Muscular System 2 Flashcards
What are the three layers of connective tissue?
Epimysium
Perimysium
Endomysium
What are the main characteristics of skeletal muscle?
Composed of;
-muscle cells (fibres)
-connective tissue,
-blood vessels + nerves
-Long , cylindrical fibres with multiple nuclei
smaller diameter in small muscles
and larger in large muscles.
Develop from myoblasts; numbers remain constant
Striated appearance due to
light and dark banding
What is epimysium?
Layer of connective tissue that surrounds a whole muscle with many fascicles
What is muscle fascicle?
Type of connective tissue
bundle of skeletal muscle fibres surrounded by perimysium, a type of connective tissue.
What is perimysium?
denser layer of connective tissue
surrounds group of muscle fibres
Each group called a fasciculus
What is endomysium?
Loose type of connective tissue layer with reticular fibres
What is muscular fascia?
connective tissue sheet
external to epimysium
holds muscles together and separates them into functional groups
Epimysium + Perimysium + Endomysium = ?
Tendon
what is the sarcolemma?
cell membrane of muscle fibre
how many nuclei sit inside sarcolemma?
several
what are the cells within the cell membrane of a muscle packed with?
myofibrils within sarcoplasm (cell cytoplasm)
what are the main characteristics of the myofibrils within sarcoplasm of sarcolemma?
threadlike
composed of protein threads called myofilaments:
-thin (ACTIN)
-thick (MYOSIN)
sarcomeres - repeated patterns of protein myofilaments - creates striated appearance.
What are the main characteristics of actin (thin) myofilaments?
two strands form double helix extending the length of the myofilament attached at either end at sarcomere
tropomyosin
troponin
tropomyosin/troponin complex regulates the interaction between active sites on actin and myosin
