Muscle Tissue Histology Class Mind Map - PDF

Found in the walls of hollow organs (e.g., intestines, blood...

Found in the walls of hollow organs (e.g., intestines, blood **Smooth Muscle Tissue** vessels). It's involuntary, non-striated, and has spindle-shaped cells Attached to bones, responsible for voluntary movements. It's **Skeletal Striated Muscle Tissue** Always colored pink (since msucles) striated, with long, cylindrical multinucleated cells. Found in the heart, involuntary, striated, and 1. Types of Muscle Tissue **Cardiac Striated Muscle Tissue** interconnected by intercalated discs Muscle growth resulting from an increase in cell Sarcolemma The plasma membrane of a muscle cell size, rather than an increase in cell number. Common in skeletal and cardiac muscle, particularly in response to increased workload **Key Terms**: Sarcoplasm The cytoplasm within muscle fibers (e.g., resistance training or increased cardiac **Hypertrophy**: Increase in cell size demand). The increase in muscle size is due to Sarcoplasmic reticulum – A specialized form of smooth endoplasmic reticulum, in cells the reticulum endoplasmic synthetize Sarcoplasmic Reticulum the enlargement of individual muscle fibers, not important for calcium storage and release during muscle contraction lipids the creation of new fibers. 6. Muscle Growth Muscle growth due to an increase in the Spindle-shaped cells (fusiform) number of muscle cells. **Hyperplasia**: Increase in the number of cells Rare in adults but can occur during (rare in adults) Single, central nucleus development or in certain pathological conditions. **Characteristics**: No visible striation and acidophilic cytoplasm cell covered with External lamina, connected Consists of a fibrous layer and a parietal serous layer, creating a double- permits coordinated contractions Pericardium: by reticular fibers and gap junctions layered sac that encloses the heart, protecting it from friction as it beats. small: 20 µm in blood vessels The outermost layer of the heart, providing protection and anchoring the heart in place. **Fibrous Pericardium**: External covering 2. Smooth Muscle Tissue **Size Variations**: larger: 500 µm in gravid uterus The outer layer of the heart itself, continuous Sarcolemma has numerous pinocytotic vesicles, known as **Epicardium**: Outer layer of the heart **Layers**: with the visceral layer of the serous pericardium. caveolae, involved in calcium regulation and signal transduction The muscular middle layer, composed of cardiac muscle, responsible for the pumping action of the heart. **Myocardium**: Muscular layer Muscle Tissue - The smooth muscle contraction is controlled by autonomic nerve axons that form dilations, containing neurotransmitter vesicles. **Special Features**: The innermost layer, lining the chambers of the 5. Heart Structure Histology Class Mind A diagram shows key molecules involved in **Endocardium**: Inner lining heart and covering the heart valves Map contraction: actin, myosin, Ca²⁺ ions, and calmodulin. Unlike skeletal muscle, smooth Specialized conducting fibers found in the muscle contraction is regulated by a different subendocardial layer. mechanism involving the activation of myosin **Purkinje Fibers** **Associated Structures**: They transmit the electrical impulses that trigger light-chain kinase heart contraction, coordinating the heartbeat. Striated, cylindrical cells Elongated cells with striations Skeletal muscles are multinucleated, with One or two central nuclei nuclei located at the periphery of the cell Extensive network of blood capillaries **Characteristics**: **Characteristics**: Vary in Diameter: 10-100 µm (depends age, nutrition, and physical activity) A lot of connective tissue surrounds the Layer that surrounds each muscle cell= cavities of the cell (endothelium) endomysium (loose connective) Muscle fibers are organized into fascicles, covered by perimysium modified Z line that joins adjacent cells **Fascia Adhaerens**: Actin binding Epimysium= dense connective tissue Prevent separation during the powerful **Desmosomes**: attachment site of **Intercalated Discs**:are crucial for **Actin Filament**: Composed of actin contractions of the heart. intermediate filaments that joins adjacent cells synchronizing contractions 4. Cardiac Striated Muscle Tissue monomers, tropomyosin, and troponin **Gap Junctions**: Electrical coupling for **Myosin Filament**: Myosin molecules with Facilitate the spread of the action potential **Sarcomere Structure**: synchronized contraction globular heads and polypeptide chains Functions as a syncytium via gap junctions Calcium release from the sarcoplasmic reticulum (SR) **Synchronized Contraction**: binds to troponin, allowing myosin heads to bind actin Unvolontary contractions, with rythme and 3. Skeletal Striated Muscle Tissue and generate force through the sliding filament model. synchronization Smooth Muscle Tissue Motor neurons innervate skeletal muscle fibers. Each nerve branches into multiple terminals, and one nerve can control multiple muscle fibers, forming a motor unit **Contraction Mechanism**: Contraction is initiated by acetylcholine release at the neuromuscular junction, which depolarizes the sarcolemma and triggers calcium release from the sarcoplasmic reticulum Slow, continuous contraction Rich in mitochondria, myoglobin, and **Type I (Red/Slow-twitch fibers)**: abundant blood supply resistant to fatigue and are **Muscle Fiber Types**: used for endurance activities Rapid, forceful contraction **Type II (White/Fast-twitch fibers)**: High glycogen content, fewer mitochondria are better suited for short bursts of power Sarcolemma with a large quantity of pinocytosis vesicles in different formation stages – caveolae.