0% GI transport + GI Problems and Pharmacological solutions - swallowing and its phases

Question 1

What is the first phase of swallowing and what does it involve?

Answer 1

Buccal:

Moistening the food with saliva

Breaking down food via mastication

Formation of bolus

Then pushed backwards towards the oropharynx

Question 2

What is the second phase of swallowing and what does it involve

Answer 2

Pharyngeal

Conveys bolus from the oropharynx down to the
oesophagus

Controlled by the vagus nerve via Ach on Nicotinic
receptors

UOS relaxes

Question 3

What is the third phase of swallowing and what does it involve?

Answer 3

Oesophageal

From oesophagus to the stomach by
peristalsis

initiated by swallowing and passes
right throughout

Secondary peristalsis- initiated by
local distension, from distension
point stomach

LOS relaxes