biology

Omphalocele

Omphalocele is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Omphalocele rather than just read about it. In short: An omphalocele or omphalocoele, also known as an exomphalos, is a rare abdominal wall defect. Beginning at the 6th week of development, rapid elongation of the gut and increased liver size reduces intra-abdominal space, which pushes intestinal loops out of the abdominal cavity.

Key takeaways

Omphalocele belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Omphalocele to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Omphalocele from memory before moving on to harder problems.

Reference excerpt

An omphalocele or omphalocoele, also known as an exomphalos, is a rare abdominal wall defect. Beginning at the 6th week of development, rapid elongation of the gut and increased liver size reduces intra-abdominal space, which pushes intestinal loops out of the abdominal cavity. Around the 10th week, the intestine returns to the abdominal cavity and the process is completed by the 12th week. Persistence of intestine or the presence of other abdominal viscera (e.g. stomach, liver) in the umbilical cord results in an omphalocele. Omphalocele occurs in 1 in 4,000 births and is associated with a high rate of mortality (25%) and severe malformations, such as cardiac anomalies (50%), neural tube defect (40%), exstrophy of the bladder and Beckwith–Wiedemann syndrome. Approximately 15% of live-born infants with omphalocele have chromosomal abnormalities. About 30% of infants with an omphalocele have other congenital abnormalities.

Signs and symptoms The sac, which is formed from an outpouching of the peritoneum, protrudes in the midline, through the umbilicus (navel). It is normal for the intestines to protrude from the abdomen, into the umbilical cord, until about the tenth week of pregnancy, after which they return to inside the fetal abdomen. The omphalocele can be mild, with only a small loop of intestines present outside the abdomen, or severe, containing most of the abdominal organs. In severe cases surgical treatment is made more difficult because the infant's abdomen is abnormally small, having had no need to expand to accommodate the developing organs. Larger omphaloceles are associated with a higher risk of cardiac defects.

Complications Complications may occur prenatally, during birth, management, treatment or after surgery. Both prenatally and during birth, the exomphalos can rupture. During birth there may be trauma to the liver for giant omphaloceles. During management exomphalos can act as a metabolic drain affecting nitrogen balance which can lead to failure to thrive, as well as hypothermia. Use of a non-absorbent patch during surgery can lead to wound sepsis post-surgery. Herniation from the patch is also a possibility. Intestinal dysfunction for a few weeks after the surgery is common, therefore parenteral feeding is continued post-surgery, however prolonged use of this may lead to hepatomegaly and cholestasis. If intestinal dysfunction persists it can lead to intestinal necrosis. Intestinal atresia can occur, which is where the mucosa and submucosa of the intestine form a web that obstructs the lumen which leads to malabsorption. Obstruction of the bowel can occur which results in short bowel syndrome. For the first few years of life there is a high incidence of gastroesophageal reflux which can be complicated by oesophagitis. Post-surgery the umbilicus (navel) is deficient or abnormally placed that causes dislike amongst many patients. Umbilical reconstruction can be difficult due to scar tissue and lack of extra skin for surgical use, though this can be overcome by using tissue expanders below the skin and umbilicoplasty. Ultimately, prognosis depends on the size of the defect and whether associated abnormalities are present or complications develop. Mortalities and morbidities still occur, with the mortality rate for large omphaloceles with associated abnormalities being higher. Most surviving omphalocele infants have no-long-term problems and grow up to be normal individuals.

Causes

Omphalocele is caused by malrotation of the bowels while returning to the abdomen during development. Some cases of omphalocele are believed to be due to an underlying genetic disorder, such as Edward's syndrome (trisomy 18) or Patau syndrome (trisomy 13). Beckwith–Wiedemann syndrome is also associated with omphaloceles.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Omphalocele

Start with the simplest possible case. Write down what Omphalocele claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Omphalocele before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Omphalocele ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Omphalocele

In research: Omphalocele appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Omphalocele in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Omphalocele is common in secondary-school and first-year university syllabi. It links to neighbouring topics Congenital disorders of digestive system, Congenital disorders of musculoskeletal system, Genetic disorders with OMIM but no gene, so understanding it makes those chapters shorter.
In everyday life: Look for Omphalocele outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Omphalocele in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Omphalocele means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Omphalocele out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Omphalocele in simple terms?

Why does Omphalocele matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Omphalocele?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Omphalocele.