Muscles & Muscle Tissue Flashcards
(28 cards)
What are the functions of muscles?
- produce movement of skeleton (pulling on bone)
- maintain posture and body position
- stabilize joints
- generate heat
- nutrient reserve
What is a muscle?
a group of fascicles that work together to cause a specific movement
Whole muscle is surrounded by…
the epimysium
What is a fascicle?
a bundle of muscle fibers
Fascicles are wrapped in…
perimysium
What is a muscle fiber?
it is a multinucleate muscle cell
Muscle fibers are wrapped in…
endomysium
What is the cell membrane called?
Sarcolemma
What are the transverse tubules?
enfolding’s of the sarcolemma that encircle the myofibrils
What are myofibrils?
bundles of myofilaments
What does the sarcoplasmic reticulum do?
wraps each myofibril
What is the cytoplasm called?
sarcoplasm
What are the cisternae?
sac-like structures of the SER (stores calcium)
What is a triad?
T tubule and cisternae junction site
What are myofilaments made of?
actin and myosin
What are glycosomes?
granules of glycogen
What is the mitochondria?
site of oxidative respiration
What is a sarcomere?
contractile unit of a muscle fibril
What does troponin do?
binds calcium
What does tropomyosin do?
covers actin binding sites
Where is calcium stored?
The cisternae
What are the 5 changes in the sarcomere with contraction?
- sarcomere shortens
- Z lines move closer together
- A bands get closer but stay the same width
- I bands get smaller
- H zone gets smaller
Define Isotonic
muscle contraction results in a change in muscle length
Define Isometric
tension forms but no change in muscle length
