Module 7.6 Stomach Flashcards
The ___\_ is a J-shaped chamber
The stomach is a J-shaped chamber
The stomach is divided into three parts:
- _____,
- _____
- _____.
The stomach is divided into three parts:
- fundus,
- body
- antrum.
- The entrance to the stomach is sealed by the ___________ sphincter, and
- the exit from the stomach is sealed by the _____ sphincter.
- The entrance to the stomach is sealed by the lower esophageal (gastroesophageal) sphincter, and
- the exit from the stomach is sealed by the pyloric sphincter
The stomach folds, called ______ make it possible for the stomach to expand from its empty volume of approximately ___\_mL to its full volume of approximately ____\_ mL.
The stomach folds, called rugae make it possible for the stomach to expand from its empty volume of approximately 50 mL to its full volume of approximately 1,000 mL.
Gastric motility involves three stages:
- _____,
- _____, and
- ______
Gastric motility involves three stages:
- filling,
- mixing, and
- emptying
The filling of the stomach is mediated by r______\_of the _____________\_ of the stomach wall, which is regulated by ______\_ activity
The filling of the stomach is mediated by receptive relaxation of the smooth muscle layers of the stomach wall, which is regulated by vagal nerve activity
The pacemaker cells of the upper fundus generate the ____________\_, which results in weak peristaltic contractions in the fundus
The pacemaker cells of the upper fundus generate the gastric basic electric rhythm (BER), which results in weak peristaltic contractions in the fundus
The ______\_ cells of the upper fundus generate the gastric basic electric rhythm (BER), which results in weak peristaltic contractions in the fundus
The pacemaker cells of the upper fundus generate the gastric basic electric rhythm (BER), which results in weak peristaltic contractions in the fundus
Peristaltic contractions from the basic electric rhythm (BER) increase in strength as they move toward the __________\_
Peristaltic contractions from the basic electric rhythm (BER) increase in strength as they move toward the pyloric sphincter
mixing occurs primarily in the ______\_, whereas the _____\_ of the stomach functions primarily in storage
mixing occurs primarily in the antrum, whereas the body of the stomach functions primarily in storage
_______\_ peristaltic contractions force small amounts of chyme through the _______ sphincter in the process of emptying
Strong antral peristaltic contractions force small amounts of chyme through the pyloric sphincter in the process of emptying
Outline the steps of Gastric Emptying and Gastric Mixing:
- A _____\_contraction originates in the ______ ______and sweeps down toward the pyloric _____\_
- The contraction becomes more vigorous as it reaches the thick-muscled _____\_
- The ______ ______ peristaltic contraction propels the chyme forward
- A small portion of chyme is pushed through the partially open sphincter into the _____\_. The stronger the antral contraction, the more chyme is emptied with each contractile wave
- When the peristaltic contraction reaches the _____\_ sphincter, the sphincter is tightly closed and no further emptying takes place
- When chyme that was being propelled toward hits the closed sphincter, it is tossed back into the _____\_ with each peristaltic contraction
- A peristaltic contraction originates in the upper fundus and sweeps down toward the pyloric sphincter
- The contraction becomes more vigorous as it reaches the thick-muscled antrum
- The strong antral peristaltic contraction propels the chyme forward
- A small portion of chyme is pushed through the partially open sphincter into the duodenum. The stronger the antral contraction, the more chyme is emptied with each contractile wave
- When the peristaltic contraction reaches the pyloric sphincter, the sphincter is tightly closed and no further emptying takes place
- When chyme that was being propelled toward hits the closed sphincter, it is tossed back into the antrum with each peristaltic contraction
Gastric motility is regulated through ______\_, ____\_, and ______\________\__ factors
Gastric motility is regulated through cephalic, gastric, and intestinal phase factors
Fill in the table
How do the factors within the stomach effect Gastric motility and emptying?
Volume of Chyme:
Fluidity:
Volume of Chyme:
- Direct effect - stretching has effect on excitability
- Increased volume stimulates motility and emptying
Fluidity:
- Direct effect: contents must be fluid to be ejected
- Increased fluidity = faster emptying
How do factors within the duodenum effect Gastric motility and emptying?
- Presence of fat, acid, hypertonicity, or distension
Presence of fat, acid, hypertonicity, or distension
- initiates enterogastric reflex or triggers release of enterogastrones
- Inhibit further gastric motility and emptying until duodenum has coped with factors already present
Secretory cells are located in _____ ____\_
Secretory cells are located in gastric pits
Complete the tabe for the secretions from each type of cell
Cellular mechanism of gastric acid secretion:
- Carbon dioxide (CO2) is metabolically produced by the cell or diffuses into the cell from the plasma and combines with water (H2O) and carbonic anhydrase (CA) to produce carbonic acid (H2CO3) which is then broken down into _____\_and _____\_.
- The H+ moves across the luminal border of the parietal cell by _____\_ pump, a primary active transport protein.
- K+ is recycled across the luminal border as it moves back from the cell into the lumen by a _____\_
- HCO3- moves across the _____\_ border of the parietal cell by ______, a secondary active transport protein.
- In such a way, Cl- is moved into the cell across the _____\_ border and will move down its electrochemical gradient through luminal Cl- channels.
Cellular mechanism of gastric acid secretion:
- Carbon dioxide (CO2) is metabolically produced by the cell or diffuses into the cell from the plasma and combines with water (H2O) and carbonic anhydrase (CA) to produce carbonic acid (H2CO3) which is then broken down into hydrogen ions (H+) and bicarbonate ion (HCO3-).
- The H+ moves across the luminal border of the parietal cell by H+/K+ ATPase pump, a primary active transport protein.
- K+ is recycled across the luminal border as it moves back from the cell into the lumen by a K+ channel.
- HCO3- moves across the basolateral border of the parietal cell by HCO3-/Cl- exchange protein, a secondary active transport protein.
- In such a way, Cl- is moved into the cell across the basolateral border and will move down its electrochemical gradient through luminal Cl- channels.
Explain the image on defence against stomach acid:
- The luminal membranes of the gastric mucosal cells are ______ to H+ so that ______ ______ ______ into the cells
- The cells are joined by ______ ______ that ______ ______ from ______ between them
- A _____ ______ over the gastric mucosa offers further protection
Explain the image on defence against stomach acid:
- The luminal membranes of the gastric mucosal cells are impermeable to H+ so that HCl cannot penetrate into the cells
- The cells are joined by tight junctions that prevent HCl from penetrating between them
- A mucus coating over the gastric mucosa offers further protection
Activation of pepsinogen in the gastric lumen:
- Pepsinogen is secreted in an inactive form and is activated to its active: _______\_, in the gastric lumen by ____________\_.
- Pepsin begins digestion of _____\_and ________\_ activates more ______\_.
Activation of pepsinogen in the gastric lumen:
- Pepsinogen is secreted in an inactive form and is activated to its active form, pepsin, in the gastric lumen by hydrochloric acid (HCl).
- Pepsin begins digestion of protein and autocatalytically activates more pepsinogen.
Cephalic-phase control of gastric secretion
Gastric-phase control of gastric secretion
