Muscle Basics & Types
What are the four main jobs of the muscular system in the body?
Producing movement, maintaining posture, stabilizing joints, and generating heat
What tough, cord-like tissue attaches muscles directly to bones?
Tendons
What energy molecule must be present for myosin heads to pull on actin filaments during a contraction?
ATP
What movement decreases the angle at a joint, bringing two bones closer together (like bending your elbow)?
Flexion
What grade of muscle strain is a mild stretch with damage to less than 5% of muscle fibers?
Grade 1 strain
Which of the three types of muscle tissue is attached to your bones and voluntarily controlled?
Skeletal muscle.
What is the outer protective layer that wraps around an entire muscle?
Epimysium
In muscle contraction, which filament is known as the "thin" filament, and which is the "thick" filament?
Actin is the thin filament, and myosin is the thick filament.
What is the term for moving an arm or leg away from the center line of your body?
Abduction
What does each letter in the PRICE first-aid protocol stand for?
Protect, Rest, Ice, Compress, Elevate
Which type of muscle tissue is found in the heart, and is it voluntary or involuntary?
Cardiac muscle, and it is involuntarily controlled
What do we call a wrapped bundle of muscle fibers inside a muscle?
A fascicle.
What is the name of the theory that explains how actin and myosin slide past each other to shorten a muscle?
The sliding filament theory
Pointing your toes downward toward the floor uses which specific foot movement?
Plantar flexion
What medical term describes a severe injury where a muscle belly is completely torn in two?
A Grade 3 strain.
Where in the body do you find smooth muscle tissue?
In the walls of internal organs, like the stomach or intestines
What is the delicate connective tissue membrane that wraps around a single muscle cell?
Endomysium
When a muscle runs out of oxygen during intense exercise, what acid builds up and causes muscle fatigue and burning?
Lactic acid
In a working muscle pair, what do we call the primary muscle that contracts to do the work, and what do we call the opposing muscle that relaxes?
The prime mover (or agonist) is the working muscle, and the antagonist is the relaxing muscle.
What dangerous medical condition happens when extreme swelling inside a tight muscle compartment cuts off blood flow?
Compartment syndrome
Under a microscope, skeletal muscle has stripes what is the correct term for them?
striations
What is the name of the tiny, repeating unit inside a muscle cell where muscle contractions actually take place?
A sarcomere.
Why does an athlete breathe heavily after a fast sprint (a state known as "oxygen debt")?
To repay the oxygen needed to break down accumulated lactic acid and rebuild ATP stores.
What is the difference between a muscle's "origin" and its "insertion"?
The origin attaches to the stationary bone, while the insertion attaches to the bone that moves.
What emergency surgery is performed to cut open skin and fascia to release severe swelling pressure?
A fasciotomy