The Muscular System. Muscle tissue overview All muscle cells are elongated, thus, all muscle cells,...
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The Muscular System. Muscle tissue overview All muscle cells are elongated, thus, all muscle cells, regardless of type, are called muscle fibers The ability
Muscle tissue overview All muscle cells are elongated, thus,
all muscle cells, regardless of type, are called muscle fibers The
ability of muscle to shorten or contract depends on 2 types of
myofilaments Prefix: -myo/mys: muscle -Sarco: flesh
Slide 3
Muscle Types skeletal muscle cardiac muscle smooth muscle
attached to bone;walls of heart; Muscle type: Body location: walls
of hollow organs; single, very long multi- cylindrical, multi-
nucleatestriations nucleate, striations; branching chains,
uninucleate striations uninucleate, striations; Single, spindles,
uninucleateno uninucleate, no striations striations; Cell Shape:
Regulation of Contraction: voluntary voluntary, nervous system
controls; involuntary involuntary, ner- vous system controls,
hormones; involuntary involuntary, ner- vous system controls,
hormones, chemicals, stretch; Contraction Speed/Rhythmic : Slow to
fast/no; Slow/yes; Very slow/some
Skeletal Muscle Skeletal muscle fibers: are packed into the
organs called skeletal muscles that attach to the bodys skeleton
Skeletal muscle fibers are cigar-shaped, multinucleate cells, and
are the largest of the muscle fiber types It is also known as
striated muscle because its fibers appear to be striped It is also
known as voluntary muscle because it is the only muscle type
subject to conscious control Skeletal muscle tissue can contract
rapidly and with great force, but it tires easily and must rest
after short periods of activity
Slide 6
Connective tissue wrapping Each muscle fiber is enclosed in a
delicate connective tissue sheath called an endomysium A bundle of
muscle fibers called a fascicle are surrounded by a connective
tissue called the perimysium A bundle of fascicles are surrounded
by a connective tissue called the epimysium
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Tendons The epimysia blend into the strong, cordlike tendons
Tendon connects muscle to bone Tendons provide durability and
conserve space
Cardiac Muscle Is found only in the heart Cardiac muscle is
like skeletal muscle in that it is striated and like smooth muscle
in that it is involuntary and cannot be consciously controlled by
most of us Cardiac muscle fibers are branching cells joined by
special junctions called intercalated disks
Slide 10
Cardiac Muscle The cardiac muscle is cushioned by small amounts
of soft connective tissue and arranged in spiral or figure 8
bundles Cardiac muscle usually contracts at a fairly steady rate
set by the hearts pacemaker, but can also be stimulated by the
nervous system
Smooth Muscle Smooth muscle has no striations and is
involuntary Found in the walls of hollow visceral organs such as
the stomach, urinary bladder etc.
Slide 13
Smooth Muscle Smooth muscle cells are arranged in 2 layers:
-One layer runs circularly -The other running longitudinally The
two layers alternately contract and relax, and this changes the
size and shape of the organ, resulting in the movement of food,
wastes, etc.
Slide 14
4 Muscle Functions stabilizing joints producing movement
maintaining posture generating heat walking; swimming; move eyes;
Smile Frown move fluid; move food. help reinforce bones that do not
articulate well with the skeleton; Ex.: shoulder allow you to stand
up straight against the force of gravity. ATP used to cause muscles
to contract; ATP energy is lost as heat; This helps maintain body
temperature.