Deglutition

Hello Everyone!

 Today lets discuss deglutition. Human's love this process :) .

1.What is Deglutition?

Process by which food  moves from mouth into stomach.

2.What are the different stages?

Oral

Pharyngeal

Oesophageal

3.Is it voluntary?

No, Only the Oral stage is voluntary.

4.What is the oral stage?

Bolus is pushed by the tongue into the Oropharynx.

What is the pharyngeal stage?

It is a involuntary stage. Here bolus moves from pharynx to oesophagus. Bolus has got 4 paths in pharynx

Back in mouth: This is prevented by position of tongue against soft palate.
Upward into nasopharynx: Prevented by elevation of soft palate.
Forward into larynx: Prevented as follows(Only if you don’t talk while swallowing food :P

• Approximation of vocal cords
• Forward and upward movement of vocal cords
• Backward movements of epiglottis to seal opening of larynx
• This causes Deglutition Apnea

Enters the Oesophagus:

• Pharyngoesophageal sphincter relaxes.
• Also upward movement of larynx stretches opening of oesophagus.

What is Oesophageal Stage?

Food from oesophagus enters the stomach.Peristaltic waves aid in this process.Two types of Waves are seen:
Primary peristaltic contractions
Secondary peristaltic contractions

What is the role of lower oesophageal sphincter(LES)?

It undergoes Receptive Relaxation. i.e. it relaxes only upon entry of bolus. Otherwise it is constricted.We have 2 clinical conditions associated with it:

1.Achlasia cardia : Failure of sphincter to relax during swallowing. Causes accumulation of food in oesophagus.

2.Gastroesophageal Reflex disease(GERD): Due to incompetence of LES. Acidic content from stomach regurgitates back into pharynx.

That's all,
Thank you,
Chaitanya Inge