atrophy

Examples of atrophy in the following topics:

• Muscular Atrophy

  • Muscle atrophy can occur from disuse (decreated activity) or disease, resulting in power loss or immobility.
  • Most cases of muscle atrophy in the general population results from disuse.
  • This type of atrophy is reversible with vigorous exercise.
  • Muscle atrophy that results from disease rather than disuse is generally one of two types:
  • Even minor muscle atrophy usually results in some loss of mobility or power.

• Muscular Atrophy and Hypertrophy

  • Muscle atrophy is the decrease in muscle strength due to a decrease in muscle mass, or the amount of muscle fibers.
  • Atrophy can be partial or complete, varying in the extent of muscle weakness.
  • Starvation can also result in muscle atrophy.
  • Muscle atrophy is typical to some extent during aging.
  • Atrophy over time due to aging is known as sarcopenia.

• Amyotrophic Lateral Sclerosis

  • Amyotrophic lateral sclerosis (ALS) is caused by degeneration of upper and lower motor neurons, resulting in muscle weakness and atrophy.
  • The disorder causes muscle weakness and atrophy throughout the body as a result of degeneration of the upper and lower motor neurons.
  • Unable to function, the muscles weaken and atrophy.
  • The earliest symptoms of ALS are typically obvious weakness and/or muscle atrophy.
  • Symptoms of lower motor neuron degeneration include muscle weakness and atrophy, muscle cramps, and fleeting twitches of muscles that can be seen under the skin (fasciculations).

• Hypoglossal (XII) Nerve

  • Progressive bulbar palsy is a neuromuscular atrophy associated with combined lesions of the hypoglossal nucleus and nucleus ambiguous upon atrophy of motor nerves of the pons and medulla.
  • Tongue muscle atrophy may also occur.

• Embryological and Fetal Events

  • A large part of the head end of the mesonephros atrophies and disappears; of the remainder the anterior tubules form the efferent ducts of the testis; while the posterior tubules are represented by the ductuli aberrantes, and by the paradidymis, which is sometimes found in front of the spermatic cord above the head of the epididymis.
  • In the female the Wolffian bodies and ducts atrophy.
  • In the male the Müllerian ducts atrophy, but in the female the Müllerian ducts persist and undergo further development.

• Stress and Disease

  • This atrophy of the hippocampus is thought to represent decreased neuronal density.
  • However, other studies suggest that hippocampal changes are explained by whole brain atophy, and generalized white matter atrophy is exhibited by people with PTSD.

• Stability and Range of Motion at Synovial Joints

  • These include the shape of articular surfaces (how close they fit); strength and tension of capsule and ligaments (dependent on position); arrangement and tension of muscles; contact with soft parts such as adipose tissue; hormones; disuse causing decrease in synovial fluid, flexibility of ligaments and tendons, and muscle atrophy; gravity; and atmospheric pressure.

• Accessory (XI) Nerve

  • Patients with spinal accessory nerve palsy may exhibit signs of lower motor neuron disease such as atrophy and fasciculations of both the sternocleidomastoid and trapezius muscles.

• Hair and Hormones

  • Male baldness is the result of genetic sensitivity of hair follicles to dihydrotestosterone that causes hair follicles to atrophy.

• Tonsils

  • Similarly to the thymus, the tonsils tend to reach their largest size near puberty, and they gradually undergo atrophy thereafter.