Upper GI Tract Flashcards
- Give a brief definition of digestion
- Give a brief definition of absorption
Process of breaking down macromolecules to allow absorption
Process of moving nutrients and water across a membrane
- Describe the distribution in the number of teeth in the oral cavity
8 incisors
4 canines 8 premolars 12 molars
- What is the largest jaw muscle and the muscle in charge for biting?
- What are the 2 enzymes released by the salivary glands?
Masseter
Lingual lipase (fat digestion) Salivary amylase (carbohydrate digestion)
- What are the intrinsic muscles of the tongue responsible for?
- What are the extrinsic muscles of the tongue responsible for?
Fine motor control and moving food
Gross movement of tongue Assists mechanical digestion
- Which vertebrae is the oesophagus between?
- What are the three subdivisions of the oesophagus?
C5 and T10
Cervical oesophagus - cricopharyngeal muscle to suprasternal notch Thoracic oesophagus - suprasternal notch to diaphragm Abdominal oesophagus - diaphragm to cardia of stomach
- What is the function of the oesophagus?
- How does the structure of the oesophageal epithelium relate to its function?
Conduit for food, drink and swallowed secretions from pharynx to stomach
Non-keratinising Wear & Tear lining - to withstand extreme temperatures and aid texture Lubrication - mucus secreting glands (goblet cells)
- What is the Z line in the oesophagus?
Line where the pink mucosa of the oesophageal sqaumous epithelium meets the red mucosa of the gastric columnar epithelium
- What is the significance of this Z line in Barrett’s oesophagus?
- What is Barrett’s oesophagus?
Here, the epithelium of the lower oesophagus undergoes metaplasia
So the gastric mucosa extends into the oesophagus, meaning it would be important to determine the Z line in these cases
when the separation between pink (oesophagus) and red (stomach) mucosa is higher than normal
- Is the upper or lower oesophageal sphincter a true sphincter?
- Is skeletal muscle found in the upper or lower oesophagus?
- Is smooth muscle found in the upper or lower oesophagus?
upper
both
lower
- Why does this epithelial transition at the gastro-oesophageal junction occur and how does this develop to cancers?
Acid reflux means that the lower oesophagus is more acidic than normal
To cope with this, the squamous cells above the gastro-oesophageal junction become columnar epithelium- columnar are more resistant to acid This change to columnar epithelium makes the cells unstable, leading to dysplasia and then becomes cancers
- Why is a hiatus hernia a risk factor for developing cancer of the oesophagus?
Because the opening of the diaphragm causes it to be larger and so there is a portion of the stomach that slips into the chest which prolongs exposure to the lower oesophagus, associating with acid reflux
- How does the anatomical orientation of the stomach to the oesophagus reduce the risk of acid reflux?
Stomach lies at an angle to the oesophagus
Other ligaments also suspend the gastro-oesophageal junction at an acute angle to prevent acid reflux
the diaphragm also prevents reflux
- what are gastric folds
- Why are the gastric folds present?
coiled tissue in mucosal and submucosal layers of stomach
To increase the surface area of the epithelium of the gastro intestinal tract so that more amount of digestion and more absorption can occur
What happens in the oral phase of swallowing?
Chewing and saliva prepare bolus
Both oesophageal sphincters constricted
What happens in the Pharyngeal Phase?
Pharyngeal musculature guides food bolus towards oesophagus
Both oesophageal sphincters open