Esophagus, Stomach, & Intestines (Exam 2) Flashcards
What are the digestive tract organs?
-esophagus (lower, or abdominal)
-stomach
-SI (duodenum, jejunum, ilieum)
-LI (including sigmoid colon)
What are the accessory organs of the duodenum?
Liver, gallbladder, and pancreas
What are the urinary tract organs?
-kidneys (renal) glands
-ureters (upper, or abdominal)
What are the 4 layers of the digestive tract?
1) serosa or adventitia
2) muscularis externa (muscularis propria)
3) submucosal
4) mucosa
How many layers are in the muscularis externa in most of the digestive tract?
2 layers of smooth muscle
-outer layer is longitudinal
-inner layer is circular
What does the submucosa of the digestive tract contain?
CT containing blood, lymph, and nerve fibers
What is the innermost epithelial lining of the digestive tract?
Mucosal layer
What is the function of the mucosal layer of the digestive tract?
-secrete mucous
-absorb nutrients
The stomach is the only part of the digestive tract that has 3 layers for the muscularis externa. What are the 3 layers?
-outer = longitudinal layer
-middle= circular layer
-inner= oblique layer
What are the 4 features of the lower esophagus?
-diaphragmatic constrictions
-cardiac (also known as lower esophageal, gastroesophageal, or cardio-esophageal) sphincter
-cardiac notch
-cardiac orifice
What are the 3 esophageal constrictors?
1) cervical constriction (upper esophageal sphincter)
2) thoracic (broncho-aortic) constriction
3) diaphragmatic constriction
The cardiac sphincter (also known as gastroesophageal or cardio-esophageal sphincter) is a ____________ muscle ring. Is it voluntary or involuntary?
Test q
Smooth, involuntary
Where is the cardiac sphincter (also known as gastroesophageal or cardio-esophageal sphincter) located and what does it prevent?
Test q
-located between the diaphragmatic constriction where the esophagus meets the stomach
-prevents reflux of stomach contents
What are the muscles of the esophagus?
Muscularis mucosae and muscularis propria/externa
What are the sympathetic nerves of the esophagus?
T1-T10
What are the parasympathetic nerves of the esophagus?
CN X (vagus n.) from the esophageal plexus
What artery innervates the esophagus?
Esophageal branches of the L gastric a. (bottom 1/3 of esophagus)
The esophageal v. drains into the…..
L gastric v. (bottom 1/3 of esophagus)
What are the 4 parts of the stomach?
1) cardia
2) fundus
3) body
4) pylorus
What does the pyloric sphincter regulate?
Test q
Passage of chyme from stomach into SI
What are the characteristics of the mucosal layer of the stomach?
-has mucus membrane
-has folds and rugae
-contains gastric pits and glands
Note: gastric glands are cells that are located in the pits (lamina propria) and open into bases of the gastric pits
What epithelium makes up the mucosal layer of the stomach?
Simple columnar epithelium
What are rugae?
-also known as gastric folds
-it’s longitudinal wrinkles in the gastric mucosa
-allows for expansion of the stomach
What are gastric pits and what are they lined with?
-indentations of gastric mucosa
-contain entrances to gastric glands
-lined with surface mucus cells
What do the foveolar cells secrete?
Test q
Mucus
What do the parietal (oxyntic) cells secrete?
Test q
HCI and intrinsic factor (aids in absorption of vitamin B12 in the terminal ileum)
What do the chief (zymogenic) cells secrete?
Test q
Pepsinogen and gastric lipase
What do the enteroendocrine cells secrete?
Test q
Hormones
-gastrin
-ghrelin
-serotonin
-somatostatin
Where is gastrin secreted from and what does it stimulate?
Test q
-secreted by G cells
-stimulates parietal cells to produce HCI (gastric acid)
What is ghrelin and what does it stimulate?
Test q
-“hunger hormone”
-stimulates appetite
-increases food intake and fat storage
What is the function of serotonin?
Test q
Arousal, mood, and emotions
What does somatostatin inhibit?
Test q
Gastric secretions
What are the sympathetic innervations to the stomach, liver, gallbladder, pancreas, and adrenal medulla?
Test q
T5-T9 -> greater splanchnic n. -> celiac prevertebral ganglia -> stomach
What is the parasympathetic innervation of the stomach, liver, gallbladder, pancreas, and adrenal medulla?
Test q
CN X
What are the 3 parts of the SI?
Duodenum, jejunum, and ileum
Which section of the SI surrounds the head of the pancreas?
Test q
Duodenum
Which section of the SI has the most chemical digestion?
Test q
Duodenum
Which section of the SI starts intraperitoneal but ends retroperitoneal?
Duodenum
Which section of the SI is the shortest?
Jejunum
Which section of the SI is where most absorption of nutrients occurs?
Test q
Jejunum
Which parts of the SI are intraperitoneal?
-top half of duodenum
-jejunum and ileum are fully intraperitoneal
Which section of the SI is the longest?
Ileum
The ileum joins the _____ at the ileocecal valve
LI
What is absorbed in the duodenum?
Calcium and iron
What is absorbed in the terminal ileum?
Vitamin B12
What is absorbed along the entire length of the SI?
Water and lipids
What features does the mucosal layer of the SI have?
-plicae circulares
-villi
-mucosal cells (enterocytes)
-microvilli (brush border)
-crypts of Lieberkuhn
What are the other names for plicae circulares?
-circular folds
-valvulae conniventes
-valves of kerkring
What are the circular folds of the mucosal layer of SI called?
Test q
Plicae circulares
Where are plicae circulares found and what is its function?
Test q
-mostly in lower duodenum and jejunum
-increases surface area
What are vili and what is their function?
test q
-finger like extensions in the mucosal layer of SI on the surface of plicae
-further increases SA for absorption
Where are mucosal cells found and what is their function?
test q
-also known as enterocytes
-on the surface of villi
-line lumen of SI
-absorb nutrients
What are microvilli (brush border)?
test q
-tiny projections on plasma membrane of mucosal cells
-increases SA of plasma membrane
What are crypts of lieberkuhn and where are they found?
test q
-vault or pit between villi
-lined by intestinal glands/cells
What cells are found in the crypts of lieberkuhn?
test q
-stem cells
-argentaffin (enteroendocrine cells)
-paneth cells
What do stem cells in the crypts of lieberkuhn produce?
test q
enterocytes (absorptive) cells
What do argentaffin (enteroendocrine) cells found in crypts of lieberkuhn produce?
test q
hormone producing cells
*****CCK and secretin are secreted in the crypts located in the duodenum
What do paneth cells found in the crypts of lieberkuhn produce?
test q
antimicrobial proteins and regulate flora
The submucosa of the SI has Brunner’s (duodenal glands) that produce _______________ and the ducts empty into the crypts of lieberkuhn. This neutralizes acidic chyme from the stomach
test q
alkaline mucous
note: the further into the duodenum, the less Brunner’s glands there are
The submucosa of the SI has peyer’s patches that are lymph follicles and those increase as they approach….
test q
the end of the SI
T/F: the intestinal juice contains ALL substances released by the cells that line the crypts of Lieberkuhn in the mucosa and Brunner’s glands in the submucosa
test q
true
Intestinal juice is clear to pale yellow color and is a watery secretion that is alkaline. It is found in the mucous formed from goblet cells in the SI and houses hormones from enteroendocrine (argentaffin) cells, along with antimicrobial proteins from….
Paneth cells
Which part of the SI surround the head of the pancreas?
test q
duodenum
What does the duodenum absorb?
test q
calcium and iron
What hormones are found in the duodenum?
test q
CCK and secretin
What are the 4 parts of the duodenum from proximal to distal?
test q
1) superior
2) descending
3) inferior
4) ascending
Which part of the duodenum is the location of major duodenal papillae (from the hepatopancreatic duct) and minor duodenal papillae (from accessory pancreatic duct)?
test q
descending part of duodenum
The transpyloric plane line is at ______
L1
Which hormone is secreted in the mucosa of the duodenum in the crypts of Lieberkuhn in response to acidity of chyme from the stomach and stimulates secretions of enzymes from pancreas?
test q
secretin
Which hormone is secreted by the mucosa of the duodenum in the crypts of Lieberkuhn in response to the presence of fats and stimulates release of bile from the gallbladder?
test q
CCK
The ligament (muscle) of treitz, aka suspensory ligament of duodenum, is a band of CT and smooth m. from the celiac trunk and diaphragm that connects to the _____________________- demarcates the border between the duodenum and jejunum therefore upper and lower GI
test q
duodenojejunal flexure
Which part of the SI empties into the LI?
ileum
What is the valve called between the ileum of SI and cecum of LI?
test q
ileocecal valve
What are the sympathetic innervations to the SI?
L1 > lumbar splanchnic n. > superior mesenteric ganglia > SI
What is the parasympathetic innervation to the SI?
vagus n.
Which artery supplies the SI?
test q
superior mesenteric a.
Which vein drains the SI?
test q
superior mesenteric v.
What are the 4 subdivisions of the LI?
1) cecum
2) colon
3) rectum (in the pelvis)
4) anus (in the pelvis)
What are the 4 features of the LI?
test q
1) epiploic appendages (small fat filled appendages of visceral peritoneum)
2) taeniae coli (muscularis externa reduced to 3 bands/ribbons)
3) haustra (pocket-like sacs, giving segmented appearance)
4) plicae semilunares (half moon shaped folds of colon walls formed by contraction)
The mucosa from the cecum to the upper 1/2 of anal canal is ___________________ epithelium
test q
simple columnar
The lower 1/2 of anal canal mucosa is _____________________ epithelium
test q
stratified squamous nonkeratinized
Generally, the mucosa of the trachea and lower 1/2 of anus is stratified squamous epithelium but anything in between is….
test q
simple columnar epithelium
What is the first part of the large intestine called?
cecum
Which part of the LI is a “blind pouch”?
cecum
Which part of the LI is intraperitoneal with NO mesentery?
cecum
Which quadrant of the abdomen is the cecum found in?
test q
RLQ
Which organ arises from the posteromedial aspect of cecum and is inferior to the iliocecal junction?
test q
appendix
Which abdominal quadrant is the appendix in?
test q
RLQ
Which organ is intraperitoneal and has a short triangular mesentery called mesoappendix?
appendix
What are the 4 parts of the colon?
1) ascending colon
2) transverse colon
3) descending colon
4) sigmoid colon
Where is the R colic flexure/hepatic flexure located?
test q
-RUQ below the liver
-its a sharp bend between the ascending and transverse colon
Where is the L colic flexure/splenic flexure located?
test q
-LUQ below the spleen
-its a sharp bend between the transverse and descending colon
Which part of the colon is this?
-R side of abdomen
-between cecum and R colic flexure/hepatic flexure
-retroperitoneal
ascending colon
Which part of the colon is this?
-longest most mobile part of colon
-between R and L colic flexures
-intraperitoneal
-has mesentery called transverse mesocolon
transverse colon
Which part of the colon is this?
-between L colic flexure/splenic flexure and sigmoid colon
-retroperitoneal
-no mesentery
descending colon
Which part of the colon is this?
-S shaped
-connects descending colon to the rectum at S3 level
-intraperitoneal
-rectosigmoid junction is where the epiploic appendages and taeniae coli terminate
sigmoid colon
What are the sympathetic innervations of the LI?
L1 > superior mesenteric ganglion > LI up to and including 1st 2/3 of transverse colon
L2> inferior mesenteric ganglion> last 1/3 of transverse colon to the sigmoid colon
L3-L5> superior hypogastric plexus> last 1/3 of transverse colon to sigmoid
What are the parasympathetic innervations of the LI?
vagus n. goes to LI up to the first 2/3 of transverse colon
S2-S4 go to the last 1/3 of transverse colon up to sigmoid colon
