Flashcards
Sarcomere Structure
Flashcards do conjunto (16)
- 1What are the connective tissue layers of skeletal muscle?Epimysium → dense sheath on surface
Perimysium → lies between fascicules
Endomysium → separates muscle fibres - 2Define: SarcolemmaThe cell membrane that encloses a muscle cell
- 3Define: SarcoplasmCytoplasm of muscle cells
→ intracellular fluid that fills the space between myofibrils - 4What are myofibrils mainly comprised of?Actin & myosin
- 5What is a sarcomere?the portion of a myofibril whihc lies between 2 successive Z-discs
- 6What is the protein make-up of thick filaments?Myosin: 1.6 micrometers
Tail = 2 intertwined heavy chains
2 globular heads extend out forming cross-bridges
→ these contain heavy & light chains
→ contain binding site for actin and ATP - 7What are the thin filaments made up of?Actin
Tropomyosin
Troponin - 8What is actin?A contractile protein with a binding site for myosin
- 9Function of tropomyosinRegulatory protein → regulates the activity of actin & myosin and their contractile movements as it blocks binding when in a relaxed state
- 10Function of troponinRegulatory protein
→ forms a complex w/ actin & tropomyosin
→ binds Ca reversibly changing its conformation to pull tropomyosin away from myosin binding site
→ Ca binding to troponin regulates contraction of skeletal muscle - 11What are the structural proteins?Titin - connectin
Z-line protein (alpha-actinin)
M-line proteins (myosin, m-protein)
Nebulin - 12What are the contractile proteins?Actin
Myosin
Tropomyosin
Troponin complex - 13Describe the makeup of the: 1. I band 2. H zone 3. M line 4. A band1. actin filaments bisected by z-line
2. region of A band containing myosin only
3. myosin linked w/ accessory proteins
4. region of overlap BUT primarily myosin - 14—A = Z-line
B = M-line
C = I band
D= H zone
E = A band - 15Describe the structure of T-tubulesWall continuous with sarcolemma
Fluid continuous with external environment - 16What does the junction between the T-tubule and SR involve?2 integral membrane proteins
→ 1 in each of the 2 membranes
→ T-tubule protein = DHPR
→ SR protein = RyR3
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- MD2002 FlashCards sobre Sarcomere Structure, criado por Lareyna Mcmenemy em 09-05-2018.
- Criado por
- Lareyna Mcmenemy
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