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Biology 2nd Baccalaureate

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10.4. Musculoskeletal disorders

We will distinguish between diseases that affect the locomotor system and the injuries that can occur:

Musculoskeletal diseases

  • OsteoporosisProgressive loss of bone mass that weakens the bones making them more brittle. It is produced by a lack of extracellular collagen matrixon which calcium phosphate has to accumulate. It is a normal process during aging, which can be aggravated by the hormonal changes of menopause.
  • Arthritis. Pain produced by inflammation of a joint.
  • Arthrosis. Joint pain due to degeneration of the cartilage of the joints, usually associated with age. It causes pain and deformation of the joint.
  • Childhood rickets. Poor growth and weakening of the bones due to lack of vitamin Dcalcium or phosphorus in the diet.

Musculoskeletal injuries

Injuries are not only suffered by athletes or when we exercise. They can be derived from poor posture, excessive load, disease, age, overweight ... Depending on the structure affected, we distinguish:

Bone injuries

They affect the bones, are usually caused by a blow or osteoporosis:

  • Fissures. Cracks that occur in the bones without part of it separating. It is a partial break of the bone.
  • Fractures: Total breakage of the bone. Can be:
    • Internal fracture: the bone does not pass through the skin.
    • External fracture: the bone passes through the skin and is exposed.

Communitive midshaft humeral fracture callus.jpg

By Bill Rhodes from Asheville (mid-shaft humeral compound comminuted fx lat) [CC BY 2.0], via Wikimedia Commons

Answer in your notebook

10.8.- Osteoporosis is a fairly common disease in older people. Find information about this disease and briefly explain what this disease consists of and what healthy habits you would recommend to avoid suffering from this disease.

Muscle injuries

  • Muscle contusion. Produced by a blow that compresses the muscle against the bone. It causes pain when stretching the muscle and an inflammatory edema.
  • Contracture. There is an involuntary permanent contraction of the muscle, producing a tension of the muscle even in a relaxed state. The muscle does not relax, and the area remains hard and bulky.
  • Cramp. Involuntary contraction of one or more muscles with mild or severe pain that can make those muscles tighten. It can be caused by insufficient oxygenation of the muscles or by the loss of fluids and mineral salts as a result of overexertion .
  • Muscle tear or muscle pull. Breakage of several muscle fibers due to a blow or overexertion, in addition to the breakage of the blood vessels that run through the muscle, causing bleeding. It causes severe pain that prevents the muscle from contracting.
  • Shoelaces. Although traditionally, in Biology books, it was said that it was a muscle pain due to the accumulation of lactic acid in the muscle fibers when subjected to an effort to which they were not used (lactic fermentation), the most accepted theory currently is which is due to micro-tears of muscle fibers.
  • Tendinitis. Inflammation of a tendon  due to an overuse, a blow, or age.

Joint injuries

  • Sprain. Overstretching of a ligament, usually of the ankle or wrist, caused by a twist of the joint. It causes severe pain, swelling, and the joint cannot be moved.

Crossword: The locomotor system.

Activity: Musculoskeletal injuries.


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