Term
| The Gastric mucosa has 2 distinct regions based on their structures. What is these 2 regions? |
|
Definition
1. Oxyntic glandular region
2. Pyloric glandular region |
|
|
Term
| The Oxyntic glandular gland contains 80% of this region of the stomach. |
|
Definition
|
|
Term
| The Pyloric gland is 20% of this part of the stomach. |
|
Definition
|
|
Term
| What is the functions of the stomach? |
|
Definition
1. Reservoir for meals
2. Mixing secretions with ingested food
3. Regulate emptying of chyme into duodenum
4. Secretion of certain things |
|
|
Term
| What things are secreted by the stomach? |
|
Definition
1. HCl
2. Pepsin
3. Water
4. Mucus
5. HCO3-
6. Intrinsic factor |
|
|
Term
| List the cells that are located in the Oxyntic gland of the stomach. |
|
Definition
1. Enterochromaffin like cells (ECL)
2. Chief cells
3. Parietal cells
4. Mucus cells |
|
|
Term
| ECL cells store and release ______________. |
|
Definition
|
|
Term
| Chief cells are aka _____________ and secrete ________________. |
|
Definition
|
|
Term
| What cells of the oxyntic gland secrete HCl and gastric intrinsic factor? |
|
Definition
|
|
Term
| T/F: The mucus cells of the Oxyntic gland only secrete mucous. |
|
Definition
| False; they also secrete HCO3- |
|
|
Term
| What is intrinsic factor? |
|
Definition
| A glycoprotein secreted by the parietal cells of the stomach that is required for the absorption of Vit. B12. It binds it. |
|
|
Term
| What types of cells can be found in the Pyloric gland of the stomach? |
|
Definition
1. Chief cells
2. Mucus cells
3. G cells |
|
|
Term
|
Definition
|
|
Term
|
Definition
| A group of proteases secreted by chief cells that digest proteins |
|
|
Term
| The chief cells secrete pepsinogen (inactive form), but is stored in zymogen granules. What 2 thing cause the release of pepsinogens fromt he zymogen granules? |
|
Definition
|
|
Term
| How is pepsinogen activated to its active form pepsin? |
|
Definition
| Cleavage by HCl at low pH |
|
|
Term
| In the stimulated state of parietal cells what happens? |
|
Definition
1. rise in intracellular levels of 2nd messengers
2. TVEs move and fuse to the PM
3. H-K-ATPase secretes protons |
|
|
Term
| In the resting state of parietal cells, the H-K-ATPases are restricted to ________________. |
|
Definition
| the Tubulovesicular elements (TVEs) |
|
|
Term
What is the unstimulated basal level of gastric secretion?
What about stimulated? |
|
Definition
|
|
Term
| T/F: The number of parietal cells in peeps vary and is responsible for the wide range of HCl secretion. |
|
Definition
|
|
Term
| What does the ionic composition of gastric juice depend on? |
|
Definition
|
|
Term
| At High flow rates, gastric juice predominantely contains ______ and ________. |
|
Definition
|
|
Term
| What are the 3 major stimulators of HCl from parietal cells? |
|
Definition
|
|
Term
| How does Gastrin and AcH regulate Gastric secretions? |
|
Definition
1. Gastrin binds to CCK-B coupled to Gq whereas AcH binds to M3R coupled to the same Gq (synergistic effect).
2. Both send signal transduction to increase IP3
3. IP3 releases Ca2+
4. Ca2+ activates the H-K-ATPase and releases H+ into lumen
5. Also activates transport of Cl- out to lumen
(makes HCl) |
|
|
Term
| Histamine is made from Histidine. What enzyme is responsible for this conversion? |
|
Definition
|
|
Term
| What stimulates the release of Histamine from ECL cells? |
|
Definition
| Gastrin binding to CCK receptors on the ECL cells |
|
|
Term
| What is the pH in the lumen of the gastric gland? What about in the parietal cell? |
|
Definition
|
|
Term
| The pumping of H+ leaves an excess of ___________. This flows down its electrochemical gradient across the basolateral PM. |
|
Definition
|
|
Term
| With gastric acid secretion mechanism, Cl- moves against its gradient into the cell with the help of the _______________. |
|
Definition
| Cl-, HCO3- countertransporter |
|
|
Term
| When the stomach is empty for several hours, HCl is secreted at a ___________ level which is approximately _____ % of the max rate. |
|
Definition
|
|
Term
| List the 3 phases of increased acid secretion in response to a meal. And when are they each elicited? |
|
Definition
1. Cephalic phase = b4 food reaches stomach
2. Gastric phase = food in stomach
3. Intestinal phase = mechanisms that originate in the duodenum and upper jejunum |
|
|
Term
| In the cephalic phase of gastric secretion, what condition reflexes stimulate the vagus nerve? |
|
Definition
1. Taste
2. Smell
3. Chewing
4. Sight
5. Swallowing
6. Hypoglycemia |
|
|
Term
| What things in the gastric phase of gastric acid secretion increase the secretion? |
|
Definition
1. Distension of stomach
2. A.A.
3. Peptides |
|
|
Term
| What 2 things inhibit the release of Gastrin from the G cells thus decreases the response of parietal cells? |
|
Definition
Secretin
Somatostatin - bind to the G cell receptor |
|
|
Term
| ____________ is released from D cells in the gastric antrum in response to the presence of _______. |
|
Definition
|
|
Term
| What 2 things form the Gastric mucosal barrier? |
|
Definition
|
|
Term
| What is the function of the Gastric Mucosal Barrier? |
|
Definition
| Protects the luminal surface of the stomach form HCl and pepsin |
|
|
Term
| Mucus has secretions that have glycoprotein mucins that make it sticky and viscous. What cells secrete mucus? |
|
Definition
| Mucus neck cells and surface epithelial cells |
|
|
Term
| ___________ stimulates the release of mucus from there cells as well as HCO3-. |
|
Definition
|
|
Term
| HCO3- is secreted by surface epithelial cells and makes the mucus layer ___________. |
|
Definition
|
|
Term
| How thick is the mucus bicarb gel layer? |
|
Definition
|
|
