GI Tract II Flashcards
What is the function of enzymes on food particles
increase SA - volume ratio
Where does mastication occur
mouth
Why is food smashed
increase SA, reduce damage to GI tract
What does the presence of the bolus initiate
reflex inhibition of muscles of mastication
Describe the process of chewing
muscles of mastication contract and elevate, bolus compressed against mouth lining
What are the muscles of chewing/mastication
mandible, teeth
What is chewing
movement of the mandible, open and closure of teeth
What is the oesophagus lined with
mucosa
What are the lower two thirds of the oesophagus made of
smooth muscle
What is the upper third of the oesophagus made of
skeletal muscle
Describe where the oesophagus is placed/lies
runs posterior to trachea, runs anterior to vertebrae, pierces the diaphragm
Describe primary peristalsis
peristalsis - starts in oropharynx - spreads to oesophagus
What is secondary peristalsis
moves any food left over
What triggers secondary peristalsis
distension of oesophagus
What nerve controls smooth muscle of oesophagus
cranial nerve 10 - vagus
Name a disease of the oesophagus
Barrett’s oesophagus
What are the symptoms of Barrett’s oesophagus
NO symptoms
TRUE or FALSE - metaplasia occurs in Barrett’s oesophagus
True
Describe the metaplasia in barrett’s oesophagus
abnormal change of cells lining the lower oesophagus
What cells are transformed in Barrett’s oesophagus
normal stratified squamous epithelium becomes simple columnar epithelial cells with goblet cells
What is Barrett’s oesophagus associated with
gastric reflux, heartburn
How is Barrett’s oesophagus treated
proton pump inhibitor
What is the effect of a proton pump inhibitor treating Barrett’s oesophagus
inhibits production of acid
How does food enter the stomach
forms concentric circles around orad portion of stomach
What is the vagovagal reflex
stomach relaxes and stretches out
What does the vagovagal reflex reduce
muscular tension in stomach
Describe the structure of the mucosa
folded
Why are the mucosa folded
expand inner lining of stomach
What is the mucosa
membrane with layers of epithelial cells
What do the gastro glands produce
gastric acid
Where are the gastro glands found
entire lumen of the stomach
What do G cells secrete
gastrin
What does gastrin control
emptying of stomach
