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73 Cards in this Set
- Front
- Back
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the parts of the GI tract include:
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Mouth with the parotid and salivary glands
Esophagus Stomach Small intestines(deudenum, jejunum, ileum) Large intestines (ascending, transverse, descending) rectum anus |
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What are the accessory glands for the GI tract
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Salivary glands
Parotid glands Liver Pancreas |
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How is the GI tract composed
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cylindrical tube- like the inside of a donut
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When is something considered to be inside the body
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when it is absorbed across the walls of GI tract somewhere in the stomach, intestines, or large bowel.
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the outermost boundary/lining made up of connective tissue that holds everything together
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Serosa
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the smooth muscle layer located right inside the serosa boundary that run up and down vertically
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longitudinal muscles
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smooth muscle that is located right inside the longitudinal muscle that are oriented in a cirumferential way
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circular muscles
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What do the layers of the submucosa contain?
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Glandular tissue
Blood vessels Nerve fibers |
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What determines whether the mucosa will secrete or reabsorb
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The area of the gut
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What is the main absorbing surface
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Mucosa
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What is the nervous system of the GI tract
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the enteric nervous system
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what makes up the enteric nervous system
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2 nerve plexuses
Myenteric (Auerbach)nerve plexus Meissner's nerve plexus |
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Where is the Myenteric nerve plexus located
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located between the 2 muscle layers (longitudinal and circular)
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Where is the Meissner's nerve plexus located
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Located within the submucosa level
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What plexus deals with movements within the GI tract such as peristalsis
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Myenteric Nerve plexus
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What plexus deals with secretion and absorption activity within the gut
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Meissner's Nerve Plexus
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What makes the enteric nervous system function
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It can function perfectly well by itself in trms of its nerve control and nerve physiology
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What is the role of the autonomic nervous system in the enteric nervous system
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modifies the activities of the enteric nervous system
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Are the 2 nerve plexuses connected
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Yes they have interneurons that run between them and they can communicate
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What is the Basal Electrical Rhythm
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slow waves that drift up and down throughout the GI tract (-50 to -40)
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What creates a spike potential in the GI tract
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stimulation by the PNS or something in the GI tract such as stretch, ACH, Hormones
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Does the SNS initiate a spike potential
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No
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What stimulates the spinchter of smooth muscles to contract
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Catecholamines (Epi, NE)
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What are spike potentials
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additional spiking potentials that are superimposed at the plateau regions of the slow waves
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What is the BER of athe stomach
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3-5/min
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BER of the duodenum
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12/min
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BER of the Jejunum
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10/min
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BER of the Ileum
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7-8/min
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BER of the cecum
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9/min
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BER of the Sigmoid
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16/min
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What is the strengh of contraction after spiking determined by
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amplitude of the spike and the duration of the slow wave
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Catecholamines do what to smooth muscle, BER, spiking and sphincter
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smooth muscle- inhibits
BER- no effect Spiking- inhibits Sphincter- contraction |
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Parasympathetic (Ach, histamine, serotonin) do what to smooth muscle, BER, spiking and sphincter
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smooth muscle- contraction
BER- no effect Spiking- + sphincter- inhibits |
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What are the major functions of the GI tract
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Sectretion
Motility Absorption Excretion |
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What does the GI tract secrete and why
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digestive enzymes, HCl, saliva, mucous for the purpose of lubrication of the tract and to breakdown food
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What are the two types of activity in the gut
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triturition- mixing it up
propulsive movement- transient motility to move the food |
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What is the purpose of absorption
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to get caloric energy from food
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What is the purpose of excretion
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taking material out of the blood and actively moving it into the intestines to be removed from the body
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What are the striations in the GI tract
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specialized sphincter muscles
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what are the 4 specialized areas of sphincter muscles
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Esophageal sphincter
Pyloric sphincter Ileosecal valve Rectal sphincter |
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what are the 2 esophageal sphincters
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Superior esophageal sphincter (upper)
Inferior esophageal sphincter (Lower) |
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the lower esophageal sphincter is also known as
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cardiac sphincter
Inferior esophageal sphincter Gastroesophageal sphincter |
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Where is the pyloric sphincter
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at the end of the stomach and beginning of the small intestines
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What does the pyloric sphincter respond to
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enteric and extrinsic nervous system
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what does the ileosecal valve do
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controls emptying from small intestines into large intestines
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What does the rectal sphincter do
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controls emptying of large bowel
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what is the first thing that happens to food to aid in digestion
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chewing- forms a ball mixed with mucous to aid in swallowing
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what initiates swallowing
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Phase I- voluntary- elevation of the tongue and pushing the food against the back of the throat
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When does phase II of swallowing begin
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when the bolus of food hits the pharyngeal wall
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Is phase II voluntary or involuntary
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involuntary along with the remainder of the swallowing process
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What controls the swallowing reflex and where is it located
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The deglutition center located in the brainstem
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what nerve fibers are involved in the swallowing process
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CN V, IX, X, and XII
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how many times a day on average do we swallow
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600/day
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peristolic waves move in which direction
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orad to anal
top to bottom |
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when the sensory fiber in the pharynx are stimulated by food what happens?
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Apposition of the pharyngeal wall
Elevation of the uvula and soft palate Elongation of the pharynx Approximation of the epiglottis and vocal cords |
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what does the elevation of the uvula and soft palate do
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closes off the nasal nares so food doesnt come back up
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what does elongation of the pharynx do
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pulls up the epiglottis
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what does approximation of the epiglottis do
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covers the glottis so the opening into the trachea is closed
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what does approximation of the vocal chords do
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covers the vocal chords food particles don't get caught there when it passes by
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where does the bolus of food pass once it leaves the back of the throat
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passes the pharynx, larynx, glottis, and hits the upper esophageal sphincter- this ends phase II
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the enteric nervous system releases what during swallowing
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VIP which causes relaxation to allow for easy passage
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What happens when the food bolus hits the upper esophageal sphincter
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it causes the sphincter to relax and initiate peristaltic wave by the ANS releasing Ach or by stretching of the esophagus and causing contraction behind the food bolus
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what stimulates the opening of the lower esophageal sphincter
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the presence of food
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what are the 3 primary pairs of salivary glands
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parotid
Submandibular Sublingual |
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Where is the parotid gland and how much saliva does it produce
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at the angle of the jaw
produces 20% of daily saliva |
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How much saliva does the submandibular gland secrete
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70% of daily saliva
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How much saliva does the sublingual gland secrete
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10% of daily saliva
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How much saliva is produce per day
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1.5 L/day
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What are the salivary glands controlled by
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the autonomic nervous system
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What happens to the ANS control of the GI system the further you go down
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The ANS has less and less control- most of the control is hormonal and from the enteric system
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what effect does the PSNS have on saliva
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increases water, mucous and blood flow
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what effect does the SNS have on saliva
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Decrease in flow, increase in mucous
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What are some important actions of saliva
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Mucous, Digestion, Speech, Swallowing, Dental Health, Taste
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