Human Anatomy & Physiology: muscles and muscle tissues Flashcards


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structure of skeletal muscle

ALL OF THESES TISSUE SHEATHS ARE CONTINUOUS WITH ONE ANOTHER AS WELL AS WITH THE TENDONS THAT JOIN MUSCLES TO BONES IN AT LEAST TWO PLACES

Nerve & blood supply: in general one nerve, on artery, and one or more veins serve each muscle. All of these structures enter or exit near the central part of the muscle and branch through its connective tissue sheaths. unlike cells of cardiac and smooth muscle tissues, which contract w/out nerve stimulation, every skeletal muscle fiber is supported with a nerve ending that controls its activity. skeletal muscle has very rich blood supply. This makes sense because contracting muscle fibers use huge amounts of energy and require almost continuous delivery of oxygen and nutrients via the arteries.

Connective Tissue Sheaths: In all intact muscle tissues, several different sheaths wrap individual muscle fibers. Collectively, these sheaths support each cell and reinforce and hold together the muscle as a whole. There connective tissue sheath types:

  1. Epimysium: (outside the muscle)-overcoat of dense irregular tissue surounding the whole muscle.
  2. Perimysium and fasicals: (withen the muscle)- the muscle fibers are grouped into fascicles. Surrounding (Peri) each fascicle is a layer of fibrous connective tissue called permysium.
  3. Endomysium-(within the muscle)- a sheath of CT that surrounds each individule muscle fiber. Consists of fine areolar tissue.
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Masseter:

  1. What is the orgin?
  2. What is the Insertion?
  1. Orgin-Zygomatic arch and zygomatic bone.
  2. Insertion-angle and ramus of mandible.
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Digastric:

  1. What is the orgin?
  2. What is the function?
  1. Orgin- lower margin of mandible and mastoid process of temporal bone.
  2. Insertion- by a conective tissue loop to hyoid bone.
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Sternohyoid:

  1. What is the orgin?
  2. What is the insertion?
  1. Orgin-manubrium and medial end of clavicle
  2. Insertion- lower margin of hyoid bone.
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Sternothyroid:

  1. What is the orgin?
  2. What is the insertion?
  1. Orgin- posterior surface of manubrium of sternum.
  2. Insertion- thyroid cartilage.
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Sternocleidomastoid:

  1. What is the Orgin?
  2. what is the insertion?
  1. Orgin- Manubrium of sternum and medial portion of clavicle
  2. Insertion- Mastoid process of temporal bone and superior nuchal line of occipital bone.
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Scalenes:

  1. What is the orgin?
  2. What is the insertion?
  1. Orgin- transverse processes of cervical vertebrae
  2. Insertion-anterolaterally on first two ribs.