Hood gutter reflex

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Mucous membrane inside the hood. 1 esophageal mouth, 2 hood lips, 3 hood strips, 4 hood psaltery opening

The gullet reflex (obsolete gullet reflex ) is an involuntarily controlled movement ( reflex ) in the hood ( reticulum , also called reticulum) in ruminants in the suckling phase. The purpose of the reflex is to transport the absorbed milk directly to the abomasum via the shortest route , where it can curdle through the rennet and hydrochloric acid .

The morphological prerequisite for the reflex are two muscularly supported mucous membrane bulges in the hood (hood lips), which lead from the mouth of the esophagus to the gizzard (syn. Psalter). Via the stimulation of chemoreceptors in the oral cavity by the milk during suckling, impulses are transmitted via the 9th cranial nerve ( glossopharyngeal nerve ) to the elongated medulla ( medulla oblongata ). This sends a reflex response via the 10th cranial nerve ( nervus vagus ), which triggers a spiral rotation of the two hood lips and an opening of the hood psaltery opening. As a result, the milk is conveyed from the esophageal opening via the hood groove between the two hood lips to the Psalter and in this via the Psaltery groove directly into the abomasum. The reflex can be conditioned , i.e. its expression can be intensified by other sensory stimuli. With the development of the fore-stomachs, the hood groove reflex disappears.

Experimentally, a hood trough reflex can also be by administration of copper - or sodium - salts trigger. The reflex can be suppressed by administering local anesthetics or atropine .

In the case of the wrong feeding regime, the reflex in calves can take place insufficiently, as a result of which milk gets into the still underdeveloped rumen and is fermented incorrectly by bacteria ("rumen drunkards"). The result is indigestion and diarrhea. Possible errors are e.g. B. drinking milk that is too cold or keeping the calf incorrectly when feeding.

literature

  • M. Kaske: The hood groove reflex. In: W. v. Engelhardt, G. Breves (Ed.): Physiology of domestic animals. 2nd Edition. Enke-Verlag, Stuttgart 2000, ISBN 3-8304-1039-5 , pp. 335-336.