PHYSL210B Lecture 8: Digestion Lecture 2

• School: University of Alberta
• Department: Physiology
• Course: PHYSL210B
• Professor: Jamie Mitchell

Document Summary

Body likes to work on fine small particles because it makes digestion more efficient. Round mastication chewing swallowing: oral phase- voluntary. Using the tongue to make the food roll up in a ball bolus. Closing the lips and clenching teeth prevent bolus from going out of the mouth. Tip of the tongue presses firmly against behind the front tip and a wave like motion propels the food back into the pharynx. Comes in contact with mucosa in the pharynx and that initiates reflex action: pharyngeal phase- involuntary. The larynx is raised and closes off the entrance to the trachea. Multiple muscles in the pharynx contract against the bolus and propel it forward (100mmhg pressure) Epiglottis as bolus is going by it covers the opening of the trachea (extra protection but not essential to the process: oesophageal phase- involuntary. Starts as the bolus movement causes the opening of the ues and bolus goes into the oesophagus breathing.