FALSEWhy?The rotator-cuff muscles surround the head that the humerus, with the major stabilizing role of hold the humeral head in the glenoid fossa. The lack of bone sustaining the shoulder joint requires that this muscles and also their connected tendons job-related as stabilizers to protect against subluxation or dislocation that the humeral head indigenous the glenoid fossa.
You are watching: The quadriceps femoris is the prime mover of knee extension.
FALSEWhy?The quadriceps femoris is the prime mover because that knee expansion when acting concentrically. The hamstrings are the primary knee flexors.
TRUEWhy?The sartorius is the longest muscle in the body, originating indigenous the anterior remarkable iliac spine (ASIS) and inserting top top the medial tibia, just below the knee. This multijoint muscle flexes, abducts, and externally rotates the hip if flexing and internally rotating the knee.
TRUEWhy?The hamstrings are described as a biarticular team of muscles, creating knee flexion and also hip expansion when exhilaration concentrically. Additionally, the lateral hamstring, the biceps femoris, is an outside rotator the the knee.
FALSEWhy?Although lock originate from different areas, all 4 quadriceps muscle converge and also share one tendon that insertion, the patellar tendon.
RelaxWhy?One of the Golgi tendon organ"s attributes when the senses muscle contraction is to reason inhibition of the contraction (or relaxation). It has been theorized that this role adjusts muscle calculation in response to fatigue.
Muscle spindles respond to muscle fibers gift overstretched by bring about a _______________, known as the _______________.
Muscular contraction; stretch reflexWhy?The muscle spindle stretches as soon as the muscle chin experiences a big force, thereby exciting the muscle spindle and causing a reflex contraction in the muscle, well-known as the big reflex.
When the muscle spindle"s reflex convulsion occurs, it reasons the antagonist muscle group to relax. This is recognized as _______________.
Reciprocal inhibitionWhy?The muscle spindle"s reflex convulsion of its linked muscle simultaneously causes the antagonist muscle team to relax. This is referred to as reciprocal inhibition. For example, if the gastrocnemius is stretched rapidly, the muscle spindles in ~ the muscle belly reason it to contract. In ~ the same time, if the anterior tibialis (opposing muscle group) is contracting, the muscle spindle reflex reasons it come relax.
TRUEWhy?Type IIx muscle fibers fatigue an ext easily than type I muscle fibers. In fact, this fibers cannot sustain their initiative for more than a few seconds.
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TRUEWhy?Type IIx fibers are the largest and fastest, and also are capable of producing the most pressure of all the bones muscle fibers, but are significantly less effective than form I muscle fibers.