Gastrointestinal Principles Flashcards
1
Q
What are the four generalised components of the digestive tract wall?
A
Mucosa
Submucosa
Muscaularis Externa
Serosa
2
Q
What is the alimentary canal?
A
The whole passage along which food passes through the body from mouth to anus during digestion
3
Q
What are the four major functions of the alimentary canal?
A
Motility
Secretion
Digestion
Absorption
4
Q
What happens to the lumen when circular muscle contracts?
A
It becomes narrower and longer
5
Q
What happens to the intestine when longitudinal muscle contracts?
A
It becomes shorter and fatter
6
Q
What happens when the muscularis mucosae contracts?
A
Change in absorptive and secretory area mucosa and mixing activity
7
Q
What is the function of the Myenteric Plexus?
A
Regulates motility and sphincters
8
Q
What is the function of the Submucous Plexus?
A
Modulates epithelia and blood vessels
9
Q
What is glycogenesis?
A
Synthesis of glycogen from glucose
10
Q
What is glycogenolysis?
A
Breakdown of glycogen to form glucose
11
Q
What is gluconeogenesis?
A
De novo synthesis of glucose from metabolic precursors
12
Q
What are the metabolic precursors for the synthesis of glucose?
A
Lactate
Amino Acids
Glycerol
13
Q
What is the role of Glycogen Synthase?
A
Synthesis of glycogen from UDP-glucose by extending chains of glycogen
14
Q
What are the three components of the small intestine?
A
Duodenum
Jejunum
Ileum
15
Q
What are the three components of the large intestine?
A
Caecum
Appendix
Colon
16
Q
What are the three additional features of the digestive system?
A
Liver and Gallbladder
Pancreas
Salivary Glands
17
Q
Where is the myenteric plexus located?
A
Muscularis Externa
18
Q
Where is the submucosal plexus located?
A
Submucosa
19
Q
What is the name of gastrointestinal pacemaker cells?
A
Interstitial cells of cajal
20
Q
What type of epithelium is in the oesophagus?
A
Stratified Squamous Epithelium
21
Q
What type of epithelium is in the stomach?
A
Stratified Columnar Epithelium
22
Q
What do chief cells in the stomach secrete?
A
Digestive enzymes
23
Q
What do parietal cells in the stomach secrete?
A
Hydrochloric acid
24
Q
What is the top portion of the stomach called?
A
Cardia
25
What is the middle main part of the stomach called?
Body/Fundus
26
What is the bottom portion of the stomach called?
Pylorus
27
How does the Muscularis Externa differ in the stomach?
It has an additional oblique muscle layer to aid with the churning of food
28
Where is the pyloric sphincter?
Between the stomach and the duodenum of the small intestine
29
What are enterocytes?
Cells of the digestive system. Tall columnar cells with a brush border and are the principle absorptive cells
30
What is the role of goblet cells?
Produce mucin to protect epithelium and lubricate passage of material
31
What are Paneth Cells?
Found at the base of the crypts of Lieberkuhn and have a defensive function
32
What is the role of neuroendocrine cells in the small intestine?
Produce hormones that contribute to the control of secretion and motility
33
What is the role of stem cells in the small intestine?
Found at the base of the crypts of Lieberkuhn to divide to replenish epithelium
34
What are Peyer's Pathches?
Aggregation of lymphoid tissue
35
What is in the portal triad?
Hepatic Artery
Portal Vein
Bile Duct
36
What type of collagen is in reticular fibres?
Type III Collagen with some Type I Collagen
37
What are hepatic stellate cells?
Modified fibroblasts that deal with connective tissue and store vitamin A within fat droplets
38
What are kupffer cells?
Resident macrophages within the liver sinusoids that remove particular matter from the blood and help remove worn out blood cells
39
What is a mesentery?
A fold of the peritoneum which attaches the stomach, small intestine, pancreas, spleen, and other organs to the posterior wall of the abdomen
40
What is the omenta?
A fold of peritoneum connecting the stomach with other abdominal organs
41
What nerves form the parasympathetic innervation of the GI tract?
Vagal and Pelvic Nerves
42
Where do the vagal nerves originate to supply the GI tract?
Medulla Oblongata
43
Where do the pelvic nerves originate to supply the GI tract?
Sacral Spinal Cord
44
What does excitatory parasympathetic innervation of the GI tract cause?
Increased gastric, pancreatic and small intestinal secretion
Increased blood flow
Increased smooth muscle contraction
45
What does inhibitory parasympathetic innervation of the GI tract cause?
Relaxation of some sphincters
| Receptive relaxation of the stomach
46
Where do the sympathetic nerves of the GI tract originate from?
Thoraco-lumbar region
47
What does excitatory sympathetic innervation of the GI tract cause?
Increased sphincter tone
48
What does inhibitory sympathetic innervation of the GI tract cause?
Decreased motility
Decreased secretion
Decreased blood flow
49
What is colonic mass movement?
A powerful sweeping movement that forces faeces into the rectum
50
What is the migrating motor complex?
A powerful sweeping contraction from the stomach to the terminal ileum
51
What are tonic contractions?
Sustained contractions that can occur at varying pressures at different points in the GI tract
52
What joint opens the mouth?
Temporomandibular joint
53
What are the three pairs of jaw closing muscles?
Masseter
Temporalis
Medial Pterygoid
54
What muscle is involved in jaw opening?
Lateral Pterygoid
55
What nerve innervates the muscles of the jaw?
Mandibular division of the trigeminal nerve - CN V3
56
What are the three main salivary glands called?
Parotid
Submandibular
Sublingual
57
What are the four extrinsic muscles of the tongue?
Palatoglossus
Styloglossus
Hyoglossus
Genioglossus
58
At what vertebral level does the pharynx become the oesophagus?
C6 vertebral level
59
What are the two neuroendocrine hormones that report fat status to the brain?
Leptin
| Insulin
60
What is the major site of amino acid degredation?
Liver
61
What is the function of aminotransferases in transamination?
Move the amino group for alpha amino acids to alpha keto acids
62
What are the major carriers of nitrogen in the blood to the liver?
Alanine and Glutamine
63
What chemicals digest protein?
Pepsin and Hydrochloric Acid
64
What chemicals digest carbohydrates?
Salivary Amylase
65
What do mucous cells in the GI tract secrete?
Mucous and Bicarbonate
66
What do parietal cells in the GI tract secrete?
Hydrochloric acid
67
What do endochromaffin-like cells in the GI tract secrete?
Histamine
68
What do G cells in the GI tract secrete?
Gastrin
69
What do D cells in the GI tract secrete?
Somatostatin
70
What do chief cells in the GI tract secrete?
Pepsinogen
71
What is glycogenin?
An enzyme that acts as a glycogen primer by polymerises the first few molecules of glucose to form the glycogen primer for glycogen synthesis
72
What is transglycosylase?
A branching enzyme that introducglycosidic branches onto glycogened alpha 1-6
73
What is the role of brunners glands and where are they located?
They broduce and alkaline substance to neutralise the chyme and are found in the submucosa of the duodenum
74
What are the strips of smooth muscle in the large intestine called?
There are 3 Teniae Coli
75
What is billirubin?
A normal by-product of the breakdown of red blood cells
76
What are the four anatomical segments of the liver?
Right lobe
Left lobe
Caudate lobe
Quadrate lobe
77
What artery provides blood supply to the gallbladder?
Right hepatic artery
78
What are the three branches of the celiac trunk?
Splenic artery
Hepatic artery
Left gastric artery
79
What are the branches of the hepatic artery?
Gastroduodenal then Superior pancreatico-duodenal
80
What arteries supply the lesser curvature of the stomach?
Right and left gastric arteries
81
What arteries supply the greater curvature of the stomach?
Right and left gastro-omental arteries
82
What vein drains the organs of the foregut?
Splenic vein
83
What vein drains the organs of the hindgut?
Inferior mesenteric vein
84
What vein drains the organs of the midgut?
Superior mesenteric vein
85
What does the endoderm give rise to in GI embryology?
Epithelium of the mucosa
| Associated ducts and glands
86
What does the visceral mesoderm give rise to in GI embryology?
```
Lamina propria
Muscularis Mucosa
Muscularis Externa
Connective tissue of the submucosa
External Connective tissue
```
87
What does the neural crest give rise to in GI embryology?
Enteric nervous system
Meissners plexus
Auerbachs plexus
88
What hormone triggers the Migrating Motor Complex?
Motilin
89
What hormones inhibit the Migrating Motor Complex?
Gastrin
| Cholecystokinin
90
Where is gastrin released?
Released from G cells of gastric antrum and duodenum
91
What is the action of gastrin?
Stimulates proton secretion by gastric parietal cells
| Stimulates growth of gastric mucosa
92
Where is secretin released?
Released from S cells of the duodenum in response to protons and fatty acids in the lumen
93
What is the action of secretin?
Promotes secretion of pancreatic and biliary bicarbonate
94
Where is Cholecystokinin released?
Released from I cells of the duodenum and jejunem in response to monoglycerides, free fatty acids, amino acids and small peptides in the lumen
95
What is the action of Cholecystokinin?
Inhibits gastric emptying
Causes secretion of pancreatic enzymes required for digestion
Stimulates relaxation of the sphincter of oddi and contraction of the gall bladder to eject bile into the duodenum
Potentiates the action of secretin
96
Where is Glucose dependent insulinotropic peptide released?
Released from K cells of the duodenum and jejunum in response to glucose, amino acids and fatty acids
97
What is the action of Glucose dependent insulinotropic peptide?
stimulates release of insulin from pancreatic β-cells (incretin action)
inhibits gastric emptying
98
Where is Glucagon like peptide 1 released?
from L cells of the distal ileum, released primarily in response to glucose and fats
99
What is the action of Glucagon like peptide 1?
stimulates insulin secretion (incretin action)
inhibits glucagon secretion from pancreatic α-cells
decreases gastric acid secretion and emptying and also appetite
100
Where is Motilin released?
from M cells of duodenum and jejunum, secreted during fasting state
101
What is the function of Motilin?
initiates the migrating motor complex
102
Where is Ghrelin released?
from Gr cells of the gastric antrum, small intestine and elsewhere (e.g. pancreas)
103
What is the function of Ghrelin
stimulates appetite
104
What receptor do peptide hormones bind to?
G-protein coupled receptors
105
What is the juice secreted from the small intestine called?
Succus Entericus
106
Where are the digestive enzymes of the pancreas released from?
Blind ended ACINAR CELLS
107
Why is there a high bicarbonate solution released from the pancreas into the duodenum?
To neutralise the acidic chyme
108
What mediates the cephalic phase of pancreatic secretion?
Vagus stimulation of mainly acinar cells
109
What mediates the gastric phase of pancreatic secretion?
gastric distension evokes a vagovagal reflex resulting in parasympathetic stimulation of acinar and duct cells
110
What phase results in the majority of pancreatic secretion?
Intestinal phase
111
What are the two types of digestion in the small intestine?
Luminal digestion
| Membrane digestion
112
What mediates luminal digestion?
Pancreatic enzymes
113
What mediates membrane digestion?
Enzymes situated at the brush border of epithelial cells
114
What is absorption?
the processes by which the absorbable products of digestion are transferred across both the apical and basolateral membranes of enterocytes (absorptive cells of the intestinal epithelium)
115
What is the term that encompasses digestion and absorption?
Assimilastion
116
Give examples of polysaccharides...
Starch
| Glycogen
117
Give examples of oligosaccharides...
Sucrose
| Lactose
118
What are the limits of alpha amylase?
Cannot cleave terminal alpha 1,4 links, alpha 1,6 links or alpha 1,4 links next to branch points
119
What can alpha amylase break amylose into?
Maltotriose
| Maltose
120
What can alpha amylase break amylopectin into?
Maltotriose
Maltose
Alpha limity dextrins
121
Why is there a rate limit on assimilation?
The rate of digestion is faster than the rate of absorption (except for lactose)
122
What is the name of the space between the endothelial cells and hepatocytes in the sinusoids of the liver?
Space of Disse
123
What type of collagen supports the parenchyma of the liver?
Type III collagen along with some type I collagen in the space of disse.
124
What are hepatic stellate cells?
They are modified fibroblasts involved in connective tissue. They store vitamin A fat droplets in the cytoplasm.
125
What can happen to hepatic stellate cells in some pathological conditions?
They can transform into myofibroblasts and create scar tissue.
126
What are Kupffer cells?
They are resident macrophages in the sinusoids. They remove particulate matter from the blood and remove worn out RBC.
127
What is bile?
Bile is an alkaline solution containing water, ions, phospholipids, bilirubin and bile salts.
128
What is bilirubin?
This is a pigment responsible for the breakdown of haemoglobin. It is excreted in the bile and results in the brown colour of faeces.
129
What are bile salts?
They are used for the emulsification of fats in the digestive tract.
130
What are bile canaliculi?
These are small channels that bile flows through that is formed by tight junctions of adjacent hepatocytes.
131
What enzyme activates the proenzyme trypsinogen from the exocrine pancreas?
Enteropeptidases
132
What is the role of vomiting?
It is a defence mechanism triggered by the emetic centre located in the brainstem
133
What different systems act on the vomiting centre?
```
Higher cortical centres
Vestibular nuclei
Chemoreceptor trigger zone
Vagal afferents
Enterochromaffin cells
```
134
What drugs act on the higher corticol centres?
Antihistamines
135
What drugs act on the vestibular nuceli?
Antimuscarinics
136
What drugs act on the chemoreceptor trigger zone?
```
Phenothiazines
Domperidone
Metoclopramide
Dopamine receptor antagonists
5-HT3 Receptor andagonists
```
137
What drugs act on enterochromaffin cells?
Nablione
Metoclopramide
5-HT3 Receptor andagonists
Neurokinin-1 receptor antagonists
138
What are the main neurotransmitter systems involved in nausea and vomiting?
5-HT, dopamine and ACh
139
Examples of antihistamines...
Cyclizine
Promethazine
Diphenydramine
140
Examples of antimuscarinics...
Scopolamine (hyoscine)
141
Examples of 5-HT3 receptor antagonists...
Ondasetron
Granisetron
Palonosetron
142
Examples of dopamine receptor antagonists...
```
Chlorpromazine
Droperidol
Haloperidol
Prochlorperazine
Metoclopramide
```
143
Examples of neurokinin-1 receptor antagonists...
Fosaprepitant
| Aprepitant
144
What is the action of antihistamines?
Antagonist at histamine H1 receptors in the brain
145
What is the action of antimuscarinics?
Antagonist at muscarinic acetylcholine M1 receptors in the brain
146
What is the action of 5-HT3 receptor antagonists?
Act primarily as antagonists at 5-HT3 receptors in the chemoreceptor trigger zone of the medulla in the hindbrain.
Also act on 5-HT3 receptors in the GI tract
147
What is the action of dopamine receptor antagonists?
Act primarily as antagonists at D2 receptors in the chemoreceptor trigger zone in the medulla.
Also act on D2 receptors in the GI tract
148
What is the action of neurokinin-1 receptor antagonists?
Act primarily as NK1 receptors in the GI tract and the chemoreceptor trigger zone of the medulla, blocking the effects of substance P which evokes vomiting
149
Examples of antidiarrhoeal drugs...
Loperamide, diphenoxylate
150
Examples of laxatives...
Ispaghula husk, senna, lactulose
151
What is the action of loperamide and diphenoxylate?
Opiates that bind to nano-opiate receptors.
152
What is the peritoneum?
A thin, transparent, semi-permeable serous membrane that lines the abdominal cavity.
153
What is an intraperitoneal organ?
An organ that is covered on both the anterior and posterior side by the visceral peritoneum
154
What is a retroperotineal organ?
An organ that is covered only on the anterior surface by the visceral perotineum
155
What is a mesentery?
A double layer of visceral perotineum that suspends the organ from the posterior abdominal wall
156
How do the greater and lesser peritoneal sacs communicate?
Through the omental foramen
157
What organs are retroperitoneal?
SAD PUCKER
S- Supraadrenal glands
A- Aorta
D- Duodenum
```
P- Pancreas
U-Ureters
C- Colon
K- Kidneys
E- (O)esophagus
R- Rectum
```
158
Describe the greater omenta...
It consists of four layers pf visceral peritoneum. It descends from the greater curvature of the stomach and proximal part of the duodenum and doubles back up to attach to the anterior portion of the transverse colon.
159
What type of nerves supply the abdominal organs?
Sensory- Visceral Afferent
Motor- Autonimic Motor Nerves
The Enteric Nervous System
160
Derscribe the route of visceral afferent nerves from the abdomen...
They typically run alongside sympathetic fibres back to the spinal cord.
161
At which spinal cord level do foregut visceral afferents enter?
T6-T9
162
At which spinal cord level do midgut visceral afferents enter?
T8-T12
163
At which spinal cord level do hindgut visceral afferents enter?
T10-L2
164
At what level do the sympathetic fibres leave the spinal cord to reach abdominal organs?
T5-L2
165
Describe the route of sympathetic nerves to the abdominal organs...
1. They leave the spinal cord between T5-L2
2. They move into the sympathetic truck but don't synapse
3. The move out of the sympathetic trunk through abdominopelvic splanchnic nerves and synapse at the prevertebral ganglia
4. They then move alongside the branches of the aorta and other nerves as part of a periatrerial plexus
5. They then reach the smooth muscle and glands of the organs
166
Name the nerves that supply the abdominal body wall...
Thoracoabdominal nerves
Subcostal Nerve
Iliohypogastirc Nerve
Ilioinguninal Nerve
167
Name the three branches of the coeliac artery...
Common hepatic artery
Splenic artery
Left gastric artery
168
Name some branches of common hepatic artery...
Gastroduodenal artery
| Superior pancreatic duodennal artery
169
What vessels are the main blood supply of the stomach?
Right and left gastric arteries- lesser curvature
| Right and left gastro-omental arteries - greater curvature
170
What vessels supplies blood to the gall bladder?
Cystic artery
171
What muscles facilitate the closure of the jaw?
Masseter
Medial Pterygoid
Temporalis
172
What muscle facilitates the opening of the jaw?
Lateral Pterygoid
173
What cranial nerve supplies the muscles of mastication?
The mandibular division of the trigeminal nerve (CN V3)
174
What is the name of the upper dental arch?
Maxillary
175
What is the name of the lower dental arch?
Mandibular
176
What is the course of CN V3?
1. Pons
2. Foramen Ovale
3. Muscles of mastication and general sensory area
177
What is the course of CN V2?
1. Pons
2. Foramen Rotunda
3. Sensory Area
178
Which nerves supply sensation to the anterior 2/3rds of the tongue?
```
General sensory (touch) - CN V3
Special Sensory (taste) - CN VII
```
179
Which nerve supplies the posterior 1/3rd of the tongue?
General and special sensory - CN IX
180
What is the course of CN VII?
1. Pontomedullary Junction
2. Internal Acoustic Meatus
3. Stylomastoid Foramen
4. Sensory and Motor Area
181
What is the chorda tympani?
Branch of the facial nerve (CN VII) that connects to the lingual branch of CN V3
182
What are the exrinsic muscle of the tongue?
Palatoglossus
Hyoglossus
Styloglossus
Genioglossus
183
What nerve supplies the muscles of the tongue?
Hypoglossal (CN XII)
184
What nerves supplied the longitudinal muscles of the pharynx?
CN X and CN IX
185
What nerve supplies the circular muscles of the pharynx?
CN X
186
Where does the oesophagus begin?
The inferior edge of the cricopharyngeus muscle ( @ vertebral level C6)
187
Where are peptic ulcers most commonly located?
Duodenal bulb or the antrum of the stomach
188
What is the cause of peptic ulcers?
Acid pepsin results in mucosal damage and gastric ulcers
189
What are the two kinds if peptic ulcers?
Gastric and duodenal ulcers
190
What is the most common cause of peptic ulcers?
H. Pylori
191
What are some other causes of peptic ulcers?
Long term use of NSAIDs
192
How can we differentiate between gastric and duodenal ulcers?
Gastric - worsened by eating
| Duodenal - improved by eating
193
What are the investigations for H. Pylori Infection?
Urea breath test or stool antigen test
194
Eating what food can lead to Bacillus Cereus?
Reheated rice
195
What is the role of chief cells?
Release pepsinogen which is changed to pepsin in the presence of HCL
196
ECL cells
Release histamine which is used to help with acid secretion
197
Parietal cells
Macin acid secreting cells, also secreted intrinsic factor which absorbs B12
198
What are the three phases of digestion?
1. Cephalic phase
2. Gastric Phase
3. Intestinal Phase
199
What are the triggers of the cephalic phase?
Psychological triggers
200
What mediates the cephalic phase?
Vagus nerve and ACh mediates response
201
What is the role of ACh in the cephalic phase?
Stimulates acid and histamine release directly
202
What is the role of the Vagus Nerve in the cephalic phase?
Stimulates gastrin releasing peptide for gastrin secretion
203
What triggers the gastric phase?
Distention of the gastric wall
204
What mediates the gastric phase?
Distention detected by vagal afferent and increases vagal efferent activity for acid secretion.
Local plexuses activated
205
In which digestive phase is the highest amount of acid secreted?
Gastric phase
206
What triggers the intestinal phase?
Triggered when food enters the duodenum
207
What mediates the intestinal phase?
CCk released from I cells and GIP released fromK cells due to the presence of lipids and carbohydrates
208
What is the role of secretin and CCK in the intestinal phase?
Secretin and CCK stimulates pancreatic and biliary stimulation
209
What activates the parietal cells?
ACh
Vagus Nerve
Gastrin - directly and indirectly via ECL and histamine route
210
What inhibits the parietal cells?
Somatastatin - Directly and indirectly by inhibiting gastirn release
211
What is the relevence of the proton pump in the partieal cells?
This pumps out H+ which combines with Cl- to produce acid.
212
What is the action of H. Pylori?
Damage gut epithelium and increase acid. This can lead to peptic ulcers.
213
What is the proton pump?
H+/K+ ATPase
214
What supplies blood to the foregut?
Coeliac Trunk (T12)
215
What supplies blood to the midgut?
Superior mesenteric artery (L1)
216
What supplies blood to the hindgut?
Inferior mesenteric artery (L3)
217
What does the Left gastric artery supply?
Lower oesophagus, lesser curvature of the stomach
218
Midgut
Superior Mesenteric Vein
219
What drains the Foregut?
Splenic Vein
220
What drains the Midgut?
Superior Mesenteric Vein
221
What drains the Hindgut?
Inferior mesenteric Vein
222
What is the Portosystemic anastamoses?
Communitcation between veins in the hepatic system and vena cavae system
223
Where is referred pain from the hindgut?
Hypogastrium
224
Where is referred pain for appendicitis?
Periumbilical region T8-T10
225
What is the cisterna chyli?
Major lymph duct in the abdomen, next to the crus of the diaphragm and becomes that thoracic duct after passing up through the diaphragm
226
Transcellular
Transport mechanisms through the cell then pumped out through the basolateral membrane
227
What is reponsible for secretion in the gut?
Crypts of Lieberkuhn
228
What cells are in the crypts
Stem cells, proliferating cells and differentiating cells
229
What factors affect absorption and secretion?
```
Nutrient intake
Gastric motility
Intestinal motility
Number and state of enterocytes
Blood and lymph supply
Luminal factors, irritants, bile and bacterial toxins
```
230
Water absorbed
Jejunum
231
What is responsible for absorption in the gut?
Villi
232
Where is the majority of the water absorbed?
Jejunum
233
What is the action of the SGLT1?
Pumps sodium ions with glucose into the enterocytes, setting up an electrochemical gradient for water to follow via the paracellular route
234
What are the nerves that signal between the ENS and the CNS?
Vagal and spinal afferents signal from gut to CNS
| Vagal and splanchnic efferents signal from CNS to gut
235
What is the role of the plexuses of the ENS?
Senses Luminal contents
| Controls muscles and glands, blood flow, motility, secretion, mucosal growth
236
What are the 5 parts of the pancreas?
```
Head
Uncincate pancreas
Neck
Body
Tail
```
237
What is the uncicate pancreas?
A projection that arises from the lower part of the has and extends medially to lie beneath the body of the pancreas.
238
What is the role of acinar cells in the pancreas?
Synthesise, store and secrete enzymes
239
What does the sphincter of oddi do?
Controls the opening and closing of the major duodenal papilla.
240
Examples of proteases...
Chymotrypsin and Trypsin
241
What is the role of lipase?
Break down triglycerides
242
What is the role of amylase?
Break down starch into sugars
243
How is trypsinogen activated?
Enterokinases activate trypsinogen into trypsin
244
What vein drains blood from the foregut to the liver?
Splenic Vein
245
What vein drains blood from the midgut to the liver?
Superior Mesenteric Vein
246
What vein drains blood from the hindgut to the liver?
Inferior Mesenteric Vein
247
What vein drains cleaned blood away from the liver?
The hepatic veins draining into the inferior vena cave
248
What are the two reccesses in the peritoneal cavity in relation to the liver?
Subphrenic recess
| Hepatorenal recess
249
What are the three layers of the mucosa?
Epithelium
Lamina Propria
Muscularis Mucosa
250
Where are peyers patches located?
Lamina propria
251
What is the Auerbach's Plexus?
Mesenteric Plexus
252
What is the Meissners Plexus?
Submucosal Plexus
253
What is the role of the serosa?
Prevents friction with other abdominal organs
254
What are exocrine secretions?
Enzymes and digestive juices
255
What are endocrine secretions?
Hormones
256
What are the constituents of the saliva
```
Water - 99.5%
Amylase
Mucus
Lysozyme
Lactoferin
```
257
What innervates the sublingual and submandibular glands?
Branch of the facial nerve
258
What innervates the parotid gland?
Branch of the glossopharyngeal duct
259
What is the function of the saliva?
Digestion and antimicrobial properties
260
What is xerostomia?
Dryness in the mouth often caused by salivary gland hypofunction
261
What is an other name for swallowing?
Deglutination
262
What are the two phases of swallowing?
Oropharangeal - voluntary
| Oesophageal - involuntary
263
What contains the major blood vessels supplying the mucosa of the GI tract?
Submucosa
264
What is the function of enterochromaffin-like cells?
Secrete histamin whcih stimulates G cells to produce gastrin
265
How many litre of human saliva is produced a day?
1-2 litres
266
Where is cholecystokinin released from?
Enteroendocrine cells of the duodenum and jejunum due to lipids and protein.
267
What is the action of cholecystokinin?
Signals via sensory nerves to the hindbrain and stimulates it
268
Where is Peptide YY released from?
From Endocrine mucosal L-cells after a meal
269
What is the action of peptide YY?
Inhibits gastric motility, slows gastric emptying and reduces food intake
270
Where is glucagon-like peptide 1 released from?
Product of the pro-glucagon gene. it is also released from L-cells in response to food indigestion
271
What is the action of glucagon like peptide 1?
Inhibits gastric emptying and reduces food intake
272
Where is oxyntomodulin released from?
Product of the pro-glucagon gene and is released from oxyntic cells and L-cells of the small intestine after a meal
273
What is the role of oxyntomodulin?
Acts to suppress appetite however the mechanisms by which it does this are unclear
274
Where is obestatin released from?
Produced from the gene that encodes ghrelin and is released from cells lining the stomach and small intestine.
275
What is the action of obestatin?
I tis thought to reduce food intake and may antagonise the actions fo ghrelin, but the mechanism by which it does this is unknown
276
What are satiation signals?
These are signals that are given off during a meal to help limit the meal size?
277
What are the gut peptide satiation signals?
```
Cholecystokinin
Peptide YY
Glucagon like peptide 1
Oxyntomodulin
Obestatin
```
278
What is ghrelin?
The hunger signal
279
Where is ghrelin released from?
Oxcyntic cells in the stomach
280
When are ghrelin levels high?
Before a meal, during periods of fasting and hypoglycaemia
281
What is the action of ghrelin?
Stimulates food intake, decreases energy expenditure, decreases fat utilazation
282
What is the name of the strands of smooth muscle in the large intestine?
Taeniae Coli
283
What is the name of the bulges on the large intestine?
Haustra
284
What mediates ileocaecal sphincter tone?
Enteric neurones, the vagus nerve, sympathetic nerves and hormonal signals
285
What occurs in the gastroileal reflex?
Relaxation of the ileocaecal valve
Increased contractions of the ileum
Delivery of chyme from the ileum to the caecum
286
What are the triggers of the gastroileal reflex?
GI hormones - Gastrin and CCK
| Extrinsic autonomic hormones
287
Where does the appendix emerge from the posteriomedial caecal wall?
Appendiceal orriface
288
What does the colon absorb?
Na+, Cl-, H2O
| Short chain fatty acids
289
What does the colon secrete?
K+, HCO3-, mucus
290
What are the primary functions of the colon?
Absorption
Secretion
Resevoir
Periodic elimination of faeces
291
What is the content of faeces?
H2O
| Solids - cellulose, bacteria, bilirubin, small amount of salt
292
What is the function of colonocytes?
Mediate electrolyte absorption, driving H2O absorption
293
What is the function of crypt cells in the colon?
Mediate ion secretion
294
What do goblet cells secrete?
Mucous containing glycoaminoglycans
| Trefoil proteins for host defence
295
What enhances Na+ and K+ absorption?
Aldosterone
296
What is the role of gut commensal bacteria?
Compete with pathogenic microbes
Promote motility and maintain mucosal integrity
Synthesise vitamin K2 and free fatty acids that are absorbed
Activate some drugs
297
What does the common hepatic duct join with to form the common bile duct?
Cystic duct from the gall bladder
298
What is the ampulla of vater?
Join of the bile duct and pancreatic duct
299
Where does the ampulla of vater drain into?
2nd part of the duodenum through the major duodenal papilla
300
What are the three sphincters of the bile duct?
Sphincter of oddi
Bile duct sphincter
Pancreatic duct sphincter
301
What are the main causes of jaundice?
Gallstones
| Carcinoma of the head of the pancreas
302
What are the exocrine cells of the pancreas?
Acinar Cells
303
What are the endocrine cells of the pancreas?
Islets of Langerhans
304
What is produced by the endocrine portion of the pancreas?
Insulin and Glucagon
305
What nerves innervate the pancreas?
Vagus
| Abdomino pelvic splanchnic nerves
306
What mediates pancreatic secretion?
Hormones
307
Describe the blood supply to the pancreas?
Mainly splenic artery
also
Superior pancreaticoduodenal arteries
Inferior pancreaticoduodenal arteries
308
Where does the superior pancreaticoduodenal arteries come from?
Gastroduodenal artery
309
What are the 4 parts of the duodenum?
Superior
Descending
Horizontal
Ascending
310
Where does the jejunum begin?
Duodenaljejunal flexure
311
Where does the ileum end?
Ileocaecal junction
312
What are the differences between the jejunum and ileum?
Jejunum mucosa - plicae circulares (highly folded)
| Ileum mucosa - much smoother
313
What is the blood supply to the jejunum and ileum?
Superior mesenteric artery via the jejunal and ileal arteries
314
What is the venous drainage from the jejunum and ileum?
Jejunal and ileal veins to superior mesenteric veins to hepatic portal vein
315
What is the role of bile?
It helps for the absorption of fats from the GI tract lumen into the intestinal cells
316
What are lacteals?
Specialied lymphatic vessels of the small intestine
317
What lymph nodes drain foregut organs?
Celiac nodes
318
What lymph nodes drain midgut organs?
Superior mesenteric nodes
319
What lymph nodes drain hindgut organs?
Inferior mesenteric nodes
320
What lymph nodes drain the kidneys, posterior abdominal wall, pelvis and lower limbs?
Lumbar nodes
321
What are the adiposity signals?
Insulin and Leptin
322
How do the adiposity signals work?
They inform the hypothalamus to alter the energy balance, hence to eat less and increase energy burn. This can malfunction in obesity
323
Where is leptin released?
It is made and released from fat cells
324
Where is insulin released?
It is made and released from pancreatic beta cells
325
What are the two main causes of leptin resistance?
Defective leptin transport into the brain
| Altered signal transduction following leptin
326
What are thermogenic adipocytes?
They increase energy expenditure uncoupling of oxidative metabolism from ATP production
327
What is the process of digestion?
1. Protein digestion by pepsin and HCl
| 2. Carbohydrate digestion by salivary amylase
328
Where are gastric juices produced?
Gastric glands in the gastric mucosa
329
What is the orad stomach?
Fundus and Proximal Body
330
What is the caudad stomach?
Distal body and antrum
331
What are the gastric factors that allow stomach emptying?
Fluidity of the Chyme
| Volume of the Chyme
332
What is the enterogastric reflex?
This decreases antral activity by signals from intrinsic nerve plexuses and the ANS
333
What are the two gland areas in the stomach?
Oxcyntic gland area
| Pyloric gland area
334
What are the gastric secretions for the oxyntic cells of the stomach?
```
HCl
Pepsinogen
Intrinsic Factor
Gastroferrin
Mucous
Histamine
```
335
What is the function of HCl in gastric secretion?
activates pepsinogen to pepsin, denatures proteins and kills most of the micro-organisms ingested with food
336
What is the function of pepsinogen?
The inactive form of pepsin
337
What is the function of intrinsic factor?
Binds to vitamin B12 and facilitates subsequent absorption
338
What is the function of Gastroferrin?
Binds to Fe2+ and facilitates subsequent absorption
339
What is the function of histamine?
Stimulates HCl secretion from parietal cells
340
What is the function of mucous in the stomach?
To protect the stomach
341
What secretions are produced from the pyloric glands?
Gastrin
Somatostatin
Mucous
342
What is the function of gastrin?
Stimulates HCl secretion and motility
343
What is the function of somatostatin?
Stimulates HCl secretion and motility
344
What is H. Pylori?
Gram -ve curvilinear rod
345
Where are the three main anastomoses in the GI tract?
Oesophageal, anterior abdominal wall, rectum
346
What are the sites of water absorption in the GI tract?
Small (majority in the jejunum) and Large intestion
347
Where is the main site for cobalamin (vitamin B12) absorption?
Terminal Ileum
348
How much water do we excrete each day?
100ml
349
Where is the main site of paracellular transport?
Small Intestine
350
Where is the main site of transcellular transport?
Large intestine
351
What is the barrier in the stomach to protect it from acid?
Mucus-bicarbonate barrier
352
What are the hormones involved in gut repair?
Gastrin
353
Where is the main site of peyer's patches?
Ileum and colon
354
What are the antigen presenting cells in peyer's patches?
M cells
355
What is the main antibody involved in gut immunity?
IgA
356
What is secreted locally to cause vasodilation in the case of acid penetration in the stomach?
CGRP and NO
357
What binds to crypt cells to stimulate intestinal secretion?
ACH and VIP
358
What are chylomicrons made of?
Triglycerides, phospholipis and cholesterol
359
What are firmicutes bacteria?
Microbacteria that ferment dietary fibre to short chain fatty acids
360
What are the main types of firmicutes bacteria?
Buterate
361
Where is intrinsic factor released?
Parietal Cells
362
Where does peristalsis occur?
Oesophagus and intestines
363
Which two muscles are used to close the mouth?
Temporalis and masseter
364
What are the three phases of swallowing?
1. Oral
2. Pharyngeal
3. Oesophageal
365
What regulates the flow of bile and pancreatic juice?
Sphincter of oddi
366
What hormone relaxes the sphincter of oddi?
CCK
367
What does the sphincter of oddi surround?
Ampulla of vater
368
Where is CCK produced?
I cells
369
What connects the gallbladder to the common bile duct?
Cystic duct
370
What is bilirubin excreted as in faeces?
Stercobiligen
371
What is a carrier protein produced by the liver?
Albumin
372
What is dysbiosis?
An alteration in the microbiome caused by a change in the microbiomes composition
373
What cells produce saliva?
Acinus cells
374
What innervates the submandibular and sublingual glands?
Facial nerve
375
What innervates the parotid gland?
Glossopharyngeal nerve
376
Where is iron absorbed in the body?
Duodenum and upper jejunum
377
What is carcinoid of the appendix?
Cancer of the crypts of lieberkuhn in the appendix
378
What are adhesions?
Areas of scar tissue that can cause organs or tissues in the abdomen to stick together
379
What increases the surface area of the small intestine?
Villi- finger like projections created by folds in the mucosa
Microvilli - brush border on the luminal surface of the enterocytes
380
What is the glycolax layer?
This is a gelatinous layer that coats the brush border microvilli
381
What blood vessel supplies the small intestine?
Superior mesenteric artery
382
What are the different types of ingested lipids?
Triacylglycerols
Phospholipids
Cholesterol
Fatty Acids
383
What are the main types of phospholipids?
Glycerophospholipids
384
How does emulsification occur in the GI tract?
Chewing in the mouth
Gastric churning in the stomach - mixed with digestive enzymes
Segmentation and peristalsis in the small intestine - pancreatic and biliary secretion
385
What are lamellae?
A coat of amphiphillic moclecules that form a surface layer on the emulsion droplets
386
What are contained within laemellae?
Products of lipid digestion
Biliary phospholipids
Cholesterol
Bile Salts
387
When are bile salts added to the lamellae?
As the droplets become from multilamellar to unimellar, further bile salts are added
388
What are the uses of bile salts in emulsification?
Act as detergents to help emulsify large lipid droplets to small droplets
389
How is gastric lipase secreted?
From chief cells in response to gastrin
390
Why is gastric lipase inactivated when it leaves the stomach?
Unfavourable pH
| Broken down by pancreatic proteases
391
What is the main enzyme involved in lipid digestion?
Pancreatic Lipase
392
Where is pancreatic lipase secreted?
Acinar cells of the pancreas in response to CCK
393
What TAGs does gastric lipase hydrolyse?
Position 3
394
What TAGs does pancreatic lipase hydrolyse?
Position 1 and 3
395
Where are bile salts released?
Hepatocytes of the liver
396
What can a failure to secrete bile salts result in?
Lipid malabsorption
| Secondary vitamin deficiency due to a failure to absrod fat soluble vitamins A, D, E, K
397
What is colipase?
An amphipathic polypepetide that binds to bile salta and lipase allowing access of the lipase to tri- and di-acylglycerols
398
How is colipase secreted?
It is secreted as procolipase which is activated by trypsin
399
What protein is used in the transport by endocytosis of chylomicrons?
Niemann-Pick C1-like 1 protein
400
How is calcium absorbed when there is a high lumenal concentration of calcium?
Passive paracellular diffusion
401
How is calcium absorbed when there is a low lumenal concentration of calcium?
Calcium channels via active absorption
402
Where is iron absorbed?
Duodenal Enterocytes
403
What form of iron can be absrobed?
Fe2+ ferrous ion
| Haem
404
What promotes reduction of Fe3+ to Fe2+?
[HCl] in stomach
Vitamin C
Duodenal Cytochrome B
405
What prevents Fe2+ forming insoluble anion salts?
Binding of Fe2+ to gastroferrin
406
What transports Fe2+ to the basolateral membrane?
Mobilferrin
407
What transports Fe2+ across the basolateral membrane?
Ferroportin 1
408
What does Haem oxidase convert haem into?
Fe2+ and biliverdin
409
What does vitamin B12 bind to in the stomach?
Haptocorin
410
What does vitamin B12 bind to in the small intestine?
Intrinsic factor
411
How is vitamin B12 absorbed in the terminal ileum?
Vitamin B12-intrinsic factor complex is absorbed by endocytosis
412
What are the major mechanisms for the absorption of Na+ from the jejunum?
Na+/glucose and Na+/amino acid co transport
Na+/H+ exchange
Na+/H+ and Cl-/HCO3- exchange in parallel
Epithelial Na+ channels (ENAC)
413
What is the pH of the lumen of the jejunum?
Alkaline due to the presence of bicarbonate from the pancreas
414
What is the overall charge of Na+ and Cl- absorption?
Electroneutral
415
What chemicals reduce sodium chloride absorption?
Intracellular cAMP, CGMP, Ca2+
416
What condition causes reduction in NaCl absorption?
Diarrhoea
417
What increases the work of the ENAC channel?
Aldosterone
418
How does Cl- absorption occur?
Passively via transcellular or paracellular routes, however there are additional mechanisms
419
What drives passive Cl- absorption in the intestines?
Negative potential due to electrogenic transport and movement of Na+
420
Where does Cl- secretion occur from?
Cells of the crypts of Liberkuhns
421
What channel on the apical membrane allows for the transport of Cl- in to the lumen?
CFTR
422
What can cause the CFTR channel to be indirectly activated?
Bacterial Enterotoxins
Several hormones and neurotransmitters
Immune cell products
Some laxatives
423
What agents cause the direct activation of the CFTR channel?
cAMP, cGMP, Ca2+
424
What are the paracolic gutters?
Potential space between the lateral edge of the ascending and descending colon and the abdominal wall.
425
What is the name of the segmented pouches of the large intestine?
Haustra - formed by the tonic contraction of the teniae coli
426
What is the most common location of the appendix?
Retrocaecal
427
Why is the sigmoid colon very mobile?
It has its own mesentery.
428
Where is the connection between the small and large intestine?
Ileocaecal valve
429
What does the abdominal aorta bifurcate to?
Common Iliacs
430
What do the lateral branches of the abdominal aorta supply?
Kidneys
Adrenal Glands
Gonads
Body wall
431
What are the branches of the superior mesenteric artery?
```
Inferior Pancreaticoduodenal
Middle Colic
Right Colic
Ileocolic
Jejunal and Ileal Branches
Appendicular
```
432
What are the branches of the inferior mesenteric artery?
Left colic
Sigmoid colic
Superior rectal
433
What is the marginal artery of drummond?
An anastomosis between the branches of the SMA and IMA around the large intestine
434
Where dos the hindgut extend to?
Pectinate line
435
What supplies the remainder of the GI tract beyond the pectinate line?
Internal Iliac Artery
436
What drains the foregut organs?
Splenic Vein
437
What are the locations of the three anastomoses of the two venous systems?
Distal end of the oesophagus
Skin around the umbilicus
Rectum and the anal canal
438
What is diffuse type gastric cancer?
This is seen in younger patients and has worse prognosis. Can spread in all layers in the gastric wall
439
What is intestinal type gastric adenocarcinoma?
H. PYLORI. This is more common in the elderly and in Eastern Asia. It is a progression from normal mucosa to chronic gastritis to atrophic gastritis and can lead to intestinal metaplasia and dysplasia that can lead to cancer.
440
What are the three acinar zones of the liver?
1. Periportal zone
2. Mid acinar zone
3. Pericentral zone
441
What is the progression of liver disease?
Insult
Inglammation
Fibrosis
Cirrhosis
442
What are the three types of jaundice?
Pre-Hepatic Jaundice
Hepatic Jaundice
Post-Hepatic Jaundice
443
What is Pre-Hepatic Jaundice?
This is where there is too much haem to break down due to conditions that heighten the bloods rate of haemolysis
444
What is hepatic jaundice?
Liver cells are injured of dead due to diseases of the liver
445
What is post-hepatic jaundice?
Bile cannot escape into the bowel due to an obstructed biliary system
446
What is cirrhosis?
This is when there are bands of fibrosis separating degenerative nodules of hepatocytes
447
What is the viral pathogen of hepatitis A?
Ebstein-Barr Virus
448
What is the viral pathogen of Hepatitis B?
Yellow fever virus
449
What is the viral pathogen of Hepatitis C?
Herpes Simplex Virus
450
What is the viral pathogen of Hepatitis E?
Cytomeglovirus
451
What is the viral pathogen of Hepatitis D?
Delta Agent
452
How is Hepatitis A spread?
Faecal oral route
453
How is Hepatitis B and C spread?
Sexually . by blood products (Hep B also spread vertically)
454
What is haemochromoatosis?
The presence of excess iron in the liver
455
What is the cause of primary haemochromatosis?
Genetic condition causing excess iron absorption
456
What is the cause of secondary haemochromatosis?
Ion overload from the diet, transfusions and iron therapy
457
What is Wilson's Disease?
An inherited autosomal recessive disorder of copper metabolism
458
What are the effects of somatostatin?
```
DECREASE
Inhibits pancreatic enzyme secretion
Decreases gastric acid secretion
Decreases gastrin release
Decreases pepsin release
Decreases glucagon release
```
459
During which digestion phase is the most gastric acid secreted?
Gastric Phase
460
What is diverticulosis?
This is mucosal herniation through the mucus coat in the colon
461
What is diverticulitis?
Inflammation due to known diverticulosis
462
What is a true diverticula?
The diverticula includes all layers of the bowel wall
463
What is a false diverticula?
The diverticula includes only the serosa and mucosal layer
464
What is the most common complication of diverticular disease?
Pericolic Abscess
465
What is a fistula?
A communication between two epithelialised organs
466
What are the common types of colitis?
```
Infective
Ulcerative
Crohn's
Ischaemic
Radiation
```
467
What is colonic angiodysplasia?
Submucosal lakes of blood, usually on the riht side of the colon
468
What are the commonest causes of large bowel obstruction?
Colorectal cancer
Benign Stricture
Volvulus
469
What is a volvulus?
Bowel twists on the mesentery. This may become gangrenous
470
What is a pseudo-obstruction of the bowel?
This is where the patient acts as though they have an obstruction but have no real mechanical obstruction
471
What is gastroenteritis?
Inflammation of the lining of the stomach, small intestine and large intestine
472
What are the viral causes of gastroenteritis?
Rotovirus
Norovirus
Adenovirus
473
What pathogen causes gastroenteritis after eating reheated rice?
Bacillus Cerus
474
What are the main causes of bowel obstuction?
Adhesions
Hernias
Malignancy
475
What is 'third-spacing'?
Fluid loss into an area where fluid is not normally lost
476
What are adhesions?
Scar tissue that binds the abdominal contents together causing a kinking or squeezing of the bowel.
477
What is coeliac disease?
A systemic autoimmune condition triggered by dietary gluten peptides.
478
What causes coeliac diseae?
Intolerance to protein called prolamins
479
What antibodies are involved in coeliac disease?
Anti-TTG antibodies
| Anti-endomysical antibodies
480
What is faecal calprotein?
A sensitive marker for intestinal inflammation. This is released following the degranulation of neutrophils
481
What is the most common family of pathogens in the GI tract?
Enterobacteriaceae
482
What type of bacteria is the enterobacteriaceae?
Gram negative rods
483
What is the normal bowel flora in the mouth?
```
Strep. Viridans
Neisseria sp.
Anaerobes
Candida sp.
Staphylococci
```
484
What is normal bowel flora in the stomach and duodenum?
Usually sterile
Few candida sp.
Staphylococci
485
What is the normal bowel flora of the jejunume?
Coliforms
| Anaerobes
486
What is the normal bowel flora of the colon?
Coliforms
Anaerobes
Enterococcus faecalis
487
What is the normal bowel flora of the bile ducts?
Usually sterile
488
What are the three levator ani muscles of the pelvic floor?
Iliococcygeus
Pubococcygeus
Puborectalis
489
What are the dual nerve supply to the levator ani muscles?
'Nerve to levator ani'
Pudendal Nerve
Both of the sacral plexus
490
Whereabouts in the rectum are faecal masses held?
Rectal Ampulla
491
Where is the pouch of douglas?
Rectouterine Pouch
492
Where is the anorectal junction?
Tip of the coccyx
| Anorectal angle
493
Where do the visceral afferents to the rectum enter the spinal cord?
Run with parasympathetics to S2-4
494
Where do the sympathetic fibres to the rectum originate?
T12-L2 - Then travel via periarterial plexuses around branches of IMA
495
Where do the parasympathetic fibres to the rectum originate?
S2-4 - Then travel via pelvic splanchnic nerves and synapse in the walls of the rectum
496
Where does the somatic motor innervation to the rectum originate?
S2-4 - Pudendal Nerves
| S3-4 - Nerves to the levator ani
497
What is the pectinate line?
This marks the junction between part of the embryo which forms the GI tracy and part of that formed by the skin
498
What is the blood supply above the pectinate line?
Arterial - Inferior mesenteric artery
| Venous - portal venous system - IMV
499
What is the blood supply below the pectinate line?
Arterial - Internal Iliac Artery
| Venous - Systemic venous system - Internal Iliac
500
What are haemorrhoids?
Prolapses of the rectal venous plexuses
501
What are rectal varices?
They form in relation to portal hypertension
502
What are the four common areas of hernia in the GI tract?
Umbilical
Epigastric
Inguinal
Femoral
503
What are the two factors required for a hernia?
Structural weakness
| Increased pressure
504
What is a direct inguinal hernia?
Caused by a weakness in the posterior wall of the inguinal canal
505
What is an indirect inguinal hernia?
The abdominal contents pass through the deep inguinal ring to pass through the inguinal canal.
506
How does bilirubin move to the liver?
It binds to albumin. This forms delta bilirubin.
507
How is bilirubin secreted into the biliary system?
It is conjugated with glucouronic acid
508
What is the difference between conjugated and unconjugated bilirubin?
Conjugated - bound with glucouronic acid
| Unconjugate - not bound with glucouronic acid
509
What is direct bilirubin?
Conjugated and delta bilirubin
510
What is indirect bilirubin?
Unconjugated bilirubin
511
What is urobilinogen?
In the colon, the glucouronic acid is removed by bacteria from the conjugated bilirubin. This forms urobilinogen
512
What is stercobilin?
Metabolised urobilinogen. This gives faeces their brown colour
513
What do beta islet cells produce?
Insulin
514
What do alpha islet cells produce?
Glucagon
515
What do delta islet cells secrete?
Somatostatin
516
What do f islet cells secrete?
Pancreatic polypeptide
517
What are secretions from pancreatic acinar cells?
Protease
Pancreatic lipase
Pancreatic amylase
518
What do the epithelial cells lining the duct release?
Bicarbonate
| Water
519
What type of epithelium lines the gallbladder?
Simple columnar epithelium
520
What are Brunner's Glands?
They are glands in the duodenum that secrete mucus that is rich in bicarbonate ions
521
What is the action of prostaglandins in the stomach and duodenum?
Stimulate mucus and bicarbonate secretion and vasodilation of nearby blood vessels.
522
Which muscle makes up the pelvic floor?
Leviator Ani
