Download MUSCLE TISSUE 1

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MUSCULAR TISSUE
Dr. MOHAMMED SHAMIA
General characteristic of muscles
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Structures & functional units are formed of muscle
fibers.
The cell membrane is known as sarcolemma.
The cytoplasm of muscle fibers or cells is called
sarcoplasm.
Sarcoplasm contain all cell organoid &cell inclusions.
Cytoplasm is rich in fat, glycogen, pigments,
mitochondria & myofibrils.
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Myofibrils are responsible for muscle contractions.
3 types of muscles:
1)
Smooth Muscle.
2)
Skeletal Muscle.
3)
Cardiac Muscle.
Muscle fibers with transverse striation (skeletal &
cardiac muscle)
No striation (smooth muscle)
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1- Smooth Muscle
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(involuntary muscles)
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Covered by thin sarcolemma.
They are spindle-shape with central oval Nuclei.
Arranged in layer as in the wall of stomach.
Cytoplasm is acidophilic rich in mitochondria,
ribosomes, golgi bodies & glycogen.
Poor in granular endoplasmatic reticulum.
Cytoplasm contains longitudinal myofibrils with no
striations.
SMOOTH MUSCLE
Smooth Muscle Fiber (Cell)- spindle shaped
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transverse
section
longitudinal section
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Myofibrils are three types :
A- Actin.
B- Myosin.
C- Intermediate filaments: (Dysmin – Vememtin)
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All smooth muscle originate from the (mesoderm)
Except: muscle of the iris and Myoepithelial cells
around the acini of the gland. (Ectoderm)
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Smooth muscle are involuntary in action innervated
with sympathetic &parasympathetic nerves.
LOCATIONS OF SMOOTH MUSCLE
DIGESTIVE TRACT
CAPSULE OF GLANDS
RESPIRATORY PASSAGES
URINARY & GENETAL TRACT
ARTERIES AND VEINS
IRIS & CILIARY BODY
UTERUS
BLADDER
STOMACH
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2- Skeletal Muscle
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Sites: attached to the skeleton.
 Form the muscle of the limbs, neck, diaphragm,
tongue, muscle of the face.
 Skeletal muscle are voluntary muscle.
Except: upper third of esophagus & some muscles of
the pharynx.
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Sections of skeletal muscle:
1- C.T. fascia(epimysium)around the whole muscle.
2- Perimysium C.T. septa between the muscle bundles.
3- Each muscle fiber is surrounded by C.T. endomysium.
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SKELETAL MUSCLE FIBERS
SKELETAL MUSCLE FIBER (Cell)- syncytium
Nuclei
Muscle
Fasicle
Epimysium
Perimysium
Endomysium
Fiber (cell)
Fibril
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Filaments
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They are formed of striated muscle fibers.
 Muscle fiber is single cells, do not branch except :
tongue & face muscles.
 Each muscle fiber is multinucleated cells.
 The nuclei are peripheral in position.
 The sarcoplasm in acidophilic rich in glycogen &
myoglobin.
 Myoglobin is formed of pigmented protein.
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The sarcoplasm(cytoplasm)contain many ribosomes,
mitochondria& smooth endoplasmic reticulum is
called sarcoplasmic reticulum.
The sarcoplasm contain longitudinal fibrils known as
myofibrils or sarcostyles.
The arrangement of myofibrils near each other
show transverse striation in the muscle fibers due to
presence of alternating dark & light bands on each
myofibril.
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Type Of Skeletal Muscle
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Muscle contain pigmented protein called myoglobin,
is red in color similar hemoglobin of RBCs.
Repair of muscles occur by the proliferation of
satellite cells which are present under the
sarcolemma & can differentiate into new muscle
fiber.
Human muscle contain 3 types of muscle fiber.
Classifications of skeletal muscles:
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Type I: Red muscle fibers: have large amounts of
myoglobin, they can sustain contraction for along
time without fatigue, energy is derived from
oxidation of fatty acids.
Type II: white muscle fibers: small amount of
myoglobin, few mitochondria, contraction are quick,
they become fatigue easy, energy is derived from
glycolysis
Type III : intermediate muscle fibers: They have
intermediate characters between type I & type II
SKELETAL MUSCLE FIBER TYPES
Red Muscle
(e.i. chicken leg)
Red Fibers
White Fibers
slow twitch
less tension
high endurance
numerous
mitochondria
fast twitch
more tension
fatigues
rapidly
fewer
mitochondria
Fiber Types Stained
white muscle fiber
for Glycogen (PAS)
red muscle fiber
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Striated Muscle Fibers-Long. Section
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Striated Muscle Fibers- Long. & Trans. Sects.
MYOTENDONOUS JUNCTION
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SMOOTH MUSCLE IN TUBES
Longitudinal Fibers
Changes
Caliber
Peristalsis
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Circular
Fibers
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