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77 Cards in this Set
- Front
- Back
Depressions in the epithelial lining of the stomach.
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Gastric Pits
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What is at the bottom of the gastric pits in the stomach?
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Gastric glands
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What cells produce the enzymes of gastric juice?
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Chief Cells
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What cells produce stomach acid?
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Parietal cells
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What is the pH of gastric secretion?
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1.0-3.5
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The mucous produced by mucus-secreting cells is very _____ and protects the stomach wall from being exposed to the highly _____ gastric secretions.
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Alkaline
Acidic |
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What part of the stomach are parietal cells located?
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Body (fundus)
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What part of the stomach are the chief cells located?
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Body (fundus)
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What part of the stomach are the G cells located?
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Antrum
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What part of the stomach are the mucous cells located?
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Antrum
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What are the secretion products of parietal cells?
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HCL
Intrinsic factor (essential) |
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What are the secretion products of chief cells?
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Pepsinogen (converted to pepsin at low pH)
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What are the secretion products of G cells?
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Gastrin
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What are the secretion products of Mucous cells?
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Mucus pepsinogen
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What is the stimulus for secretion for Parietal cells?
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Gastrin
Vagal Stimulation (ACh) Histamine |
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What is the stimulus for secretion for chief cells?
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Vagal Stimulation (ACh)
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What is the stimulus for secretion for G cells?
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Vagal stimulation (via GRP)
Protein |
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What is the stimulus for secretion for Mucous cells?
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Vagal stimulation (ACh)
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Gastric inhibitory peptide slows/speeds up gastric emptying.
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Slows
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Activation of the sympathetic nervous system slows/speeds up gastric emptying.
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Slow
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Activation of the parasympathetic nervous system slows/speeds up gastric emptying.
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Speeds up
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Cholecystokinin slows/speeds up gastric emptying.
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Slow
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Secretin slows/speeds up gastric emptying.
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Slow
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Activation of the enteric nervous system slows/speeds up gastric emptying.
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Slow
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Ingestion of food and its presence in the stomach slows/speeds up gastric emptying.
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Speeds up
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What stimulates the release of hormones in the GI tract?
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Food entering duodenum esp. fats and acidic chyme
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What are the hormones that are stimulated which inhibit the pyloric pump?
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Cholecystokinin
Secretin Gastric inhibitory peptide (GIP) |
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What is stomach emptying enhanced by?
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Presence of food in the stomach and gastrin
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In what ways does the small intestine send inhibitory signals to the stomach to slow secretion and motility?
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Nervous and Endocrine
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Distension of the small intestine, as well as _____ and _____ irritation in the mucosa, is transduced into gastric inhibitory impulses which are known as what?
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Enterogastric reflex
chemical osmotic |
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What are the hormones that are released from the small intestine which contribute to suppression of gastric activity?
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Cholecystokinin
Secretin |
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What are the two major types of contractions in the GI tract?
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Peristalsis
Mixing contractions |
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Contractions that generate propulsive movements.
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Peristalsis
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Contractions which serve to spread out the foodstuffs and increase the surface area available for digestion and absorption.
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Mixing Contractions
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What are the three secretions from the enteric endocrine system that stimulate the pancreas?
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Cholecystokinin
Secretin Gastrin |
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What are the three secretions from the pancreas acinar cells?
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Amylase
Chymotrtpsin Trypsin |
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What is the single secretion from the pancreas duct cells?
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Bicarbonate ion
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What nerve innervates the pancreas and the stomach?
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Vagus nerve
requires low level stimulation |
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What is the daily secretion of the pancreas?
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0.7-2.5
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What is the pH of pancreatic secretions?
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7.5-8.8
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What are the enzymes involved in protein breakdown that are secreted from the acinar cells of the pancreas?
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Trypsin
Chymotrypsin Carboxypolypeptidase |
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What is the enzyme involved in carbohydrate breakdown that is secreted from the acinar cells of the pancreas?
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Amylase
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What are the enzymes involved in fat breakdown that are secreted from acinar cells of the pancreas?
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Lipase
Cholesterol Esterase Phospholipase |
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What is the inactive form of the secreted pancreatic enzymes?
Where is it activated? |
Zymogen
Small intestine |
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What is composed of mucous, parietal, and chief cells and makes up the gastric juice?
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Exocrine gastric glands
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What is the daily secretion of gastric juice?
What is the pH? |
2-3 liters
1.0-3.0 |
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What is the pH of intestinal secretions?
What are they mainly? What are they secreted by? |
6.5-7.8
Mucus Goblet cells / Enterocytes |
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What is the pH of Bile?
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7.8
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What does bile aid in?
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Emulsification, digestion, and absorption of fats
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What is the hormone that is produced by the wall of the upper part of the intestine?
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Cholecystokinin
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What does cholecystokinin stimulate?
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Contraction of gall bladder, releasing bile
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What are the three regions in the stomach which delineate the different secretory glands?
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Cardiac
Gastric Pyloric |
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Mucus secreting glands found primarily in the proximal stomach
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Cardiac glands
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Glands which release gastrin, pepsinogen, and mucous.
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Gastric/oxyntic glands
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Glands where mucous secretion into the stomach and gastrin into the blood occurs. Found in the Antrum.
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Pyloric glands
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Produces an acid environment that helps to kill bacteria and to activate pepsin. Solubilizes connective tissue.
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HCL
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What increases the secretion of HCL?
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Acetylcholine
Gastrin Histamine |
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The proteolytic enzyme secreted in an inactive form _____ and converted by stomach acidity or by autocatalysis to pepsin. Active at pH _____.
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Pepsin
Pepsinogen <5 |
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Viscous and alkaline, produces a barrier along the walls of the stomach to protect the stomach from acid and abrasion.
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Mucous
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A glycoprotein that is essential for normal absorption of vitamin B12 in the intestine. Without it _____ _____ develops.
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Intrinsic Factor
Pernicious Anemia |
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What are the coordinated contractions of smooth muscle which facilitate digestion and absorption by chopping, mixing and rolling food?
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Segmentation contractions
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What is the semifluid contents of the stomach consisting of partially digested food and gastric secretions?
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Chyme
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What constitutes the bulk of dietary fat which is composed of a glycerol backbone with each carbon linked to a fatty acid?
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Neutral fat or triglyceride
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What two processes have to occur in order for triglycerides to be absorbed?
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Emulsification
Enzymatic breakdown into monoglycerides and free fatty acids |
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Large aggregates of dietary triglyceride, which are virtually insoluble in an aqueous environment, must be broken down physically and held in suspension by what process?
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Emulsification
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How does a monoglyceride or free fatty acid enter an enterocyte?
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Simple Diffusion
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What are the key components to the breakdown of triglycerides?
Where does this take place? |
Bile Salts
Pancreatic Lipase W/ chyme in the small intestine |
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What are the end products of protein digestion?
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Dipeptides
Amino Acids |
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What facilitates the final stage of digestion?
How is absorption across the brush boarder of the lumen done? |
Peptidases
Secondary active transport |
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What kind of secondary transporters are used in the absorption of dipeptides and amino acids?
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Sodium or Hydrogen Co-transporters
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What are used to hydrolyze disaccharides and small glucose molecules at the brush boarder during absorption?
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Lactase
Sucrase Maltase Alpha-dextrinase |
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How are glucose and galactose absorbed into the lumen?
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Sodium secondary active transporters
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How is Fructose absorbed into the lumen?
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Facilitated Diffusion
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What are the three phases of gastric secretion?
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Cephalic Phase
Gastric Phase Intestinal Phase |
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In this phase sensations of thoughts about food are relayed to the brainstem, where parasympathetic signals to the gastric mucosa are initiated. This directly stimulates gastric juice secretion and stimulates the release of gastrin, which prolongs and enhances the effect.
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Cephalic Phase
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The presence of food, especially the distension food causes, triggers local parasympathetic nervous reflexes that increase the secretion of gastric juice and gastrin. Products of protein digestion can also trigger the gastrin mechanism.
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Gastric Phase
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As food moves into the duodenum, the presence of fats, carbohydrates, and acid stimulates hormonal and nervous reflexes that inhibit stomach activity.
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Intestinal Phase
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