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Muscle
is a specialized body tissue which allows movement to take place
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Skeletal muscle tissue is made of
muscle cells
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Muscle main function
to provide movement
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Most important characteristic of muscle
is its ability to contract
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Contractility
it is able to shorten and thicken muscle
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Elasticity
"return to its resting state, original shape after contraction or extension"
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Extensibility
stretch beyond its relaxed resting state - become thinner and longer
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Excitability
ability to contract in response to a stimulus
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Effort
"Weight of the child acts as a resistance force, the weight of the second child acts as a force to overcome the resistance of the first"
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For movement to occur we need
"a lever, a fulcrum and 2 forces - the resistance and the effort"
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Bones act as levers and joints function as
fulcrums
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Contraction of the muscles provider
the effort
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Ends by attaching to
the radius
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Contact
short and thicken- capable only of pulling not pushing
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Bulk of the muscle is near
the upper attachment to bone
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Attachment of the muscle to the scapula and humerus stationary bone called
the origin
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Bone that moves called
the insertion
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belly
fleshy bulk of muscle between the 2 attachment points
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Tendon
"attachment of muscle of muscle to bone, strong fibrous cord"
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Muscle allow movement to take place
by contraction and relaxation
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If we want to straighten the arm
need the biceps to relax
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Every action has a muscle to carry out
its opposite action
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Muscles act
in relationship to one another
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One muscle contracts to
prime mover or agonist
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the other muscle relaxes
antagonist
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In bending the elbow
the biceps is the agonist and the triceps is the antagonist
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In straightening the elbow
the triceps is the agonist and the biceps is the antagonist
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Skeletal muscle is mainly
voluntary muscle
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voluntary muscle
it is under our will
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Skeletal muscle
"Striped or striated so also also called striated muscle, Voluntary"
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Muscle cells are
"cylindrical in shape, Striated, Vary in length, Also called muscle fibers"
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Each fiber has several nuclei situated beneath
the cell membrane or sarcolemma
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Each muscle fiber or cell also has a connective tissue layer called
the endomycium
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the muscle fibers run
parallel to each other
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Muscle fibers form
a bundle or fascicles
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a bundle or fascicles
is surrounded by another connective tissue layer - perimycium
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bundles of fascicles form the whole muscle
surrounded by a connective tissue sheath - epimycium
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Muscle is composed of
"75 0/0 protein, 20 0/0 water, 5 0/0 mineral salts, glycogen, glucose and fat"
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Individual muscle fibers
"All or none law, Cannot partially contract"
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Aerobic respiration
"Energy provided by the breakdown of carbohydrate and fat, Oxygen required"
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Anaerobic respiration
Inadequate oxygen
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Lactic acid
Results in the accumulation of intermediate metabolic products
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Muscle tone - When movement does not occur the muscles are in a state of
partial contraction
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Muscle tone
is essential to maintain posture
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Hypertonic
Excess muscle tone
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Hypotonic
Poor muscle tone
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Nerves
Carrying internal electrical stimuli
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External
electrical current
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Temperature
Both hot and cold
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In the body the main stimulus provided by
the nervous system
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Synapse
Point where the nerve and the muscle meet
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Minute gap
The contact at the synapse between muscle and nerve is across
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"The nerve causes certain chemical substances to cross the gap,"
"carrying the electrical stimulus to the muscle, which then contracts"
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Electrical impulses
"Effective if placed over a specific point of the muscle, Motor point, When applying faradic pads to specific muscles"
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Muscles relax
when exposed to moderate heat.
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Excessive heat will
stimulate muscle contraction as part of the reflex action to move away from harm
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Cold contract
causing shivering maintaining body temperature
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Erector pili muscles
Attached to hairs to contract trapping heat on the skin
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Tapping a muscle may
cause it to contract
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Isometric contraction
Do not result in body movement but use energy
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Isotonic contraction
This type of contraction produces movement
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Movement
Voluntary or involuntary contraction in all internal organs
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Heat production
"Shivering, erector pili muscles, physical exercise"
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Protection
Abdominal cavity
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Transverse
Transfersus abdominis ( across the midline)
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Oblique
Internal oblique ( cross)
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Trapezius
Trapezoid (4 unequal sides)
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Temporal is lies over
temporal bone
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Tibialis anterior is in front of
tibia
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Sternocleidomastoid
has origin at sternum and clavicle and insertion at mastoid process of temporal bone
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