Activity 2 - Name at least two muscles that actively contracts during the following activities and name its action and innervation:
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Throwing a baseball overhead
Muscle A: Deltoid
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Action: abducts and extends arm, anterior fibers flex and medially rotates at shoulder; while posterior fiber lengthen and laterally rotates arm at shoulder, specifically on joint.
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Innervation: Axillary nerves
Muscle B: Latissimus dorsi
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Action: adduction, extension, and medial rotation of the arm; posterior and inferior movement of the arm; costal attachment that enables deep inspiration and also forced expiration
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Innervation: Thoracodorsal nerve
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Kicking a Ball
Muscle A: Quadriceps Femoris
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Action: extension of thigh at hip joint; leg flexes at the knee joint;
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Innervation: Femoral nerve
Muscle B: Rectus Femoris
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Action: four (4) heads extends leg at knee joint; flexing of thigh at hip joint
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Innervation: Femoral nerve
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Doing Sit-Ups
Muscle A: Rectus abdominis
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Action: vertebral column flexes (lumbar region); RMA: flexing of pelvis on the vertebral column
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Innervation: Thoracic spinal nerves (T7-T12)
Muscle B: Transversus abdominis
- Action: compression of abdomen
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Innervation: (1) Thoracic spinal nerves (T8-T12) , (2), iliohypogastric nerve, and (3) ilioinguinal nerve
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Breathing
Muscle A: Diaphragm
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Action: contraction causes an increase in the vertical dimension of the thoracic cavity, which allows inhalation; relaxation causes an upwards movement which decreases the vertical dimension of the thoracic cavity, which allows exhalation
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Innervation: Phrenic nerve
Muscle B: External intercostals
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Action: contractions elevates the ribs which increases anteroposterior and lateral dimensions of thoracic cavity, which allows in inhalation; the relaxation depresses the ribs which decreases the anteroposterior and lateral dimensions of thoracic cavity, which allows in exhalation
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Innervation: Thoracic spinal nerves (T2-T12)
Tortora, G. J., & Derrickson, B. H. (2017). Tortora’s Principles of Anatomy & Physiology. Wiley.