Muscle Contraction Flashcards
caused by minor muscle contractions in
the area, or uncontrollable twitching of a
muscle group that is served by a single
motor nerve fiber.
Muscle Twitch
3 Phases of Muscle Twitch
1) Latent Period
2) Period of Contraction
3) Period of Relaxation
time between the stimulus
and the initiation of contraction
Latent Period
Causes of Muscle Twitch
• Lack of Sleep
• Exercise
• Lack of nutrients
• Stress & Anxiety
• Autoimmune disorders
• Drug Overdose
a state of sustained contraction of a
muscle during which the muscle does
not relax to its initial length or tension,
induced by a rapid succession of stimuli.
Tetanus
the process by which different
motor units are activated to
produce a given level and type
of muscle contraction.
Recruitment
The occurrence of additional twitch
contractions before the previous twitch
has completely relaxed.
Summation
Skeletal muscle contractions can be
grouped based on the _____ and ______.
length and frequency of contraction.
Two major types of skeletal muscle fibers
• slow-twitch muscle fiber
• fast-twitch muscle fiber
also known as muscle cells, are the
individual cells that make up skeletal muscles and are responsible for their contraction and relaxation. They help to control the physical forces within the body. When grouped together, they can facilitate organized movement of your limbs and tissues.
Muscle Fibers
• also known as the type I fibers.
• cause the fibers to contract more
slowly and be more resistant to fatigue
• are used or adapted for endurance
activities
Slow-twitch
• also known as the type II fibers
• cause the fibers to contract quickly and to fatigue quickly
Fast-twitch
Two types of Fast-twitch muscle fibers
• Type IIa
• Type IIb
Type IIa also called as _____
fast-oxidative glycolytic fibers
Type IIb also called as ______
fast-glycolytic fibers
• are characterized by their high
resistance to fatigue and their reliance
on aerobic metabolism
• have a large number of mitochondria
• rich in capillaries which allows them to
efficiently generate ATP using oxygen
and glucose
SLOW-TWITCH
• contracts slowly:
better suited for activities that
require endurance, such as long-
distance running or cycling.
• are more fatigue-resistant than fast-
twitch muscle fibers
• respond relatively slowly to nervous
stimulation.
SLOW-TWITCH
are characterized by their high
resistance to fatigue and their reliance
on _____________
aerobic metabolism
Slow-twitch have a large number of ______
mitochondria
rich in _____ which allows them to
efficiently generate ATP using oxygen
and glucose
capillaries
Slow-twitch are more ______ than fast-twitch muscle fibers
fatigue-resistant
The enzymes on the myosin heads
responsible for the breakdown of
ATP are called __________
myosin ATPase
_______ fibers break down
ATP slowly because their myosin
heads have a slow form of myosin
ATPase which causes the muscle to
contract slowly.
Slow-twitch
________ is the primary source for ATP synthesis in slow-twitch muscles. Their capacity to perform aerobic respiration is enhanced by a plentiful blood supply and the presence of numerous mitochondria. They are called oxidative muscle fibers because of their enhanced capacity to carry out aerobic respiration
Aerobic respiration
Slow-twitch fibers also contain large amounts of ______ which binds oxygen and acts as an oxygen reservoir in the muscle fiber when the blood does not supply an adequate amount. Myoglobin thus enhances the capacity of the muscle fibers to perform aerobic respiration.
myoglobin
have very little myoglobin and fewer and smaller mitochondria
Fast-twitch
have large deposits of ______ and are well adapted to perform anaerobic
respiration.
glycogen
rely on both anaerobic and
aerobic ATP production
Type IIa
rely almost exclusively on
anaerobic glycolysis for ATP
production
Type IIb
• Requires oxygen and breaks down glucose to produce ATP
• More efficient
• Can produce up to 36 ATP molecules
• Uses greater variety of molecules as energy sources.
AEROBIC RESPIRATION
Aerobic Respiration can produce up to _____ ATP molecules
36 ATP molecules
• Does not require oxygen and results in the breakdown of ATP
• Less efficient than aerobic respiration, but it is much faster, especially when insufficient is available for aerobic respiration.
ANAEROBIC RESPIRATION
• Constant state of exhaustion, burnout or lack of energy.
• Decreased capacity and reduced efficiency of performance to do activities.
• Possible sites of fatigue include the nervous system, muscles and neuromuscular junction
Fatigue
TYPES OF FATIGUE
• Psychological Fatigue
• Muscular Fatigue
• Synaptic Fatigue
• Physiological Contracture
are essential for movement and various bodily functions. Muscle contraction is the tightening, shortening, or lengthening of muscles when you do some activity. It can happen when you hold or pick up something, or when you stretch or exercise with weights.
Muscle contractions
Two types of Muscle Contractions
• ISOTONIC CONTRACTION
• ISOMETRIC CONTRACTION
the tension developed in the muscle
remains almost constant while the
muscle changes its length. It has two types: concentric and eccentric
ISOTONIC CONTRACTION
the tension generated is not enough to exceed the resistance of the object to be moved, and the muscle does not change its length
ISOMETRIC CONTRACTION
Two types of Isotonic Contraction
concentric and eccentric
• the amount of tension produced by the
muscle is constant during contraction
but the length of the muscle changes
• used for body movements and for
moving objects
• movements of the upper limbs or
fingers, as in waving or using a
computer keyboard, are predominantly
isotonic contractions.
Isotonic Contraction
are isotonic contractions in which
tension in the muscle is great enough
to overcome the opposing resistance,
and the muscle shortens
Concentric
result in an increasing tension as the
muscle shortens
Concentric
many of the movements performed by muscles require concentric contractions
Concentric
are isotonic contractions in which tension is maintained in a muscle, but the opposing resistance is great enough to cause the muscle to increase in length
Eccentric
the tension exerted by the myosin cross-bridges resists movement of a load and slows the lengthening process
Eccentric
are responsible for the constant length of the postural muscles of the body, such as the muscles that hold the spine erect while a person is sitting or standing
ISOMETRIC CONTRACTION
important for maintaining posture and for supporting objects in a fixed position
ISOMETRIC CONTRACTION
An example would be holding a dumbbell steady using an outstretched arm.
Isometric Contraction
