Lecture 6 - Digestive System II Flashcards
how many parts of the small intestine and what are they
- ) duodenum
- )Jejunum
- )Ileum
Long length (10ft living/21ft cadaver) Plicae circulares (submucosa core) Villi (fingerlike projections of mucosa) Microvilli (projections of apical membrane of intestinal absorptive cells; striated border)
Small intestine
Epithelium: Simple columnar epithelium Absorptive cells (enterocytes) Goblet cells Crypts of Lieberkühn (Intestinal Glands) Tubular glands Paneth cells Enteroendocrine cells Stem cells
mucosa of small intestine
Small Intestine – Wall Modifications
Mucosa
Epithelium:
Simple Columnar epithelium
Absorptive cells (enterocytes)
Goblet cells
Small Intestine – Wall Modifications
Mucosa Crypts of Lieberkühn
Tubular glands
Paneth cells
Enteroendocrine cells
Stem cells
Duodenum – Brunner’s glands (produce alkaline mucous)
submucosa
Muscularis Externa
Two Layers in small intestine what are they
outer longitudinal and inner circular
most outer layer of small intestine wall
serosa or adventitia
25cm in length and begins at the pyloric spinchter of stomach, smallest component of the small intestine
duodenum
second part of small intestine, about 2.5 meters in length
jejunum
the longest part of the small intestine, 3.5 meters in length (last part)
ileum
where does the ileum and the cecum from large intestine meet
ileocecal value - limits reflux
what kind of muscle is in the ileocecal value
innercircular smooth muscle
permanent circular folds of the jejunum - with submucosa folds
plicae circulares
fingerlike projections of muscosa, core of lamina propria- to increase surface area
villi
core of actin, projections of apical membrane of intestinal absorptive cells, create striated border
microvilli
core of villi
lamina propria
core of microvilli
actin
absorptive cells in the small intestine - have microvilli - and have secrection cells to finish off the 4 macromolecules
enterocytes
the number of ___ cells increases as you move distally along the small intestine
goblet cells
tubular glands between villi of small intestine
crypts of lieberkuhn
exocrine cells, large eosinophillic in their cytoplasm and secret lysomzyme
paneth cells
cells able to produce hormones to regulate GI tract
enteroendocrine cells
where do we find brunner’s glands(produce alkaline mucous to neutralize chyme)
duodenum
jejunum and ileum are covered by
serosa
retroperitunem and parts of the duodenum are surrounded by
adventitia
glands do not pass ___in the small intestine
muscularis mucosa
lymphatic capillary that absorbs dietary fats in the villi of the small intestine
lacteal
In the ileum, groups of lymphatic nodules are present in the lamina propria and submucosa. These aggregated lymphatic follicles are referred to as ___,
peyer’s patch
specialized epithelial cells in ileum overlying Peyer’s patches.
M cells
area for reabsorption of electrolytes and water
large intestine
important for the formation of feces
large intestine
how do we know we are looking at large intestine
No plicae circulares and no villi Teniae coli Haustra Omental appendages Anal columns
outer longitudinal smooth muscle group into bands on the surface of large intestine
teniae coli
small pouches caused by sacculation (sac formation), which give the colon its segmented appearance
haustra
small fatty projections of serosa on the large intestine
omental appendages or epiploic appendages
group of cells missing in the large intestine of mucosa
no paneth cells because we wont bacteria
absorptive cells in the large intestine mucosa
colonocytes
in large intestine the outer longitudinal layers group together in all areas except ___,___,____
rectum, anal canal, appendix
Mucosa Epithelium: Simple columnar epithelium Crypts of Lieberkühn (Intestinal Glands) Tubular glands Absorptive cells (colonocytes) Goblet cells Enteroendocrine cells Stem cells Lamina propria – lymphoid cells and lymphoid nodules Submucosa Muscularis Externa Two Layers Teniae coli (outer longitudinal) Serosa or Adventitia
large intestine wall
throughout most of large intestine you should not see glands in the ___, except for one location =
submucosa
anal canal will have some mucous glands in the submucosa
a place where the lympathetic nodules like to hangout in the large intestine - hanging off the cecum - small irregular lumen
vermiform appendix
in the appendix there is no___ but a lot of __
tenia coli
lymphatetic nodules -
the most distal portion of the alimentary canal
anal canal
dilated distal portion of the tract with a lot of goblet cells, about 4 cm in length
rectum
anal canal is divided into 3 zones based on
epithelium lining
3 zones of anal canal:
_1___ = superior 1/3 simple columnar epithelium
___2__ = middle 1/3, mixed of simple columnar, stratified columnar (or cuboidal), and stratified squamous
__3__= inferior 1/3, non-keratinized stratified squamous eipthelium, and at the distal end is another mucocutaneous junction , cells are much thicker (skin)
1= colorectal zone
2= anal transitional zone(ATZ)
3= squamous zone
in the anal canal you know you hit the anal transitional zone when ___ disappears
muscularis mucosea
associated digestive organs : out growths of the epithelium, located outside of the GI tract, connected via ___
pancreas, liver, gallbaldder
connected to Gi tract via ducts
specifically the jejunum
elongated gland, head portion lies in the C portion of the duodenum, body, and tail points toward the
pancreas
hylem of the spleen
pancreas: 98-99% functions as ___(compound acinar gland - for digestive system
1-2% functions as an __ gland(islets of langerhans) - for endocrine system
98-99% functions as exocrine gland (compound acinar gland)
1-2% functions as an endocrine gland (Islets of Langerhans)
pancreas exocrine cells that synthesize and secret enzymes that are going to lead to __ for digestion, also secret __ to help buffer the chyme
duodenum of small intestine
*enzymes are inactive form until it reaches small intestine
sodium bicarbonate to buffer chyme(pancreatic juice)
formed by the union of the pancreatic duct and the common bile duct. The ampulla is specifically located at the major duodenal papilla
hepatopancreatic duct
produce the enzymes (proteins) of the pancreas
pancreatic acini
endocrine part of pancreas responsible for the production of glucagon, insulin and other hormones
pancreatic islets aka islets of langerhans
part of pancreatic acini, apical portion is full of ___, eosinophillic that contain inactive enzymes and released into the lumen of ___
zyomgen granules
intercalated duct
secrete large volumes of sodium bicarbonate in pancreas
intercalated ducts
there are no striated ducts in the
pancreas
The liver receives blood from two sources:
__1__;25 % of blood, oxygenated blood
__2__; 75% of blood deoxygenated blood with newly absorbed nutrients, drugs, and possible microbes and toxins from the GI tract
1 = proper hepatic artery
2= hepatic portal vein
Where oxygen, most of the nutrients, and certain toxic substances are taken up by the hepatocytes; also where hepatocytes’ products and stored nutrients are secreted back into the blood.
liver sinusoids
the portal vein is draining the __, which is breaking down aged RBC - bilirubin (toxic)
spleen
the main functional cell of the liver
hepatocyte
the liver produces ___ that helps in the digestion of lipids
bile salts
The largest cells lining the liver sinusoids are ____(stellate macrophages); phagocytotic; involved with the breakdown of some damaged or old RBCs that reach the liver from the spleen; derived from monocytes
Kupffer Cells
___ have microvilli that extend into a perisinusoidal space (space of Disse) (i.e. the space between the endothelial cells and hepatocytes).
Hepatocytes
(also known as Ito cells) are found in the perisinusoidal space; these cells store hepatic vitamin A.
hepatic stellate cells
blood supply to the liver is a
portal triad
a classic hepatic globule, how many sides and corners? what is located on the corners
6 sides and 6 corners
portal triad areas - on the corners
center is central vein
a __ is going to be bringing blood into classic hepatic globule,
portal triad
A portal triad consists of;
__1__, an arteriole branch of the hepatic artery that supplies oxygen
__2___, , with blood rich in nutrients but low in oxygen
__3__ branches of the bile conducting system.
1 proper hepatic artery 25%
2 hepatic portal vein a venule branch of the portal vein 75%
3 one or two small bile ductules of cuboidal epithelium,
can hold up to 30-50ml of bile, storage location for bile and concentrate it,
gallbladder
__ (rokitansky aschoff sinuses) result of growth of epithelium and bacteria can get stuck here causing infections leading to gallstones
deep diverticula
