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MUSCULAR
TISSUES
Activity 4
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MUSCULARTISSUES
MOTION mediated by
muscle cells / myofibers /
muscle fibers. Conversion of chemical
energy (ATP) into mechanical
energy by the contractile
apparatus of muscle cells.
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Interaction ofactin and
myosinmediates the
contraction of muscle cells.Actin and myosin form
myofilaments arranged
parallel to the direction of
cellular contraction.
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LOCATION APPEARANCE STIMULATION TYPE OF ACTIVITY
Composed of gross
named muscles (e.g.
biceps, triceps)
attached to the
skeleton and/or
fascia of limbs, body
wall, and head/neck.
Large, long,
unbranched, cylindrical
fibers with transverse
striations (stripes)
arranged in parallel
bundles;
multiple,peripherally
located nuclei.
Voluntary (or
reflexive) by somatic
nervous system.
Strong, quick
intermittent (phasic)
contraction abobve
a baseline tonus;
acts primarily to
produce movement
or resist gravity.
SKELETAL MUSCLE
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LOGITUDINALSECTIONOFASKELETAL
MUSCLE
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HISTOLOGYOFSKELETAL
MUSCLE
Longitudinal section
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Cremaster muscle myofibrils
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TONGUE - STRIATED MUSCLE: THE CORE OF THE TONGUE CONTAINSINTERLACING BUNDLES OF STRIATED FIBERS THAT RUN IN THREE
PLANES: (A) longitudinal, (B)vertical, AND (C)transverse.
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HYPERTROPHY
With constant useskeletal muscle
undergoes
HYPERTOPHY OF USE
Number of cel ls does not
change
Amount o fcontract i le
material in EACHmyof iberincreases
AN EXAMPLE OF
HYPERTROPHY OF USE
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LOCATION APPEARANCE STIMULATION TYPE OF ACTIVITY
Muscle of the heart(myocardium) and
adjacent portions of
the great vessels
(aorta, vena cava)
Branching andanastomosing shorter
fibers with transverse
striations (stripes)
running parallel and
connected end-to-end
by complex junctions
(intercalated discs).Single, central nucleus
Involuntary;intrinsically
(myogenically)
stimulated and
propagated; rate and
strength of contraction
modified by autonomic
nervous system.
Strong, quick,continuous rhythmic
contraction, acts to
pump blood from
the heart.
CARDIAC MUSCLE
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http://webanatomy.net/histology/muscle_histology.htm
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INTERCALATED DISK
- diagnostic feature of CM
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INTERCALATED DISKS
Special structure for
COMMUNICATION &
ADHESION
3-D interlocking ofadjacent cells atends
Includes adhering
junctions & gap
junctions
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LOCATION APPEARANCE STIMULATION TYPE OF ACTIVITY
Walls of hollowviscera and blood
vessels, iris and
ciliary nody of the
eye; attached to hair
follicle of the skin
(arrector pili muscle)
Single oragglomerated, small,
spindle-shaped
fibers without
striations; single,
central nucleus.
Involuntary byautonomic nervous
system (ANS)
Weak, slow, rhythmic,or sustained tonic
contraction; acts
mainly to propel
substances (peristalsis)
and to restrict flow
(vasoconstriction) and
sphincteric activity.
SMOOTH MUSCLE
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SMOOTHMUSCLES
Largest smooth muscle cells - uterus duringpregnancy (12x600 m).
Smallest - around small arterioles (1x10 m).
Contain one centrally placed nucleus.The chromatin is finely granular and the
nucleus contains 2-5 nucleoli.
Innervated by the autonomic nervoussystem.
Visceral muscles - involuntary muscles.
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SMOOTH MUSCLE FIBER MAY
OCCUR:
Singly - in the scrotum (tunica dartos)
In small bundles or fascicles -
associated with hair follicles (arrectorpili muscles)
In well-defined, layered sheets that are
coiled - in muscular arteries.Arranged in two thick layers at right
angles to each other- in the intestines;
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SMOOTH MUSCLE FIBER MAY OCCUR:
With an additional layer in an
irregular pattern - in the stomach,
bladder, and uterus.
Branched smooth muscle fibers -
found in the nipple of the mammary
glands and in the endocardium of the
atrium of the heart.
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Smooth muscles in small
bundles or fascicles -
associated with hair
follicles.
Originate in the papillary
connective tissue and
insert on hair follicles.
Their contraction erects
hairs in animals andproduces goose flesh" in
man.
ARRECTOR PILI MUSCLE
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http://webanatomy.net/histology/muscle_histology.htm
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CM in Cross Section:
Nuclei at the centerofcell
Cells all about thesame size
Proportionally more
nuclei per unit area
than smooth muscle
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MUSCULARISMUCOSAE
Occurs throughout the GI tract fromesophagus to rectum.
A thin layer of smooth muscle at the boundary
between mucosa and submucosa.
It contains both circularand longitudinalfibers.
Thickest in esophagus.
Thinner in the rest of the tract (stomach, small
intestine, colon).
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JEJUNUM
Smooth muscles
are distributed
as:
an outerlongitudinal and
an inner circular
layer in the wall
of the jejunum.
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Because smooth muscle and collagen both share a somewhat
similar appearance (eosinophilic fibers), it may take special care
to notice the muscularis mucosae.
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UTERINEWALLENDOMETRIUM,
MYOMETRIUM,ADVENTITIA
Myometrium is the thick smooth
muscle tunic of the uterus.
This layer thickens during
pregnancy.
At parturition, powerful contraction
is triggered by oxytocin and
prostaglandin.
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Uterus - Smooth muscles with an additional layer
in an irregular pattern.
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ARTERIALWALL : COMPOSEDOF 3 LAYERS
(TUNICAE)
Tunica Intima inner
Tunica Media middle
Tunica Adventitia outer Tunica Intima
Tunica media
Tunica
adventitia
Elastin
membrane
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AORTATHELARGESTARTERY
Elastic Artery
Tunica media - the
spaces between the
elastic tissues are filled
with smooth musclefibers and fibroelastic
tissue.
Help to reduce changes
in blood pressureassociated with
heartbeat.
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MUSCULARARTERIES
Distributing arteries
distributes blood to
various organs.
The thick tunicamedia is composed
of many concentric
layers of smooth
muscle.