Chapter 5 System 3 Muscular System Flashcards
muscles comprise what % of body weight?
40% - 60%
elasticity
The tissues ability to return to normal resting length when a stress that has been placed on it is removed
extensibility
Is the ability of a muscle to stretch
irritability
Or excitability, is the capacity of muscles to receive and react to stimuli
which cells produce nearly all the movement in the body?
Muscle cells
Contractility
Is the ability of a muscle to contract or shorten and thereby exert force
superficial fascia
Situated just below the skin and covers the entire muscular system
deep fascia
The fascia penetrates to the bone, separating muscle groups and covering individual muscles
skeletal muscle
Striated and voluntary CNS (central nervous system)Cigar shapedMakes up fleshy areas of the body Attached to the skeleton, and are in turn fastened to the bones, skin, or other muscles
smooth muscle
Visceral Smooth and involuntary ANS (autonomic nervous system) Spindle shaped, nonstriated cells that overlap at the ends Doesn’t attach to boneSlow actingCan maintain a contraction for a long time Doesn’t fatigue easily
cardiac muscle
Found only in the heart Striated and involuntaryCells are quadrangular, joined end to end, and grouped in bundles supported by a frame work of connective tissue
Are muscle cells multinucleated?
Yes, a single cell can have hundreds of nuclei distributed just beneath the cell membrane. These nuclei produce the enzymes and proteins necessary in muscle contraction
spindle cells
Specialized muscle cells that have both sensory and motor functions are essential for muscle control and coordination.
Located in the belly of a muscle, alert the CNS as to the length, stretch, and speed of the muscle
how long can ATP sustain a contraction?
There is only enough ATP stored in the muscle cells to sustain a contraction for a few seconds. Within a fraction of a second, ADP is reconstituted into ATP in one of several ways
how many muscles are in the body?
Over 600 muscles, large and small
what are the 4 characteristics of muscles?***
ICEE
Irritability or excitability. Contractility.
Elasticity.
Extensibility.
endomyium
Within the fascicle, each muscle fiber has a delicate connective tissue covering Maintains its parallel position with other cells
tendon
Fibrous connective tissue bands that attach muscle to bone
ligament
Bands of fibrous tissue that connect bones to bones
neuromuscular junction
Myoneural junctionThe site where the muscle fiber and nerve fiber meet
sarcomere
The smallest functional unit of the muscle cell containing the actin and myosin filaments A band (dark, thick myosin filament)-M line-H zone-overlap zoneI band (light, thin actin filaments)-Z line
muscle fatigue
Is a condition in which the muscle ceases to respond because of oxygen debt from rapid or prolonged muscle contractions
muscle fibers types (I, II)
Type I.
Slow twitch Slow to fatigue Slow contraction Lots of mitochondriaLots of myoglobinPostural musclesType IIFast twitchFast to fatigueFast contractions (5x-10x faster)Little mitochondriaLittle myoglobinArms, legs, shoulders***chicken white breast meat
white breast meat of chicken, which fibers of muscle make it up?
Type II fibers
phasic muscle
Contains a higher proportion of type II fibersUsed for quick, infrequent, powerful movementMovers
postural muscle
Contains a higher proportion of type I fibersStabilizersSupport the body against gravity. Slower to respond to stimulation Slower to fatigue