Exam 1 - Upper GI Flashcards
1
Q
What are the five steps of the alimentary canal pathway?
A
Mouth, Esophagus, Stomach, SI, LI
2
Q
What is the name of the sphincter between the mouth and esophagus?
A
Upper Esophageal Sphincter
3
Q
What is the name of the sphincter between the esophagus and stomach?
A
Lower esophageal sphincter
4
Q
What is the name of the sphincter between the stomach and Small Intestine?
A
Pyloric sphincter
5
Q
What is the name of the sphincter between the Small Intestine and Large Intestine?
A
Ileocecal Valve
6
Q
What is the name of the sphincter between the Large Intestine and the world?
A
Anal Sphincter
7
Q
What are the three “Accessory Organs” of the GI tract?
A
Liver, Gall Bladder, Exocrine Pancreas
8
Q
Which sphincter for the Liver, Gall Bladder, Exocrine Pancreas?
A
Sphincter of Oddi
9
Q
What are the three layers of the GI tract from inner to outer?
A
Mucosa, Submucosa, Muscularis
10
Q
Which layer of the GI tract controls peristalsis?
A
Mucosa. Specifically, the Muscularis Mucosa.
11
Q
What does the Adventiva (Serosa) layer contain and is like?
A
Like saran wrap. Contains mesentary allowing blood supply, lymph, innervation
12
Q
What are the 4 major jobs of the GI tract?
A
Motility, Secretion, Digestion, Absorption
MSDA
13
Q
What is the job of the Motility process of the GI tract?
A
Physically move food/bolus through GI tract to allow secretion/digestion/absorption to occur
14
Q
Constant tone in the GI tract is called
A
Tonic Contractions
15
Q
What maintains Tonic Contractions in the GI tract?
A
Sphincters
16
Q
What is Propulsive Peristalsis and where does it occur?
A
Moving bolus down by contract and relax. In esophagus, distal stomach, small intestine, and rectum.
17
Q
What sweeps up debris in the Small Intestine?
A
Migrating Motor Complex (MMC)
18
Q
What sweeps up debris in the Large Intestine?
A
Haustrations
19
Q
What do exocrine glands secrete into the GI tract?
A
Water, electrolytes, substances necessary for digestion (mucus, enzymes, bile salts)
20
Q
What are three substances necessary for digestion which are secreted by exocrine glands into GI tract?
A
Mucus, enzymes, bile salts
21
Q
What do endocrine hormones do in the GI tract?
A
Regulate GI system
22
Q
What is digestion?
A
Process of breaking down carbohydrates, proteins, and fats into simple absorbable molecules
23
Q
Carbohydrates are absorbed as what?
A
Monosaccharides (glucose, sucrose, galactose)
24
Q
Proteins are absorbed as what?
A
Amino Acids
25
Fats are absorbed via what process?
Micelle formation. Bile emulsifies fats into small lipids. Small lipids incorporated into bile salt aggregated called "micelles", which allows for FFA and glycerol absorption
26
Fats are absorbed as what two things?
FFA and Glycerol
27
Where are the pacemaker cells of the GI tract located?
In and around muscular cell layers
28
What are the pacemaker cells of the GI tract called?
Interstitial Cells of Cajal (ICCs)
29
What activity do the ICCs maintain? In which muscle type?
Maintain tonal activity in smooth muscles.
30
APs travel through what?
Gap Junctions
31
What are the two neural systems of the GI tract?
Intrinsic and Extrinsic
32
What two nervous systems make up the Extrinsic Neural system of the GI tract?
CNS and PNS (CNs and autonomic NS)
33
Intrinsic control of the GI tract is by which nervous system?
Enteric Nervous System
34
Can the Intrinsic and Extrinsic Neural Pathways of the GI track function on their own?
Yes, with minimal adaptive changes
35
Extrinsic Control to the GI tract comes from what type of inputs?
Sensory to CNS=smell, taste, sight, emotion, feedback loop from GI tract
36
The CNS stimulates what two type of neural control to the GI tract?
1. Autonomic output to GI tract
| 2. Peripheral/Cranial nerve voluntary actions (eating, swallowing, defecating)
37
The CNS stimulates cranial nerves/peripheral nerve output for what type of motor actions?
Voluntary motor actions: eating, swallowing, defecating
38
Which nerves and nervous system are part of the PNS?
Cranial/peripheral nerves, autonomic NS
39
The cranial/peripheral nerves in the oral cavity and proximal esophagus innervate what type of muscles?
Voluntary skeletal muscle
40
Which nerves innervate the External Anal Sphincter's voluntary skeletal muscle?
S4 and Inferior Rectal Nerve (branch of pudendal nerve)
41
What are the two parts of the Autonomic Nervous System?
Sympathetic NS and Parasympathetic NS
42
The nerves of the Sympathetic Tract to the GI Tract are located in the ____ and ____ ____ regions
Thoracic and Upper Limb regions
43
Does the Sympathetic NS excite or inhibit GI Tract?
Inhibits the GI Tract
44
What two things are inhibited/decreased by Sympathetic NS stimulation of the GI Tract?
Decreased Motility Peristalsis/Secretions, Inhibit/Vasoconstrict blood flow to GI Tract
45
What are the Parasympathetic NS nerves to the GI Tract?
Vagus Nerve and Pelvic Nerves of Sacral Plexus
46
The Vagus Nerve is travels from the _____ to the ____ ____.
Esophagus to the Transverse Colon
47
Does the Parasympathetic NS excite or inhibit the GI Tract?
Excited the GI Tract
48
What three functions does the Parasympathetic NS have on the GI Tract?
1. Increase motility/peristalsis and secretions
2. Relax involuntary sphincters of the GI Tract
3. Facilitate/vasodilate blood flow to the GI Tract
49
Intrinsic Neural Control aka ____Nervous System
Enteric Nervous System
50
The Enteric Nervous System is likened to what "in the gut"?
Brain in the gut
51
The neural plexuses of the Enteric Nervous System are located where?
Within layers of the intestinal wall
52
What are the two major plexuses of the Enteric Nervous System?
1. Submucosal Plexus
| 2. Myenteric Plexus
53
Where is the Submucosal Plexus located and in which layer?
Located in Submucosa Layer in SI and LI
54
The two major roles of the Submucosal Plexus are controlling what and what?
Controlling secretions and absorption
55
Which two places is the Submucosal Plexus not found?
Esophagus and Stomach
56
Which layers are the Myenteric Plexus located in?
Between Circular and Longitudional Layers of muscularis
57
The Myenteric Plexus is distributed in the GI Tract from where to where?
From Upper Esophagus to Internal Anal Sphincter
58
The Myenteric Plexus' major role is in what?
Controlling motility
59
What is the "third" plexus of the Enteric NS and what does it respond to?
Subserosal Plexus, involved in pain response when distended.
60
Can the intrinsic system feedback on itself and act autonomously?
Yes
61
Which neurons communicate in the enteric system of the GI Tract?
Motor and Sensory neurons
62
Can the intrinsic neural system influence the extrinsic system?
Yes, and vice versa
63
What are the two functional neurons of the enteric plexus?
Sensory Neurons and Motor Neurons
64
What two things do the sensory neurons of the enteric plexus monitor?
Distention and chemical status of GI tract
65
What three things do the motor neurons of the enteric plexus control?
1. Motility of gut wall
2. Secretions of the mucosa/submucosa
3. Smooth muscle of GI vasculature
66
What does the hormone gastrin stimulate? What needs to be kept closed because of gastrin?
Stimulates acid secretion and motility. Need to keep LES closed.
67
Where is gastrin secreted and in response to what three things?
Stomach. In response to proteins, stomach distention, and parasympathetic input to stomach.
68
Where is CCK secreted and in response to what?
Duodenum and Jejunum. In response to fat or protein products in Duodenum.
69
What does CCK do?
Inhibits gastric secretion and motility, stimulates other secretions, relaxes Sphincter of Oddi
70
Where is the hormone Secretin released and in response to what?
Duodenum and Jejunum. In response to acid in duodenum.
71
What does the hormone Secretin do?
Inhibits gastric secretion and motility, stimulates other secretions
72
Where is GIP secreted and in response to what?
Duodenum and Jejunum. In response to glucose, fats, or acid in duodenum or distention of duodonem
73
What what the hormone GIP do?
Inhibits gastric secretion and motility, stimulates insulin release
74
What is appetite?
Hunger
75
What is Satiety?
Sensation of feeling full/satisfied
76
What are the two centers/nuclei in the hypothalamus that control appetite and satiety?
Lateral Center (appetite), Medial Center (satiety)
77
The Lateral Center of the Hypothalamus controls what?
Appetite
78
The Medial Center of the Hypothalamus controls what?
Satiety
79
What is the function of the Lateral Center of the Hypothalamus?
To stimulate appetite
80
What can stimulate the Lateral Center of the Hypothalamus?
Depletion of nutrient stores, smell/vision/taste/hearing, memory, hormone ghrelin
81
What is the hormone Ghrelin and where is it released from?
Hunger hormone, released from stomach. Goes to hypothalamus and brainstem, stimulates hunger.
82
What is the function of the Medial Center of the Hypothalamus?
Suppressed appetite
83
What are four hormones that stimulate the Medial Center of the Hypothalamus?
GI Hormones (CCK, GLP-1, etc), Leptin, PYY, Insulin
84
Where is Leptin released and what is the duration of it's effect?
Released by fat and chief cells. Long term in energy balance and suppressing food intake.
85
Where is PYY released and what is the duration of it's effect?
From SI after meal. Short term.
86
Where is Insulin released and what is the duration of it's effect?
Released by Pancreas and increased in BGL after meal. Short term effect.
87
Which hormone counteracts ghrelin?
PYY
88
The motility of the mouth/oral cavity is under what type of control?
Somatic control
89
What are the three salivary glands?
Submandibular, Sublingual, and Parotid
90
Which nervous systems stimulate production of saliva?
Both sympathetic and parasympathetic
91
Is secretion of saliva controlled by hormones?
NO
92
What are the three main parts of saliva?
Water, Salivary Amylase, and IgA
93
What are the five components of the water component of saliva?
Contains mucus, sodium, bicarb, chloride, and potassium.
94
What is the role of the water component in saliva?
Maintain pH in mouth to neutralize bacteria in order to prevent tooth decay
95
What is the role of Salivary Amylase in the saliva?
Initiates carbohydrate digestion in mouth
96
What is the role of IgA in the saliva?
Prevent infection. Why dogs lick their wounds.
97
What are the two parts of digestion?
Mechanical and Chemical
98
What does the mechanical part of digestion do?
Chews and softens food
99
What does the chemical part of do?
Breaks down food for absporption.
100
Which chemical begins the breakdown of carbohydrates?
Amylase
101
What part of the mouth is used for fast delivery of meds?
Sublingual capillaries
102
What type of muscle makes up the upper 1/3 and lower 2/3 of the esophagus?
Upper 1/3=Striated (voluntary) muscle
| Lower 2/3=Smooth (involuntary) muscle
103
Which CN innervates the upper 1/3 and lower 2/3 of the esophagus?
Upper 1/3=CN 10 Vagus
| Lower 2/3=CN 10 Vagus "double nerve"
104
What is the name of the muscle of the Upper Esophageal Sphincter?
Cricopharyngeus muscle
105
The Upper Esophageal Sphincter is at the junction of which two areas?
Pharynx and Esophagus
106
The Upper Esophageal Sphincter is at the level of which cartilidge?
Cricoid
107
What are the two functions of the Upper Esophageal Sphincter?
1. Prevent air from entering esophagus during ventilation
| 2. Closes after bolus enter esophagus
108
Where is the Lower Esophageal Sphincter?
At narrowing of esophagus proximal (above) to junction of esophagus and stomach
109
What is the function of the Lower Esophageal Sphincter?
Barrier of regurgitation/reflux of stomach's acidic environment
110
What maintains the tone of the Lower Esophageal Sphincter?
Increased smooth muscle tone
111
What is the normal tone range of the Lower Esophageal Sphincter?
10-45mmHg
112
Belching is when air in the stomach exceeds what?
Exceeds LES pressure
113
What happens to Lower Esophageal Sphincter smooth muscle tone during swallowing?
Relaxes
114
The Lower Esophageal Sphincter relaxes during swallowing as what approaches it?
Peristaltic wave
115
Is the Lower Esophageal Sphincter a true anatomical sphincter?
No
116
What maintains sphincters in the esophagus?
Tonic contractions
117
What two things are secreted in esophagus?
Mucus and Bicarb (HCO3-)
118
What is the job of mucus and bicarb secretion in the esophagus?
Mucus=Lubricant to protect
| Bicarb=Alkaline to protect against gastric acids
119
Does any digestion or absorption happen in the esophagus?
Nope
120
Which part of the brain is the swallowing center located in?
Brainstem
121
What is the name of the swallowing center in the brainstem?
Reticular Formation
122
Which two systems/tracts does swallowing require coordination of?
Digestive tract and Respiratory system
123
What are the three phases of swallowing?
1. Oral phase
2. Pharyngeal phase
3. Esophageal phase
124
What happens during the Oral Phase of swallowing?
Food enters and t/p to post-canine region, chewing breaks down food, tongue pushes small food into posterior oropharynx, chewing continues until all food t/p to oropharynx
125
How long does the Pharyngeal Phase of swallowing occur?
1-2 seconds
126
Which sphincter does the food bolus pass in the Pharyngeal Phase of swallowing?
Upper Esophageal Sphincter into esophagus
127
What does the Pharyngeal Phase of swallowing do to the airway?
Protects airway
128
What are the five steps of the Pharyngeal Phase of swallowing?
1. Food enters pharynx causing soft palate to elevate and close nasopharynx, 2. base of tongue pushes bolus against pharyngeal walls, 3. epiglottis and vocal cords close, 4. UES opens, 5. constrictors push bolus into esophagus
129
The UES opening during Pharyngeal Phase of swallowing happens in what three steps?
1. UES relaxes
2. Open UES by contraction of suprahyoid and thyrohyoid muscles
3. Pressure of bolus pushing through toward esophagus
130
How long does the Esophageal Phase of swallowing take?
5-10 seconds
131
What signifies the beginning and end of the Esophageal Phase of swallowing?
Begin: Bolus entering esophagus
End: Bolus enters stomach
132
Which sphincter closes to prevent bolus from going back up during the Esophageal Phase of swallowing?
UES
133
How is food bolus moved to stomach during Esophageal Phase of swallowing?
Peristaltic wave
134
What happens during Peristaltic Wave of Esophageal Phase of swallowing?
Coordinated contraction and relaxation of longitudional and circular muscles in esophagus
135
What is the range of esophageal muscle pressures of peristaltic contractions during Esophageal Phase of swallowing?
35-80mmHg or higher
136
What happens if the peristaltic contraction wave pressure during Esophageal Phase of swallowing is less than 30mmHg?
Food residue left in esophagus
137
What does distention (tension/stretch) of esophagus due to the force of contractions during Esophageal Phase of swallowing?
Increases force of contractions
138
Intense contractions of the esophageus during Esophageal Phase of swallowing can cause what?
Substernal pain similar to agina/heartburn
139
What happens to LES as the peristaltic wave nears the end of the esophageus?
LES relaxes allowing food bolus into stomach
140
What are the two types of peristalsis in the esophagus?
Primary and Secondary
141
What happens in Primary Peristalsis in Esophagus?
Normal peristaltic wave after food bolus swallowed and enters esophagus, continuation of oral and pharyngeal phases, pressure around 35-80mmHg
142
What stimulates Secondary Peristalsis in Esophagus?
Stimulates by food residue from ineffective primary peristalsis or bolus that is stuck in esophagus
143
What type of feedback is triggered by Secondary Peristalsis? What does it do?
Intrinsic Feedback, stimulates constriction above bolus and relaxation below bolus to push along
144
Which nerve controls peristalsis?
CN 10 Vagus Nerve
145
What type of parallel signaling come from CN 10 Vagus Nerve during esophageal peristalsis?
Parallel inhibitory and excitatory signaling from vagus nerve
146
What is the LES resting/basal tone pressure?
10-45mmHg
147
What three factors contribute to the basal/resting LES pressure?
1. Myogenic tone that is independent of any neural input
2. Excitatory vagal tone (cholinergic)
3. Inhibitory neural tone (nitrergic – nitric oxide)
148
What two factors increases LES tone/pressure?
1. Vagus nerve excitatory pathways via ACh release
| 2. Gastrin which stimulates acid secretion in stomach requiring LES to close to prevent regurg
149
What three things can decrease LES tone/pressure?
1. Anticholinergic meds
2. Hormones (progesterone, secretin, glucagon, CCK)
3. Common foods/substances
150
Elevated Progesterone levels in pregnancy and second half of menstrual cycle can have what sort of effect on the LES?
Reduce LES tone allowing reflex
151
A single swallow of food initiates a peristaltic wave which lasts for how long and is followed by what?
Lasts 5-10 seconds, followed by short refractory period
152
What does the 5-10 second long esophageal peristaltic wave inhibit?
Inhibits ability to swallow a second bite for 10-15 seconds
153
How long does swallowing liquids last?
1-2 seconds
154
What is Deglutitive Inhibition?
Inhbition of esophagus from contracting during swallowing by quick subsequent swallows
155
What does Deglutitive Inhibition cause the esophagus to do and allow for liquids?
Causes esophagus to stay relaxed and to allow more liquid to descend
156
How long does Deglutitive Inhibition last for and what happens after it ends?
Until last swallow. Followed by full peristaltic contraction.
157
What is a Hiatal Hernia? What can it cause?
Portion of cardia of stomach protrudes above diaphragm causing LES dysfunction. Common cause of GERD.
158
What is GERD? What causes it?
Gastoesophageal Reflex Disease allowing acid from stomach to enter esophagus. Due to hypotensive LES less than 10mmHg. Causes esophagatits.
159
What is esophagatits? What does it result in?
Chronic acid reflex into esophagus, results in inflammation/pain and eventual destruction of esophageal wall
160
What do parasympathetic drugs do to LES tone?
Increase LES tone. Tx for hypotensive LES causing GERD.
161
What is Achalasia? What is etiology?
Increase in LES tone above 45 causing pain w/eating and drinking. Unknown etiology but possibly dysfunction of intrinsic esophageal plexus causing loss of inhibitory motor neurons in esophagus.
162
What are the two "mechanical results" of achalasia?
Absent/impaired peristalsis of esophageal muscles, failure of LES to relax
163
Achalasia aka...?
Cardiospasm
164
What are four possible treatments of Achalasia?
1. Pneumatic dilation of LES to stretch out
2. Medications to relax LES (sympathetics?)
3. Myotomy
4. Botox injections
165
What is Eosinophilic Esophagatitis? AKA?
"Asthma of the esophagus", like achalasia pain and difficulty swallowing.
166
What is etiology and causes Eosinophilic Esophagatitis?
Eosinophils accumulating in esophageal wall causing inflammation. Triggered by food and other allergens.
167
How is Eosinophilic Esophagatitis diagnosed?
Biopsy of esophageal squamous mucosa showing eosinophils
168
What are Esophageal Varicies? Most common cause/consequence?
Severely dialated submucosal veins in esophaus. Consequence of portal hypertension.
169
PTs with Esophageal Varicies have a strong tendency to develop what? What are consequences?
Strong tendency to develop chronic GI bleeding. Major systemic consequences.
170
What is Barrett's Esophagus?
Stomach acid in esophagus causing mature cells to be replaced by different mature cells due to exposure to stomach acid. Metaplasia.
171
What cells are changed in Barrett's Esophagus?
Normal esophageal squamous epithelium replaced by spectrum of metaplastic columnar mucosa
172
What is Metaplasia? What condition is it found in?
One mature and physically normal cell type replaced by another type of mature and physically normal cell. Barret's Esophagus.
173
What is Metaplasia and Dysplasia?
Metaplasia=Mature and physically normal cell type replaced by another mature and physically normal cell type
Dysplasia=Abnormal development/maturation of cell
174
What is Dysplasia often an indicator of?
Early neoplastic process
175
What are the two types of Esophageal Cancer?
1. Squamous Cell Carcinoma
| 2. Adenocarcinoma
176
How do Squamous Cell Carcinoma and Adenocarcinoma of the Esophagus differ in terms of location?
Squamous Cell Carcinoma from squamous cells of entire esophagus, Adenocarcinoma in lower esophagus
177
In Adenocarcinoma normal cells are replaced with what type?
Columnar cells, through metaplasia/dysplasia
178
What is a major risk factor in the development of Adenocarcinoma?
GERD
179
GERD can lead to what type of cancer?
Adenocarcinoma
180
Where does the Small Intestine start and finish?
Start at Pyloric Sphincter and end at Ileocecal Valve
181
What is the length and sections of the SI?
Duodenum 25-35cm, Jejunum 2.5m, Ileum 3.5m. Total 5-6m.
182
Where does the Duodenum begin and end?
Begin at Duodenal Bulb, end at Ligament of Treitz
183
What does the Sphincter of Oddi (aka Hepatopancreatic Ampula) allow to enter the duodenum?
Bile and Pancreatic Enzyme secretions
184
Where are Brunner's Glands located?
Proximal Duodenum
185
What do Bunner's Glands secrete and where to?
To Proximal Duodenum. Secretes Bicarb-rich mucus to protect against chyme entering from stomach.
186
What SI portion regulates stomach emptying?
Duodenum
187
What is the triad of hormone messengers released from duodenum that regulate gastric emptying?
Secretin, VIP, CCK
188
Where is Secretin released from?
Duodenum
189
What stimulates the release of Secretin from Duodenum?
Acidity, pH less than 4-5
190
What is Secretin's action?
Inhibits gastric activity and facilitates digestion
191
Which hormone does Secretin inhibit?
Gastrin
192
Gastrin is inhibited by which hormone?
Secretin
193
What does Secretin do in the pancreas?
Stimulates secretion of watery bicarb solution
194
What does Secretin to do stomach?
Inhibit gastric motility, inhibits gastrin from producing gastric secretions
195
What does Secretin do to Brunner's Glands of Duodenum?
Stimulate secretion of alkaline/bicarb rich mucus
196
CCK is secreted by which part of the SI?
Duodenum
197
What is the stimulus of CCK?
Fatty chyme (partially digested proteins) entering duodenum
198
What two major roles does CCK do?
1. Promotes bile and pancreatic enzyme release,
| 2. Inhibitory to gastric activity
199
What does CCK do to the liver?
Stimulate bile output for fat digestion
200
What does CCK do to the Gallbladder?
Stimulates contraction to release stored bile
201
What two organs is CCK majorly connected to?
Live and Gall Bladder
202
CCK has a huge role in the digestion of what type of foodstuff?
Fat digestion. Gets bile to duodenum to start.
203
CCK, GIP, VIP, and Intestinal Gastrin are all stimulated by ___ entering the ___
Chyme entering the Duodenum
204
What is the major role of GIP?
Tells pancreas to pump out insulin when chyme/food enters duodenum
205
What is the major role of VIP?
Gets blood to intestines to promote digestion
206
What is the major role of Intestinal Gastrin?
Stimulate motility
207
Which hormone is the "housekeeper of the intestinal tract"?
Motilin
208
What are the stimuli for Motilin?
Fasting or periodic release every few hours
209
What is the action of Motilin?
Initiates MMC (migrating motor complex). Motilin active when fasting.
