GI Week 2-4 Quiz Flashcards
On the attached image which of the labels corresponds to the aponeurosis of the transversus abdominis muscle?
A. A
B. B
C. C
B. B
The anterolateral abdominal muscles have flattened tendons called aponeuroses.
These look white in contrast to the colour of the muscle fibre.
Apart from the order in which the muscles lie (superficial to deep) you can identify the muscles from the orientation of their fibres.
A is a tendinous intersection in the rectus abdominis muscle
B is the aponeurosis of the transversus abdominis muscle
C is the aponeurosis of internal oblique
Where in the GI tract will you find stratified squamous epithelia?
A. Proximal stomach
B. Terminal ileum
C. Proximal anal canal
D. Distal anal canal
D. Distal anal canal
Most of the gut is lined with simple columnar epithelium but the oesophagus and distal anus is lined with stratified squamous. Stratified squamous epithelium is good at resisting frictional forces and this helpful because contents of the gut in the oesophagus and distal anus are at their most solid (predigested in the oesophagus and desiccated in the anus).
At average flow rates the tonicity of saliva is best described as ……?
A. Hypotonic
B. Hypertonic
C. Isotonic
A. Hypotonic
When saliva is produced in the acinus of the salivary gland it is close to the tonicity of plasma (isotonic). However as it moves along the ducts of the salivary gland, the ductal cells modify the composition of saliva and there is a net removal of ions (Na, Cl) and the resulting solution is hypotonic.
As flow rates of saliva increase, the contact time the ductal cells have with the initially isotonic solution is less and less modification occurs. Therefore at higher flow rates saliva becomes less hypotonic (compared with lower flow rates).
What happens to the concentration of Bicarbonate ions (HCO3-) at higher flow rates of saliva?
A. Decrease
B. Increase
C. Stay the same
B. Increase
HCO3- ions are the exception in the production of saliva in that they actually increase at higher flow rates. HCO3- is secreted by the ductal cells in proportion to the flow rates.
This is different to the other ions in saliva, where a higher flow rate results in less movement across the ductal cells (less ductal modification).
Where in the GI tract are digestive enzymes first secreted?
A. Duodenum
B. Jejenum
C. Stomach
D. Oral cavity
D. Oral cavity
The oral cavity is the first environment in the GI tract where digestive enzymes are released (salivary amylase and lipase). Following that the stomach releases enzymes to break down protein and fat. The main producer of digestive enzymes is the pancreas which releases its enzymes into the duodenum via the major pancreatic duct.
The anterior boundary of the lesser saci s partially formed by the …..?
A. Anterior surface of the Pancreas
B. Posterior surface of stomach
C. Inferior surface of the Diaphragm
B. Posterior surface of stomach
The anterior boundary of the lesser sac is formed by the lesser omentum, the posterior surface of the stomach and even part of the greater omentum.
The diaphragm and pancreas (or at least the peritoneum covering the anterior surface of the pancreas) form part of the posterior boundary of the lesser sac.
The paracolic gutters are channels within the peritoneal cavity that connect the supracolic and infracolic compartments. Where do they lie?
A. Lateral to the mesentery of the small bowel
B. Between the rectum and the uterus
C. Lateral to the ascending and descending colon
C. Lateral to the ascending and descending colon
The paracolic gutters lie lateral to the ascending and descending colon (between the lateral aspect of the ascending and descending colon and the lateral abdominal wall).
The space between the rectum and the uterus (obviously only in females) is called the rectouterine pouch (pouch of Douglas).
What is the main reason a strangulated abdominal hernia requires urgent medical attention?
A. Patient experiencing extreme pain
B. Hernia is irreducible
C. Blood supply to hernia is compromised
C. Blood supply to hernia is compromised
A strangulated hernia is one where the blood supply to the contents of the hernia is compromised. This needs to be treated as an emergency otherwise the contents will undergo necrosis which could prove fatal for the patient.
This question was testing understanding of the term strangulated as opposed to the term incarcerated which is another way of saying the hernia is irreducible (stuck).
Where do the majority of digestive enzymes enter the gastro-intestinal tract?
Drop an answer pin by clicking on the image below.
Although there are some amylases and lipases in saliva, the majority of digestive enzymes are produced by the pancreas and released into the duodenum.
Classical appendicitis presents with vague peri-umbilical abdominal pain which some time later localises to the Right iliac fossa. Why does this pain eventually LOCALISE to the right iliac fossa?
A. Inflammation of visceral peritoneum enveloping the appendix
B. Inflammation of parietal peritoneum near the appendix
C. Rupture of appendix
B. Inflammation of parietal peritoneum near the appendix
The answer is inflammation of the parietal peritoneum near the appendix.
This question is related to how the different elements of the peritoneal cavity respond to noxious stimuli.
The peritoneal cavity is defined as the potential space between the visceral and parietal peritoneum. The visceral and parietal peritoneum develop slightly differently (although they form a continuous structure they develop along different embryological paths) with the visceral peritoneum not being able to localise pain and the parietal peritoneum being able to localise pain.
When the appendix initially becomes inflamed, the visceral peritoneum (that envelops it) is stimulated but cannot localise the pain. Being a midgut structure it refers this pain as a vague peri-umbilical pain (foregut structures refer to the epigastric area and hindgut to the supra-pubic area). However once the inflammation has progressed the parietal peritoneum in the region of the appendix can be stimulated and this will localise the pain. The pain is then felt more specifically in the right iliac fossa.
In the pharyngeal phase of swallowing, what structure helps prevent reflux of food into the naso-pharynx?
A. Epiglottis B. Pharyngeal constrictors C. Upper oesophageal sphincter D. Soft palate E. Vocal cords
D. Soft palate
The soft palate elevates to seal off the naso-pharynx. The pharyngeal constrictors effectively propel the food towards the oesophagus. The upper oesophageal sphincter prevents reflux of material from the oesophagus into the pharynx and the vocal cords adduct to protect the airway.
Indicate the internal oblique muscle on the attached image (which views the abdomen on its right side)
Drop an answer pin by clicking on the image below.
Internal oblique has fibres that pass superiorly and medially. You can also locate it because it lies directly underneath the external oblique (whose fibres run in a ‘hands in pockets’ direction).
Where in the gut wall is Meissner’s plexus found?
A. Mucosa
B. Submucosa
C. Muscularis propria
D. Serosa
B. Submucosa
Meissner’s plexus is also known as the submucosal plexus and is one of the two main plexus’ of the enteric nervous system. As its (other) name implies it lies in the submucosa. Auerbach’s plexus (myenteric plexus) is found in between the inner circular and outer longitudinal muscles of the muscularis propria.
During embryological development of the gut, which artery forms the axis of the midgut loop that herniates?
A. Coeliac trunk
B. Inferior mesenteric artery
C. Superior mesenteric artery
C. Superior mesenteric artery
The SMA forms the axis of the midgut loop that physiologically herniates during development. The SMA remains the arterial blood supply for the midgut derivatives (second part of the duodenum to 2/3 the length of the transverse colon)
Which of these is NOT a function of the stomach?
A. Protein absorption
B. Protein denaturing
C. Protein digestion
A. Protein absorption
The stomach releases HCl which helps to denature proteins and also releases pepsin (a protease enzyme) which begins the process of protein digestion. The stomach is not a site for much absorption, nutrients are absorbed mainly in the proximal small intestine.
Each label on the attached diagram is the location of an abdominal hernia.
Which label indicates a hernia that occurs below the inguinal ligament and is more common in females than in males?
A. A
B. B
C. C
D. D
D. D
Although not entirely clear on the diagram, the only label that is below the inguinal ligament is D. D is a femoral hernia and these are more common in females than in males because of the anatomy of the female pelvis. they are rare but because of the narrow femoral canal that they herniate through, incarceration and strangulation are not uncommon.
Each label on the attached diagram is the location of an abdominal hernia.
Which label indicates a hernia that affects young infants and usually spontaneously resolves in the first few years of life?
A. A
B. B
C. C
D. D
B. B
Label B is an umbilical hernia.
Due to the herniation of the midgut through the umbilical ring during embryological development, this area represents a potential weakness in the abdominal wall. Failure of closure of the umbilical ring allows these hernias to arise. The hernias are usually just observed as most spontaneously reduce within the first few years of life.
Concerning the autonomic nervous system in the gut.
Where do the parasympathetic PRE-GANGLIONIC fibres synapse in the gut?
A. Pre-vertebral ganglia
B. Sympathetic chain
C. Visceral wall
C. Visceral wall
The parasympathetic pre-ganglionic fibres synapse in the wall of the innervated viscera. There is then a very short post-ganglionic fibre which also sits within the wall of the viscera.
The sympathetic outflow in the gut passes through the sympathetic chain and then synapses in one of the pre-vertebral ganglia. Its post-ganglionic fibres are longer and extend to the walls of the viscera to innervate them.
