hollow organs | Involuntary movement (e.g., digestion) | Single, central | No | Dense bodies |
- Skeletal Muscle: Long, cylindrical fibers with striations. The function is voluntary movement. They are multinucleated and have clear connective tissue coverings (endomysium, perimysium, epimysium).
- Cardiac Muscle: Branched fibers, also striated, with a central nucleus and intercalated discs that enable coordinated contraction of the heart.
- Smooth Muscle: Non-striated with spindle-shaped fibers. Found in the walls of hollow organs such as intestines and blood vessels, involved in involuntary movements.
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- Skeletal Muscle: Long, striated fibers, multiple nuclei at the periphery.
- Cardiac Muscle: Striated, branched fibers with centrally located nuclei and intercalated discs.
- Smooth Muscle: Spindle-shaped cells with no striations and a single, centrally located nucleus.
Look for striations in skeletal and cardiac muscles, intercalated discs in cardiac muscle, and dense bodies in smooth muscle tissue slides.
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- Muscle Organ: Surrounded by the epimysium, it contains bundles of fascicles.
- Fascicle: Surrounded by the perimysium, a fascicle is a bundle of muscle fibers (cells).
- Muscle Fiber (Cell): Each fiber is surrounded by the endomysium and contains many myofibrils.
- Myofibril: Rod-like units inside the muscle fiber that contain sarcomeres.
- Sarcomere: The functional unit of contraction in muscle tissue, containing thick (myosin) and thin (actin) filaments.
On a diagram or model, these structures should be identifiable, with connective tissue coverings and tendons (attachment points) clearly labeled.
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Key parts to label on a diagram or model:
- Muscle fiber (cell): The basic cellular unit of muscle.
- Endomysium: Connective tissue surrounding each muscle fiber.
- Fascicle: A bundle of muscle fibers within a muscle.
- Perimysium: Connective tissue surrounding each fascicle.
- Muscle organ: The entire muscle, covered by epimysium.
- Tendon: Connects muscle to bone, transmitting force.
Muscle Fiber Structures:
- Nuclei: Skeletal muscles have multiple peripheral nuclei; cardiac has 1-2 central nuclei.
- Sarcolemma: The plasma membrane of the muscle cell.
- Sarcoplasmic Reticulum (SR): Specialized smooth endoplasmic reticulum that stores calcium ions.
- Mitochondria: Provide energy for muscle contraction.
- Myofilaments:
- Thin filaments: Composed of actin.
- Thick filaments: Composed of myosin.
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- Skeletal and Cardiac Muscle:
- Transverse (T) Tubules: Invaginations of the sarcolemma that allow electrical impulses to reach deep into the muscle fiber.
- Sarcomere: The repeating structural unit, bounded by Z discs.
- Z Disc: The boundary of each sarcomere.
- I Band: Contains only thin filaments (actin).
- A Band: The region containing thick filaments (myosin) with some overlap of thin filaments.
- M Line: The center of the sarcomere.
- H Zone: The center part of the A band, containing only thick filaments (in both skeletal and cardiac muscle).
Skeletal Muscle Specific:
- Neuromuscular Junction (NMJ): Where the motor neuron contacts the muscle fiber.
- Motor End Plate: The specialized region of the sarcolemma at the NMJ.
- Motor Neuron: Transmits signals from the central nervous system to the muscle fiber.
Cardiac Muscle Specific:
- Intercalated Discs: Specialized junctions between cardiac muscle cells that facilitate synchronized contraction.
Smooth Muscle Specific:
- Dense Bodies: The equivalent of Z discs in smooth muscle, where thin filaments attach.
___________________________________________________________________________
Muscle tissue is specialized for contraction, enabling movement, posture maintenance, and heat production in the body. The main properties include:
- Excitability: Ability to respond to stimuli, typically from motor neurons.
- Contractility: Ability to shorten forcefully when stimulated.
- Extensibility: Ability to stretch without being damaged.
- Elasticity: Ability to return to original length after stretching or contracting.
Functions:
- Movement: Muscles produce movement of the body (skeletal), pump blood (cardiac), and move contents through hollow organs (smooth).
- Posture and Stability: Muscles help maintain body posture and stabilize joints.
- Heat Production: Muscle contractions generate heat, which helps regulate body temperature.
- Support of Soft Tissues: Muscles in the abdominal wall support visceral organs.
___________________________________________________________________________
Type-Location-Function-Nuclei-Striations-Specialized Structures |
Skeletal | Attached to bones | Voluntary movement of skeleton | Multiple, peripheral | Yes | Neuromuscular junction, motor end plate |
Cardiac | Heart | Pump blood involuntarily | One or two, central | Yes | Intercalated discs, H zone |
Smooth | Walls of hollow organs | Involuntary movement (e.g., digestion) | Single, central | No | Dense bodies |
- Skeletal Muscle: Long, cylindrical fibers with striations. The function is voluntary movement. They are multinucleated and have clear connective tissue coverings (endomysium, perimysium, epimysium).
- Cardiac Muscle: Branched fibers, also striated, with a central nucleus and intercalated discs that enable coordinated contraction of the heart.
- Smooth Muscle: Non-striated with spindle-shaped fibers. Found in the walls of hollow organs such as intestines and blood vessels, involved in involuntary movements.
___________________________________________________________________________
- Skeletal Muscle: Long, striated fibers, multiple nuclei at the periphery.
- Cardiac Muscle: Striated, branched fibers with centrally located nuclei and intercalated discs.
- Smooth Muscle: Spindle-shaped cells with no striations and a single, centrally located nucleus.
Look for striations in skeletal and cardiac muscles, intercalated discs in cardiac muscle, and dense bodies in smooth muscle tissue slides.
___________________________________________________________________________
- Muscle Organ: Surrounded by the epimysium, it contains bundles of fascicles.
- Fascicle: Surrounded by the perimysium, a fascicle is a bundle of muscle fibers (cells).
- Muscle Fiber (Cell): Each fiber is surrounded by the endomysium and contains many myofibrils.
- Myofibril: Rod-like units inside the muscle fiber that contain sarcomeres.
- Sarcomere: The functional unit of contraction in muscle tissue, containing thick (myosin) and thin (actin) filaments.
On a diagram or model, these structures should be identifiable, with connective tissue coverings and tendons (attachment points) clearly labeled.
___________________________________________________________________________
Key parts to label on a diagram or model:
- Muscle fiber (cell): The basic cellular unit of muscle.
- Endomysium: Connective tissue surrounding each muscle fiber.
- Fascicle: A bundle of muscle fibers within a muscle.
- Perimysium: Connective tissue surrounding each fascicle.
- Muscle organ: The entire muscle, covered by epimysium.
- Tendon: Connects muscle to bone, transmitting force.
Muscle Fiber Structures:
- Nuclei: Skeletal muscles have multiple peripheral nuclei; cardiac has 1-2 central nuclei.
- Sarcolemma: The plasma membrane of the muscle cell.
- Sarcoplasmic Reticulum (SR): Specialized smooth endoplasmic reticulum that stores calcium ions.
- Mitochondria: Provide energy for muscle contraction.
- Myofilaments:
- Thin filaments: Composed of actin.
- Thick filaments: Composed of myosin.
___________________________________________________________________________
- Skeletal and Cardiac Muscle:
- Transverse (T) Tubules: Invaginations of the sarcolemma that allow electrical impulses to reach deep into the muscle fiber.
- Sarcomere: The repeating structural unit, bounded by Z discs.
- Z Disc: The boundary of each sarcomere.
- I Band: Contains only thin filaments (actin).
- A Band: The region containing thick filaments (myosin) with some overlap of thin filaments.
- M Line: The center of the sarcomere.
- H Zone: The center part of the A band, containing only thick filaments (in both skeletal and cardiac muscle).
Skeletal Muscle Specific:
- Neuromuscular Junction (NMJ): Where the motor neuron contacts the muscle fiber.
- Motor End Plate: The specialized region of the sarcolemma at the NMJ.
- Motor Neuron: Transmits signals from the central nervous system to the muscle fiber.
Cardiac Muscle Specific:
- Intercalated Discs: Specialized junctions between cardiac muscle cells that facilitate synchronized contraction.
Smooth Muscle Specific:
- Dense Bodies: The equivalent of Z discs in smooth muscle, where thin filaments attach.
