Lecture 22: Abdomen II (Gut development + Peritoneum) Flashcards
3 divisions of the primitive gut tube
foregut
midgut
hindgut
what does the foregut form
stomach
liver
gall bladder
spleen
pancreas
1/5 duodenum
what does the midgut form
remaining duodenum
jejunum
ileum
cecum
ascending and 2/3 of the transverse colon
what does the hindgut form
1/3 transverse colon
descending and sigmoid colons
rectum
what does the peritoneum develop from
the intraembryonic coelom (the main body cavity in animals)
The intraembryonic coelom is divided into what 4 body cavities
(1) pericardial cavity
(2) pericardioperitoneal canals
(1) peritoneal cavity
- septum transversum
- pleuropericardial membrane
- pleuroperitoneal membrane
single serous layer of flattened mesothelial cells supported by a fibroelastic connective tissue that attaches to a body wall, diaphragm and visceral structures
peritoneum
the space (cavity) enclosed by the peritoneum
peritoneal cavity
fluid secreted by mesothelial cells into the peritoneal cavity that allows layers of the peritoneum to glide against one another
peritoneal fluid
what is the lubrication provided by the peritoneal fluid vital for
gastrointestinal motility and preventing the viscera from attaching to the abdominal wall
where is the peritoneal fat stored
b/w peritoneal layers
what is the clinical relevance of the peritoneum having a large, rapidly absorptive surface area?
toxins are readily absorbed by it & the warm and moist peritoneal cavity provides ideal conditions for bacterial growth
what part of the primitive tube develops faster than all others
midgut
as the midgut migrates ventrally, 2 layers of peritoneum migrate together, forming what is called the ______
dorsdal MESENTERY
- acts as support to the midgut that is hanging from the dorsal wall. Also supports and provides pathway to the blood vessels, nerves, and lymphatics going to and from the structure
why is the midgut forced to herniate into the umbilical cord
bc it grows faster than the body cavity
term for organs that are suspended from the dorsal abdominal wall & are surrounded by peritoneum on all sides
intraperitoneal (ex: midgut)
term for organs that are directly joined to the abdominal wall (lie behind the peritoneum) have no mesentery or peritoneum dorsally
retroperitoneal
what is the main function / benefit of the dorsal mesentery
allows the intestines to move as a normal part of digestion without bowels becoming twisted or blocked
what is a volvulus
loop of intestine and mesentery that becomes twisted, can lead to strangulated and obstructed bowels
function of the greater omentum (a double fold of peritoneum)
prevents adhesions b/w abdominal viscera (organs) and the ventral abdominal wall
prevents spread of infection from perforations in the intestines by sealing off sites of perforation
what is the omentum
connecting peritoneum that attaches the stomach to the body wall or other organs. an extended mesogastrium
what are the 4 basic alimentary layers
- mucosa
- submucosa
- muscularis externa
- circular & longitudinal - adventitia (rough) or serosa (smooth)
what is the celiac trunk innervated by (sympathetic and parasympathetic)
sympathetic: celiac ganglion
parasympathetic: vagus (X)
what is the cranial mesenteric artery innervated by (sympathetic and parasympathetic)
sympathetic: cranial mesenteric ganglion
parasympathetic: vagus (X)
what is the caudal mesenteric artery innervated by (sympathetic and parasympathetic)
sympathetic: caudal mesenteric ganglion
parasympathetic: pelvic splanchnic nerve
what is lamina propria
CT layer with immune cells
what is present in the submucosa
CT layer with blood vessels and glands
what is the function of the muscularis mucosa
contracts the mucosa, consists of multiple smooth muscle layers
