MUSCULAR SYSTEM Flashcards
Number of skeletal muscles in your body
640 skeletal muscles
Muscles never what?
Muscles never push, they always pull
> > MUSCLES ARE ACTUALLY PULLING THIER
INSERTIONS TOWARD THEIR
Origin
Example where the insertion point is
Top of humerus
Example where the origin is
Sternum
Whatever one muscle do, another muscle can?
Whatever one muscle do, another muscle can undo
Different skeletal muscles
• prime movers
• antagonists
• synergists
• fixators
agonist muscle
Prime movers
Muscles for Adduction
Prime movers
BRINGS A LIMB TOWARD THE
BODY
Adduction
MOVES IT AWAY
FROM THE BODY.
Abduction
Working in reverse of that particular movement
Antagonists
Example of Antagonists muscle
Deltoids
Example of prime movers musc5
✓ Pecs
✓ Lats
Help the prime movers lending a little extra oomph stabilizing joints against dislocation
Synergists
Example of synergists muscle
✓ infraspinatus
✓ teres minor
IF A SYNERGISTS IMMOBILIZES THE
MUSCLES’ ORIGIN BONE SO THAT THE
PRIME MOVER CAN BE MORE EFFECTIVE,
THEN THE SYNERGIST MUSCLES IS CALLED
Fixator
A group of muscle fibers that all get their signals from the same single motor neuron
Motor unit
Motor neurons may synapse with, and innervate, a thousand muscle fibers
Large motor unit
3 different skeletal muscle periods
✓ Latent period
✓ period of contraction
✓ Relaxation period
They’re generally affected by both the frequency and strength with which they’re stimulated
Graded muscle responses
INCREASE THE FORCE BY ___________ WITH WHICH OUR MOTOR
NEURONS ARE FIRING.
INCREASING THE
FREQUENCY
A PRODUCT OF HOW MANY
MYOSIN HEADS ARE BOUND TO ACTIN IN
EACH SARCOMERE,
Muscle force
_________MEANS
MORE AVAILABLE BINDING SITES,
__________MEANS EVEN MORE
CALCIUM,
✓ More calcium
✓ MORE FREQUENT ACTIVATION
IS THE CONTRACTION OF A MUSCLE
FIBER IN RESPONSE TO A STIMULUS
Muscle twitch
A MUSCLE TWITCH USUALLY INVOLVES
ALL THE _________ IN A MOTOR UNIT
Muscle fibers
This is what makes it impossible to maintain vigorous muscle activity indefinitely
Finite supply of ATP
Is the only way to create a GRADE OF FORCE
Frequency
RECRUITMENT OR MULTIPLE
MOTOR UNIT SUMMATION
- __________ INTENSIFIES AS MOTOR
NEURONS STIMULATES MORE AND MORE
MOTOR FIBERS
CONTRACTION
THE FORCE OF MUSCLE CONTRACTION
ALSO DEPENDS ON THE _________.
SIZE OF THE
FIBERS
The bigger the muscle, the _____.
(THE BIGGER THE MUSCLE
THE
MORE THE TENSION)
change in length but the tension is
constant
Isotonic contraction
2 types of contraction
• isotonic
• isometric
A contraction which a muscle shortens
while it exerts a constant force that
matches the load being lifted by the
muscle
Isotonic contraction
no change in length but tension increases
Isometric contraction
A contraction in which the external length
of the muscle does not change because
the force being generated by the muscle is
insufficient to move the load to which it is
attached
Isometric contraction
3 SOURCES OF ENERGY OF MUSCLE
CONTRACTION
✓Phosphorylation (Anaerobic Respiration)
✓ Glycogen (Creatinine Phosphate)
✓ Oxidative Metabolism (Aerobic
Respiration)
Prolong and strong contraction of muscle
Muscle fatigue
Decrease the capacity to work and reduced efficiency of
performance.
Muscle fatigue
Causes of fatigue:
• Build up of metabolic products in the tissue owing to insufficient
blood flow
• Transmitter depletion in the NMJ.
• Insufficient supply of nutrients to maintain contraction
Painful, spastic contraction of a muscle; usually due to a buildup of lactic acid
Cramps
Non-life threatening, chronic, widespread pain in muscle with no known cure
Fibromyalgia
Also known as the chronic muscle pain syndrome
Fibromyalgia
Enlargement of a muscle due to an increased number of myofibrils, as occurs with increased muscle use
Hypertrophy
Decrease in muscle size due to a decreased number of myofilaments, can occur due to disuse of a muscle, as in paralysis
Atrophy
Group of genetic disorders in which all types of muscle degenerate and atrophy
Muscle dystrophy
Muscles are weak and fail to relax following forceful contractions; affects the hands most severely
Myotonic muscular dystrophy
Inflammation of a tendon or its attachment point due to overuse of the muscle
Tendinitis
Symptoms:
• muscle weakness
• muscle atrophy
• contractures
Treatment:
• physical therapy to prevent contractures
• no effective treatment to prevent atrophy
DMD
Duchene Muscular Dystrophy
