Deglutition or swallowing is probably a reflex phenomenon. Higher centres facilitate this reflex. Once aroused, the swallowing centre in the medulla evokes the complete act of swallowing by discharge through six nuclei and the motor neurones. This reflex act occurs in three stages: (1) First or oral, (2) Second or pharyngeal, and (3) Third or oesophageal (Fig. 9.46). (1) First [...]
The various humoral (chemical) factors controlling the different secretions in the gastro-intestinal tract may be summarised as follows: 1. For Gastric Secretion: i. Gastrin- Responsible for gastric phase. ii. A chemical substance may be a hormone or secretagogue - Responsible for intestinal phase. iii. Enterogastrone- Inhibits gastric secretion. 2. For Pancreatic Secretion: i. Secretin- Main chemical stimulus. ii. Pancreozymin. iii. [...]
In this article we will discuss about:- 1. Mechanism of Gastric Secretion 2. Hormones of Gastric Secretion 3. Effects of Various Chemicals and Drugs 4. Investigation. Mechanism of Gastric Secretion: The mechanism of gastric secretion has been chiefly studied on animals. Some direct evidence has been obtained in man, from cases of accidental gastric fistula through which gastric juice could [...]