Gastrology Flashcards
What is a choledochal cyst
sever liver dysfunction
+ / - abdominal mass
large common channel drainage pancreatic and bile duct - juices cause wall destruction this with stenosis cause cysts
What would be seen in protein-losing enteropathy
high levels of alpha-1 antityrptase in stool
Hypoalbuminae
Name a type of protein-losing enteropathy
lymphangiectasis
high levels of alpha1 antitryptase in stool
Hypoalbuminae
Loose stools
Embryology of diaphragm
formed between 5th and 7th week
Fusion of septum transverse, pleuroperitoneal folds, cervical somites
Septum transverse - central tendon
Pleuroperitoneal folds - parietal membranes surrounding viscera
Cervical somites - C5-C7 muscular components
Embryology of GI tract
Endoderm - epithelial lining of GI tract
Mesoderm - smooth muscle
ectoderm - enteric nervous system
What structures make up the foregut
Pharynx
Oesophagus
Stomach
Proximal duodenum
What structures make up mid gut
forming distal duodenum
Small bowel
Distal colon
What structures Make up hind gut
Distal colon
Rectum
Timeline of rotation of GI tract
5th week - intestine elongates and form loop - protrudes into umbilicus
6th week - stomach and duodenum rotate 90 degrees
8th week - duodenum and jejunum herniate further from superior mesenteric artery
11th week - GI retracts into abdomen
What is villous atrophy
Villi surrounding small intestine erode away
What causes villious atrophy
Coeliac disease
NSAIDS
Giardsis
H. pylori gastritis
What produces gastric acid
Parietal cells in the stomach
Maintained by H+ / K+ / ATPase pump
What is stomach pH ?
around 2
1.5-3.5
Pathophysiology of gastric acid production
Sodium and chloride cells secreted from parietal cells to canniculis
Negative gradient - K+ and Na cells move down into it
H20 and CO2 from to make carbonic anhydrase
Carbonic anhydrase dissociates - H + move out of cells into stomach lumen, Na and K+ move into cells - leaves Cl and H+ ions in cannaiculis
What increases gastric cell production
Vagal nerve stimulation
Gastrin release
Histmaine release
Where is the gastrin released from
Released from G cells in pyloric antrum and duodenum
How does gastrin work
Directly- Stimulates parietal cells to release HCL
Indirectly work on enterochromaffin cells - binds to CCK2 receptors -> releases histamines -> parietal cells
Where is pepsinogen released
chief cells
Other functions of gastrin
Causes chief cells to release pepsinogen -> pepsin
Promotes muscle contraction
Strengthens antrum contractions - > increases rate of gastric emptying
Induces pancreatic secretions
What factors increase gastrin
partially digested proteins
Hypercalcaemia
Stomach distension
Vagal stimulation
What inhibits gastrin
Too much HCl - negative feedback
Glucagon
Somatostatin
GIP / VIP
What pH of the duodenum
7-8
What released CCK
presence of proteins, fats and low pH
Where is CCK released from
I cells of duodenum
Where is secretin released from
s cells of duodenum
How does CCK act
inhibits smooth muscle contractions from stomach - slow process of food movement
acts on pancreas to increase digestive enzyme - > protease and amylases (break down of carbs)
How does secretin acts
Released due to carbs in duodenum
Increase production of bicarbonate ions from pancreases and liver (with CCK)
What does bicarbonate do
Binds to H+ ions in chyme
Rise pH
Cause of acute pancreatitis
Mumps - need to test rNA
Risk factors of pyloric stenosis
Bottle feeding
Male
Macrolide use
White ethnicity
Family Hx
Smoking
Prematurity
In pyloric stenosis what affect does hypochlormia have?
Increases plasma bicarbonate levels as there is an increase in excretion of bircarbonate to maintain pH
Urine is alkaline
In pyloric stenosis what affect does hypovolaemia have
Causes stimulation of aldosterone which acts of distal tubule -> retain Na and excrete K+ and hydrogen ions = causing hypokalmaia
What defiency is likely to be present in binary atresia
Fat-soluble vitamin defiency
A, D, E, K
Reduced absorption lack to bile
Pathophysiology biliary areas
Progression of obliteration of extra-hepatic biliary duct -> obstruction of bile flow
Features of biliary atresia
jaundice
pale stools
dark urine
hepatemegly
Where is mUCIN 2 produced
goblet cells of intestines
Action of Mucin 2
Act to organise two mucus layers
How does lack of fibre affect Mucin 2
increase in inner layer mucus degradation due to lack of energy from intestinal microbes
Commonest cause of acute pancreaitis
gall stones - most common cholesterol
When do you complete an UGI biopsy if suspecting coeliac disease with duodenal biopsy
If tTG is <10 time s upper limit of normal
What HLA is ass. with coeliac disease
HLA-DQ2 - DQ 8 - test if tTG >10 times upper limit of normal
Histological findings of biliary atresia
bile duct proliferation and fibrosis
portal tract oedema a
inflammation
bile duct bile plugs
Which type of cells act as a protective layer in stomach
mucus neck cells
Produce bicarbonate and mucus
Protect from mechanical trauma from peristalsis auto digestion acid
Where is somatostatin produced
D cells in stomach
D cells in pancreas
Inhibits everything
What are the 6 secretions from the stomach
Hcl - parietal cells -> absorb vit B 12 by intrinsic factor
Pepsinogen - chief cells
Gastrin - G cells
Moucous - goblet cells mucus cells - protective, alkaline
Somatostatin - delta cella
Histamine - enterchromffain cells - > pepsinogen
What is pernicious anaemia
Autoantibodies against parietal cells in stomach -
reduced intrinsic factor
reduced vit B12
macrocytosis
Where does CCK act in pancreas
acincar cells
Where does secretin act in pancreas
duct
Vasoactive intestinal peptide
Relaxes smooth muscle
Vasodilation of blood cells
Decrease gastric motility and secretions
Glucose dependent insulinotropic peptide
Gastric inhibitory peptide
where is it secreted from
K cells upper part of SI
GIP function
helps release insulin when eaten glucose
motilin
Pro - motility
from M cells of upper part of SI
What is octreotide
mimics somatostatin
What is octreotide used for
Treatment for
oesophageal varice
gastronoma
insulinoma
glucagonoma
What absorbs first - iron folate vit b12
Iron your clothes - iron
Fold you clothes - folate
then you put them in your closest - cobalamin vit b12
