Lecture 22: Abdomen II (Gut development + Peritoneum)

Question 1

3 divisions of the primitive gut tube

Answer 1

foregut
midgut
hindgut

Question 2

what does the foregut form

Answer 2

stomach
liver
gall bladder
spleen
pancreas
1/5 duodenum

Question 3

what does the midgut form

Answer 3

remaining duodenum
jejunum
ileum
cecum
ascending and 2/3 of the transverse colon

Question 4

what does the hindgut form

Answer 4

1/3 transverse colon
descending and sigmoid colons
rectum

Question 5

what does the peritoneum develop from

Answer 5

the intraembryonic coelom (the main body cavity in animals)

Question 6

The intraembryonic coelom is divided into what 4 body cavities

Answer 6

(1) pericardial cavity
(2) pericardioperitoneal canals
(1) peritoneal cavity
- septum transversum
- pleuropericardial membrane
- pleuroperitoneal membrane

Question 7

single serous layer of flattened mesothelial cells supported by a fibroelastic connective tissue that attaches to a body wall, diaphragm and visceral structures

Answer 7

peritoneum

Question 8

the space (cavity) enclosed by the peritoneum

Answer 8

peritoneal cavity

Question 9

fluid secreted by mesothelial cells into the peritoneal cavity that allows layers of the peritoneum to glide against one another

Answer 9

peritoneal fluid

Question 10

what is the lubrication provided by the peritoneal fluid vital for

Answer 10

gastrointestinal motility and preventing the viscera from attaching to the abdominal wall

Question 11

where is the peritoneal fat stored

Answer 11

b/w peritoneal layers

Question 12

what is the clinical relevance of the peritoneum having a large, rapidly absorptive surface area?

Answer 12

toxins are readily absorbed by it & the warm and moist peritoneal cavity provides ideal conditions for bacterial growth

Question 13

what part of the primitive tube develops faster than all others

Answer 13

midgut

Question 14

as the midgut migrates ventrally, 2 layers of peritoneum migrate together, forming what is called the ______

Answer 14

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

Question 15

why is the midgut forced to herniate into the umbilical cord

Answer 15

bc it grows faster than the body cavity

Question 16

term for organs that are suspended from the dorsal abdominal wall & are surrounded by peritoneum on all sides

Answer 16

intraperitoneal (ex: midgut)

Question 17

term for organs that are directly joined to the abdominal wall (lie behind the peritoneum) have no mesentery or peritoneum dorsally

Answer 17

retroperitoneal

Question 18

what is the main function / benefit of the dorsal mesentery

Answer 18

allows the intestines to move as a normal part of digestion without bowels becoming twisted or blocked

Question 19

what is a volvulus

Answer 19

loop of intestine and mesentery that becomes twisted, can lead to strangulated and obstructed bowels

Question 20

function of the greater omentum (a double fold of peritoneum)

Answer 20

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

Question 21

what is the omentum

Answer 21

connecting peritoneum that attaches the stomach to the body wall or other organs. an extended mesogastrium

Question 22

what are the 4 basic alimentary layers

Answer 22

1. mucosa
2. submucosa
3. muscularis externa
   - circular & longitudinal
4. adventitia (rough) or serosa (smooth)

Question 23

what is the celiac trunk innervated by (sympathetic and parasympathetic)

Answer 23

sympathetic: celiac ganglion
parasympathetic: vagus (X)

Question 24

what is the cranial mesenteric artery innervated by (sympathetic and parasympathetic)

Answer 24

sympathetic: cranial mesenteric ganglion
parasympathetic: vagus (X)

Question 25

what is the caudal mesenteric artery innervated by (sympathetic and parasympathetic)

Answer 25

sympathetic: caudal mesenteric ganglion
parasympathetic: pelvic splanchnic nerve

Question 26

what is lamina propria

Answer 26

CT layer with immune cells

Question 27

what is present in the submucosa

Answer 27

CT layer with blood vessels and glands

Question 28

what is the function of the muscularis mucosa

Answer 28

contracts the mucosa, consists of multiple smooth muscle layers