Ma2 - Esophagus And Stomach

Front 1

serosa not present where

Back 1

in areas where retroperitoneal organs are attached to the abdominal wall

Front 2

adventitia is not covered by

Back 2

NOT covered by mesothelium whereas serosa is. it is present however where retroperitoneal organs are attached to the abdominal wall

Front 3

2 components of nerves of GI tract

Back 3

1) extrinsic - parasympathetic and sympathetic

2) intrinsic - enteric

Front 4

extrinsic nerves

Back 4

-preganglionic parasympathetic fibers
-from vagus nerve and pelvic splanchnic nerves

-postganglionic sympathetic fibers
-from celiac, superior, inferior mesenteric ganglia

Front 5

preganglionic parasympathetic fibers synapse on

Back 5

-synapse on neurons of the enteric plexuses (meissner's and auerbach's)

-stimulate smooth muscle contraction; hcl, pepsin, mucus release from stomach

Front 6

postganglionic sympathetic nerve fibers terminate directly...

Back 6

directly on the smooth muscle and induce relaxation

Front 7

intrinsic/enteric nervous system - form 2 major plexus

Back 7

1) auerbach
2) meisnner

Front 8

meissner's plexus neurons (2)

Back 8

1) enteric sensory neurons - chemoreceptors and mechanoreceptors

2) enteric motor neurons - innervate smooth muscle layers to stimulate peristalsis and innervate enteroendocrine cells for hormone secretion

Front 9

difference between the mucous glands found in the mucosa of the esophagus versus those found in its submucosa

Back 9

in the mucosa of the esophagus, the mucus glands are the Esophageal Cardiac Glands that PRODUCE MUCUS with a neutral pH

in the submucosa of the esophagus, the mucous glands are called the Esophageal Glands Proper and PRODUCE AN ACIDIC SECRETION

Front 10

majority of esophagus is attached to adjacent structures via...

how much of it is covered by serosa?

Back 10

adventitia

only lowest 2-3 cm of esophaguse is covered by serosa

Front 11

parietal cells are found in what glands and secrete what

Back 11

found in gastric glands

secrete HCL and Intrinsic Factor

Intrinsic factor is a glycoprotein that binds to vitamin B12 and allows for the absorption of the vitamin in the Ileum. B12 needed for formation of RBCs. Deficiency results in Pernicious Anemia.

Front 12

Tubulovesicular System

Back 12

stacks of cisternae that are recruited to join with the existing plasma membrane. Act as a MEMBRANE RESERVE that can form more MICROVILLI to increase surface area for acis sercetion.

Front 13

Acid secretion stimulated by what three things from vagus nerve.

Back 13

initiated by stretching of gastric lumen.

-Gastrin
-Histamine
-Acetylcholine
all stimulate acid secretion. Their receptors on parietal cells are stimulated by Gastrin, Histamine, and Acetylcholine from Enteroendocrine Cells, which are stimulated by Meissner's Plexus, which are stimulated by preganglioned vagal nerve fibers

Front 14

Chief Cells

Back 14

also found in gastric glands, basophilic, contains granules of Pepsinogen.

Pepsinogen is converted to Pepsin when released from the cell by exocytosis. Secretion method is same as parietal cells (Gastin, Histamine, Acetylcholine).

Pepsin cleaves peptide bonds
Lipase is also synthesized in Chief Cells, hydrolyzes fat.

Front 15

Ulcers result from

Back 15

combined action of HCL from Parietal Cells and Pepsin from Chief Cells. Occur most often from infection by bacterium Helicobacter Pylori.

Front 16

Enteroendocrine Cells (APUD) - 2 productions, part of what family

Back 16

produce polypeptide hormones and biogenic amines

part of Diffuse Neuroendocrine System (DNES)

Front 17

Endocrine Secretion from Enteroendocrine Cells

Back 17

basal cytoplasm contains membrane-bound secretory granules which may be released into nearby underlying capillaries

Front 18

Paracrine Secretion from Enteroendocrine Cells (2 examples)

Back 18

Some cells have long basal cytoplasmic processes that contact other cell types

Others secrete into the local subepithelial connective tissue

Front 19

"Open" Types of cells versus "Closed" Types of cells

Back 19

"Open" Types have a tuft of microvilli extending into the glandular lumen to sample changing composition of the local environment.

"Closed" Types of Cells contact only the basement membrane and not the lumen. “Closed” type is stimulated
by motor component
of enteric nervous system

Front 20

Enteroendocrine Cells of the stomach secrete (4)

Back 20

1) Gastrin
2) Histamine
3) Somatostatin
4) Ghrelin

Front 21

Gastrin

Back 21

-secreted directly into bloodstream, meaning its a TRUE HORMONE, stimulates acid secretion by parietal cells

Front 22

Histamine

Back 22

secreted by cells throughout GI tract, secreted into CT then diffuses to affect other enteroendocrine cells (paracrine secretion), stimulates gastric acid secretion

Front 23

Somatostatin

Back 23

Paracrine Hormone, secreted by cells throughout GI tract, INHIBITS the secretory activity of neighboring enteroendocrine cells (negative feedback control)

Front 24

Ghrelin

Back 24

produced by enteroendocrine cells of the stomach, its levels rise after fasting, causing hunger sensation -> increase food intake and inhibition of fat utilization -> weight gain

Front 25

Bombesin

Back 25

Neurocrine hormone that stimulates gastric secretion.

Front 26

Submucosa of Stomach

Back 26

no glands present, meissner's located here

Front 27

Muscularis Externa of Stomach (layers)

Back 27

1) Oblique
2) Circular
3) Longitudinal

Auerbach's Plexus is present between circular and longitudinal layer and coordinates the contractions that churn and homogenize ingested food.

Front 28

Serosa of Stomach

Back 28

CT covered by mesothelium, continuous with greater and lesser omentum, AKA Visceral Peritoneum