Histo- digestive organs
Terms
undefined, object
copy deck
- What is the largest glandular organ?
- liver
- What is the thin CT layer on the surface of the liver (except for the bare area)?
- glisson's capsule
- What is the hepatic lobule?
-
-found inside the liver arranged around blood vessels and the bile duct
-hexagonal structure
-at each angle there is a portal area - What is the portal area/portal triad/portal canal?
- -is at each corner of the hexagon of the hepatic lobule
- What three structures are found in the portal area/portal triad/portal canal?
-
-branch of the bile duct surrounded by simple cuboidal epithelial cells
-branch of the hepatic artery
-branch of the portal vein - What are liver parenchymal cells called?
- hepatocytes
- What is a hepatocyte?
-
-parenchymal liver cell contained on the outside of the liver sinusoids
-usually lined in cords
-is a cuboidal shaped cell
-contain microvilli on the surface pointing into the sinusoid
-contains large amounts of smooth and rough ER as well as golgi bodies - What is the space of disse in the liver?
- perisinusoidal space that goes around the sinusoid, where the cytoplasm of the hepatocyte microvilli project into
- What is a biliary canal?
- combo of the bile canaliculi and the bile duct
- What is the bile canaliculi?
-
-diamond shaped canal formed by two neighboring hepatocytes that connect to the branch of the bile duct in the portal area
-held together by zonula occludens(tight junctions) - What is the bile duct?
- duct connected to the bile canaliculi in the liver that brings bile to the gallbaldder for storage
- What is the blood flow from the portal area out of the liver?
-
-portal area
-into sinusoids
-into the central vein
-to hepatic vein - Does venous and articular blood mix in the sinusoids from the portal vein and the hepatic artery?
-
-yes
-75% venous and 25% arterial mix
-therefore cells require less oxygen than most cells to function - Why is the epithelium in the sinusoids of the liver discontinuous?
- to allow rapid transport of material into and out of the cell
- What does "discontinuous" epithelium mean?
- there are spaces within the wall of the endothelial cells lining the sinusoid and there are holes in the underlying basement membrane of teh endothelial cells
- What type of epithelium are sinusoids of the liver lined with?
- simple squamous epithelium
- What are kupffer cells?
- phagocytic cells derived from blood monocytes that live in the lining of the liver endothelial cells
- What does the hepatic lobule look like?
-
-6 sided structure
-center is central vein
-each corner has portal area
-blood flows from the portal areas to the central vein (outside - in)
-bile flows from the inside to the outside of the structure
-containes hepatocyte cords and sinusoids - What is the acinus of the liver?
-
-an oval shaped configuration
-the two distal the tips are located at a central vein
-the two closer tips are located at the portal systems
-is separated into zone I, II, III -
In the acinus, where is zone I located?
What is its function? -
-closest to the portal areas
-drains blood first, recieves the most nutrients - Does zone II of the ascinus recieve the blood in the liver second?
- yes
- What is the main function of zone III?
- detoxifies drugs and alcohol in the blood
- What type of general functions does the liver have?
- exocrine, endocrine and metabolic
- What is the exocrine function of the liver?
- makes bile and dumps it into the gall bladder
- What is the endocrine function of the liver?
- makes plasma proteins like albumin and carrier proteins for hormones like steroid hormones that go into the blood
- What is the metabolic function of the liver?
- cholesteol synthesis, fat and glycogen stroage, steroid hormone breakdown and drug detoxification
- What layers are included in the tunica mucosa of tubular organs?
-
-epithelium
-lamina propria- loose areolar CT
-muscularis mucosae - What is in the tunica submucosa of tubular organs?
-
-is a mixture of loose and dense irregular CT
-contains large blood vessels and organized glands(mainly mucous secreting) - What is meissner's plexus?
- autonomic ganglion in the tunica submucosa, is smaller than aurbach's
- What is the tunica muscularis composed of?
-
-2-3 layers of mostly smooth muscle with some skeletal muscle
-arranged longitudinally in inner layers and transversly - What is auerbach's plexus?
- autonomic ganglion important in contraction of smooth muscle (peristalsis) in the entire GI tract
- What is the Tunica adventitia?
- is a layer of CT only that is only retroperitoneal
- What is the tunica serosa?
-
is intraperitoneal and consists of 2 parts
-CT and simple squamous epithelium - The simple squamous epithelium of the tunica serosa is called what?
- mesothelium
- In the esophagus, what type of tissue lines the tunica mucosa?
- stratified squamous non-keratinized epithelium
- In the esophagus,what is present in the tunica mucosa?
-
-folds in the basal region= papillae
-mucous glands in the lamina propria of the upper and lower parts of the esophagus, not the middle
-lymph nodules can also be present
-many capillaries in the upper layer of the lamina propria - In the esophagus,what is present in the tunica submucosa?
-
-contains large folds that allow the esophagus to expand
-mucous glands - In the esophagus, what is present in the tunica muscularis?
- -inner and outer longitudinal layers of muscle w/ auerbach's plexus sandwiched between the two layers
- In the esophagus, what type of muscle is present in the tunica muscularis of the upper esophagus, middle esophagus, and lower esophagus?
-
-upper = both layers are all skeletal
-middle = mix of both skeletal and smooth muscle
-lower = both layers are 100% smooth muscle - In the esophagus, where is the tunica adventitia and tunica serosa?
-
-T. adventitia through most of the esophagus length
-once the esophagus penetrates the diaphragm, it becomes T. serosa (mesothelium is simple squamous epithelium) - What is the function of the esophagus?
-
-carries food from the oral cavity to the stomach
-no digestion
-yes heat exchange, reason for lots of capillaries close the B. membrane
-mucous glands lubricate the esophagus for food and to buffer food contents
-lymphocytes may be present - In the stomach, what does the T. mucosa contain?
-
-gastric areas
-gastric pits
-gastric glands - What are the gastric areas of the tunica mucosa in the stomach?
- mushroom shaped areas (folds) on the rugae
- What are the gastric pits of the tunica mucosa in the stomach?
-
-crevaces in between the gastric areas as well as hols in the actual gastric area
-is an epithelial-lined area - What are the gastric glands of the tunica mucosa in the stomach?
- epithelial lined gland the pit runs into that extends the depth of the tunica mucosa
- What type of epithelium lines the stomach and pits?
- simple columnar epithelium
- What does the surface epithelial cells of the stomach look like?
-
-simple columnar epithelial cells
-all cells rest on the basal lamina and lines the gastric pit and gastric areas of the stomach
-contain short microvilli
-contain a junctional complex with many tight junctions
-contains mucous granules which contain the mucous product these cells make
- - What are the three divisions of the glandular epithelium of the stomach fundus/body?
-
-isthmus
-neck
-base - What types of cells are found in the isthmus of theglandular epithelium of the fundus/body of the stomach?
-
-surface epithelial cells
-parietal cells - What are parietal cells?
-
-cells filled w/ mitochondria
-cell surface is not smooth, has indentations called intercellular cannaliculi
-makes HCL
-makes gastric intrinsic factor
-stains pink, has fuzzy look - What are intracellular canaliculi of the parietal cells for?
- increase surface area of the parietal cell so it can make hydrochloric acid
- What does gastric intrinsic factor that is made by the parietal cell do?
- binds vitamin B12
- What does HCL that is made by the parietal cell do?
- breaks down food
- What cells are found in the neck of the glandular epithelium of the fundus/body of the stomach?
-
parietal cells
mucous neck cells - What do mucous neck cells look like?
-
-looks like a minature goblet cell
-makes mucous that is depositied into the lumen of the gland itself - What cells are found at the base of the glandular epithelium of the fundus/body of the stomach?
-
-parietal cells
-chief cells - What are chief cells?
-
-found only at the base of the gland
-pyramidal in shape
-blue stain, due to lots of RER
-makes protein, specifically pepsinogen - Describe the glandular epithelium of the fundus/body of the stomach.
-
-these are very long glands
-the galnds are 4x as long as the pits
-each has a lamina propria separating each gland that is nutritive - Describe the glandular epithelium of the cardiac/pylorus region of the stomach.
-
-gland depth is about equal to the depth of the pit
-gland epithelial cells are not specific, but resemble mucous neck cells
-glands and pits are surrounded by a lamina propria - What is a feature of the tunica submucosa of the cardiac/pylorus region of the stomach?
- -makes the rugae
- Describe the tunica muscularis of the cardiac/pylorus region of the stomach.
-
-is 3 layers of smooth muscle
-inner oblique layer
-middle circular layer
-outer longitudinal layer
**Auerbach's plexus is located between the circular and longitudinal layers - Does the cardiac/pylorus region of the stomach have a tunica serosa or tunica adventitia?
- tunica serosa= CT and mesothelial layer
- What are some functions of the stomach?
-
-general obvious functions
-prodigestion in chief cells
-HCL helps digest protein
-gastric intrinsic factor- helps intestine absorb B12 - What are the divisions of the small intestine?
-
-duodenum = where digestion occurs
-jejunum = large plicae circularis
-ileum = small plicae circularis - What does the tunica mucosa of the small intestine include in general?
-
-intestinal crypts
-villi
-peyer's patches (only in the ileum) - What are intestinal crypts/glands in the small intestine?
-
-glands that villi lead into
-are very short as compared to the stomach - What are villi in the small intestine?
-
-fingerlike projections that are folds of the tunica mucosa
-each villus has a core of lamina propria
-each villi leads into an intestinal gland/crypt - What are peyer's patches?
- -is a large collection of lymph nodules in the ileum
- What is the epithelium of the small intestine composed of?
-
-absorptive cells
-goblet cells
-lymphocytes - What are the absorptive cells of the small intestine?
-
-most abundant cell in epithelium
-simple columnar cell w/ junctional complexes
-contain microvilli w/ striated border and glycocalyx on top - What is the glycocalyx?
- glycoprotein and glycolipid layer on the surface of microvilli of absorptive cells
-
What do goblet cells secrete?
Where are they found? -
-mucous
-seen near the striated border of the tunica mucosa - How do lymphocytes arrive in the epithelium of the small intestine?
-
-they migrate through the basement membrane and junctional complexes of the lamina propria
-seen in the middle of the tunica mucosa inbetween absorptive cells - Where and what are paneth cells?
-
-seen at the base/bottom of the glands
-contain an antibacterial substance called lysozyme
-contain bright red granuls - What does the tunica submucosa of the small intestine contain?
-
-plicae circulares
-brunners glands (only in the duodenum) - What are plicae circulares?
-
-large folds of the tunica submucosa
-present in all three areas of the small intestine
-highly developed in the jejunum - What are brunner's glands?
-
-in the duodenum only
-mucous producing gland that neutralizes the acidic pH of the stomach so that the enzymes of the pancreatic duct can function - What does the tunica muscularis of the small intestine contain?
-
-2 layers of smooth muscle
-inner circular layer
-outer longitudinal layer -
Where is the tunica serosa in the small intestine?
Where is the tunic adventitia in the small intestine? -
-serosa = 1st part of duodenum, all of jejunum and ileum
-adventitia = 2nd and 3rd part of duodenum because it is retroperitoneal - What is the function of the small intestine?
-
-digestion and absorption
-neutralization of the acidic pH from the stomach
-glycocalyx functions in immunology - What is the general structure of the large intestine?
-
-no villi
-no plicae circularis
-yes tenia coli= regionalized compartments of longitudinal muscle - What does the tunica mucosa of the large intestine contain?
-
-simple columnar epithelial cells
-lots of goblet cells, has the highest ratio of goblet cells to epithelial cells
-goblet cells function to lubricate feces - What does the tunica submucosa of the colon contain?
-
-lymph nodules
-folds that are not "true", folds are made by haustra coli not submucosa - What does the tunica muscularis of the colon contain?
-
-2 layers of smooth muscle
-inside circular layer
-outside longitudinal layer called teniae coli - Does the colon have tunica adventitia or tunica serosa?
-
both
-adventitia is retroperitoneal
-serosa is intraperitoneal - What is the function of the colon?
-
-very little digestion occurs here
-water and electrolytes are absorbed here
-small hormonal activity and lubrication by the goblet cells