Alimentary Flashcards
Name x5 functions of the gastrointestinal tract
Digestion Absorption Hormone regulation Immunity Excretion
Which part of the colon passes down to the anus?
Sigmoid colon
Why is the gastrointestinal tract known as an external membrane?
It can be accessed through sphincters without crossing a membrane.
Recall the common signs and symptoms of gastrointestinal tract disease (general and upper)
General GI disease: Malaise, rapid weight loss, anorexia, anaemia
Upper GI tract: Haemoptysis, malaena, nausea, vomiting, dysphagia, odynophagia, heartburn
What is the difference between signs and symptoms?
Signs = externally visible Symptoms = internally experienced by the patient. Only noticeable to the patient.
Define malaise
Being generally unwell from an indeterminable cause.
Define malaena
Black tarry stool
What is malaena usually due to?
Upper GI bleeding
Define vomiting
Rapid ejection of stomach contents
Define odynophagia
Sensation of pain whilst swallowing food/ fluid.
What usually causes heartburn?
Acid regurgitation
Define belching
Excess air in the stomach escaping through the mouth
Define ‘referred pain’
When pain is felt in one location of the body but felt in another.
What is epigastric pain?
Discomfort in the central upper abdomen
In which quadrant is most liver and gallbladder pain usually felt?
In the right upper quadrant.
Name x5 indications a patient may present with for hepatobiliary disease
Pain in the right upper quadrant Biliary colic Jaundice Ascites Pale stool Dark urine
What happens in a biliary colic
Contraction of the gallbladder
Define jaundice
Yellowing of the skin, sclera and mucus membranes
What causes jaundice?
Increased amounts of circulating bilirubin
Name x1 hallmark symptom of liver failure
Jaundice
What causes dark urine?
Elevated conjugated bilirubin
What is the name of the substance which is responsible for giving poo its brown colour?
Stercobilin
Give x3 causes of ascites
Liver failure
Cancer
Malnutrition
What is ascites?
Accumulation of fluid in the abdominal cavity (>30mL).
Define steatorrhoea
Excess fats in stool caused by e.g. reduced lipase activity
Name 4 symptoms/signs of Mid GI tract disease
Diarrhoea
Steatorrhoea
Abdominal pain
Abdominal distension
Name x4 symptoms/signs of Lower GI tract disease
Abdominal pain
Rectal bleeding
Constipation
Diarrhoea
Give x2 causes of incontinence
Neural damage to anal sphincters
Mechanical damage to anal sphincters
Define cachexia
Muscle wasting
What is the term for enlargement of the lymphoid tissue
Lymphadenopathy
Define Koilonychia
Spooning of nails
In which quadrant is the liver located?
The upper right quadrant
Define haemorrhoids
Swollen superficial blood vessels (internal = painless, external = discomfort).
Define fistula
Alternate pathway e.g. anal fistula = not through the entire anal canal.
Define fissure
Tear/ ulceration of the mucosal lining
Define proctitis
Inflammation of the inner rectum
Name one diagnostic technique used in identifying proctitis
Sigmoidoscopy
Name 3 key factors to approaching pain
History
Examination
Investigations
What is the abbreviation in investigating pain?
SOCRATES
How will the signs of an upper gastrointestinal bleed (e.g. oesophagus) differ from a lower gastrointestinal bleed?
Upper GI bleed = malaena and haematemesis
Lower GI bleed = blood in urine/ stool; has not been modified by GI enzymes.
How many teeth does an adults have normally?
32 teeth
How many incisors does an adult have?
8
How many canines does an adult have?
4
How many pre-molars does an adult have?
8
How many molars does an adult have?
12
Which teeth are responsible for grinding the teeth down into smaller pieces?
Premolars and molars.
What is the proper name for the jawbone?
The mandible
Which is the largest muscle in the jaw and the one responsible mainly for biting?
The Massater muscle
Which are the two different places that the oral cavity can lead?
Lungs and stomach
Which are the two muscles which control whether oral contents go to the lungs or down the oesophagus to the stomach?
Epiglottis and the upper oesophageal sphincter
Describe the two types of muscle making up the upper oesophageal sphincter
Constrictor pharyngeus medius
Constrictor pharyngeus inferior
Describe the components of the lower oesophageal sphincter
Internal component = makes up circular smooth muscle of the oesophageal wall.
External component = makes up the diaphragm (voluntary).
Describe the pressure differences between the stomach and the pancreas
The stomach is under positive pressure whereas the oesophagus is mainly under negative pressure.
What is the epithelial lining arrangement of the oesophagus?
Non-keratinising stratified squamous epithelium until reaching the lower oesophageal sphincter (LOS), where the lining becomes simple columnar.
How many phases of swallowing are there and name each one.
There are 4 phases of swallowing: 0 - oral phase 1 - pharyngeal phase 2 - upper oesophageal phase 3 - lower oesophageal phase
Describe segmentation in the stomach
Pushes fluid towards the pyloric sphincter and solid chyme back to the body of the stomach.
What is the main protein secreting cell of the stomach?
Chief cell. Will see many RER and GA.
Which cell in the stomach secretes pepsinogen?
The Chief cell.
Which cell in the stomach secretes HCl?
The Parietal cell.
What structures will you see in the parietal cell?
Mitochondria, canaliculi, long cytoplasmic tubulovesicles which contain H+/K+ ATPase.
What will you see in an active parietal cell?
Tubulovesicles fuse with the canaliculi
How would inhibition of carbonic anhydrase influence acid secretion in the stomach?
This would decrease the amount of H+ being formed
Decrease HCl
Name one treatment to decrease HCl concentration in the stomach
Carbonix anhydrase inhibitor
What activates the breakdown of pepsinogen to pepsin?
HCl.
What is the most difficult to digest out of carbohydrates, protein and fats?
Protein. Pepsin’s role is to breakdown proteins into smaller fragments.
Name one substance which stimulates HCl production
Histamine (released from chromaffin cells)
Name the three phases of gastric secretion
Cephalic, gastric, intestinal
Name the three substances which are released from the intestine and inhibit stomach action
Cholecystokinin, secretin, gastric inhibitory peptide
What is the mechanism of Omeprazole?
Inhibits the Proton pump. = targets H+/K+ ATPase pump.
How does blood enter the liver?
Dual blood supply
Hepatic artery
Hepatic portal vein
What percentage of resting cardiac output goes to the liver?
25%
What is the difference between the hepatic artery and hepatic portal vein roles?
Hepatic artery: oxygenates liver
Portal vein: Contains everything absorbed from the small intestine and colon
What is the functional unit of the liver?
Acini
Give x2 disadvantages of switching from carbohydrate to fat metabolism
Fats provide less energy and fat metabolism is a slower process.
What are the products of transamination between alanine and a-ketoglutarate?
Pyruvate and glutamate
Which lipoprotein has the highest fatty acid content?
VLDL
What is segmentation?
Mixes contents of the lumen through contraction of the lumen circular muscle.
Alternate contraction and relaxation of circular muscle in the gut wall. Major effect = mixing and mechanical breakdown. Minor effect = propulsion.
Give one function of segmentation
Mixes enzymes with chyme
Where does most digestion of carbohydrates occur?
In the small intestine
What is the role of pancreatic amylase?
To digest COMPLEX carbohydrates to disaccharides or oligosaccharides (not monosaccharides; this is done by other enzymes).
What is the function of emulsification?
To increase the surface area of digestion
Through which two pathways are triglycerides made from FFAs and monoglycerides?
Monoglyceride acylation
Phosphatidic acid pathway
Segmentation involves sequential contraction. True or false.
False; involves random contraction
What is the function of bile salts?
Solubilise the products of lipid digestion
Islet tissue is most abundant in which part of the pancreas?
The tail
Can you swallow whilst upside down?
Yes; peristalsis is stronger than gravity.