Abstract
Digestion is a process by which foods are broken down chemically and mechanically into smaller units that can be then absorbed. The organs of digestive system facilitate this process via movement of nutrients, water, and electrolytes from the external environment into the body’s internal environment.
The broad functions of digestive tract include secretory and motility functions that ultimately aid in digestion and absorption. Apart from the enzymes secreted from the gut itself, there is significant contribution from other organs like liver and pancreas in the process of digestion. Both secretory and motility functions of gastrointestinal (GI) tract are tightly regulated by intrinsic control mechanism via enteric nervous system apart from direct control of vagus nerve. In addition to the neural control, the GI tract is also controlled by hormones secreted by GI tract itself that predominantly act in autocrine and paracrine manner. The avian digestive system is modified to accommodate flight. This chapter focuses on all of the above discussed aspects with additional excerpts on recent advances.I. Hyder
College of Veterinary Science, Sri Venkateswara Veterinary University, Garividi, Andhra Pradesh, India
P. R. K. Reddy
Veterinary Dispensary, Animal Husbandry Department, Taticherla, Andhra Pradesh, India
J. Mukherjee (X)
Department of Veterinary Physiology, West Bengal University of Animal & Fishery Sciences, Kolkata, West Bengal, India
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023
P. K. Das et al. (eds.), Textbook of Veterinary Physiology, https://doi.org/10.1007/978-981-19-9410-4_13
Description of the graphic: Monogastric digestive tract is a long hollow tube extending from the mouth to anus together with some accessory organs in between. The digestion process starts at the mouth cavity by mechanical force of mastication/chewing. The saliva lubricates feed particles for swallowing. The enzymes present in the saliva partially digest the feed. The feed enters into the stomach through oesophagus. Stomach secrets gastric HCl and enzymes to digest proteins. The final stage of digestion is occurred at the small intestine with brush boarder enzymes. The absorption of nutrients occurs at the small intestine. The liver produces bile that helps in the digestion and absorption of lipids.
Keywords
13.1