Chapter 10 Flashcards
skeletal muscle
muscle that covers bone. striated and voluntary
cardiac muscle
heart, striated, involuntary
smooth muscle
hollow visceral organs, non-striated and involuntary
7 skeletal functions
movement, posture, supports soft tissues, stabilizing joints, guards opening, generate heat, stores nutrients
muscle fibers
muscle cells thousands of which make up a muscle
epimysium
dense layer of collagen that surrounds the entire muscle; connects to deep fascia
perimysium
divides muscles into compartments; within each is a fascicle (a bundle of muscle fibers)
endomysium
surrounds individual muscle fibers; flexible, elastic connective tissue contains: capillaries, nerve fibers and myosatellite cells
These three layers fuse at the end of a muscle to create a tendon or aponeurosis that attaches to a bone
tendons, origin, insertion
tendons
fibrous connective tissue that merges with the periosteum of bones, connects muscles to bones or other muscles
origin
immobile bone muscle attachment
insertion
moveable bone muscle attachment, it always moves toward the origin
Muscle cells are extremely ____ and ____?
large
multinucleate
Myoblasts
primitive muscle cells that fuse during development contributing to the large size and multinuclea features
Myosatellite
myoblast cells that have NOT fused and are found in adult muscle tissue. they are stem cells that aid in muscle repair
Sarcolemma
muscle cell membrane
Sarcoplasm
the cytoplasm of a muscle cell
T-Tubules
(transverse tubules
extensions of the sarcolemma that run deep into the muscle cell so that an action potential can effectively depolarize a muscle cell quickly/completly
Myofibrils
cylindrical structures within a muscle fiber that contain proteins responsible for contraction. 100-1000 in ea. cell, they run the length of the cell and attach at the ends to a tendon
myofillaments
bundles of protein filaments within myofibrils, they contain; actin, myosin and titin
Actin
a THIN protein filament
contains myosin binding sites to aid in contraction; also contains troponin and tropomyosin
Myosin
a THICK protein filament. contains a myosin head which interacts with the thin filament
High amounts of ____ and ____ are found scattered among the myofibrils for high ____ production
glycongen, mitochondria, energy
Sarcoplasmic reticulum
a modified form of the ER found in muscle cells
The SR is a reservoir for calcium ions that can be released into sarcoplasm to stimulate contraction
Terminal Cisternae
expanded chambers that form when sarcoplasmic reticulum fuse
Triad
a combo of a pair of terminal cistern and a t-tubule
Sarcomeres***
know figure 10-4 and 10-5!
this is the FUNCTIONAL unit of the muscle, a chain of smaller contractile units within myofibril
A bands
the DARK bands found at the center of ea. sarcomere
M line
found in the MIDDLE of the A band; connect nerighboring thick filaments
H band
a lighter region on either side of the M line; contains thick filaments but no thin filaments
Zone of overlap (fig. 10-5)
dark region where thin filaments and thick filaments overlap; 3 thick filaments surround ea. thin filament and 6 thin filaments surround ea. thick filament
I bands
light bands containing thin filaments only and extend from the A band of one sarcomere to the A band of the next
Z line
protein discs that are the end lines of a sarcomere and interconnect thin filaments of adjacent sarcomeres; actin (thin) attach to the Z line on ea. end of the sarcomere; Z lines give striates muscle its stripes
Titin
elastic protein strands that anchor myosin to the Z line; inhibits muscles from stretching too far (stretch and recoil)
Troponin and Tropomyosin
inhibitory proteins that prevent actin from sliding with myosin
neuromuscular junction
where the motor neuron terminates on the muscle fiber; ea. muscle fiber has its own neruromuscular junction that controls it