o Striated in appearance but is involuntary Muscle Innervation is the

O striated in appearance but is involuntary muscle

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o Striated in appearance but is involuntary Muscle Innervation - is the stimulation of a muscle by an impulse transmitted by a motor nerve o Motor nerves enable the brain to stimulate a muscle to contract. When the stimulation stops, the muscle relaxes. Antagonistic Muscle Pairs Contraction - the tightening of a muscle. As is contracts, it becomes shorter and thicker causing the belly to enlarge Relaxation - occurs when a muscle returns to its original form. As the muscle relaxes it becomes longer and thinner, belly is no longer enlarged. Flexion - decreasing the angle Extension - increasing the angle Muscles named for their location Pectoalis major – anterior chest wall Lateralis - means toward the side Medialis - towards the midline Muscles named for their direction
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Oblique - slanted or at an angle Rectus - means in a straight alignment with the vertical axis of the body Sphincter – ring like Transverse Muscles named for number of divisions Biceps brachii Triceps brachii Muscles names for their size or shape Gluteus Maximus- largest muscle of the butt Deltoid Muscle - shaped like an inverted triangle Muscles named for strange reasons Hamstring group- consist of 3 separate groups biceps femoris, semitendinosus, and semimembranosus muscles. Function- knee flexion and hip extension Head Frontalis - in the forehead and raises and lowers the eyebrows Temporalis - moves the lower jaw up and back to close the mouth Masseter - which is one of the strongest in the body, moves the lower jaw up to close the mouth when chewing Trunk External and Internal Oblique- o External - flex and rotate the vertebral column; flex the torso and compress the abdomen. o Internal - flex the spine, support the abdominal contents, help breathe, and rotate the spine. Rectus Abdominis - helps flex the trunk, assists in breathing, and supports the spine Transverse Abdominis - located on the side of the abdomen. Engaged when a person laughs or coughs. Shoulders and Arms Deltiod - forms the muscular cap of the shoulder Trapezius - muscle moves the head and shoulder blade Biceps Brachii - located in the anterior upper arm, flexes the elbow Triceps Brachii - located in the posterior upper arm, extends the elbow
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Muscles of the legs Rectus Femoris - extends the leg at the knee Quadriceps femoris - made up of 4 muscles including vastus lateralis and vastus medialis, which flex and extend the leg at the knee Hamstring group - involved in knee flexion and hip extension Gastrocnemius - the calf muscle that flexes the knee and bends the foot downward. Muscle Disorders Myalgia - tenderness or pain in the muscles Myorrhexis - the rupture or tearing of a muscle Rhabdomyolysis - can result from a direct or indirect muscle injury. Death of muscle fibers releases their contents into the bloodstream, where they can lead to complications such as renal failure.
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