Paralysis
From Free net encyclopedia
Paralysis is the complete loss of muscle function for one or more muscle groups. Major causes are stroke, trauma, poliomyelitis, amyotrophic lateral sclerosis (ALS), botulism, spina bifida, multiple sclerosis, and Guillain-Barré syndrome.
Paralysis may be localized, or generalized, or it may follow a certain pattern. For example, localized paralysis occurs in Bell's palsy where one side of the face may be paralysed due to inflammation of the facial nerve on that side. Patients with stroke may be weak throughout their body (global paralysis) or have hemiplegia (weakness on one side of the body) or other patterns of paralysis depending on the area of damage in the brain. Other patterns of paralysis arise due to different lesions and their sequelae. For example, lower spinal cord damage from a severe back injury may result in paraplegia, while an injury higher up on the spinal cord, such as a neck injury, can cause quadriplegia.
Poisons that interfere with nerve function, such as curare, can also cause paralysis.
Famous people with paralysis include the late actor Christopher Reeve; the architect Michael Graves; Sam Sullivan, mayor of Vancouver, British Columbia, Canada; and Jesse Billauer from the movie Step Into Liquid; and hundreds of thousands of others around the world.
Paralysis in the animal world
Many species of animals use paralyzing toxins in order to capture prey, evade predation, or both. One famous example is the tetrodotoxin of fish species such as Takifugu rubripes, the famously lethal pufferfish of Japanese fugu. This toxin works by binding to sodium channels in nerve cells, preventing the cells' proper function. A non-lethal dose of this toxin results in temporary paralysis. This toxin is also present in many other species ranging from toads to nemerteans. Another interesting use of paralysis in the natural world is the behavior of some species of wasp. In order to complete the reproductive cycle, the female wasp first paralyzes a prey item such as a grasshopper and then places it into her nest. Eggs are then laid on the paralyzed insect, which is devoured by the larvae after they hatch. Many snakes also exhibit powerful neurotoxins that can cause non-permanent paralysis or death.
See also
- Paraplegia
- Quadriplegia
- Muscle relaxant
- Ptosis
- Sleep paralysis
- Hemiparesis
- Beriberi
- Jesse Billauer
- Neuroprosthetics
- Brain-computer interfacede:Lähmung