Chapter 7: Muscular System Flashcards
- set of tissues in the body with the ability to change shape
- produces body movements, maintains posture, and produces body heat
Muscular System
Functions of Muscular System
- Movement of the Body
- Maintenance of Posture
- Respiration
- Production of Body Heat
- Communication
- Constriction of Organs and Vessels
General Properties of Muscle Tissue
- Contractility
- Excitability
- Extensibility
- Elasticity
also called as striated muscle because transverse bands/striations can be seen in the muscle under the microscope
Skeletal Muscle
3 Connective Tissue Coverings of Muscle
- Epimysium
- Perimysium
- Endomysium
connective tissue sheath that surrounds each skeletal muscle
Epimysium
loose connective tissue that separates muscle fascicles from each other
Perimysium
loose connective tissue that surrounds each muscle fiber
Endomysium
Muscle Fiber Structures
- Sarcolemma
- Transverse tubules, or T tubules
- Sarcoplasmic Reticulum
- Sarcoplasm
- Myofibrils
cell membrane of the muscle fiber
Sarcolemma
many tubelike inward folds in the sarcolemma, located along the surface of the muscle fiber
Transverse tubules or T tubules
an enlarged portion of the smooth ER that is associated in T tubules
Sarcoplasmic Reticulum
cytoplasm of a muscle fiber
Sarcoplasm
bundles of protein filaments in the sarcoplasm
Myofibrils
basic structural and functional unit of the skeletal muscle and the smallest portion of a skeletal muscle capable of contracting
Sarcomeres
separates one sarcomere from the next and a network of protein fibers that forms a stationary anchor for actin myofilaments to attach
Z-disks
- dark
- consists of an overlap between actin and myosin myofilaments
- extends length of myosin myofilaments
- stays same size during contraction
A-band
- Light
- consists of actin myofilaments only
- decrease in size during contraction
- spans each Z disk and ends at myosin myofilaments
I-band
- smaller, lighter staining regioon in the center of each A band
- contains only myosin myofilaments
H-zone
consists of fine protein filaments that anchor the myosin myofilaments in place
M-line
- thin filaments
- consists of actin, troponin, and tropomyosin
Actin
binding sites for calcium ions
Troponin
block myosin myofilament binding sites on actin myofilament in an unstimulated muscle
Tropomyosin
thick filaments and resembles bundles of tiny golf clubs
Myosin
highly specialized, electrically excitable cells that are polarized which creates an electrical charge difference across the cell membrane
Muscle Fibers