Gastrointestinal System Flashcards
1
Q
What are some functions of the alimentary tract?
A
Entry point for food Break up Storage Chemical digestion Kill pathogens Move along tract Absorb nutrients Eliminate residual waste
2
Q
What are the contents of saliva (apart from water)?
A
Amylase
Lipase
Bacteriostatic agents (IgA)
High calcium to protect teeth
3
Q
What is the difference between the upper and lower oesophageal muscles?
A
Upper - striated (voluntary control)
Lower - smooth (not voluntary)
4
Q
What are rugae in the stomach?
A
Longitudinal folding of the mucosa
5
Q
What is receptive relaxation in the stomach?
A
Relaxation of the walls as food enters to stop a rise in pressure
6
Q
What is the function of parietal cells, chief cells and G-cells in the stomach?
A
Acid and intrinsic factor
Pepsin
Gastrin
7
Q
What is the function of Brunner’s gland in the duodenum?
A
Produce bicarbonate-rich mucus to neutralise stomach acid
8
Q
What is the function of bile salts?
A
Emulsify fats
9
Q
In the alimentary tract, when does absorption begin?
A
Duodenum
10
Q
What are plicae circularis in the small intestine?
A
Circular folds in the mucosa and submucosa
11
Q
What key things are actively absorbed in the duodenum, jejunum and ileum?
A
Duodenum - iron
Jejunum - sugar, amino acids, fatty acids
Ileum - vitamin B12, bile acid, nutrients
12
Q
What type of epithelia is found in the colon?
A
Simple columnar
13
Q
What areas of the alimentary tract are under somatic control?
A
Mouth, first third of the oesophagus, last anal sphincter
14
Q
What two plexuses are found in the gut?
A
Submucosal plexus - beneath submucosa (plexus of Meissner)
Myenteric plexus.p - between muscle layers
15
Q
What sphincter is at the top of the oesophagus and relaxes on swallowing?
A
Cricopharyngeal sphincter (upper oesophageal sphincter)
16
Q
What type of cancer would you see in the top part of the oesophagus?
A
Squamous cell carcinoma
17
Q
What type of cancer would you see in the bottom part of the oesophagus?
A
Adenocarcinoma
18
Q
What is Barrett’s oesophagus?
A
A pre malignant condition caused by chronic acid reflux.
Metaplasia to cuboidal epithelium, appears red and inflamed.
19
Q
From top to bottom, what are the areas of the stomach?
A
Fundus
Cardia
Body
Pylorus
20
Q
What is the significance of the incisura angularis of the stomach?
A
An anatomical notch indicating the boundary between the body and pylorus
21
Q
What is the omentum?
A
Layers of peritoneum attaching the stomach to other abdominal organs
22
Q
What is a peptic ulcer?
A
Lesion in the mucosa caused by the digestive action of pepsin and stomach acid. Frequently due to a loss of mucosal protection.
23
Q
What valve separates the ileum and colon?
A
Ileocaecal valve
24
Q
Briefly, what is ulcerative colitis?
A
Chronic ulceration which begins in the rectum then continues up the colon. Causes diarrhoea, often bloody. Can predispose to cancer.
25
What is a colonic volvus?
A twist in the colon which can cut off the blood supply and cause necrosis. Needs a colostomy.
26
What are colonic diverticulae?
Pouches which form in the wall of the colon.
Can cause bleeding and obstruction, may become infected and perforate.
Associated with left iliac fossa pain.
27
What are the layers that make up the musosa of the gut, from lumen out?
Epithelia
Lamina propria (mucus cells, Peyer's patches)
Muscularis mucosa
28
When is peak salivary production?
In the afternoon
29
Give some substances which are found in saliva.
```
Mainly water
May have mucus
Antibodies
Electrolytes
Lymphocytes
Amylase/lipase
Bacterial flora
Neutrophils
Epithelial cells
```
30
What does the duodenum detect to slow gastric emptying?
Lipids
pH
Hypertonicity
31
What are the large salivary glands?
Sublingual
Parotid
Submandibular
32
What is the affect of having low ANS stimulation of the salivary glands?
Dry mouth
Halitosis
Poor dental hygeine
33
What are the three types of saliva and where are they mainly produced?
Serous - thin and watery. From parotid gland
Mucus - thick, mucinous and viscid. Sublingual
Mixed - submandibular
34
Describe the location if the parotid gland.
In front of and level with the external ear, within the parotid fascia
35
What duct drains the parotid gland?
Stenson's duct
36
What is the major salivary gland?
Submandibular gland
37
Where is the submandibular gland located?
In the floor of the mouth
38
What duct drains the submandibular gland?
Wharton's duct
39
Histologically, how can you differentiate between serous and mucus cells in a mixed acinus?
Serous have faint nuclei
| Mucus have large, rounded nuclei
40
What cells surround secretory units in salivary glands and what is their function?
Myoepithelial cells
| Pump secretions into the intercalated ducts
41
What are the primary and secondary stages of plasma production?
Primary - occurs in the acini, which secretes fluid which is isotonic with plasma
Secondary - undergoes modification in the striated duct
42
Give some conditions which can cause problems swallowing from the mouth to oesophagus.
```
Cleft palate
Cleft uvula
Stroke (paralysis of nerves supplying soft palate)
Hypertrophy of pharyngeal tonsils
Drug overdose with CNS depression
```
43
Describe the tonsillar pillars and the location of the tonsils in relation to them.
Anterior tonsillar pillar has the palatoglossal arch
Posterior tonsillar pillar has the palatopharyngeal arch
The palatine tonsils are between the pillars
44
Describe the oral phase of swallowing.
Voluntary formation of a bolus
Activates receptors in the anterior tonsillar pillars and pharyngeal phase of tongue
Initiates swallowing
45
Describe the pharyngeal phase of swallowing.
Soft palate closes the border with the nasal/oropharynx
| Hyoid bone and larynx are raised
46
Describe the oesophageal phase of swallowing.
Controlled by swallowing centres of the brain
Upper oesophageal sphincter relaxes
Reflex peristalsis initiated
47
What muscle forms the upper oesophageal sphincter?
Cricopharyngeal muscle
48
What is a hiatus hernia?
When the upper stomach herniates into the thoracic cavity through the lower oesophageal sphincter. Causes reflux.
49
What is the somatodeum of the gut tube?
Future mouth
50
What is the proctodeum of the primitive gut tube?
Future anus
51
What embryonic layer does the inner lining of the gut tube arise from?
Endoderm
52
What embryonic layer is the outer lining of the gut tube derived from?
Splanchnic mesoderm
53
What suspends the gut tube in the intraembryonic coelom?
Double layer of splanchnic mesoderm
54
What are the adult derivatives of the foregut?
```
Oesophagus
Stomach
Pancreas
Liver
Gall bladder
Proximal duodenum (to the entrance of the bile duct)
```
55
What are the adult derivatives of the midgut?
```
Distal 2/3 of the duodenum
Jejunum
Ileum
Caecum
Ascending colon
Proximal 2/3 of the transverse colon
```
56
What are the adult derivatives of the hindgut?
```
Distal 1/3 of transverse colon
Descending colon
Rectum
Upper anal canal
Inner lining of the urethra and bladder
```
57
Give the main arterial supply for each embryonic segment of the gut.
Foregut - coeliac trunk
Midgut - superior mesenteric artery
Hindgut - posterior mesenteric artery
58
What is the significance of an organ being close to the junction between different sections of the primitive gut, in terms of its blood supply?
It will have a dual blood supply
| E.g. Pancreas, duodenum
59
What is the difference between the dorsal and ventral mesentry?
The ventral mesentry is only in the region of the foregut, so has a free edge at the liver.
60
What happens to the right and left sacs in development of the gut?
The left sac contributes to the greater sac
| The right sac contributes to the lesser sac
61
What is mesentry?
A double layer of peritoneum, suspending the gut tube from the abdominal wall.
Gives a conduit for blood and nerve supply, allows mobility when required.
62
What are the omenta?
Specialised areas of peritoneum which allow the neurovasculature to pass along them.
63
What is located at the free edge of the lesser omentum?
Portal triad
64
What mesentry does the liver develop within?
Ventral
65
What is the difference between retroperitoneal and secondary retroperitoneal structures?
Retroperitoneal - the organ was never suspended in the peritoneal cavity
Kidneys, aorta
Secondary retroperitoneal - the organ began as part of the primitive gut tube, but became pushed against the abdominal wall and lost its mesentry.
Pancreas, duodenum
66
What has gone wrong in development to allow a tracheoesophageal fistula to form?
Incorrect formation or the absence of the tracheoesophageal septum.
67
What are the symptoms of a tracheoesophageal fistula?
Newborn unable to swallow.
Choking, coughing, vomiting, cyanosis when trying to feed
Polyhydramnios
68
What attaches the liver to the stomach?
Lesser omentum
69
What is the bare area of the liver?
Where it is attached to the diaphragm, with no peritoneal lining
70
What is the cause of duodenal atresia?
Failure to recanalise during development.
71
What are the symptoms of duodenal atresia?
Intestinal obstruction in the newborn
| Polyhydramnios
72
How is chyme altered in the duodenum?
Adds water from the ECF/circulation using the osmotic gradient and CFTR
Pancreatic secretions such as enzymes and HCO3-
Liver secretions such as bile and HCO3-
73
What is the function of the centroacinar cells in the pancreatic exocrine system?
Produce enzymes
74
Describe the passage that pancreatic secretions take to enter the duodenum.
Enters the major pancreatic duct
Joins with the common bile duct at the ampulla of Vater
Common bile duct enters the duodenum at the duodenal papilla
The sphincter of Oddi controls entry into the duodenum
75
What stimulates the acinus to produce more enzymes?
Vagus nerve
| CCK
76
What causes CCK release in the duodenum and jejunum?
Hypertonic chyme
| Lipids
77
What active enzymes are secreted by the pancreas?
Amylase
| Lipase
78
What inactive enzymes are secreted by the pancreas?
Trypsin
Chemotrypsin
Carbopeptidase
Elastase
79
Describe the formation and storage of inactive enzymes.
```
Formed on RER
Modified in golgi
To condensing vacuoles
Made into zymogen granules for storage
Release
```
80
What are zymogen granules?
Membrane-bound inactive enzyme precursors.
81
What would a high plasma amylase indicate?
Pancreatic damage, most likely pancreatitis
82
What is the function of duct cells in the exocrine pancreas?
Produce an isotonic aqueous solution with Na+, Cl-, K+, HCO3-
83
What stimulates ductal cells of the exocrine pancreas to increase their production of HCO3-?
Secretin
| Increased flow rate
84
What are the functions of the liver?
Energy metabolism
Detoxification
Plasma protein production
Bile secretion
85
What blood vessel takes blood from the gut to the liver?
Portal vein
86
What divides the liver into structural units?
Liver capsule
87
What is the functional unit of the liver?
Acinus
88
What are the short and long axes of the acini of the liver?
Short - between portal triads
| Long - to the central vein
89
Describe the significance of the different zones around each portal triad in an acinus.
1 - closest to the triad and therefore closest to the blood supply. Will be first affected by toxins
3 - furthest from the triad. Will be worst affected by hypoxia
90
What is the hepatic sinusoid?
Convergence of the portal vein and hepatic artery in the liver
91
What is a Kupffer cell?
A macrophage in the liver
92
What is the vessel called which transports bile from hepatocytes to the bile duct?
Bile canaliculi
93
Give an example of a primary bile acid
Cholic acid
| Chenodeoxycholic acid
94
Why must primary bile acids be modified before entry to the duodenum?
They aren't soluble at duodenal pH.
95
How are primary bile acids modified to bile salts?
Conjugation with amino acids e.g. Glycine/taurine
96
What is a micelle?
Bile salts surrounding the breakdown products of fat in the intestine
97
What happens to the contents of a micelle after absorption into enterocytes?
Re-esterised to form triglycerides, phospholipids, and cholesterol.
98
What happens to lipids after re-esterification to allow them to be transported around the body?
Packaged with apoproteins to form chylomicrons.
99
Describe the path chylomicrons take from the gut into the venous system.
Absorbed into lacteals
Travel to thoracic duct
Left subclavian vein
100
Where are bile salts reabsorbed?
Terminal ileum
101
What is the function of the gall bladder?
Store and concentrate bile.
102
What is the effect of CCK on the gall bladder?
Stimulates contraction
| Relaxes the sphincter of Oddi
103
Describe the basic cause and presentation of steatorrhoea
Inadequate bile salts or lipase production
Pale, foul smelling, floating faeces
104
What is bilirubin?
Bile pigment
| Breakdown product of haemoglobin
105
Where is bilirubin conjugated?
Liver
106
Give a cause and symptoms of a blockage in the biliary tree
Pre-hepatic jaundice
Pale stools
Dark urine
Pancreatic cancer
Gall stones
107
What vein drains the small intestine?
Superior mesenteric vein
108
What vein drains the large intestine?
Inferior mesenteric vein
109
What vein does the superior and inferior mesenteric veins drain into?
Splenic vein
110
What veins drain into the portal vein?
Splenic
| Right and left gastric
111
Give the branches of the superior mesenteric artery.
```
Inferior pancreatoduodenal artery
Middle colic artery
Ileocolic artery
Right colic artery
Ileal artery
Duodenal artery
```
112
What are the branches of the inferior mesenteric artery?
Left colic
Sigmoid
Superior rectal (continuation)
113
Why is the splenic flexure at especially high risk of ischaemia in a person with hypoxia?
It is a 'watershed area' where the anastamosis of arteries is poor
114
Describe the difference between a direct and indirect inguinal hernia.
Indirect
- hernial sac enters the inguinal canal through the deep inguinal ring
- lateral to the epigastric vessels
- may extend into the scrotum
- more common in males
Direct
- common in older men
- hernial sac bulges forwards through the posterior wall of the inguinal canal
- medial to the inferior epigastric vessels
115
Describe a femoral hernia.
The hernial sac descends through the femoral canal, within the femoral sheath.
More common in women
The lacunar ligament can cause strangulation by compressing the blood vessels.
116
What is an incarcerated hernia?
When a loop of intestine becomes trapped in a weak point of the abdominal wall, obstructing the bowel.
Causes pain, nausea, vomiting, and constipation
117
What is a strangulated hernia?
When the blood supply is cut off to tissue in the hernia
118
What is exomphalos?
A congenital umbilical hernia caused by failure of the midgut to return to the abdomen.
119
What is a Spigelian hernia?
Herniation through the aponeurosis of the transverse abdominis, lateral to the lateral edge of the rectus sheath.
Strangulation is a common complication.
120
What are the basic functions of the stomach?
Receive and disrupt food
Continue chemical digestion
Disinfection
121
What are the orad and caudad regions of the stomach?
Orad - fundus and proximal body. Dilates and receives food.
Caudad - distal body and antrum. Constricts and regulates gastric emptying
122
What is receptive relaxation?
Vagally mediated relaxation of the orad stomach which stops the pressure rising too much when food enters, preventing reflux.
123
What area of the stomach does peristalsis mainly happen in?
Antrum
124
Why is it important for the pyloric sphincter to maintain a small exit from the stomach?
To force pieces of food which are too large back into the body of the stomach to be further digested
125
Where are parietal cells of the stomach mainly found?
Fundus and body
126
What is the function of gastric parietal cells?
Secrete HCl and intrinsic factor
127
Why is intrinsic factor essential?
For the absorption of vitamin B12.
| Causes pernicious anaemia if absent.
128
In what region of the stomach are G cells mainly found?
Antrum
129
What is the function of G cells?
Secrete gastrin
130
What is the function of enterochromaffin-like cells in the stomach?
Produce histamine
131
What is the function of Chief cells?
Secrete pepsinogen
132
What is the function of D cells?
Secrete somatostatin
133
What is the function of mucous cells?
Secrete mucus and bicarbonate
134
What is the basic order of cells in a gastric gland from top to bottom?
Mucus cells
Parietal cells
Chief cells
Enteroendocrine cells
135
What substances stimulate parietal cells?
Gastrin (on CCK receptor)
Histamine
Acetylcholine (vagus nerve)
136
What substances stimulate G cells?
Digestive breakdown products
| Vagus nerve
137
What stimulates D cells?
Drop in pH of the stomach as it empties
138
Describe the production of acid in the stomach.
H+ and Cl- are moved into the stomach lumen by parietal cells. They combine to form HCl.
Intracellular CO2 combines with OH- to form HCO3-, which moves into the bloodstream and creates an alkaline tide.
139
Describe the cephalic stage of digestion.
Activated by smelling, tasting, chewing and swallowing food.
The vagus nerve stimulates parietal cells and releases gastrin related peptide to stimulate G cells.
140
Describe the gastric stage of digestion.
Produces 60% of the total HCl.
Distention of the stomach stimulates the vagus nerve, which stimulates parietal and G cells.
The presence of small peptides and amino acids also stimulates G cells
Food acting as a buffer removes inhibition on gastrin production.
141
Describe the intestinal stage of digestion.
Produces 10% of the total HCl.
Chyme initially stimulates gastrin secretion, but this phase is short and is soon overtaken by the inhibition of G cells.
142
How does the stomach protect itself from damage?
Production of mucus and bicarb which adheres to the lining, keeping epithelial cells at a higher pH.
High turnover of epithelial cells
Prostaglandins cause vasodilation, sustaining good blood flow for repair and regeneration.
143
Give an example of something which removes the protective layer in the stomach.
Alcohol
Heliobacter pylori
NSAIDs
144
What drugs can be used to reduce acid production in the stomach, and how?
H2 inhibitors - cimetidine. Inhibits histamine action on parietal cells
Proton pump inhibitors - omeprazole. Reduces hydrogen ion movement into the stomach lumen.
145
What connects the gut loop to the yolk sac?
Vitelline duct
146
What rotations does the gut go through during development?
3 90 degree turns anti-clockwise
147
Describe what would happen with incomplete rotation of the midgut.
Only one 90 degree rotation occurred so the limbs don't cross. Will have a left-sided colon.
148
Describe what would happen with reversed rotation of the midgut in development.
The transverse colon will be posterior to the duodenum.
149
What causes a sub-hepatic caecum?
Failure of the caecal bud to descend.
| No ascending colon.
150
Describe a vitelline cyst.
The middle of the vitelline duct remains patent and fluid filled.
Fibrous strands form at either end.
151
Describe a vitelline fistula.
Abnormal opening of the bowel causing a leak of intestinal contents through the umbilicus.
152
Describe Meckel's diverticulum.
May be attached via a fibrous cord to the anterior abdominal wall.
More common in males and may contain ectopic gastric or pancreatic tissue. (If it has this, can have inflammation of the bowel).
Rule of 2's.
153
Describe pyloric stenosis.
Common in infants
Causes projectile vomiting
Caused by muscle overgrowth
154
Describe gastroschisis
Intestinal loops are outside the body wall because the wall doesn't close and there is regression of the left umbilical vein.
Linear defects in the anterior abdominal wall
Isolated defect with good prognosis if the bowel loops are healthy.
Has skin cover
155
Describe omphalocoele.
Persistence of the physiological herniation
| No skin cover
156
What divides the anal canal and what is its significance?
Pectineal line
Above - columnar epithelium, visceral innervation (detects stretch), superior rectal artery supply, internal haemorrhoids
Below - stratified epithelium, somatic innervation (range of feeling), middle and inferior rectal artery supply, external haemorrhoids
157
What is an imperforate anus?
Congenital defect where the opening to the anus is missing or blocked.
158
What is anorectal agenesis?
Failure of the anus or rectum to form
159
What is a hindgut fistula?
A failure of the urogenital sinus and anorectal canal to separate fully, creating abnormal communication.
160
What parts of the gut retain their mesentry?
```
Jejunum
Ileum
Appendix
Transverse colon
Sigmoid colon
```
161
What are the adult derivatives of the dorsal mesentry?
```
Greater omentum
Gastrolineal ligament (stomach to spleen)
Lienorenal ligament (kidney to spleen)
Mesocolon (colon to posterior abdominal wall)
Mesentry proper
```
162
What are the adult derivatives of the ventral mesentry?
Lesser omentum
| Falciform ligament
163
What blood vessel supplies the midgut?
Superior mesenteric artery
164
What is the innervation of the midgut?
```
Vagus nerve (parasympathetic)
Superior mesenteric ganglion and plexus (sympathetic)
```
165
What is the blood supply of the hindgut?
Inferior mesenteric artery
166
What is the innervation of the hindgut?
```
Pelvic nerve (S2,3,4)
Inferior mesenteric ganglion
```
167
What is secreted by the duodenum when chyme enters?
Cholecystekinase
Secretin
Gastrin inhibitory peptides
168
Explain the change in pain location with appendicitis.
Pain is initially felt in the midgut region as the appendix has autonomic innervation.
Then the inflammation spreads into the peritoneum, which causes pain to localise due to somatic innervation.
169
What is dyspepsia?
A collection of upper GI symptoms
170
Describe the symptoms of gastro-oesophageal reflux disease.
```
Cough
Wheeze
Burning
Sore throat
Dysphagia
Regurgitation of solids if strictures form
```
171
Give an example of a condition which can cause gastro-oesophageal reflux disease.
Lower oesophageal sphincter problem
Delayed gastric emptying with increased pressure
Hiatus hernia
Obesity
172
What are the treatments for gastro-oesophageal reflux disease?
Lifestyle changes e.g small spaced out meals
Antacids
H2 antagonists
Proton pump inhibitors
173
Describe what acute gastritis is.
Transient inflammation of the stomach epithelium
174
What can cause acute gastritis?
Chronic use of NSAIDs/alcohol
Chemotherapy
Bile reflux (uncommon)
175
What are the symptoms of acute gastritis?
Mainly asymptomatic
Nausea
Vomiting
Discomfort
Bleeding
176
Give a cause of chronic gastritis.
Heliobacter pylori infection
Autoimmune
Chronic alcohol/NSAID use
177
What are the symptoms of chronic gastritis?
Can be asymptomatic
```
Anorexia
Glossitis
Peptic ulcer
Cancer
Nausea
Vomiting
Bleeding
Neurological (altered gait) and lethargy if autoimmune
```
178
Describe the causes of peptic ulcer disease.
Defects in the gastric or duodenal mucosa, most common in the first part of the duodenum or the lesser curve of the stomach.
Occurs when the normal defence mechanism is breached
E.g. Excess stomach acid, NSAIDs, H pylori, smoking (causes relapse), massive physiological stress.
179
What are the symptoms of peptic ulcer disease?
Burning or gnawing pain in the epigastric region or back
Bleeding, melaena, anaemia, haematemesis
Early satiety
Weight loss
If it perforates, leads to peritonitis
180
What tests can you do in dyspepsia?
Upper GI endoscopy
Urease breath test for H pylori
Blood test for anaemia
Erect chest x-ray to check for perforation
181
What are the treatments for dyspepsia?
```
Stop the insulting factor
Eradicate H. pylori (amoxicillin, clathromycin, omeprazole)
Endoscopy to stop bleeding ulcers
Proton pump inhibitor (omeprazole)
H2 blocker (cimetidine/ranitidine)
```
182
What is the significance of H. pylori producing urease?
It converts urea to ammonia, creating an alkali region around it to protect it against stomach acidity.
183
What type of bacteria is Heliobacter pylori?
Gram negative
| Helical rod
184
Give some ways in which Heliobacter pylori directly damages the gastric epithelium.
Cytokines cause epithelial damage
Ammonia is directly toxic
May erode mucus
Promotes inflammatory response (self injury)
185
What is the difference in the effect of Heliobacter pylori when it colonises the antrum in comparison to the body of the stomach?
Antrum - stimulates G cells and/or inhibits D cells, producing more acidic chyme. Can cause duodenal metaplasia. This may allow H pylori to also colonise the duodenum, causing duodenal ulceration.
Body - atrophy of parietal cells, leading to gastric ulcers and metaplastic changes. Can cause dysplasia and eventually cancer
186
Describe Zollinger-Ellison syndrome.
Non-beta islet cell gastrin-secreting tumour.
Can be part of multiple endocrine neoplasia type I.
Proliferation of parietal cells increases acid secretion, causing severe ulceration of the stomach and small bowel, leading to diarrhoea and abdominal pain.
187
What are the symptoms of stomach cancer?
```
Dysphagia if in the cardia
Decreased appetite
Weight loss
Malaena if eroded
Nausea and vomiting
Virchow's nodes in left clavicular region.
```
188
What increases the risk of stomach cancer?
High salt intake
Male
Heliobacter pylori
Smoking
189
What type of cancer is stomach cancer normally?
Adenocarcinoma
| Small number of lymphoma
190
Where does the liver begin to develop?
Ventral mesentry
191
What is the falciform ligament?
Attaches the anterior surface of the liver to the anterior abdominal wall
Free edge contains the ligamentum teres
192
What are the coronary ligaments of the liver?
Attach the superior surface to the diaphragm
193
What are the four anatomical lobes of the liver?
Caudate
Left
Right
Quadrate
194
What suspends the liver in the abdomen?
Inferior vena cava
195
What is contained in the porta hepatis?
Hepatic artery and vein
| Common bile duct
196
Draw the biliary tree.
Right and left hepatic ducts come from the liver, merge to form the common hepatic duct.
The cystic duct comes from the gall bladder, meets the common hepatic duct, then becomes the common bile duct.
The common bile duct then joins with the pancreatic duct
197
What is divarification of the recti?
The linea alba is weak and stretchy, allowing abdominal organs to push through. Not a hernia.
198
When would you perform a grid-iron incision?
Appendiectomy
199
Where is foregut pain felt?
Epigastric region
200
Where is midgut pain felt?
Periumbilical
201
Where is oesophageal pain generally felt?
Retrostna
202
Where is hindgut pain generally felt?
Suprapubic pain
203
Where can diaphragmatic pain be referred to?
Left shoulder tip
204
What is xerostomia?
Reduced salivary flow
Causes microbial overgrowth in the mouth and dental caries. Can lead to parotitis if Staphylococcus aureus enters Wharton's duct.
Caused by dehydration
205
What is achlorhydria?
The stomach isn't able to produce hydrochloric acid.
Seen in pernicious anaemia
Can be caused by H2 antagonist use and proton pump inhibitors
206
What features of the small intestine protect against bacterial colonisation?
```
Bile
Proteolytic enzymes
Lack of nutrients
Anaerobic environment
Shedding epithelia
Rapid transit
```
207
What are the innate cellular defences of the gut?
Neutrophils
Macrophages
Natural killer cells (kills virally infected cells)
Tissue mast cells
Eosinophils (protect against parasitic infections)
208
Briefly, how can bacterial infections in the gut cause diarrhoea?
The bacteria activate the complement pathway, which recruits mast cells. They release histamine causing huge vasodilation, leading to massive water loss.
209
Where is gut associated lymphoid tissue (GALT) mainly found?
Tonsils
Peyer's patches
Appendix
210
What tonsils drain into the cervical lymph nodes?
Nasopharyngeal
Linguinal
Pallatine
211
What is the importance of the ileocaecal valve in GI infection?
Stops reflux of bacteria into the small intestine from the colon.
212
What is present in the terminal ileum to stop infection?
Peyers patches
213
Describe mesenteric adenitis.
Right ileac fossa pain in children under 12 which mimics appendicitis.
Cocksackie virus or adenovirus take over Peyers patches
214
What effect can typhoid fever have on the ileum?
Cause Peyers patches to become inflamed and may perforate.
215
How can lymphoid hyperplasia precipitate appendicitis?
It can trap bacteria in the appendix, allowing them to proliferate and cause infection.
216
Give a cause of appendicitis
Lymphoid hyperolasia
Chicken pox
Faecoliths
217
What can cause gut ischaemia?
Embolus
Heavy haemorrhage
Systemic hypotension
Arterial disease
218
How can gut ischaemia lead to potentially fatal bacteraemia?
It breaks down the gastrointestinal tract's defensive mechanisms which allows bacteria to invade the bloodstream
219
Give the liver function tests and what functions they are testing.
```
Hepatocellular damage
ALT/AST
Y-GT
Cholestasis
Bilirubin
ALP
Synthetic function
Albumin
Prothrombin
```
220
Describe pre-hepatic jaundice.
The patient has excessive haemolysis and the liver is unable to cope with the huge load of bilirubin
221
What are the lab findings in pre-hepatic jaundice?
```
Unconjugated hyperbilirubinaemia
Reticulocytosis
Anaemia
High lactate dehydrogenase
Low haptoglobin
```
222
Give a cause of pre-hepatic jaundice.
```
RBC membrane defects (spherocytosis)
Haemoglobin abnormalities (sickle cell)
Metabolic defects
Congenital hyperbilirubinnaemias
Infection
Drugs
Burns
Acquired RBC membrane defects
Immune destruction of RBC
Mechanical destruction of RBC
```
223
Describe hepatocellular jaundice.
Deranged hepatocyte function with an element of cholestasis.
224
What are the lab findings in hepatocellular jaundice?
Raised AST/ALT
Normal or raised ALP
Mixed conjugated and unconjugated hyperbilirubinaemia
Abnormal clotting
225
Give a cause of hepatocellular jaundice.
```
Gilbert's syndrome (jaundice)
Hepatitis A, B, C, E
Autoimmune hepatitis
Alcohol
Wilson's disease
Haemochromatosis
Paracetamol overdose
Cirrhosis
Hepatocellular carcinoma
Metastases
```
226
What type of virus is hepatitis A and what infectious route does it take?
RNA
| Faecal-oral
227
What type of virus is hepatitis B and what infectious route does it take?
DNA
| Blood, saliva, sexual, vertical
228
What type of virus is hepatitis C and what infectious route does it take?
RNA
| Blood
229
Aside from the viruses, what can cause hepatitis?
Drugs (methyl DOPA, isoniazid)
Alpha-1 antitrypsin disease
Wilson's disease
Autoimmune
230
Give some consequences of alcoholic liver disease.
```
Alcoholic hepatitis
Cirrhosis
Hepatocellular carcinoma
Liver failure
Wernicke-Korsakoff syndrome
Encephalopathy
Dementia
Epilepsy
```
231
What is liver cirrhosis?
Cell necrosis with nodular regeneration which contains fibrosis.
232
What are the symptoms of liver cirrhosis?
```
Jaundice
Anaemia
Bruising
Palmar erythema
Duputrens contracture
Flapping tremor
Portal hypertension
Spontaneous bacterial peritonitis
```
233
What are the lab findings of liver cirrhosis?
```
Normal or raised AST/ALT
Raised ALP
Raised bilirubin
Low albumin
Deranged clotting
Low sodium
```
234
How do you manage liver cirrhosis?
Stop drinking alcohol
Treat complications
Transplant (if they fit strict criteria)
235
Describe primary biliary cirrhosis and its complications.
An autoimmune condition which mainly affects women
Jaundice, pruritis, xanthelasma, hepatosplenomegaly, portal hypertension
236
Describe hereditary haemochromatosis and its complications.
An autosomal recessive disorder causing abnormal iron transport and therefore deposits in organs.
Cardiomyopathy, hyperpigmentation, diabetes, hypogonadism
237
Describe Wilson's disease and its complications.
Autosomal recessive disorder causing abnormal copper transport and therefore deposit it in organs.
Hepatitis, cirrhosis, tremor, dysarthria, dementia, renal tubular degeneration, Kayser-Fleischer rings around the eyes
238
Give some causes of portal hypertension
```
Congenital obstruction
Thrombosis
Tumour
Cirrhosis
Hepatoportal sclerosis
Schistosomiasis
Sarcoidosis
```
239
Where are there porto-systemic anastamoses?
```
Oesophagus
Rectum
Mesentry + retroperitoneal veins
Liver to anterior abdominal wall
Liver to diaphragm
```
240
What is the significance of porto-systemic anastamoses in the rectum and oesophagus in portal hypertension?
It causes venous dilations which can protrude into the lumen and become ruptured or ulcerated, causing extreme haemorrhage.
241
What are the signs or symptoms of portal hypertension?
Splenomegaly
Ascites
Spider naevi
Caput medusae
242
What is fulminant hepatic failure?
Acute decompensation of hepatic function due to increased metabolic demand
243
What are the causes of fulminant hepatic failure?
```
Hepatitis A, D, E
Drugs (isoniazid, paracetamol, ecstasy)
Wilson's disease
Pregnancy
Reye's syndrome
Alcohol
```
244
What are the symptoms and signs of fulminant hepatic failure?
```
Jaundice
Encephalopathy
High ammonium
Hypoglycaemia
Haemorrhage
Low potassium and calcium
```
245
What is hepatic encephalopathy
A reversible neuropsychiatric deficit due to the inability of the liver to remove toxic substances
246
What precipitates hepatic encephalopathy?
```
Sepsis or infection
Constipation
Diuretics
GI bleeding
Alcohol withdrawal
```
247
What are the clinical features of hepatic encephalopathy?
Raised ammonia
Flapping tremors
Intellectual deterioration
248
Give some examples of benign tumours of the liver
```
Haemangioma
Focal nodular hyperplasia
Liver cell adenoma
Liver cysts
Polycystic liver disease
Cystadenoma
```
249
What is the most common malignancy in the liver?
Colorectal carcinoma (secondary metastases)
250
What is post-hepatic jaundice?
Caused by obstruction in the biliary tree
251
What will a patent with post-hepatic jaundice complain of?
Dark urine
| Pale, fatty, offensive faeces
252
What are the lab findings in post-hepatic jaundice?
Conjugated hyperbilirubinaemia
Raised ALP
Normal or high AST/ALT
253
Give some intrahepatic causes of post-hepatic jaundice.
Hepatitis
Drugs
Cirrhosis
Primary biliary cirrhosis
254
Give some extrahepatic causes of post-hepatic jaundice
```
Gallstones
Biliary stricture or atresia
Carcinoma (e.g. head of pancreas or cholangiocarcinoma)
Pancreatitis
Sclerosing cholangitis
```
255
What are the risk factors for gallstones?
```
Female
Increasing age
Obesity
Diet
Developed country
Ileal disease or resection
Haemolytic disease (sickle cell)
```
256
When can gallstones cause biliary colic?
If they are impacted into the wall of the gall bladder. The muscle contracts around it, pain mainly after eating
257
What is the cause of ascending cholangitis?
A gallstone blocking the duct, causing infection.
258
What is the triad of symptoms in ascending cholangitis?
Right upper quadrant pain
Fever
Jaundice
259
What are the main close anatomical relations to the pancreas?
Duodenum
Common bile duct
Portal vein
Coeliac trunk
260
What are the lab findings in a patient with pancreatitis?
```
High amylase
Low calcium
Hyperglycaemia
High ALP
High bilirubin
```
261
What are the signs and symptoms of pancreatitis?
```
Severe pain
Vomiting
Dehydration
Shock or SIRS
Ecchymosis
Ileus
```
262
What are the effects on the pancreas in chronic pancreatitis?
Parenchymal destruction
Fibrosis
Loss of acini
Duct stenosis
263
What are the causes of chronic pancreatitis?
Chronic alcoholism
Cystic fibrosis
Biliary disease
264
What are the causes of acute pancreatitis?
Excessive alcohol consumption
Gallstones
GET SMASHED
265
What is the main type of pancreatic carcinoma?
Ductal adenocarcinoma
266
What are some causes of pancreatic carcinoma?
Smoking
Beta-napthylamine
Benzidine
Familial pancreatitis
267
What are the signs and symptoms of pancreatic carcinoma?
```
Obstructive jaundice
Pain
Vomiting
Carcinomatosis
Gastric outlet obstruction
Malabsorption
Diabetes
```
268
From superior to inferior, what are the anterolateral abdominal muscles?
External oblique
Internal oblique
Transversus abdominis
269
What are the borders of Hesselbach's triangle?
Inguinal ligament
Inferior epigastric vessels
Lateral border of rectus abdominus
270
What type of hernia passes through Hesselbach's triangle?
Direct inguinal hernia
271
What structure does an indirect inguinal hernia pass beneath?
Inguinal ligament
272
What structure separates the supracolic and infracolic compartments of the greater sac?
Transverse mesocolon
273
Below the arcuate line, what is the posterior surface of the rectus abdominis muscles in contact with?
Transversalis fascia
274
What artery does the left gastroepiploic artery branch off?
Splenic artery
275
Is the caudate or quadrate lobe more anterior on the inferior side of the liver?
Caudate
276
What structure is in the free edge of the lesser omentum?
Hepatic artery
277
What is the role of the intestines?
Absorb nutrients, water, and electrolytes
278
What factors increase the surface area of the intestines for absorption?
Plicae circularis - permanent mucosal folds (villi) in the small intestine
Microvilli
279
Describe the different areas of the intestinal glands.
Stem cells at the bottom which are constantly dividing.
Cell amplification just up from the base
Stem cells migrate and differentiate up the crypt
280
What is the function of paneth cells in the crypts of the intestine?
Produce antibacterial and antiviral toxins as part of the innate immune system
281
What is anoikis?
Programmed cell death when they detach from the intestinal epithelia.
282
What monosaccharides are absorbed by the gut?
Fructose
Galactose
Glucose
283
Describe the molecular structure of starch.
Amylose (linear glucose, alpha 1-4) and amylopectin (branched glucose, alpha 1-6)
284
What is the function of amylase?
Breaks alpha 1-4 bonds in starch to make glucose and maltose from amyloses, and alpha dextrins from amylopectins.
285
What is the function of isomaltase?
Breaks alpha 1-6 bonds in starch
286
What enzymes involved in breaking things down into monosaccharides are found on the brush border?
Maltase (to glucose)
Alpha dextrinase (to glucose)
Sucrase (to glucose and fructose)
Lactase (to glucose and galactose)
287
Describe the transport of monosaccharides across the epithelia of the intestines?
SGLT-1 on the apical membrane to transport glucose/galactose and sodium
GLUT5 on the apical membrane to transport fructose
Na/K ATPase on the basolateral membrane for gradient
GLUT2 on the apical membrane to transport fructose, glucose, and galactose
288
Why is it important to drink sports drinks rather than just water when heavily exercising?
They are high in sugar and salt.
The uptake of sodium generates and osmotic gradient and glucose uptake stimulates sodium uptake via SGLT-1.
This allows maximum water absorption
289
What protein breakdown products can be absorbed by the intestine?
Amino acids
Dipeptides
Tripeptides
290
What enzyme breaks down proteins in the stomach?
Pepsin (from pepsinogen)
| Protein to oligopeptides or aa
291
What activates trypsinogen?
Enteropeptidase (on the brush border)
292
What produces trypsinogen?
Pancreas
293
What is the function of trypsin?
Activate proteases
294
What are the important proteases in the small intestine?
Chemotrypsin and elastase (endopeptidases)
| Carboxypeptidase A/B (exopeptidase)
295
What allows amino acid uptake into epithelial cells of the small intestine?
Na-aa cotransporters
296
What allows dipeptide and tripeptide uptake in the small intestine?
H+ cotransporter
297
What happens to dipeptides and tripeptides when they are absorbed into intestinal epithelial cells?
Broken down to amino acids by cytosolic peptidases
298
What is the difference in sodium absorption between the small and large intestines?
Large - sodium channels (induced by aldosterone)
| Small - sodium cotransporters
299
How is calcium absorbed in the intestine?
Enters the cells by facilitated diffusion
Ca+ATPase removes it on the basolateral membrane
Vitamin D allows calbindin to transport calcium across the cell
Passive paracellular absorption in the distal part of the intestine
300
Describe how iron is absorbed in the intestine.
Mostly as haem or Fe2+. Gastric acid is important.
Absorbed across the apical membrane
Binds apoferritin to move across the basolateral membrane
Binds transferrin in the circulation.
301
What vitamins can be absorbed using sodium cotransport in the intestine?
B and C
| They are water soluble
302
What is vitamin B12 absorption dependent on?
Intrinsic factor
303
Where does vitamin B12 absorption occur?
Terminal ileum
304
Describe the three types of motility seen in the small intestine.
Intestinal gradient - between meals, pacemakers have a higher frequency proximally. Drives slow caudal progression of contents
Segmentation - occurs following meals, causing a back-and-forth movement to mix contents and allow absorption.
Peristalsis - serves to move contents down the intestine
305
What are the two types of motility seen in the large intestine?
Segmentation - also known as haustral shuttling. Occurs in the proximal colon due to the 3 bands of muscle going in different directions. Agitates and mixes the contents to absorb most of the remaining water.
Mass movement - gastrocolic reflex. Occurs 1-3 times a day, moving contents rapidly from transverse colon to rectum.
306
What is the taenia coli?
Longitudinal muscle in the large intestine
307
What is the difference between the internal and external anal sphincters?
Internal - smooth muscle, parasympathetic control
External - striated muscle, voluntary control
308
Where in the GI tract can Crohn's disease occur?
Anywhere
309
Where in the GI tract can ulcerative colitis occur?
Rectum and/or colon
310
Is there rectal involvement in Crohn's disease?
No
311
Is there rectal involvement in ulcerative colitis?
Yes
312
Is there gross bleeding in Crohn's disease?
25% of the time
313
Is there gross bleeding in ulcerative colitis?
Yes
314
Is there perianal disease in Crohn's disease?
75% of the time
315
Is there perianal disease in ulcerative colitis?
Rarely
316
Is there fistula formation in Crohn's disease?
Yes
317
Is there fistula formation in ulcerative colitis?
No
318
Is there malnutrition in Crohn's disease?
Potentially
319
Is there malnutrition in ulcerative colitis?
No
320
Is there transmural inflammation in Crohn's disease?
Yes
321
Is there transmural inflammation in ulcerative colitis?
Rarely
322
Are there granulomas in Crohn's disease?
Up to 75% of the time
323
Are there granulomas in ulcerative colitis?
No
324
Is there fibrosis in Crohn's disease?
Commonly
325
Is there fibrosis in ulcerative colitis?
No
326
Are there crypt abcesses in ulcerative colitis?
Yes
327
Are there crypt abscesses in Crohn's disease?
Rarely
328
What mucosal involvement is there in Crohn's disease?
Skip lesions
329
What mucosal involvement is there in ulcerative colitis?
Continuous
330
Are there apthous ulcers in Crohn's disease?
Yes
331
Are there apthous ulcers in ulcerative colitis?
Rarely
332
Are there linear ulcers in Crohn's disease?
Yes
333
Are there linear ulcers in ulcerative colitis?
Rarely
334
Is there friable mucosa in Crohn's disease?
Rarely
335
Is there friable mucosa in ulcerative colitis?
Yes
336
Is there cobblestone mucosa in Crohn's disease?
Yes if severe
337
Is there cobblestone mucosa in ulcerative colitis?
No
338
Is there narrowing in Crohn's disease?
Yes
339
Is there narrowing in ulcerative colitis?
Rarely
340
What investigations would you do in suspected ulcerative colitis?
```
Bloods - anaemia/serum markers
Stool cultures
Plain abdominal radiographs
Barium enema if mild
CT/MRI if complicated
Colonoscopy
```
341
What is inflammatory bowel disease?
A group of conditions characterised by idiopathic inflammation of the GI tract.
342
What is the presentation of Crohn's disease?
```
Tender mass in the right lower quadrant
Mild perianal inflammation or ulceration
Low grade fever
Weight loss
Mild anaemia
Joint pains
```
343
What is the gross pathology of Crohn's disease?
```
Hyperaemia
Mucosal oedema
Discrete superficial ulcers
Deeper ulcers
Transmural inflammation (thickened bowel wall with narrowed lumen)
Cobblestone appearance
Fistulae
```
344
What investigations would you do in suspected Crohn's disease?
Bloods - anaemia
CT/MRI scans - bowel wall thickening, obstruction, extramural problems
Barium enema - stricture problems
Colonoscopy
345
What is the presentation of ulcerative colitis?
```
Mildly tender abdomen
No perianal disease
Normal temperature
Weight loss
Mild lower abdominal cramps
Mucus and blood in stools
```
346
What are the pathological changes in ulcerative colitis?
```
Chronic inflammatory filtrate of the lamina propria
Crypt abscesses
Low number of goblet cells
Pseudopolyps
Loss of haustra
```
347
Where does ulcerative colitis begin?
In the rectum
348
What extraintestinal problems can be seen in ulcerative colitis and Crohn's disease?
MSK pain - arthritis
Skin - erythema nodosum, pyoderma gangrenosum, psoriasis
Liver and biliary tree - primary sclerosing cholangitis
Eye problems
349
What pharmacological treatments are there for ulcerative colitis and Crohn's disease?
Aminosalicylates (sulphasalazine) for flares and remission
Steroids (prednisolone) for flares only
Immunomodulators for fistulas/remission
350
What effect can surgery have in Crohn's disease?
Correct strictures and fistulas
Can't treat
As little bowel must be removed as possible
351
What effect can surgery have in ulcerative colitis?
Colectomy can cure it.
| Used when there are precancerous changes or toxic megacolon
352
What is Zollinger-Ellison syndrome?
A gastrin secreting tumour or hyperplasia of islet cells in the pancreas, leading to peptic ulcers
353
What is mass movement?
Rapid movement of colonic content
354
What can be caused by a stone blocking the cystic duct?
Cholecystitis
| Biliary colic
355
What can be caused by a stone blocking the common bile duct?
Cholangitis
| Jaundice
356
What can be caused by a stone blocking the ampulla of Vater or sphincter of Oddi?
Cholangitis
Jaundice
Pancreatitis
Steatorrhoea
357
What salivary gland mainly secretes serous fluid?
Parotid gland
358
When can swallowing solids be harder than liquids?
Any physical obstruction
Cancer
Fibrous strictures
External compression
359
What are the investigations for dysphagia?
Barium swallow
OGD
CXR for external compression
360
What is the difference in opening of the peritoneal cavity in males and females?
Males - enclosed
Females - open via the ifundibulum of the fallopian tube
361
What causes Meckel's diverticulum?
Incomplete obliteration of the vitelline duct
362
What lies in front of the lesser sac in the abdomen?
Liver
Lesser omentum
Stomach
363
What structures lie anteriorly to the foramen of Winslow (epiploic foramen)?
Common hepatic artery
Common bile duct
Portal vein
364
What hormone stimulates enzyme rich pancreatic secretions?
Cholecystikinin
365
What hormone stimulates bicarbonate rich secretions from the pancreas?
Secretin
366
What are obligate anaerobes?
| Give an example.
Bacteria which die in the presence of oxygen.
| Clostridial organisms.
367
What are facultative anaerobes?
| Give an example.
Organisms which prefer oxygen but can live without it.
E. Coli
Staphylococcu
368
What are obligate aerobes?
| Give an example.
Organisms which must have oxygen to survive.
Pseudomonas
Mycobacterium tuberculosis
369
What are the anaerobic zones of the gastrointestinal tract?
Parts of the mouth (deep in taste buds, biofilm around teeth, peridontal pockets in peridontal disease)
Small bowel
Colon
370
What are the functions of human colonic bacteria?
Synthesise and excrete vitamins K, B12, thiamine
Prevent colonisation by pathogens
Kill non-indigenous bacteria
Stimulate MALT development
Stimulate production of natural antibodies
371
Describe noma oris.
An oro-facial gangrene caused by commensal organisms in the mouth when the person is malnourished, dehydrated, immunocompromised, or systemically unwell.
372
Describe oral thrush.
Candida albicans infection in the mouth creating white plaques which can be easily removed, leaving red, sore areas.
Seen in patients taking antibiotics, diabetes, inhaled steroids, newborns
373
Why are people with prosthetic heart valves at greater risk of endocarditis due to Strep viridans?
Strep viridans causes transient bacteraemia in many people when they brush their teeth. It is unable to stick to cells due to their protective membranes.
Prosthetic heart valves don't have these membranes, so the bacteria can more easily stick to them and colonise, causing endocarditis.
374
What is the difference between bacteraemia and septicaemia?
Bacteraemia - bacteria are cleared quickly from the bloodstream.
Septicaemia - bacteria multiply in the bloodstream, symptoms of sepsis develop.
375
What are the principles in prophylactic antibiotic treatment for surgery on the gut?
An antibiotic which kills anaerobes with a broad-spectrum antibiotic
376
How does lactobacillus in the vagina prevent colonisation by other bacteria?
Converts glycogen to lactic acid, creating an acidic environment which other bacteria can't grow in.
377
What is the most common cause of urinary tract infections?
E. coli
378
What types of bacteria don't cause urinary tract infections?
Gram positive bacilli (lactobacillus)
| Gram negative cocci (gonococci)
379
Which organisms causing a urinary tract infection would you expect to have underlying pathology associated with?
Klebsiella
Proteus
Pseudomonas
380
What are the symptoms of tetanus?
```
Muscle spasm
Risus sardonicus (sardonic smile)
Lockjaw
Opisthotomas
Spasm of the larynx
```
381
What makes up the superior wall of the inguinal canal?
Internal oblique and transversus abdominis muscles
382
What makes up the anterior wall of the inguinal canal?
Aponeurosis of the external oblique and internal oblique.
383
What makes up the lower wall of the inguinal canal?
Inguinal and lacunar ligaments
384
What makes up the posterior wall of the inguinal canal?
Transversalis fascia and the conjoint tendon
385
Give the borders of Hesselbach's triangle.
Medial: lateral margin of the rectus sheath (Linea semilunaris)
Inferior: inguinal ligament
Superolateral: inferior epigastric vessels
