Conjoined Twins and Split Brain Patients
Conjoined Twins and Split Brain Patients
Conjoined twins are identical twins[1] joined in utero. An extremely rare phenomenon, the occurrence is estimated to range from 1 in 49,000 births to 1 in 189,000 births, with a somewhat higher incidence in Southwest Asia and Africa.[2] Approximately half are stillborn, and an additional one-third die within 24 hours. Most live births are female, with a ratio of 3:1.[2][3]
Two contradicting theories exist to explain the origins of conjoined twins. The more generally accepted theory is fission, in which the fertilized egg splits partially.[4] The other theory, no longer believed to be the basis of conjoined twinning,[4] is fusion, in which a fertilized egg completely separates, but stem cells (which search for similar cells) find similar stem cells on the other twin and fuse the twins together. Conjoined twins share a single common chorion, placenta, and amniotic sac, although these characteristics are not exclusive to conjoined twins, as there are some monozygotic but non-conjoined twins who also share these structures in utero.[5]
Chang and Eng Bunker (1811–1874), Thai brothers born in Siam, now Thailand, traveled widely for many years and were labeled as The Siamese Twins. Chang and Eng were joined at the torso by a band of flesh, cartilage, and their fused livers. In modern times, they could have been easily separated.[6] Due to the brothers’ fame and the rarity of the condition, the term “Siamese twins” came to be used as a synonym for conjoined twins.[7]
ORDER NOW FOR AN ORIGINAL PAPER!!!Conjoined Twins and Split Brain Patients
As often is the case in science, the study of unique phenomenon can provide a wealth of knowledge and information about normal occurrences. This is true with regard to case studies of both split brain patients and conjoined twins. The unique experiences of these patients have contributed a great deal to our understanding of how the brain functions in a range of both normal and extraordinary circumstances.
Split brain patients are people who have had surgery to cut the corpus callosum, which you may recall, is the main pathway connecting the two halves of the cortex. Often this procedure was done to alleviate symptoms of epilepsy. These patients acted normal enough so that for the first few years after such surgeries were performed, physicians reported that there were no consequences of the procedure. Over the years, however, careful behavioral studies revealed that these patients appeared to have two minds at work in one body. One mind, mediated by the left hemisphere, could talk and respond to questions, while the other mind, in the right hemisphere, could only communicate by gestures and action. Remarkably, the left brain seemed to be unaware that another mind controlled half of the body.
In the case of dicephalic parapagus conjoined twins, (twins who share a body but have separate brains) it is clear that there are two minds because there are two separate brains and each of them can communicate. In craniopagus conjoined twins, there are two separate bodies but a shared brain or portions of brain.
The range of behavior, from relatively normal to unique, of split brain patients and conjoined twins raises questions about what it means to be a “person.” For this week’s Discussion, you compare and contrast split brain patients and conjoined twins, and explore what “personhood” means in light of what these patients can teach us about the brain and its functions.
With these thoughts in mind:
Explain how split-brain patients demonstrate the organization of the brain. Then, describe two similarities and two differences between split brain patients and conjoined twins. Finally, define “personhood” in your own words as it relates to split brain patients or conjoined twins and use the current literature to support your definition.
APA format
Plagiarism free
24/7 Nursing Homework Help
Stuck with your nursing assignment? From Essays to Complicated Dissertations? Our accredited nursing paper writers can answer it all!
