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88 Cards in this Set

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What are the four layers making up the digestive tract?
Mucosa (mucous membrane)
Submucosa
Muscularis externa 
Serosa (or Adventitia)
What makes up the layer of the mucosa immediately deep to the submucosa?
Muscularis mucosae -
2 layers of smooth muscle:
inner- thin circular
outer- longitudinal .
What part of the Mucosa holds the vessels and sometimes glands?
Is it the innermost layer?
Lamina Propria
No, the innermost layer is the Epithelium with its Basal Lamina
What is the Meissner's Plexus and in what layer of the tract is it found?
A nerve plexus derived from neural crest that is part of the ENTERIC NERVOUS SYSTEM.
It is found in the submucosa.
What forms the Muscularis Externa and what lays between the two layers?
Inner circular and outer longitud layers of smooth muscle.
Between- Auerbach (Myenteric) plexus
(part of ENTERIC-NS)
What are the two types of outermost layer of the tract, and what are they covered by?
(both layers are same inside- loose CT w vessels)

if it is a Serosa layer- covered by mesothelium

if it is an Adventitia- it is surrounded by and blends to the adjacent CT
*What glands are present in the Esophageal Lamina Propria (of mucosa) and what do they secrete?
Esophageal Cardiac Glands - secretes neutral pH mucus to protect from regurgitated acid
What is the effect of food travel on esophageal lumen?
Stays closed until bolus of food comes close, then opens.
What layer of the esophagus is thicker than average?
Muscularis Mucosa, *** but it only has longitudinal layer
Commonly called "heart burn"
Pyrosis
What is commonly able to cause adenocarcinoma in the esophagus?
Barretts esophagus
What glands are present in the submucosa of the esophagus and what do they secrete?
Esophageal glands proper - secretion of these glands is slightly acidic and functions to lubricate the lumen of the esophagus
(most numerous in LOWER esophagus)
How would one differentiate the three regions of the esophagus?
*By the Muscularis Externa!
Upper 1/3 - Skeletal muscle only
Middle 1/3 - Mixture of skeletal and smooth
Bottom 1/3 - Smooth Muscle only
What is the topmost layer layer of the esophagus below and above the diaphragm?
Above diaphragm- Adventitia (Loose CT w longitudinal vessels)

Below diaphragm- Serous (free part of esophagus just before the stomach is covered with mesothelium)
What part of the stomach attaches to the esophagus?
Cardia

(heartburn)
In what layer of the gastric mucosa are the regionally specialized glands? What region has which type of gland?
Lamina Propria
Cardia - mucus secreting cells
Fundus- Short pits, Long glands
Pyloric- Long pits, Short glands
What portion of the gastric gland gives rise to the other cells in the gland?
Neck (Undifferentiated cells)

(and Secrete different secretion than the surface mucus cells)
What are the two different specialized cells in the gastric glands, and where in the gland are they located?
Parietal/ Oxyntic cells- upper part

Chief/ Zymogenic cells- lower part
Which cells in the gastric gland are acidophilic, have little RER, and canaliculi? What do they do?
Parietal Cells

Splits H+ from Carbonic Acid using Carbonic anhydrase-->
actively pumps H+ out of cell from invaginations in apical membrane to elaborate HCl
What is needed chemically for the absorption of Vitamin B12? What cells make this?
Secret Intrinsic Factor

Parietal cells

--test question, if problem w B12, prob Parietal cells
Atrophic Gastritis can lead to lack of intrinsic factor, which leads to what form of Anemia?
What symptoms are presented and what disorder is this similar to?
Pernicious Anemia (Low RBC and hemoglobin)

B12 deficiency--> CNS degenerate (sensory disturbances like burning feet)
*may present like MS
What cells in the gastric glands are basophilic bc of high RER, have secretory zymogen granules, and release pepsinogen?
Chief (Zymogenic) cells
What cells release pepsinogen and where does pepsiongen become pepsin?
Chief (Zymogenic) cells

cleaved in the acidic environment of the lumen to become pepsin
What Epithelial cells produce gastrin? Where do the secretions go?
What does the gastrin do?
Gastric Enteroendocrine cells

Stuff diffuses into nearby cells in lamina propria

Gastrin stimulates acid production
What orientation do the 3 layers of the gatric mucularis externa have?
inner- oblique

middle- circular – (thick) forms the pyloric sphincter

Outer- longitudinal
What are the 3 levels of folds in the Small Intestines going in order from macroscopic to microscopic?
Which is the type of permanent folds?
Plicae Circulares= Permanent (core of SUBmucosa)
Villi (core of lamina propria, has Lacteal--main lymph vessel)
Absorptive cells w microvilli (core of Actin microfil's)
What layer of the small intestines' mucosa has the central lymphatic vessel? What is its core made of?
Villi, Lamina Propria (core of mucosa)
What makes the core of the absoptive cells w microvilli in the mucosa of the small intestines?
Microfilaments (Actin)
What are the intestinal glands within the lamina propria of the small intestines?
Crypts of Liberkuhn
What are the cells in the base of crypts of Lieberkuhn that have large eosinophilic granules w lysozyme (antibacterial)?
Paneth Cells
Where in the small intestines do the goblet cells begin to appear?
Duodenum, increase in frequency going down the anal canal
What cells secrete paracrine and endocrine hormones?
Enteroendrocine cells
What are modified enterocytes that cover lymph nodules of lamina propria in the small intestines?
M (microfold) cells
What are epithelial cells with microvilli?
Enterocytes
(ie the cells that secrete the IgA made by Plasma cells of the Lamina Propria into the lumen)
What is the purpose of intestinal folds?
Increase absorptive surface area
In what layer of the small intestines would you find lymphocytes, mast cells, and macrophages?
Lamina Propria
What section of the small intestines is the only one to have glands in the submucosa?
Duodenum (Brunner's Glands - secrete alkaline stuff to buffer acidic chyme when it enters)
In what layer of the small intestines is the Meissner's plexus?
Submucosa
What lies between the inner (circular) and outer (longitudinal) layers of smooth muscle in the Muscularis externa of the small Intestines?
Auerbach's plexus
(nerves and postganglionic neurons)

(primary plexus of small intestines; where the parasympathetics running around the SMA lead to)
What specialized epithelial cells cover Peyer's patches? What do they do?
M (microform) cells
Phagocytose organisms from the intestinal lumen and present to T lymphocytes in the Lamina Propria
(part of GALT)
What part of the GALT secretes IgA?
Plasma cells in lamina propria make IgA --> Enterocytes release IgA to lumen
What glands are found in the Duodenum?
(goblet cells and enteroendocrine cells)
Crypts of Lieberkuhn (in lamina propria)
Brunner's gland (in submucosa)
What activates Brunner's gland in the Duodenum and what is secreted by the gland?
Chyme (super acidic) from the stomach forces Brunner's gland to secrete an Alkaline. It optimizes pH for Pancreatic enzymes
What do the Enteroendocrine cells of the Duodenum secrete? what do they do?
CCK- stimulates release of gallbladder/pancreatic bile and enzymes, and inhibits gastric empyting.

GIP- Shuts off acid production in stomach

Secretin- stimulates pancreatic secretion, inhibits gastric acid production
What major changes occur histologically at the Gastroduodenal Junction?
Thickening of the inner circular layer of muscularis externa= Pyloric Sphincter

Transition from pyloric to intestinal mucosa: Villi, Goblet cells begin, glands in the submucosa begin
Jejunum v Ileum?
Jejunum- bigger plicae circulares, rounded Villi, less goblets than ileum

Ileum- Peyer's Patches, club-like villi, more goblet cells
Why does the large intestines have absorptive cells with thin microvilli and LOTS of goblet cells?
to absorb water and dehydrate poop and to lubricate for its passage down
What surface specialization exists only until the colon?
Villi
What is special about the Muscularis Externa of the Large Intestines?
the outer longitudinal layer is made of TENIAE COLI and is way thicker
(3 distinct longitudinal bands)
What specialized cells in the large intestines are missing in the Crypts of Lieberkuhn?
No Paneth cells in the crypts, but
Some Enteroendocrine cells
What cells are in abundance in the Crypts of Lieberkuhn of the large intestines?
Goblet cells
What are the sacculations/folds on the exterior of the large intestines?
Haustra Coli
What are the macroscopic folds within the large intestines?
Semilunar folds
What is characterized by a mucosa like that of the colon and numerous secondary lymphoid nodules amongst diffuse lymphoid tissue?
Appendix

(does NOT have tinea coli though)
What are the two types of muscle in the rectum/anal canal and what is their innervation?
Internal sphincter- smooth muscle (thickening of internal circular layer of musc extern) relaxes w parasymp, tightens w/ symp.

External Sphincter- skeletal muscle, innervated by the inferior anal (rectal) nerves, branches of the pudendal nerve (S2, S3, S4).
What is the (major glycogen storer/) largest gland in the body? Largest organ?
the liver

skin
What synthesizes Blood-coagulation proteins (albumin, fibronogen, and lipoproteins) and secretes them into the blood? What form of secretion is this?
Liver

Endocrine
What is the purpose of the bile secreted by the liver? What type of secretion is that of bile?
to help digest fats

Exocrine
1-2 cell thick interconnected plates of hepatocytes in liver
Parenchyma
What makes up the blood supply to the liver, and which is oxygenated/ de-oxygentated?
Portal vein- 75% - deoxygenated but rich with nutrients from GI tract

Hepatic artery- 25%- oxygenated
Where is the IVC in regards to the liver?
IVC on posterior aspect of liver
How do bile and blood flow in regards to each other?
Bile and blood flow in OPPOSITE directions.
Located at the corners of each lobule, what three vessels make up the portal triad, and what do they lead into/bring?
Portal vein- branches lead into venules that empty into sinusoids

Hepatic A- branches lead into arterioles that empty into sinusoids

<25% arteriole, 75% venous blood>

Bile duct- branches receive bile from 'canals of Hering' which drain the bile canaliculi

***Lymphatics ALSO in region of Triad, but not included in the triad**
The Classic Liver Lobule model is based around what? Explain.
CLL model is based upon direction of blood flow.
-hexagon-

The lobule= central vein in center w/ radiating plates of hepatocytes, separated by sinusoids and portal triads

*pig liver used for emphasis of shape
The Portal Lobule model is based around what? Explain.
The PL model is based upon the direction of bile secretion.

Triangular= Portal triad at center of portal lobule, Central veins make up the 3 corners

(not used)
Explain the Liver Acinus model shape.
Diamond shaped acinus= 2 central veins and 2 portal triads create the 4 corners, w/ center having the terminal branches of the portal triad
Why does the Liver Acinus model make the best correlation between blood perfusion, metabolic activity, and liver pathology?
Bc of creation of 3 zones based on oxygen, nutrient, and toxin levels in blood of Acinus:
1- closest to vessels; higher nutrient, oxygen, and toxin levels; higher metabolic rate; first to show changes from bile occlusion; last to die from no circulation and the first to regenerate

3- farthest from vessels but closest to terminal hepatic vein; first to show ischemic necrosis; first to show fattyness; last to respond to toxins

Zone 3 is downstream and is can get toxin fallout from other zones
What is the overlap in pathology between Central Lobular model and liver Acinus?
zone 3 = central lobular

Ischemic necrosis of the lobule is called 'Centrilobular necrosis' because Pathology follows the Central Lobular model---the central vein is in center.

In Liver Acinus model, that central vein is in Zone 3 (the zone that is the first to show necrosis)
Name and describe the 3 major phases of Alcoholic Liver Disease.
1. Fatty Liver- alcoholics accumulate liver fat, first in centrilobular hepatocytes (3), liver can gain x3 mass, reversible w cessation

2. Hepatitis- Inflammatory/ Nectrotizing to the central zone (3)- marked by neutrophils , can kill

3. Cirrhosis- (irreversible) scarring of liver--> portal hypertension/ liver failure; fibrous septa form around nodules--> structure + fcn compromised
Condition that occurs when heart failure --> liver damage --> cirrhosis. Name?
Damage to zones?
Cardiac Cirrhosis

Hepatocytes in zone 3 susceptible to ischemia and hypoxia; no change to zone 1 and 2
What occupies the space between the hepatic plates (parenchyma) or cords? What characteristic allows them to have very slow blood flow?
sinusoids

Special capillaries w/:
- dilated lumen
- discontinuous endothelial lining and basal lamina
- Fenestrae with NO diaphragm
What cells are found on the walls/ luminal surface of sinusoids?
Kupfer cells- phagocytize aged RBCs

Ito cells- store vitamin A
Where does exchange between sinusoids and hepatocytes take place?
Disssssse space

blood and stuff hits hepato microvilli
How much bile is reabsorbed from the intestines and how much is created by hepatocytes?
90% reabsorbed from GI

10% created by hepato
Intercellular channels between hepatocytes without walls of their own (formed by grooves in the surface of adjacent cells) are called?
Where do they carry to/from?
What seals them off?
Bile Canaliculi

Bile from hepatocytes --> canals of Hering --> bile ducts of portal triads

Sealed by Tight junctions
What chemical release excited gallbladder release of bile into the duodenum?
CCK
**What is the micro to macro biliary tree?
Bile from hepatocytes --> canals of Hering (ductules) --> bile ducts of portal triads

Bile ducts converge --> Hepatic duct

R&L Hepatic duct coverge --> Common Hepatic duct

Common Hepatic duct joins the Cystic duct ---> Common bile duct --> Ampulla of Vater --> Duodenum
What makes up the epithelium of the gallbladder? what is its function?
Simple columnar Absorptive cells w/ Microvilli

Forms mucosal folds that absorb water and concentrate bile
**Inside the folds there can be glands/ sinuses that secrete mucus


***NO SUBMUCOSA IN GALLBLADDER
What is special about the submucosa in a gallbladder?
It doesnt exist dummy
How might pain be described in a pt w gallstones?

Why, again, are stones from cholelithiasis brown?
RUQ/ Epigastric pain

Referred pain to R shoulder from irritation of inferior diaphragm

Brown pigment stones related to increased concentration of unconjugated BILIRUBIN in bile
What polarizes the Pancreatic Acini cells?
Basophilic RER and acidophilic Zymogen granules
*Base of cell- basophilic
*Apex of cell- acidophilic
There are NO mucus cells in the pancreas.
T/F
True, dummy
What stimulates Pancreatic Exocrine enzyme secretion?

What stimulates its bicarbonate secretion?
CCK from duodenum's Enteroendocrine cells

and

Parasympathetic (Vagus) stimulation

---------

Secretin from the duodenal enteroendocrine cells
Biliary Tree of pancreas from micro to macro?
Intercalated ducts (cuboidal cells)-->
Intralobular ducts-->
Interlobular ducts (columnar cells)-->
Main Pancreatic Duct (in head of pancreas)-->
Joins with Common Hepatic Duct --> Ampulla of Vater
What is the endocrine part of the Pancreas?
Islet of Langerhans
What cells enable the liver to take the spleen's function if its removed?
Kupffer cells (macrophages in the sinusoids)
2 common causes of splenomeglia?
Sickle cell anemia and portal hypertension
Purpose of red/white pulp in spleen?
White- lymph nodules (filters and immuno-surveys the blood)

Red- FILTER; degrades old RBCs (breaks down and recycles iron and hemoglobin)