Muscular system Part 1 Flashcards
responsible for all types of body movement
Muscles
Three basic muscle types are found in the body
Skeletal muscle
Cardiac muscle
Smooth muscle
muscle cell =
muscle fiber
Contraction of muscles is due to the
movement of microfilaments
Prefix myo refers to
muscle
Prefix mys refers to
muscle
Prefix sarco refers to
flesh
Most skeletal muscles are attached by ________ to bones
tendons
The Skeletal Muscle cells are
multinucleate
They have visible banding
Striated
Subject to conscious control
Voluntary
The skeletal Muscle Cells are surrounded and bundled by
connective tissue
A Connective Tissue Wrappings of Skeletal Muscle around single muscle fiber
Endomysium
A Connective Tissue Wrappings of Skeletal Muscle around a fascicle (bundle) of fibers
Perimysium
A Connective Tissue Wrappings of Skeletal Muscle that covers the entire skeletal muscle
Epimysium
A Connective Tissue Wrappings of Skeletal Muscle on the outside of the epimysium
Fascia
Sites of muscle attachment
Bones
Cartilages
Connective tissue coverings
____________ blends into a connective tissue attachment
Epimysium
A cord-like structure of connective tissue attachment
Tendon
A sheet-like structure of connective tissue attachment
Aponeuroses
no conscious control
Involuntary
-Has no striations
-Spindle-shaped cells
-Single nucleus
-Involuntary
-Found mainly in the walls of hollow organs
Smooth Muscles
-Has striations
-Usually has a single nucleus
-Joined to another muscle cell at an intercalated disc
-Involuntary
-Found only in the heart
Cardiac Muscle
They Produce movement, Maintain posture, Stabilize joints, & Generate heat
Muscles
The muscle cells are
multinucleate
Nuclei are just beneath the __________
sarcolemma
They are specialized plasma membrane
Sarcolemma
They are specialized smooth endoplasmic reticulum
Sarcoplasmic reticulum
They are Bundles of myofilaments that are aligned to give distrinct bands
Myofibril
light band
I band
dark band
A band
Contractile unit of a muscle fiber
Sarcomere
Organization of the sarcomere
myosin (thick) filaments & actin (thin) filaments
Thick filaments
myosin filaments
These filaments are Composed of the protein myosin and has ATPase enzymes
myosin filaments
These filaments are composed of the protein actin
actin filaments
These filaments have heads (extensions, or cross bridges)
Myosin filaments
It is for storage of
calcium in muscles
Sarcoplasmic reticulum
(SR)
When muscles at rest, there is a ____ ____ that lacks actin filaments
bare zone
ability to receive and respond to a stimulus
Irritability
ability to shorten when an adequate stimulus is received
Contractility
ability of the muscle cells to be stretched
Extensibility
ability to recoil and resume their resting length
Elasticity
Skeletal muscles must be stimulated by a _____ to contract
nerve
Composed of One neuron and Muscle cells stimulated by that neuron
Motor unit
association site of nerve and muscle
Neuromuscular junctions
The gap between nerve and muscle
Synaptic cleft
Nerve and muscle do not make contact and the Area between nerve and muscle is filled with interstitial fluid
Synaptic cleft
A chemical released by nerve upon arrival of nerve impulse
Neurotransmitter
The neurotransmitter for skeletal muscle is
acetylcholine
Neurotransmitter attaches to receptors on the
sarcolemma
Sarcolemma becomes permeable to
sodium (Na+)
______ rushing into the cell generates an action potential. Once started, muscle contraction cannot be stopped
Sodium
Activation by nerve causes _____ _______ (crossbridges) to attach to binding sites on the thin filament
myosin heads
then bind to the next site of the thin filament
Myosin heads
This continued action causes a sliding of the ______ along the ______
myosin , actin
The result is that the muscle is
shortened (contracted)
Muscle fiber contraction is
“all or none”
Within a _________ _________, not all fibers may be stimulated during the same interval
skeletal muscle
Different combinations of _______ ______ contractions may give differing responses
muscle fiber
different degrees of skeletal muscle shortening
Graded responses
A type of response where it is Single, brief contraction. It is not a normal muscle function
Twitch
A type of response where One contraction is immediately followed by another. The muscle does not completely return to a
resting state.The effects are added. It is the summing of contractions.
Tetanus
A type of response where it is
some relaxation occurs between contractions. The results are summed
Unfused (incomplete) tetanus
A type of response where there is No evidence of relaxation before the following contractions. The result is a sustained muscle contraction.
Fused (complete) tetanus
______ _____ depends upon the number of fibers stimulated
Muscle force
More fibers contracting results in greater
Muscle tension
Muscles can continue to contract unless they run out of _______
energy
Initially, muscles used stored ___ for energy
ATP
Bonds of ATP are broken to release energy, Only _____ ________ worth of ATP is stored by muscles
4-6 seconds
The Muscle cells contain creatine phosphate (CP). After ATP is depleted, ADP is left. CP transfers energy to ADP, to regenerate ATP
CP supplies are exhausted in about 20 seconds
Direct phosphorylation
a high-energy molecule
creatine phosphate (CP)
Series of metabolic pathways that occur in the mitochondria. Glucose is broken down to carbon dioxide and water, releasing energy.
Aerobic Respiration
This is a slower reaction that requires continuous oxygen
Aerobic Respiration
Reaction that breaks down glucose without oxygen. Glucose is broken down to pyruvic acid to produce some ATP
Anaerobic glycolysis
IT is where Pyruvic acid is converted to lactic acid
Anaerobic glycolysis
This reaction is not as efficient, but is fast. The Huge amounts of glucose are needed and Lactic acid produces muscle fatigue
Anaerobic glycolysis (continued)
The common reason for muscle fatigue is
oxygen debt
When a muscle is fatigued, it is unable to
contract
Oxygen must be “repaid” to tissue to remove oxygen debt. Oxygen is required to get rid of accumulated ______ _____
lactic acid
Increasing acidity (from lactic acid) and lack of ATP causes the muscle to ______ ____
contract less
Myofilaments are able to slide past each other during contractions. The muscle shortens
Isotonic contractions
Tension in the muscles increases
The muscle is unable to shorten
Isometric contractions
The process of stimulating various fibers is under
involuntary control
Different fibers contract at different times to provide
muscle tone
Some fibers are contracted even in a
relaxed muscle
Movement is attained due to a muscle moving an __________ ____
attached bone
Muscles are attached to at least two points
Origin & Insertion
attachment to a moveable bone
Origin
attachment to an immovable bone
Insertion
resistance or isometric exercises
Increase in muscle size
aerobic or endurance type of exercise
Increase in muscle strength
-Increase in muscle efficiency
-Muscle becomes more fatigue resistant
-Increase in muscle size
-Increase in muscle strength
Effects of Exercise on Muscle