Digestive II Flashcards
1
Q
duodenum
A
- c-shapes
- upper right quadrant
- first/proximal segment of the small intestine
- becomes continuous with jejunum at duouenjejunal flexure (midline)
- major duodenal papilla is the site where bile and pancreatic secretions enter the duodenum
2
Q
jejunum
A
- middle segment of small intestine
- primary region for chemical digestion and nutrient absorption
3
Q
ileum
A
- last/distal segments of the small intestine
- distal end terminates at the ileocecal valve, a sphincter that controls the entry of materials into the large intestine
4
Q
histology of small intestine lumen
A
- mucosal and submucosal tunics are in folds called circular folds called plicae circulares
- microscopic fingerlike projections called villi ca be seen on the surface of circular folds
- microscopic fingerlike projections called microvilli can been seen on the surface of the villi
- microvilli are cytoplasmic extensions that stick up into a lumen to increase absorption, they don’t move
- greater surface area= greater absorption
5
Q
large intestine
A
- 3 sided perimeter around small intestine
- 6.5 cm in diameter but shorter vs 2.5 cm of small intestine but longer
- absorbs fluids and ions and compacts indigestible wastes and solidifies them into faces
- really good at retrieving water out of chyme
- stores the faces until defecation
6
Q
structures of large intestine
A
- cecum
- ascending colon
- transverse colon
- descending colon
- rectum
- anal canal
7
Q
cecum
A
- first part of large intestine
- blind sac located in lower right quadrant of abdomen
- ileocecal valve represents junction between small and large intestine, it stays closed until chyme is ready to exit the small intestine
8
Q
appendix
A
- vermiform appendix
- though to have a role in immunity (MALT) and maintaining bacterial gut flora
- commonly removed when blocked, inflamed, or in danger of bursting
9
Q
ascending colon
A
- originates at the ileocecal valve and ascends right side of abdoment
- more forceful peristalsis
- as it approaches the inferior border of the liver it makes a 90 degree turn toward that left side of the abdominal cavity
- this bed is called the right colic flexure (hepatic flexure) and the liver sits right on top of it
10
Q
transverse colon
A
- originates at the right colic flexure and approaches the spleen in the upper left abdominal quadrant
- suspended by the transverse mesocolon, a curtain of connective tissue that keeps it in position
- makes a 90 degree turn inferiorly at the sleep, this is the left colic flexure (splenic flexure) and the sleep is right on top of it
11
Q
descending colon
A
- originates at left colic flexure
- less forceful peristalsis
- found along the left side of the abdomen
- makes contact with ileum and terminates into the sigmoid colon
12
Q
sigmoid colon
A
- shape resembles S
- turns inferomedially and is suspended by the sigmoid mesentery
- terminates at the rectum
13
Q
rectum
A
- muscular tube that readily expands to store accumulated fecal material prior to defamation
- no absorption function
- three thick transverse fold of the rectum call rectal valves, ensure that fecal material is retained during the passage of gas
- terminates at the anal canal
14
Q
anal canal
A
- terminal few cm of large intestine
- 3 folds called rectal valves permit passage or fermentation gas while retaining fecal waste (~500ml/day), kind of like the threads on a screw
- anal column line internal surface of anal canal
- anal sinuses secrete mucin for lubrications during defecation, this needs to happen because you have absorbed all the material out of the waste and will result in bleeding if not functioning properly and could be a sign of colon cancer
- internal and external anal sphincters open and close the anal canal during defecation
15
Q
hemorrhoids
A
- blood pooling in rectal veins
- results in veins swelling
- rupturing can cause mix of blood and fecal. material causing infection