Gastro - Upper GI Flashcards
Give a brief definition of digestion
Process of breaking down macromolecules to allow absorption
Give a brief definition of absorption
Process of moving nutrients and water across a membrane
Label the diagram of the components of the GI system
Label the diagram showing the layers of the gut wall
g - Epithelium
f - Lamina propria
e - Muscularis mucosae
d - Submucosa (connective tissue)
c - Longitudinal muscularis
b - Circular muscularis
a- Serosa/Adventia (connective tissue +/- epithelium)
Describe the distribution in the number of teeth in the oral cavity
32 teeth
8 incisors
4 canines
8 premolars
12 molars
What is the largest jaw muscle and the muscle in charge for biting?
Masseter
What are the 2 enzymes released by the salivary glands?
Lingual lipase (fat digestion)
Salivary amylase (carbohydrate digestion)
What are the intrinsic muscles of the tongue responsible for?
Fine motor control and moving food
What are the extrinsic muscles of the tongue responsible for?
Gross movement of tongue
Assists mechanical digestion
Which vertebrae is the oesophagus between?
C5 and T10
What are the three subdivisions of the oesophagus?
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?
Conduit for food, drink and swallowed secretions from pharynx to stomach
How does the structure of the oesophageal epithelium relate to its function?
Non-keratinising squamous epithelium
Wear & Tear lining - to withstand extreme temperatures and aid texture
Lubrication - mucus secreting glands
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?
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
Is the upper or lower oesophageal sphincter a true sphincter?
Upper
Is skeletal muscle found in the upper or lower oesophagus?
Both
Is smooth muscle found in the upper or lower oesophagus?
Lower
Why does this epithelial transition at the gastro-oesophageal junction occur and how does this develop to cancers?
Acid reflux means that the upper oesophagus is more acidic than normal
To cope with this, the squamous cells above the gastro-oesophageal junction become columnar epithelium
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 on the fringe oesophageal ligaments to prevent acid reflux