Non progressive contraction of Esophagus are classed as which of the following?
Correct Answer: Teiary
Description: There are three types of oesophageal contractions: primary, secondary, and teiary. Teiary contractions represents uncordinated contractions of the esophageal smooth muscle and are responsible for esophageal spasm. They are non peristaltic, non progressive and occur with both voluntary and involuntary swallow. Primary peristaltic contractions are the major stripping wave that are initiated by the act of swallowing and that propel ingested material through the entire length of the oesophagus into the stomach. Primary peristaltic contractions are progressive and move down the oesophagus at rate of 2 to 4 cm/sec and reach the LES about 9 seconds after the initiation of swallowing. It relaxes the lower oesophageal sphincter before the bolus reaches it. Secondary peristaltic contractions are also progressive, similar to primary peristalsis but elicited by different stimuli. Rather than beginning with swallowing, as in primary peristalsis, the secondary peristaltic wave occurs in response to distension or irritation anywhere along the oesophagus. It begins at the level of the focus of stimulation and propels oesophageal contents distally. In effect, secondary peristalsis is a mechanism for ridding the oesophagus of refluxed gastric contents or material left behind after the progression of the primary peristaltic wave.
Category:
Physiology
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