Muscle Characteristics Flashcards
What causes contractions and shortening of muscles
Movement of microfilaments
Encloses a single muscle fiber
Endomysium
Wraps around a fascicle of muscle fibers
Perimysium
Covers the entire skeletal muscle
Epimysium
On the outside of the epimysium
Fascia
What can the epimysium blend into
Tendons or aponeuroses
What are tendons made of
Collagen fibers
Why do tendons cross joints
Toughness and small size
What are tendons
Cord like structures that attach muscle to bone
What are aponeuroses
Sheet like structures that attach muscles indirectly
Four basic functions of muscles
Produce movement
Maintain posture
Stabilize joint
Generate heat
All movement come from what
Muscle contraction
To maintain posture what occurs
Tiny adjustments are being made constantly
ATP uses energy to make muscles contract and how much of that is released as heat
3/4
Skeletal muscles account for how much of the body mass
20%
What type of muscle generate s the most heat
Skeletal
Specialized plasma membrane
Sacrolemma
Long organelles inside muscle cells
Myofibrils
Specialized smooth endoplasmic reticulum
Sacroplasmic reticulum
What do Myofibrils look like
They are aligned in a way that makes them look banded
I band
Light band
I band contains what
Thin filaments
A band
Dark band
Dark bands contain what
Thick filaments
Contractile unit of a muscle fiber
Sarcomere
Thick filaments
Myosin
Thin filaments
Actin
What are thin filaments attached to
Z discs
What is special about thick filaments
Have heads
What is the h zone or bare zone
Area where ther is no actin filaments
What is the function of the SR
Stores and releases calcium
Location of the SR
Surrounds the Myofibrils
Other name for a muscle cell
Muscle fiber
