Digestive System: Stomach Flashcards
-is an enlarged segment of the digestive tract that primarily functions as a storage and mixing chamber.
-It is located in the left superior part of the abdomen
-Its shape and size vary from person to person, even within the same individual from time to time, depending on food content and body posture.
stomach
opening from the esophagus into the stomach
gastro-esophageal opening
also called the cardiac sphincter, surrounds the cardiac opening.
lower esophageal sphincter
A part of the stomach to the left of the cardiac part, the________ is actually superior to the cardiac opening.
fundus
largest part of the stomach
body
The largest part of the stomach is the body, which turns to the right, creating___________ and _____________
greater curvature and a lesser curvature.
Part of the stomach which The body narrows to form the funnel-shaped
pyloric part
The wider part of the funnel, toward the body of the stomach,
pyloric antrum
narrow part of the funnel
pyloric canal
The pyloric canal opens through the __________ into the small intestine.
pyloric orifice
The pyloric orifice is surrounded by
pyloric sphincter,
is a common defect of the stomach in infants, in which the pyloric sphincter is greatly thickened and thus interferes with normal stomach emptying.
Hypertrophic pyloric stenosis
is the outermost tunic of the stomach.
It consists of an outer layer of simple squamous epithelium and an inner layer of connective tissue.
serosa, or visceral peritoneum
(TRUE OR FALSE)
The muscularis of the stomach consists of three layers: an outer longitudinal layer, a middle circular layer, and an inner oblique layer
true
Deep to the muscular layer are the submucosa and the mucosa, which are thrown into large folds called______
rugae
(TRUE OR FALSE)
The stomach is lined with simple columnar epithelium. The epithelium forms numerous, tubelike gastric pits, which are the openings for the gastric glands
true
are found on the surface and lining the gastric pit.
surface mucous cells
gastric glands which produce mucus;
mucous neck cells
gastric glands which produce hydrochloric acid and intrinsic factor;
parietal cells
gastric glands which produce pepsinogen;
chief cells,
gastric glands which produce regulatory hormones and paracrine factors.
endocrine cells
Once food enters the stomach, it is mixed with stomach secretions to form a semifluid material called_______
chyme
is a glycoprotein that binds with vitamin B12 making the vitamin more readily absorbed in the ileum.
Intrinsic factor
produces the low pH of the stomach’s contents, which is normally between 1 and 3.
Hydrochloric acid
Hydrogen ions
are then actively transported across the mucosal surface of the parietal cell into the lumen of the stomach by a Ht-K+
exchange pump, often called________
proton pump
results in an elevated blood pH in the veins that carry blood away from the stomach,
alkaline tide
Chief cells within the gastric glands secrete_____
pepsinogen
Pepsinogen is packaged in___________.
zymogen granules
the term for an inactive enzyme.
zymogen
exhibits optimal enzymatic activity at a pH of 3 or less.
Pepsin
phase of gastric regulation, several types of stimuli act on the centers within the medulla oblon-gata to influence gastric secretions
Cephalic phase
Parasympathetic stimulation of the stomach mucosa results in the release of the neurotransmitter acetylcholine, which increases the secretory activity of both the parietal and the chief cells and stimulates the secretion of________________ from endocrine cells.
gastrin and histamine
greatest volume of gastric secretions is produced during this
gastric phase
phase of gastric secretion primarily inhibits gastric secretions.
It is controlled by the entrance of acidic chyme into the duodenum of the small intestine, which activates both neural and hormonal mechanisms.
Intestinal phase
inhibits gastric secretion by inhibiting both parietal and chief cells.
secretin
Fatty acids, other lipids, and to a lesser degree protein digestion products in the duodenum and the proximal jejunum initiate the release of the hormone_________ which inhibits gastric secretion.
cholecystokinin
consists of a local reflex and a reflex integrated within the medulla oblongata that reduce gastric secretion.
enterogastric reflex
which are peristaltic-like contractions that occur about every 20 sec-onds, proceeding from the body of the stomach toward the pyloric sphincter.
mixing waves
The peristaltic contractions responsible for moving chyme through the partially closed pyloric opening
pyloric pump
contractions are increased by low blood glucose levels and are strong enough to create uncomfortable sensations
hunger pangs
