Chapter 9 Flashcards
what are the three types of muscle tissues?
skeletal, cardiac and smooth
what are the four basic properties of the muscle tissues?
excitability, contractility, extensibility, and elasticity
what are the five functions of skeletal muscle?
produce skeletal movement, maintain posture and body position, support soft tissues, regulate entering and exiting of material, maintain body temperature
what are the three layers of the connective tissue of muscle?
epimysium, perimysium, endomysium
what is the epimysium?
dense irregular connective tissuelayer that surrounds the entire skeletal muscle
what is the perimysium?
divides the muscle into a series of internal compartments.
a bundle of muscle fibers is called?
fascicle
what is the endomysium?
a delicate network of reticular fibers that surrounds each skeletal muscle fiber
what are the two functions of the endomysium?
binds each muscle fiber to its neighbor, supports capillaries that supply individual fibers
what do satellite cells do?
repair damaged muscle tissue that lie between endomysium and the muscle fibers
what are aponeuroses?
think, flattened sheets formed by tendons
sacrolemma
cell membrane
sacroplasm
cytoplasm
what is a myofibril?
cylindical structure that is responsible for skeletal muscle fiber contraction
what are myofilaments?
protein filaments consisting of the proteins actin and myosin
actin filaments are found where?
in thin filaments
myosin filaments are found where?
in thick filaments
actin and myosin filaments are organized into what?
sacromeres
sacroplasmic reticulum is…
a sleeve made up of membranes surrounding each myofibril
sacromeres are the … functional units of the muscle fibers
smallest
thick filaments lie in the center of the sacromere linked by proteins of the…
M line
what are Z lines?
filaments at either end of the sacromere attached to interconnecting proteins and extend toward the m line
what is the zone of overlap?
thin filaments that pass between the thick filaments
what is the A band?
area containing thick filaments
what does the A band include?
the M line, the H band, and the zone of overlap.
what is the I band?
the region between the A band and the Z line and containas oly thin filaments
what does a thin filament contain?
the proteins tropomyosin and troponin
what are the actinins?
open meshwork created by proteins
myosin heads are also known as what?
cross bridges
what is the sliding filament theory?
sliding occurs when the myosin heads of thick filaments bind to active sites on thin filaments
what are the four features of the sliding filament theory?
the H and I band get smaller, the zone of overlap gets larger, Z lines move closer together and the width of the A band remains constant through contraction
what is the immediate trigger of a contraction?
the appearance of free calcium and ions in the sacroplasm
electrical impulses is distributed by what?
transverse tubules that extend deep into the sacroplasm of the muscle fiber
what cocks the myosin head and prepares it for binding to an active site on actin
ATP
describe the axon
extends to the periperphy, to reach the neuromuscular junction of that muscle fiber
what is the synaptic terminal?
expanded tip of the axon at the neuromuscular junction
what are synaptic vesicles?
mitochondria and dmall secretory vesicles
acetylcholine is an example of what?
neurotransmitter
the amount of muscle tension produced depends on what two factors?
the frequency of stimulation and the number of motor units involved
what is the all or none principal?
each muscle fiber either contracts completely or does not contract at all
