Muscle I- Skeletal Muscle Structure and Function Flashcards
What are bundles of fascicles called?
Muscles
What do skeletal muscle do?
Apply force to bones to control posture and body movements. Mostly under voluntary control
What does “T” stand for in T-tubules
transverse
How do muscles develop force?
Contracting/ shortening
What 3 proteins are involved with excitation of the muscle cell?
- The voltage gated sensor (DHPR)
- The ryanodine receptor (RyR)
- The SR Calcium- ATPase (SERCA)
What are the two types of myofilaments?
Actin (thin filament)
Myosin (thick filament)
What are fibres, fascicles, and muscles sheathed in?
connective tissue
What is. the cell membrane of the muscle fibre called?
sarcolemma
What is the “thick” myofilament?
myosin
What is the Sarcoplasmic reticulum?
extensive membrane network associated with T-tubules at regular intervals
What is a muscle fibre composed of? What is the answer composed of?
myofibrils- repeating units called sarcomeres
Where are cardiac muscles in the body?
Cardiac muscle is only the heart to generate force to pump blood around body. (not under conscious control)
What is the shortened name for the Ryanodine receptor and what does it do?
- RyR
- acts as a passive calcium channel on the SR that can open to allow calcium ions out into the cell
what is made of actin and myosin?
sarcomeres
Explain the processes that allow relaxation of the muscle to occur
- SERCA senses the rise in intracellular calcium
- It then burns some ATP to produce energy which is then used to pump calcium back into the SR, against concentration gradient
- the removal of calcium ions from the call stops the signalling event and allows the muscles to relax
Explain the processes involved with the “excitement” section of EC coupling
- Signal coming from nerves is transmitted down T tubules
- This signal activates the DHPR which interacts with the RyR, causing them to open
- calcium ions pour out into the cell from SR
- This calcium diffuses through the cell, activating myofilaments and causing contraction
What is the shortened name for the voltage gated sensor and what does it do?
- DHPR
- receives signals from the T tubules and interacts with the ryanodine receptor
What are the tube-like extensions of the sarcolemma called?
T- tubules
What are sarcomeres made of?
contractile proteins called myofilaments
What is EC-coupling?
The pairing of a signalling event ( excitation of muscle cell) with a mechanical event (contraction of the muscle cell)
What are T-tubules?
tube-like extensions of the sarcolemma
What are fascicles?
Bundles of muscle fibres
Is actin the “thick” or “thin” myofilament?
thin
Where are smooth muscles in the body?
Mainly line hollow organs ( not under conscious control)
