Muscular System Flashcards
Where is Cardiac Muscle found and is it voluntary or involuntary?
Found only in heart; involuntary
Where is Smooth Muscle found and is it voluntary or involuntary?
Found in digestive tract, blood vessels, airways & uterus; involuntary
Where is Skeletal Muscle found and is it voluntary or involuntary?
Found attached to bones; voluntary
What is a skeletal muscle cell called?
Muscle Fiber
What covers each muscle fiber?
Edomysium- a connective tissue
What are fascicles?
Muscle fibers grouped in bundles
What is the Perimysium?
A sheath of connective tissue encasing fascicles
What is the sarcolemma?
The plasma membrane surrounding each muscle fiber
What is the Fascia?
Connective tissue surrounding the muscle outside the epimysium
What is the Epimysium?
A layer of connective tissue surrounding the muscle as a whole and binds all the muscle fibers together.
What is the Endomysium?
A connective tissue covering each muscle fiber
What is the name for the cytoplasm of the cell?
Sarcoplasm
What forms a myofibril?
The thin and thick myofilaments stacked together
Explain a thick filament
Hundreds of myosin molecules stacked together with the myosin heads facing outward
Explain a thin filament
Consisting of two chains of the protein Actin, thin myofilaments look like a string of beads. Entwined with the actin are two other proteins; tropomyosin, and troponin.
What is the Threshold?
The minimum voltage needed to cause a muscle fiber to contract
What is a Twitch?
A single, brief contraction.
What is the Neuromuscular Junction?
The connection between a motor neuron and a muscle fiber
What is the length-tension relationship?
The strength of a contraction depends upon the length of the fibers before a contraction.
When are the muscles able to contract the strongest?
When the thin and thick filaments are partially overlapped.
What does the All or Nothing principle state?
that under given conditions the response of a nerve or muscle fiber to a stimulus at any strength above the threshold is the same: the muscle or nerve responds completely or not at all.
What is Incomplete Tetanus?
Rapid contraction with only partial relaxation
What is Complete Tetanus?
One prolonged contraction due to the impulses arriving so fast the muscle cannot relax between stimuli
What is Treppe?
Phenomenon is which each successive twitch contracts more forcefully than the previous one
What is Isometric Contraction?
Condition of rapid muscle contraction with only partial relaxation
What is Isotonic Contraction?
Contraction in which the muscle changes length to move a load
What is Aerobic Respiration?
Process that breaks down fatty acids for energy when oxygen is not plentiful
What is Anaerobic Respiration?
Process that breaks down glucose for energy when oxygen is not plentiful
What is Muscle Tone?
Continuous state of partial muscle contraction that allows for the maintenance of posture
What does the Origin refer to?
The end of the muscle that attaches to the more stationary bone
What does the Belly refer to?
The thick midsection of the muscle
What does the Insertion refer to?
The end of the muscle that attaches to the more moveable bone
What does the Frontalis do?
Raises the eyebrows?
What does the Orbicularis oculi do?
Closes the eye when blinking or squinting
What does the Zygomaticus do?
Draws the mouth upward when laughing
What does the Orbicularis Oris do?
Closes the mouth and purses the lips
What does the Buccinator do?
Assist in smiling and blowing
What does the Temporalis do?
Aids in closing the jaw
What does the Masseter do?
Closes the jaw
What does the Sternocleidomastoid do?
Flexes head, when one side contracts, rotates head to opposite side
What does Trapezius do?
Extends head, flexes head to one side; also elevates the shoulder
What does the External Intercostal do?
Elevate ribs during inspiration
What does the Internal Intercostal do?
Depress the ribs during forces exhalation
What does the Diaphragm do?
Enlarges the thorax to trigger inspiration
What does the Rectus Abdominis do?
Flexes lumbar bending forward at waist; from sternum to pubic bone
What does Transversus Abdominis do?
Compresses the contents of the abdomen
What do the Internal Oblique do?
Stabilize spine, maintain posture, permit rotation of waist
What do the External Oblique do?
Stabilize spine during heavy lifting; support posture; aids forceful expiration
