Download File - Andrus alta anatomy

The Muscular System
Functions of Muscle Tissue
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Movement
Facilitation
Thermogenesis
Postural Support
Regulation of Organ
Volume
Pumps Blood
(HEART)
Characteristics of Muscle
Tissue
 Contractility

ability to
become short
and thick while
producing
movement
Characteristics of Muscle
Tissue
 Extensibility
 The
ability of
muscle tissue
to be
elongated or
stretched
 Smooth
muscle
Characteristics of Muscle
Tissue

Elasticity
 ability
to
return to its
normal resting
length

Skeletal from being
shorter—smooth—
from extended
Characteristic of Muscle tissue
Excitability
(irritability)
 ability to receive
and respond to a
stimulus
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Cardiac Muscle
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Forms heart wall
(Myocardium)
striated
involuntary
Fibers quadrangular &
branching
centrally located
nucleus
sarcolemmas
connected by
intercalated discs
gap junctions
Smooth (Visceral) Muscle
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walls of hollow
internal surfaces such
as:
– blood vessels stomach
– urinary bladder intestines
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non striated
involuntary
can be stretched to
great lengths
allows for tremendous
size variability
Skeletal Muscle
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attached to bones
striated
voluntary
Multinucleated
Characteristics of Skeletal Muscle
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Muscle origin: where muscle begins--tendon
attaches to immovable bone (proximal)
Muscle insertion: where muscle ends--tendon
attaches to moveable bone (distal)
Belly (gaster): fleshy portion of muscle between
tendons
Key terms

Sarcolemma muscle cell
membrane
Sarcoplasm =
muscle cell
cytoplasm
Key terms
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Myofilaments or
myofibril--contain
contractile
elements of
muscle fiber
Sarcomere: one
section of
contractile
filaments
Actin
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Thin Myofilaments
2 regulatory proteins
Tropomyosin- follows
contour of filament
Troponin = protein on
tropomyosin
Receptor site for Ca+
on Troponin
Myosin
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Thick Myofilaments
globular head
Heads aka as cross
bridges
SLIDING FILAMNET THEORY
OF MUSCLE CONTRACTION
Muscle--Nerve Interaction
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Motor Neuron =
nerve cell that
excites muscle
fiber
Motor Unit = motor
neuron & all the
muscle fibers it
can effect
Neuromuscular Junction
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Neuromuscular
Junction = place
between axon
terminal & muscle
fiber
Motor End Plate location on muscle
fiber next to the
axon
Acetylcholine
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Acytelcholine (Ach) = neurotransmitter released
to begin muscle contraction (action potential)
Acytelcholine Receptors—on motor end platemakes membrane more permeable to Na+
Roles of Skeletal Muscles
Agonist--Antagonist

Agonist (Prime
Mover)
– Main muscle
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Antagonist
– opposite movement
Roles of Skeletal Muscles
Synergist
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Synergist—
assists agonist
provides
additional force
Roles of Skeletal Muscles
Fixator
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Fixator (Stabilizer)
stabilizes a body
segment
prime mover can act
more effectively
SKELETAL MUSCLE
ORGANIZATION
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Muscle fibers: elongated muscle cells
Endomysium: membrane around muscle fibers
Perimysium: membrane around fascicles
Epimysium: membrane around entire muscle
(fascia)
The end