Upper GI Tract Physiology

Question 1

Describe the voluntary phase of deglutition

Answer 1

Food is chewed between teeth and mixed with salivary enzymes

The tongue moves food to the back of the mouth

Question 2

Describe the pharyngeal phase of deglutition

Answer 2

The soft palate moves upwards to stop food entering the nasal cavity
The tongue moves food towards the pharynx and larynx
The epiglottis closes the trachea and the glottis constricts the trachea
Food moves past the pharynx and larynx
The oesophageal sphincter opens

Question 3

Describe the oropharyngeal phase of deglutition

Answer 3

Peristasis pushes food down the oesophagus
The soft palate and the epiglottis move upwards
The glottis relaxes and the traches dilates

Question 4

Describe receptive relaxation in the oesophagus

Answer 4

As food is approaching the lower oesophageal sphincter, the smooth muscle relaxes to dilate the lumen. This allows food to enter the stomach without pressure increasing

Question 5

Which nerves control deglutition?

Answer 5

Cervical nerves innervate pharynx and larynx
Vagal nerve innervates longitudinal and circular muscle of the upper oesophagus and the plexus which controls the lower oesophagus

Question 6

Which cells mediate peristalsis?

Answer 6

Interstitial cells of Cajal

Question 7

Where in the stomach are the biggest peristaltic waves?

Answer 7

Pylorus

Question 8

Describe retropulsion

Answer 8

Food is pushed from the duodenum into the pylorus