| Popis: |
Disorders which mimic the distal colonic obstruction typical of Hirschsprung’s disease are described under a number of terms including adynamic bowel, pseudo- Hirschsprung’s disease, megacystis-microcolon hypoperistalsis syndrome, and visceral neuropathies and myopathies. They may be caused by a wide variety of different disorders including conditions which are intrinsic to the enteric neuromusculature as well as disorders where the environment in which the neuromusculature operates is abnormal such as in inflammatory conditions. Most of these diseases have their effect by disrupting the normal control mechanisms of the motor apparatus of the gut. The normal patterns of contraction of the muscle coats of the gut are dependent upon the control mechanisms which act upon the smooth muscle cells of the muscularis propria at many different levels to produce the required effects. The control mechanisms consist of properties of the smooth muscle cells themselves, an intrinsic network of nerves, the enteric nervous system with multiple neurotransmitters modulated by extrinsic nerves, paracrine and endocrine hormones, and other neuromuscular active compounds. |
