Term
| Name the layers of the gastrointestinal tract wall from outer to innermost |
|
Definition
Serosa
Muscularis Externa
Submucosa
Mucosa |
|
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Term
| The outermost lining of the GI wall; is in contact with the abdominal wall. |
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Definition
|
|
Term
| Found within each muscle bundle, muscle fibers are connected via gap junctions which allows low-resistance movements of ions from one muscle cell to the next. |
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Definition
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|
Term
| Electrical signals that initiate muscle contractions can travel readily from one fiber to the next within each bundle in this layer of the GI wall |
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Definition
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Term
| Name the 2 layers of the muscularis externa |
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Definition
Longitudinal Smooth Muscle Layer
Circular Smooth Muscle Layer |
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Term
| Extends longitudinally down the intestinal tract. Shortens with contracted. |
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Definition
| Longitudinal Smooth Muscle Layer |
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Term
| Extends around the gut and closes diameter when contracting. |
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Definition
| Circular Smooth Muscle Layer |
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Term
| Comprised of nerve plexuses and blood vessels |
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Definition
|
|
Term
| Comprised of all secretory cells |
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Definition
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Term
| Saliva passes thru all of the layers of the GI wall via what? |
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Definition
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Term
| Control mechanisms of this system are governed by the volume and composition of the luminal contents rather than by the nutritional state of the body. |
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Definition
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Term
| Lies entirely in the wall of the gut, beginning in the esophagus and extending to the anus; composed of 100 million neurons (almost exactly same amount as spinal cord) |
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Definition
| Neural Regulation (Enteric Nervous System) |
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Term
| Neural regulation is composed of what 2 plexuses? |
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Definition
Myenteric Plexus (Auerbach's)
Submucosal Plexus (Meissner's) |
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Term
| The outer plexus lying between longitudinal and circular layers. Controls GI movements. Signals control of ms contraction. |
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Definition
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|
Term
| The inner plexus that lies in the submucosa. Controls GI secretion and local blood flow. |
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Definition
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Term
| Can function independently of extrinsic control, but stimulation of parasymt and symp systems can greatly enhance or inhibit GI functions. |
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Definition
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Term
| There are an upwards of 12 neurotransmitters secreted by enteric neurons. What are the 2 most important. |
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Definition
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Term
| PSNS; most often excites GI activity |
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Definition
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|
Term
| SNS; almost often inhibits GI activity. This is also true to epi |
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Definition
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|
Term
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Definition
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Term
| Occur within the 2 nerve plexuses. |
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Definition
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Term
| Local reflexes that are integrated entirely within the gut wall enteric system. Control GI secretion, peristalsis, mixing contractions, local inhibitory effect, etc. |
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Definition
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Term
| Reflexes from the gut to the prevertebral ganglia and back to the gut |
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Definition
| Transmit signals long distances to other regions of GI; this allows for communication btwn different sections of GI |
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Term
| Signals from the stomach to cause evacuation of the colon |
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Definition
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|
Term
| Signals from the colon and small intestine to inhibit stomach motility and stomach secretion |
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Definition
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Term
| Signals from the colon to inhibit emptying of ileal contents into the colon |
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Definition
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Term
| 3 things that occur from reflexes from the gut to the spinal cord or brain stem and then back to GI |
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Definition
1. Reflexes from stomach and duodenum to the brain sten and back to the stomach to control gastric motor and secretory activity
2. Pain reflexes that cause general inhibition of the entire GI tract
3. Defecation reflexes that travel from the colon and rectum to the spinal cord and back to produce powerful colonic, rectal and abdominal contractions required for defecation |
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Term
| Name the 5 hormones of the GI system. |
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Definition
Gastrin
CCK (Cholescytokinin)
Secretin
GIP (Gastric Inhibitory Peptide)
Motilin |
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Term
| What is the stimuli for secretion for Gastrin |
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Definition
| Protein, Distention, Nerve |
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Term
| What is the stimuli for secretion for CCK? |
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Definition
|
|
Term
| What is the stimuli for secretion for Secretin |
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Definition
|
|
Term
| What is the stimuli for secretion for GIP? |
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Definition
| Protein, Fat, Carbohydrate |
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|
Term
| What is the stimuli for secretion for Motilin? |
|
Definition
|
|
Term
| What are the sites of secretion for Gastrin? |
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Definition
cells of antrum (stomach)
Duodenum, jejunum (sm. intestine) |
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|
Term
| What are the sites of secretion for CCK? |
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Definition
| cells of duodenum, jejunum, and ileum (sm. intestine) |
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|
Term
| What are the sites of secretion for Secretin? |
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Definition
| cells of duodenum, jejunum, and ileum (sm. intestine) |
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|
Term
| What are the sites of secretion for GIP? |
|
Definition
| cells of duodenum and jejunum (sm. intestine) |
|
|
Term
| What are the sites of secretion for Motilin? |
|
Definition
| cells of duodenum and jejunum (sm. intestine) |
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|
Term
| What are the actions of Gastrin? |
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Definition
| Stimuates gastric acid secretion and mucosal growth |
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|
Term
| What are the actions of CCK? |
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Definition
| Stimulates pancreatic enzyme and bicarb secretion, gallbladder contraction, growth of exocrine pancreas. Inhibits gastric emptying |
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|
Term
| What are the actions of Secretin? |
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Definition
| Stimulates pepsin secretion, pancreatic and biliary bicarb secretion, growth of exocrine pancreas. Inhibits gastric acid secretion |
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|
Term
| What are the actions of Motilin? |
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Definition
| Stimulates gastric and intestinal motility |
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|
Term
| What are the actions for GIP? |
|
Definition
Stimulates the release of insulin
Inhibits gastric acid secretion |
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Term
| Name the 3 phases of gastric secretion. |
|
Definition
Cephalic
Gastric
Intestinal |
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|
Term
| Name the 3 phases of when the stomach secretes HCL. |
|
Definition
Cephalic
Gastric
Intestinal |
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|
Term
| Occurs while food is being eaten, before it enters the stomach; can be stimulated from the sight, smell, thought, or taste of food. The greater the appetite the more intense the stimulation. |
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Definition
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|
Term
| Neurogenic signals in the cerebral cortex, amygdala, and hypothalamus are transmitted thru the dorsal motor nuclei of vagi, thru the vagus nerve to the stomach. |
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Definition
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|
Term
| Accounts for 30% of the gastric secretion associated with eating a meal. |
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Definition
|
|
Term
| Triggered by the food entering the stomach and the stomach being distended or stretched. |
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Definition
|
|
Term
| Excites log vagovagal reflexes from the stomach to the brain and back to the stomach. Excites local enteric reflexes and gatrin mechanism which causes secretion of gastric juice druing hours while food remains in the stomach. |
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Definition
|
|
Term
| Accounts for 60% of total gastric secretion; most of the total daily gastric secretion of 1500 mL |
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Definition
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|
Term
| Stimulated by the presence of food in the upper portion of the small intestine; duodenum |
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Definition
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|
Term
| Causes stomach secretion of small amounts of gastric juice. 10% of acid response to a meal. |
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Definition
|
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Term
| Broken down into peptide fragments by pepsin, trypsin, and chymotrypsin. |
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Definition
|
|
Term
| Peptide fragments are further digested to free amino acids by what 2 things? |
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Definition
Carboxypeptidase
Aminopeptidase |
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|
Term
| What types of vitamins are absorbed like other lipids? |
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Definition
|
|
Term
| __ vitamins are absorbed by diffusion or mediated transport except for vitamin B12 which must first bind to a transport protein known as intrinsic factor. |
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Definition
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|
Term
| 2 things that are absorbed by diffusion primarily within the small intestines. |
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Definition
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|
Term
| __ secretion of sufficient water and electrolytes is a necessity |
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Definition
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|
Term
| Nervous secretion causes water and salts to pass thru the glandular cells in profusion, washing organic substances thru the secretory border of the cells at the same time. |
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Definition
| Secretion of salivary glands |
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Term
| What is secreted by the mouth, pharynx, and esophagus? |
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Definition
| Saliva (controlled by both PSNS and SNS) |
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|
Term
| What is absorbed by the mouth, pharynx, and esophagus? |
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Definition
|
|
Term
| What is the motility (main action) of mouth, pharynx, and esophagus? |
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Definition
| Swallowing - pressure reflex, involves skeletal and smooth ms, peristaltic contractions |
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|
Term
| What is secreted by the stomach? |
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Definition
| HCL, pepsinogen/pepsin, mucus, gastrin |
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|
Term
| What is absorbed by the stomach? |
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Definition
|
|
Term
| What is the motility of the stomach? |
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Definition
| Receptive relaxation and peristaltic waves |
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|
Term
| Name the 2 tissues of the pancreas |
|
Definition
Acini
Islets of Langerhans |
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|
Term
| Secretes digestive juices into the duodenum |
|
Definition
| Acini tissues of pancreas |
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|
Term
| Secretes insulin and glucagon into the blood |
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Definition
| Islets of Langerhans tissues of pancreas |
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|
Term
| What type of cells secrete glucagon? |
|
Definition
| Alpha cells (islets of langerhans) |
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|
Term
| What type of cells secrete insulin and amylin? |
|
Definition
| Beta cells (islets of langerhans) |
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|
Term
| What type of cells secrete somatostatin? |
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Definition
| Delta cells (islets of langerhans) |
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Term
| Cell to cell communication directs the control of secretion of some of the hormones by the other hormones. Ex: insulin inhibits glucagon secretion. |
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Definition
| Islets of langerhans (tissue of pancreas) |
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|
Term
| Name the 3 secretions of the pancreas? |
|
Definition
Pancreatic Juice
Insulin secretion
Glucagon secretion |
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|
Term
| Pancreatic juice enzymes help to digest proteins. Name 3 proteins |
|
Definition
Trypsin
Chymotrypsin
Carboxypolypeptidase |
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|
Term
| Pancreatic juice enzymes help to digest carbohydrates. Name 1 |
|
Definition
|
|
Term
| Pancreatic juice enzymes help to digest fat. Name 3 fats |
|
Definition
Pancreatic lipase
Cholesterol esterase
Phospholipase |
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|
Term
| Pancreatic juice also has bicarb ions and water. What secretes those? |
|
Definition
| Epithelial cells of ducts |
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|
Term
| Can provide large quantity of alkali in pancreatic juice than serves to neutralize hydrochloric acid emptied into duodenum from stomach. |
|
Definition
| Bicarb ions and water from pancreatic juice |
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|
Term
| Name 4 functions of insulin secretion by the pancreas. |
|
Definition
1. Promotes ms glucose uptake and metabolism
2. promotes liver uptake, storage, and use of glucose
3. Promotes fat synthesis and storage
4. Promotes protein synthesis and storage |
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|
Term
| Name 4 functions of glucose secretion by the pancreas. |
|
Definition
1. Causes glycogenolysis and increased blood glucose concentration
2. Increases gluconeogenesis
3. Activates adipose cell lipase
4. In high concentrations, it enhances strength of heart, increases blood flow to kidneys, enhances bile secretion, inhibits gastric acid secretion |
|
|
Term
| What is absorbed by the pancreas? |
|
Definition
|
|
Term
| What is the motility of the pancreas? |
|
Definition
| Movement of substrates thru pancreatic duct to small intestine |
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|
Term
| What is secreted from the liver? |
|
Definition
| Bile seceted by hepatocytes and epithelial cells |
|
|
Term
| Plays an important role in fat digestion and absorption by emulsifying large fat particle of food into minute particles and aiding in absorption of the digested fat end products thru the intestinal mucosal membrane |
|
Definition
|
|
Term
| Helps with excretion of several important waste products from the blood such as bilirubin and cholesterol. |
|
Definition
|
|
Term
| What is absorbed by the liver? |
|
Definition
| Bile salts (via portal vein back to liver) |
|
|
Term
| What is the motility of the liver? |
|
Definition
| Contraction of gallbladder to release bile |
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|
Term
| What is secreted by the small intestines? |
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Definition
| Water, mineral ion, and mucus (from Brunner's gland in response to tactile or irritating stimuli, vagal stimulation and GI hormones, especially secretin) |
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|
Term
| What is the function of water, mineral ions, and mucus being secreted from the small intestines? |
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Definition
| To protect the duodenal wall from digestion by the acidic gastric juice emptying from the stomach |
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|
Term
| What all is absorbed in the small intestines? |
|
Definition
Water
Chloride
Bicarb
Na
Ca
Iron
Phosphate
Magnesium
Carbs
Fats
(most of the meal is absorbed here) |
|
|
Term
| Transported thru the intestinal membrane entirely by diffusion to either dilute (diffusion from the plasma into the chyme) or concentration of chyme (diffusion from the chyme into plasma |
|
Definition
|
|
Term
| Actively transported thru the intestinal membrane, and some of it is transported via co-transporters (glucose, amino acid, or H+) |
|
Definition
|
|
Term
| Greatly enhances Na absorption |
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Definition
|
|
Term
| Large amounts of __ can be released from the adrenal cortices in response to dehydration. Within 1-3 hours, an increase in Na ( and thus Cl and water) absorption occurs. |
|
Definition
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|
Term
| Large amounts of __ must be reabsorbed from the upper small intestine because of the large secretions into the duodenum from the pancreatic secretions and bile. The same mechanisms in the renal tubules occurs here. |
|
Definition
|
|
Term
| __ activats Vitamin D, which regulates the reabsorption of Ca from the small intestine |
|
Definition
|
|
Term
| What is the motility of the small intestine? |
|
Definition
| Segmentation fro the thorough mixing of chyme |
|
|
Term
| Alternate contractions of the muscuar wall |
|
Definition
|
|
Term
| What is secreted by the large intestine? |
|
Definition
| Mucus - secretes moderate amounts of bicarb ions (including the ileum) in exchange for reabsorption of chloride |
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|
Term
| Provides and alkaline ion to neutralize acid products formed by bacteria and feces of the colon. |
|
Definition
|
|
Term
| Protects the intestinal wall against excoriation, provides an adherent medium for holding fecal matter together. |
|
Definition
|
|
Term
| What is absorbed in the large intestine? |
|
Definition
| Almost all remaining Na, water, undigested fiber, and vitamins are absorbed within the colon; especially the proximal 1/2. The distal 1/2 functions mainly for feces storage until time for excretion. |
|
|
Term
| What is the motility for the large intestine? |
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Definition
| Smooth muscle contractions, propulsion of material toward anus, mas movement, defecation |
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|
Term
| Which part of the colon is mainly for storage of feces until time for defecation? |
|
Definition
|
|
Term
| Feeling of hunger or satiation is driven by what? |
|
Definition
|
|
Term
| Inflammation of the gastric mucosa (lining of stomach) |
|
Definition
|
|
Term
| Caused by chronic bacterial infection of gastric mucosa, or excessive ingestion of irritants like alcohol or aspirin. |
|
Definition
|
|
Term
| With gastritis, the __ __ permeability is increased allowing hydrogen ions to diffuse into the stomach epithelium. |
|
Definition
|
|
Term
| Leads to stomach mucosal damage, atrophy, or ulcers. Can be superficial or penetrate deeply into the gastric mucosa causing almost complete atrophy of the gastric mucosa. In severe cases it can cause ulcerative excoriation of the stomach mucosa. |
|
Definition
|
|
Term
| How can gastritis be treated? |
|
Definition
| Intensive regimen of antibacterial therapy |
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|
Term
| An excoriated area of stomach or intestinal mucosa caused by the digestive action of gastric juice or upper small intestine secretions. |
|
Definition
|
|
Term
| Where is the most frequent site of ulcers? |
|
Definition
| Within a few centimeters of the pylorus, along the lesser curvature of the antral end of the stomach or in the lower end of the esophagus where stomach juices frequently reflux. |
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|
Term
| The cause of this is an imbalance between the rate of scretion of gastric juice and the degree of protection afforded by the gastroduogenal mucosal barrier and the neutralization of the gastric acid by the duodenal juices. |
|
Definition
|
|
Term
| Can be caused by excess secretion of acid and pepsin by the gastric mucosa or diminished ability of the gastroduodenal mucosal barrier to protect against the digestive properties of the somach acid-pepsin secretion. |
|
Definition
|
|
Term
| Failure of the pancreas to secrete pancreatic juice intothe small intestine occurs in 1)pancreatitis, 2) when the pancreatic duct is blocked by a gallstone or 3) after the head of the pancreas has been removed b/c of malignancy |
|
Definition
|
|
Term
| When a loss of pancreatic juice and enzymes causes fat, proteins, and carbs entering the small intestines to be unabsorbed. |
|
Definition
|
|
Term
| Is pancreatitis always acute? |
|
Definition
|
|
Term
| Causes of this include drinking excess alcohol and blockage of the papilla by a gallstone. The pancreatic enzymes can be dammed in the ducts and begin to digest large portions of the pancreas, destroying the ability to secrete digestive enzymes. |
|
Definition
|
|
Term
| The means by which upper GI tracts rid itself of its contents when almost any part of the upper tract becomes excessively irritated, over-distended or over-excitable. |
|
Definition
|
|
Term
| Excessive distention or irritation of the duodenum provides a srong stimulus for __ |
|
Definition
|
|
Term
| Sensory signals that initiate __ originate from pharynx, esophagus, stomach, upper portions of small intestine. |
|
Definition
|
|
Term
| Nerve impulses are transmitted by vagal and sympathetic nerve fibers to nuclei in brain stem called the what? |
|
Definition
|
|
Term
| Motor impulses that cause actual act of vomiting are transmitted by what 5 cranial nerves along with the vagal, sympathetic, and spinal nerves. |
|
Definition
|
|
Term
| The conscious recognition of subconscious excitation in an area of the medulla closely associated with or part of the vomiting center, and it can be caused by 1) irritative impulses comming from the GI tract, 2) impulses that originate in the lower brain associated with motion sickness, or 3) impulses from the cerebral cortex to initiate vomiting. |
|
Definition
|
|
Term
| Caused by cancer, fibrotic constriction resulting from ulceration or from peritoneal adheasions, spasma of a segment of the gut and paralysis of a segment of the gut. The consequences depend on the point in the GI tract that this happens to. |
|
Definition
|
|
Term
| The slow movement of feces thru the large intestines; associated with large quantities of dry, hard feces in the descendin colon that accumulate because of over-absorption of fluid |
|
Definition
|
|
Term
| Causes of this include irregular bowel habits, spasm of a small segment of sigmoid colon and any pathology of the intestines that obstruct movement of intestinal contents such as tumors, adhesions or ulcers. |
|
Definition
|
|
Term
| Severe constipation with tremendous amounts of fecal matter accumulation in the colon, causing it to distend to a diameter of 3 to 4 inches. Frequently caused by a lack or deficiency of ganglion cells in the myenteric plexus in a segment of the sigmoid colon which doesn't allow defecation reflexes or strong peristaltic motility. |
|
Definition
| Megacolon (Hirshsprung's Dz) |
|
|
Term
| Occurs when a segment of the large intestine becomes intensely irritated, as occurs when bacterial infection becomes rampant during enteritis, the mucosa secretes extra large quantities of water and electrolytes in addition of the normal viscid alkaline mucus. |
|
Definition
|
|
Term
| Acts to dilute the irritating factors a to cause rapid movement of the feces toward the anus |
|
Definition
|
|
Term
| Results in loss of large quantities of water and electrolytes. Also washes away irritant factors, which promotes earlier recovery from the disease that might otherwise occur. |
|
Definition
|
|
Term
| Initiated by accumulating feces in the rectum - spinal cord mediated defecation reflex from rectum to conus medullaris and back to colon, sigmoid, rectum, and anus |
|
Definition
|
|
Term
| Causes the voluntary portion of the defecation act to be blocked while the basic cord reflex is still intact. Voluntary action is lost (increased abdominal pressure and relaxation of voluntary anal sphincter) but reflex can still occur, usually with small enema to excite action of reflex |
|
Definition
| Spinal cord injury (between conus medullaris and brain) |
|
|
Term
|
Definition
|
|
Term
| Name 3 ways in which gases can enter the GI tract |
|
Definition
1. Swallowed air
2. Gases formed in gut as a result of bacterial action
3. Gases that diffuse from the blood into GI tract |
|
|
Term
| Most gases in stomach are normally mixtures of nitrogen and oxygen from swallowing air which causes what? |
|
Definition
|
|
Term
| Gases here are derived from bacterial action, including CO2, methane, and hydrogen. |
|
Definition
|
|
Term
| When __ and __ mix with O2, an actual explosive mixure can be formed. |
|
Definition
|
|
Term
| Name 6 foods that can cause a greater expulsion of flatus thru the anus |
|
Definition
Beans
Cabbage
Onion
Cauliflower
Corn
Vinegar (irritant foods) |
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