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41 Cards in this Set
- Front
- Back
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Which NTs from the ENS are smooth mm contractors?
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Ach
Enkephalins (opiates) Sub P |
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Which NTs from the ENS are smooth mm relaxors?
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Nepi
NPY VIP |
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Which NTs from the ENS are secreted from mucosal neurons/smooth mm?
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VIP
NPY Enkephalins |
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Which NTs from the ENS are secreted from neurons of the gastric mucosa?
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GRP
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Which NTs from the ENS increase intestinal secretions? which organ doe they stimulate?
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Ach (Stomach, Pancreas)
VIP (pancreas) GRP (stomach) |
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Which NTs from the ENS affect salivary secretion?
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Ach
Sub P Nep |
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Which NTs from the ENS decrease intestinal secretions?
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Enkephalins
NPY |
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what affect does the SNS have on the GI tract? When are these neurons stimulated? where do they synapse?
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They slow GI secretion/motility
secreted in the fight/flight response synapse in ganglia outside of the GI tract |
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What affect does the PSNS have on the GI tract? when are these neurons stimulated? where do they synapse?
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they increase GI secretion/motility
secreted during rest/digest phase the vagus/pelvic splanchnic nerves synapse on the myenteric and submucosal plexuses. |
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what are the functions of the GI peptides?
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stimulate contraction/relaxation of the smooth mm/sphincters
stimulate secretion of enzymes for digestion stimulate secretion of fluid/electrolytes |
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what is the purpose of chewing food?
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grind/mix food with saliva
stimulate taste buds reflexly increase salivary/gastric/pancreatic/bile secretions |
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which salivary gland produces a mucous type secretion?
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the submandibular gland-mucus cells produce mucin glycoproteins
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what kind of saliva is produced when salivary glands are stimulated by the PSNS?
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watery, enzyme-rich
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what kind of saliva is produced when salivary glands are stimulated by the SNS?
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less volume, mucus-rich (active with stress)
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is salivary secretion hormonally regulated?
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no, only ANS regulated
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what is the order of structures the salivary reflex takes?
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pressure/chemoreceptors in mouth
salivary center in medulla (afferent) cerebral cortex salivary center in medulla (efferent) autonomic nerves salivary glands salivary secretion |
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what is xerostoma?
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decreased saliva production
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what causes xerostoma?
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staph/strep infection
stones in salivary glands mumps (viral infection in parotid) chemotherapy or radiation medications (for BP, depression) |
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what are the symptoms for xerostoma?
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dry mouth
difficulty chewing dysphagia inarticulate speech dental caries face pain |
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What is Achalasia?
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when the LES doesn't relax when swallowing and the food bolus doesn't enter the stomach
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how would you treat achalasia?
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you would either do surgery or give meds to decrease LES sphincter tone
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what are the three phases of the swallowing reflex? injury to the swallowing center of the medulla would prevent which phase from working properly?
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oral phase
pharyngeal phase-would be inhibited in injury to swallowing center (the pharynx is the one that starts the peristaltic movement of the food) esophageal phase |
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What mediates the relaxation of the LES to allow food to enter the stomach?
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VIP secreted by the vagus n.
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What is the underlying cause of GERD?
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the LES sphincter tone is decreased and gastric contents are allowed back up into the esophagus
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What are the three ways to diagnose a swallowing disorder?
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Cineradiography-swallow barium prep, X-ray and videotape movement
Upper endoscopy Manometry-measure timing and strength of esophageal and valve contractions |
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What is Schatzki's ring?
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an abnormal ring of mucosal tissue that forms where the LES is
causes narrowing of the lower esophagus-sometimes a birth defect |
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What are some degenerative neurological disorders associated with swallowing?
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ALS
Myasthenia Gravis |
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how does the stomach account for an increase in volume?
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"Receptive Relaxation"
the rugae flatten out triggered by eating, mediated by the vagus nerve eating over 1.5L of food will over distend the stomach and increase intragastric pressure |
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What is the vagovagal reflex?
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its the same thing as the Receptive Relaxation in the stomach
called vagovagal b/c both limbs (afferent and efferent) are mediated by the vagus nerve and the release of VIP vagotomy will abolish this reflex |
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what is succus entericus?
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is the exocrine secretions of the SI
mucus and aqueous salts (no digestive enzymes) |
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what enzyme reduces iron at the BBM?
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iron reducatse
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what transporter absorbs iron on the BBM?
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DCT1
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what enzymes oxidizes iron back to ferric iron?
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feroxidase
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what transporter transports iron across the BL membrane?
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IREG1
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what causes idiopathic hemochromotosis?
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increased levels/synthesis of DCT1 and IREG1
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what is amebiasis?
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parasitic bowel infection caused by Entamoeba histolytica
caused by intake of poorly sanitized water symptoms include painful urge to defecate (tenesmus) treat w/ oral metronidazole, IV rehydration therapy |
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what ions are secreted from the colon?
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HCO3/K+
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which ions are absorbed the colon?
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Na via the ENAC channel with water following paracellularly
ENAC can be upregulated by aldosterone |
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what is the rectosphincteric reflex?
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when stool enters the rectum it contracts and the internal anal sphincter relaxes
when the rectum fills up to 25% with stool it elicits the urge to defecate |
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what are the main movements of the GI tract and how often do they happen?
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mass movements by the colon: 1-3/day
haustral contractions: every 30 min Duodenal peristalsis: 12/min Ileal peristalsis: 9/min MMC: every 90 min Total time through GI: 3-5 hours |
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what is the gastrocolic reflex?
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distention in the stomach stimulates colonic motility via the secretion of CCK and gastrin
the PSNS is also stimulated when food enters the stomach and increases the frequency of mass movements. |
