Embryology 1 Flashcards by Freddie Philbrook

What structures comprise the alimentary canal?§

Mouth to anus - including all associated glands and organs

How well did you know this?

Not at all

Perfectly

At what week of development does the primordial gut form?

4th

How well did you know this?

Not at all

Perfectly

Which membranes enclose the primordial gut at its cranial and caudal end respectively?

Cranial - oropharyngeal membrane

Caudal - cloacal membrane

How well did you know this?

Not at all

Perfectly

What is the process of gastrulation?

Formation of trilaminar disc (echo, end and mesoderm)

How well did you know this?

Not at all

Perfectly

What three regions is the primordial gut divided into?

Foregut, midgut and hindgut

How well did you know this?

Not at all

Perfectly

What does the endoderm of the primordial gut form?

Most of the gut, epithelium and glands

How well did you know this?

Not at all

Perfectly

Epithelium from the cranial and caudal end of gut are derived from what two structures? Give specific names

Ectoderm (stomodeum) and anal pit (proctodeum)

How well did you know this?

Not at all

Perfectly

What forms the embryonic body cavity at the forth week of development?

Intraembryonic coelom

How well did you know this?

Not at all

Perfectly

The embryonic body cavity divides into what three well defined structures?

Pericardial and peritoneal cavity plus two pericardia-peritoneal canals

How well did you know this?

Not at all

Perfectly

What are the derivative structures of the foregut?

Primordial pharynx
Lower resp. tract
Oesophagus and stomach 
Duodenum
Liver and biliary apparatus (including pancreas)

How well did you know this?

Not at all

Perfectly

What is the pharynx?

Space in the throat which is a shared for both digestive and respiratory systems

How well did you know this?

Not at all

Perfectly

What is the duodenum?

Proximal tubing of intestines to the stomach where bile is secreted

How well did you know this?

Not at all

Perfectly

What is oesophageal atresia?

Congenital non-seperation/blockage/extensive narrowing of oesophagus

How well did you know this?

Not at all

Perfectly

What is abnormal deviation of trachea-oesophageal septum called?

Oesophageal fistula

How well did you know this?

Not at all

Perfectly

What is polyhydramnios?

Too much amniotic fluid around the foetus, sue to atresia

How well did you know this?

Not at all

Perfectly

Outline the main events in the development of the stomach

Rotation of stomach (90 degrees clockwise)

- Mesenteries of stomach and mental bursa (lesser sac) develop

How well did you know this?

Not at all

Perfectly

What is hypertrophic pyloric stenosis?

Overgrowth of the pyloric sphincter (opening from stomach into duodenum)

How well did you know this?

Not at all

Perfectly

What is the prevalence of hypertrophic pyloric stenosis?

1 in 150 for males

1 in 750 for females

What are potential causes for hypertrophic pyloric stenosis? What evidence supports it?

Genetic factors (high presence in monozygotic twins)

What is the only treatment for hypertrophic pyloric stenosis?

Surgery

Outline the development of the liver and biliary apparatus?

Hepatic diverticulum septates… thats about it so far

What anomalies of the hepatic system are possible?

Accessory hepatic ducts (5% of population) and extrahepatic biliary atresia (obliteration of the bile ducts)

What occurs if the ventral bus fails to migrate around the duodenum correctly?

Annular pancreas

Describe accessory pancreatic tissue?

Pancreatic tissue may form in other areas of the foregut

Explain the origins and development of the spleen

End of the 4th week a mesenchymal condensation develops forming the dorsal mesogastrium During the 5th week the mesenchyme differentiates into spleen tissue

What laminar disc does the spleen develop from?

Mesoderm

Outline the main events of the midgut loop

- Herniation (physiological umbilical herniation) - Rotation of midgut 90 degrees anticlockwise in the umbilical cord - Retraction of intestinal loops - 180 degrees more anticlockwise rotation - Fixation of intestines

In what percentage of people does the small vitelline duct persist?

2-4%

What does a persistent vitelline duct form?

Merkel diverticulum

What complications can raise from a persistent vitelline duct?

Fistula or cyst

What is omphalocele?

Herniation of abdominal viscera through an enlarged umbilical ring

What visceramay an omphalocele include?

Herniation of liver, stomach and intestinal loops

What covers the viscera of an omphalocele?

Amnion

What is amnion?

A membrane which closely covers embryo

What is herniation of abdominal contents directly through the body wall into the amniotic cavity called?

Gastroschisis

What are suggested causes for rising prevalence in births with babies afflicted with gastroschisis, especially from young women?

Cocaine use

What is the prevalence of gastroschisis not associated with?

Chromosomal defects

What structures comprise the hindgut?

Distal third of transverse colon, descending colon, sigmoid colon, rectum and upper part of anal canal

What does the endoderm of the hindgut also form?

The lining of the bladder and urethra

What is the cloaca?

The expanded terminal part of the hindgut and endoderm lined chamber

What is the allantois?

The ventral diverticula of cloaca

What is the function of the cloacal membrane?

Separates cloaca and the anal pit

Describe the partitioning of the cloaca

1. Week 7 - the cloacal membrane ruptures (opening for hindgut) 2. Ectoderm proliferates at the anal canal and closes caudal end 3. Week 9 - anal canal re-opens

List hindgut developmental anomalies

Urorectal fistula Rectovaginal fistula Rectoanal atresia Imperforate anus