Term
| What transporters are involved in Na+ absorption in the GI tract? |
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Definition
| Na+/H+ antiport, Na+/solute symport, Na+/Cl- symport, and ENaCs |
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Term
| Where in the GI tract are the following transporters found: Na+/H+ antiport, Na+/solute symport, Na+/Cl- symport, and ENaCs? |
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Definition
1. duodenum and jejunum
2. duodenum, jejunum, and ileum
3. ileum, colon, and rectum
4. ileum, colon, and rectum |
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Term
| What transporters are involved in Cl- absorption in the GI tract? |
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Definition
| electrical gradient, HCO3- dependent Cl- absorption, and Na+/Cl- symport |
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Term
| Where are the following methods of Cl- absorption found in the GI tract: electrical gradient Cl- absorption, HCO3- dependent Cl- absorption, and Na+/Cl- symport? |
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Definition
1. everywhere from the duodenum to the rectum
2. the ileum, colon, and rectum
3. the ileum, colon, and rectum |
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Term
| What transporters for K+ are in the GI tract? |
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Definition
| facilitated diffusion, non-facilitated diffusion, passive secretion, active secretion, and active absorption |
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Term
| Where are the following found for K+ in the GI: facilitated diffusion, non-facilitated diffusion, passive secretion, active secretion, and active absorption? |
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Definition
1. duodenum, jejunum, and ileum
2. colon and rectum
3. colon and rectum
4. colon and rectum
5. rectum |
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Term
| What is achalasia? What causes it? What does/can it cause? |
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Definition
1. a disorder reducing the ability of the esophagus to move food into the stomach
2. damage or congenital defect of the myenteric plexus
3. megaesophagus and possibly esophageal rupture |
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Term
| What conditions (non-traumatic) can cause paralysis of swallowing muscles? |
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Definition
| muscular distrophy and myasthenia gravis |
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Term
| What conditions can cause damage to the swallowing center of the CNS? Where is that center located? |
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Definition
1. polio and encephalitis
2. the brain stem |
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Term
| Damaging which nerves will cause problems/inability to initiate a swallowing reflex? |
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Definition
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Term
| What is gastroparesis? What causes it? What can it cause? |
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Definition
1. decreased ability of the stomach to empty
2. damage to the ANS
3. malnutrition, decreased antral peristalsis |
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Term
| What are some complications that can occur when a swallowing reflex cannot be initiated? |
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Definition
| a patient may have malnutrition or may choke/aspirate on food |
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Term
| What is gastritis? What causes it? What does it cause? |
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Definition
1. damage/inflammation of the mucosa
2. bacterial infection or irritant substances leading to damage of the protective barrier (including alcohol and aspirin)
3. low or no stomach acid (hypo- or achlorohydria), which means low or no pepsin activation and low or no intrinsic factor |
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Term
| What can excessive stomach acid cause? |
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Definition
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Term
| What is IBD? What are the subtypes of IBD? |
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Definition
1. irritable bowel disorder
2. ulcerative colitis and Crohn's disease |
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Term
| What is Crohn's disease? What age group does it affect most? List some characteristics of it. |
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Definition
1. an autoimmune disease that can cause a host of problems in the GI tract, including constipating, pain, watery stool, loss or appetite, etc
2. affects age groups 15-30 and 55-60, mostly
3. it is an autoimmune disorder and can be familial; it can be treated with steroids |
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Term
| What is IBS? What age group does it affect most? List some characteristics of it. |
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Definition
1. irritable bowel syndrome
2. 15-40
3. it has no autoimmune etiology, mostly involves damage to the colonic mucosa, is chronic and non-recurring, and surgical removal of the affected area is curative |
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Term
| What are the types of neoplasms? |
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Definition
| carcinomas, adenomas, and polyps |
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Term
| What is the difference between familial and non-familial neoplasms? |
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Definition
| familial is caused by a mutation in the DNA repair or TS gene, can present with polyps, and can increase the risk of other cancers in the lifetime; non-familial has no inherited mutation and does not increase the risk of other cancers |
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Term
| What is the difference between sessile and predunculated polyps? |
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Definition
| sessile polyps have more free malignancies and removal of them will decrease the risk of cancers; predunculated are less malignant |
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Term
| What is H. pylori and what does it do? How does it cause that? |
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Definition
1. it is a bacteria
2. it can break down the gastroduodenal mucosa barrier and stimulate gastric acid secretion, leading to peptic ulcers; this infection can be life-long without therapy
3. it can burrow into the mucosa and secrete ammonium, which liquifies the mucous barrier and stimulates acid secretion |
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Term
| What is Hirschsprung's disease? |
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Definition
| severe constipation resulting from a lack of ganglion cells in the myenteric plexus in a segment of the sigmoid colon; without many ganglion cells, neither defecation nor strong peristalsis can occur |
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Term
| What is enteritis? What causes it? What can it cause? How is it treated? |
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Definition
1. inflammation of the intestinal tract
2. either a virus or bacteria in the intestinal tract
3. it can cause infectious diarrhea and loss of a lot of electrolytes and fluid (in an attempt to wash the infection through the GI tract)
4. antibiotics and possibly IV fluids |
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Term
| What is psychogenic diarrhea? |
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Definition
| excessive stimulation of the PSNS, exciting motility and excess secretion of mucus in the distal colon, yielding diarrhea |
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Term
| What is ulcerative colitis? What causes it? What can it cause? How is it treated? |
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Definition
1. extensive areas of the colon become inflamed and ulcerated
2. unknown, but some people think it is allergic or autoimmune or an infection that is not understood; there is a strong hereditary susceptibility, though
4. ileostomy, allowing the small intestine contents to drain to the exterior instead of the colon, or removal of the colon
3. increased colon secretions and persistent mass movements, causing repeated diarrhea |
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Term
| How is defecation affected with a spinal cord injury between the brain and the conus medullaris? |
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Definition
| the defecation reflex cannot be initiated by voluntary action (via the Val Salva maneuver); patients usually control their bowel movements via a small enema after the first meal of the day |
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Term
| What is antiperistalsis? How is it initiated? Where is it initiated? |
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Definition
1. peristalsis in the reverse direction
2. overdistension, excessive GI irritation, or certain drugs like morphine, apomorphine, or digitalis derivatives
3. anywhere from the ileum up |
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Term
| What are the steps of the vomiting reflex? |
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Definition
| overdistension or excessive GI irritation cause reverse peristalsis until |
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Term
| What is the nervous center that controls the vomiting reflex? Where is it located? What is the nervous pathway for the signals for vomiting? |
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Definition
1. the chemoreceptor trigger zone
2. it exists bilaterally on the floor of the fourth ventricle; this only controls one vomiting reflex, not one originating from irritation in the GI tract
3. afferent signals are send from the upper GI tract to via the vagus nerve to the vomiting center and sympathetic nerves to the dorsal horns of the spinal cord and then to the vomiting center; from there, motor impulses are sent via CN V, VII, IX, X, and XII to the upper GI tract and through CN IX and sympathetic nerves to the lower GI tract |
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Term
| What are the steps of the act of vomiting (steps which the vomiting reflex cause)? |
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Definition
| the patient takes a deep breath, the hyoid bone and larynx is raised to close the airway and open the esophagus, the soft palate is lifted to close the posterior nares; the diaphragn is then contracted down and the abdominal muscles contract to build up pressure in the stomach and cause the vomiting act |
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Term
| What is nausea? What causes it? |
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Definition
1. a conscious recognition of subconscious excitation in the vomiting center
2. irrtative impulses from the GI tract, impulses from the lower brain associated with motion sickness, and impulses from the cerebral cortex to initiate vomiting |
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Term
| What are possible causes of GI obstructions? What occurs if there is an obstruction in the following places: the pylorus, the small intestine, large intestine? |
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Definition
1. cancer, fibrotic constriction due to ulceration, spasms, paralytic ileus, and adhesions
2. a. persistent vomiting occurs, causing loss of acid and yielding metabolic alkalosis
b. antiperistalsis can cause small intestine and pancreatic secretions and bile to be pushed to the stomach and vomited, causing possible dehydration (from water loss/electrolyte loss) and acid/base problems, depending on how much HCO3- and H+ is lost
c. usually less vomiting and more constipation from feces building up in the colon; severe vomiting will occur when no more chyme can move from the ileum into the large intestine and prolonged colic obstruction can cause dehydration and circulatory shock |
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Term
| What is flatus? What can cause it? |
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Definition
1. gases in the GI tract
2. swallowed air, gases from bacterial action, and gases diffusing from the blood into the GI tract |
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Term
| What gases are most common in the GI tract? What are produced by bacterial action? What is a danger concerning the later? |
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Definition
1. nitrogen and oxygen
2. CO2, methane, and hydrogen
3. they can be explosive and ignite during electric cautery |
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Term
| About how much gas is formed in the large intestine daily? About how much is expelled anally daily? |
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Definition
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