Chapter 3: Abdomen, Pelvis, and Perineum (continued 2) Flashcards
What is duodenal atresia caused by?
when the lumen of the duodenum is occluded owing to failed recanalization
Symptoms of duodenal atresia?
polyhydramnios, bile-containing vomitus, and distended stomach
What is omphalocele?
when the midgut fails to return to the abdominal cavity and remains in the umbilical stalk
What is gastrochschisis? Pathology?
When the abdominal viscera herniate through the body wall directly into the amniotic cavity, usually to the right of the umbilicus
Defect in the closure of the lateral body folds and weakness of anterior wall
What is ileal Meckel diverticulum?
occurs when a remnant of the vitelline duct persists, thereby forming a blind pouch on the antimesenteric border of the ileum
What are some causes of Meckel’s diverticulum inflammation?
if it contains ectopic gastric, pancreatic, or endometrial tissue which may produce ulceration
What is the rule of 2’s for Meckel’s diverticulum?
found 2 feet from the ileocecal junction, 2 inches long, and appears in 2% of the population
What is a vitelline fistula?
occurs when the vitelline duct persists, thereby forming a direct connection between the intestinal lumen and the outside body at the umbilicus
What is malrotation of the midgut?
occurs when the midgut undergoes only partial rotation and results in abnormal position of abdominal viscera
What can malrotation of the midgut be associated with?
volvulus (twisting of intestines)
What is another name for Hirschsprung disease?
Colonic aganglionosis
What is Hirschsprung disease?
when there is failure of the neural crest cells to form the myenteric plexus in the sigmoid colon and rectum
What are symptoms of Hirschsprung disease?
loss of peristalsis and immobiilty of the hindgut, fecal retention and abdominal distention of the transverse colon (megacolon)
What is the portal triad composed of?
the hepatic artery proper, common bile duct, and portal vein
The hepatopancreatic ampulla drains into which part of the duodenum?
2nd part of the duodenum
The head of the pancreas receives its blood supply from where?
superior and inferior pancreaticoduodenal branches of the gastroduodenal and superior mesenteric arteries
What structure may be compressed in carcinoma of the pancreas?
carcinoma of the pancreas commonly occurs in the head of the pancreas and may constrict the main pancreatic duct and the common bile duct.
The neck, body, and tail of the pancreas receive their blood supply from which artery?
splenic artery
What is a sliding hiatal hernia?
involves movement of the gastroesophageal junction and part of the stomach into the chest cavity.
A sliding hernia can damage which structure?
vagal trunks
A fracture of which ribs may cause a laceration of the spleen?
fracture of 9th, 10th, or 11th rib on the left side
The splenic artery and vein reach the hilus of the spleen by traversing which structure?
splenorenal ligament
What is the smooth muscle in the wall of the duodenal papilla also known as?
sphincter of Oddi
The foregut terminates at which part of the GI?
terminates at the entry of the common bile duct
What part of the pelvic diaphragm pulls the anorectal flexure forward helping to maintain fecal continence?
puborectalis component
What produces voluntary control for the external anal sphincter?
inferior rectal branch of the pudendal nerve and relaxes during defecation
The anal canal is divided into upper and lower parts separated by what?
the pectinate line, an elevation of the mucous membrane at the distal ends of the anal column
Compare/contrast sensory innervation above and below the pectinate line?
visceral (ANS) sensory innervation (above)
somatic sensory innervation (below)
Compare/contrast venous drainage above the pectinate line to below it?
portal venous drainage above and
caval venous drainage below
Describe drainage of lymph above pectineal line to below.
above drains to iliac lymph nodes
below drains to superficial inguinal lymph nodes
Describe how hemorrhoids are felt when they occur above pectineal to below the pectineal line.
Above: internal hemorrhoids (painless)
Below: external hemorrhoids (painful)
Describe the embyrological origin of the anal canal above the pectinate line and below.
Above the pectinate line is endoderm
Below the pectinate line is ectoderm
What are the 4 layers that the walls of the GI are composed of?
mucosa
submucosa
muscularis externa
serosa/adventitia
What makes up the layers of the mucosa of the GI tube?
epithelium
lamina propria
muscularis mucosa
What is the purpose of the muscularis mucosa as a component of the mucosa of the GI? Also what is it?
thin smooth-muscle layer that is part of the mucosa
confers some motility and facilitates gastric secretions from glands
What are some major components of the submucosa of the GI?
layer of loose connective tissue that attaches mucosa to muscularis externa and houses the larger blood vessels and mucous secreting glands
What are the 2 layers of muscle that comprise the muscularis externa of the GI?
2 layers:
Inner circular
Outer longitudinal
What is the epithelium of the oral cavity?
stratified squamous epithelium
What type of epithelium covers the stomach.
simple columnar epithelium
What are the parts of the stomach?
cardia, body, fundus, and antrum, pylorus
Proteins are hydrolyzed to polypeptide fragments in the stomach by what enzyme?
pepsin
What are the 2 types of mucous secreted by the stomach mucous secreting cells?
the surface mucous is composed of neutral glycoproteins,
while the mucous secreted by the neck mucous cells is composed of acidic glycoproteins
What is another name for parietal cells?
oxyntic cells
What do the parietal cells secrete? What a few signals of secretion for release of parietal cell contents.
HCl into the stomach lumen and bicarbonate ions into the lamina propria (a byproduct of the acid production) in response to histamine, gastrin, and acetylcholine.
Also secrete IF
What is IF?
intrinsic factor is a glycoprotein necessary for absorption of vitamin B12
Where is the location of the parietal cells in the gastric glands?
upper region of the gastric glands
What are drugs that inhibit histamine release?
cimetidine and H2 antagonists
What do chief or peptic cells secrete?
pepsinogen, an enzyme precursor that is stored in secretory zymogen granules before its induced secretion
What is the environment in the stomach for pepsinogen to be converted to pepsin?
low pH
Hematamesis meaning.
the vomiting of blood.
Melena meaning.
dark sticky feces containing partly digested blood.
Are hematemsis and melena common findings of helicobacter pylori infection?
yes
The stem cells responsible for the regeneration of all types of cells in the stomach epithelium are located where?
in the gastric isthmus
Another name for the plicae circulares?
circular folds or valves of Kerchkring
What are the valves of Kerchkring?
Foldings of the inner surface that involve both mucosa and sub-mucosa
What are the crypts of Lieberkuhn?
they are analagous to the glands of the stomach they are where the luminal surface of the small intestine is perforated by openings of numerous tubular invaginations
What is the name of the glands that secrete mucous in the duodenum and in the mucosa throughout the intestine respectively?
Brunner glands
goblet cells
What part of the small intestine is the plicae circulares best developed?
in the jejunum
What are the 5 types of differentiated cells found in the simple columnar intestinal epithelium that are derived from a common pool of stems cells?
goblet cells
enterocytes
paneth cells
enteroendocrine cells
stem cells
Where are Paneth cells located?
Both location in glands and part of GI
cells located at the base of the crypts, expecially in the jejunum and ileum
What do enteroendocrine cells of the small and large intestine secrete?
secrete hormones that control the function ofthe GI tracts and associated organs
Compare the location in the layers of the GI and location of Brunner’s glands and Peyer’s patches?
duodenum contains submucosal Brunner’s glands
ileum contains Peyer’s Patches in the lamina propria
Does the jejunum have Brunner’s glands or Peyer’s patches?
Peyers patches
Where are stem cells located in the intestines?
located in the crypts, about one-third of the way up from the bottom
The epithelial lining of the small intestine, particularly that covering the villi, completely renews itself how often?
every 5 days or longer during starvation
