Digestive System Flashcards
What is a Batch Reactor?
Found in some hydra and herbivores; Coelenterates. There is one hole that is used for the input and the output of matter; all the matter is added at the same time (discontinuous), and one batch is processed and eliminated before the second batch is brought in. Pulsed, uniform composition.
What is a Continuous-flow Stirred-tank Reactor?
Found in Herbivores, allowing them to digest cellulose. It’s a ruminant fore-stomach. Has a hollow, tubular cavity that allows for the continuous flow and processing of the material. The mixture is well mixed; homogenous and uniform. Overflow passes on.
What is a Plug-flow Reactor?
Example: Small Intestine
The bolus of food moves through a continuous tubular vessel. There is a gradient throughout the tube, therefore the composition of the mixture changed according to the position of the tube.
What does extracellular digestion permit?
An animal to store and break down larger varieties and quantities of food items. This is very cost effective. The food in the gut is not stored in the body, it has to be absorbed.
What type of extracellular digestion do Cnidarian pages have?
A blind-end sac lined by gastrodermis.
What do advanced organisms with extracellular digestion have?
A tube with an entrance (mouth) and exit (anus). The lumen (space inside the gastrointestinal track) is technically part of the external environment.
What four regions is the gut tube divided into?
Headgut, foregut, midgut, and hindgut.
What are the accessory organs of the digestive track of vertebrates?
Salivary glands, exocrine pancreas, and biliary system (liver and gallbladder).
What is the stomach called in ruminants?
Rumen.
What is the stomach called in bird?
Proventriculus-gizzard complex.
What alimentary canals are found in vertebrates?
Mouth, pharynx, esophagus, stomach, small and large intestine, anus.
Basic summary of the Alimentary Canal.
Materials in the canal move in one direction, through regions with specialized tasks. In these regions they are subjected to mechanical, chemical, and bacterial treatments before being absorbed or excreted.
What are the functions of the Headgut?
The head gut is involved in feeding and swallowing, with associations like teeth, salivary glands, and the tongue. In many species this is a common pathway for both digestion and respiratory gases, so there is a valve-like structure involved.
What are Salivary Glands for?
To produce saliva, which helps for lubrication during swallowing and provides mucin, enzymes, and anticoagulants.
What is the Tongue for?
The tongue in chordates helps with mechanical digestion and swallowing, and contains chemoreceptors (taste buds).
What is the process of Swallowing (deglutition)?
Process of moving food from the mouth, through the esophagus, and into the stomach. It starts with the bolus of food being forced (by the tongue) into the pharynx. The pharyngeal pressure receptors send afferent impulses to the medulla oblongata, where the swallowing centre activates a programmed all-or-none sequence of highly coordinated activites.
What are the two phases of the swallowing reflex?
Oropharyngeal phase and esophageal phase.
What is the Oropharyngeal Phase of the swallowing reflex?
The uvula is elevated, sealing off the nasal passage. The glottis is closed, and covered by the epiglottis to ensure food does not enter the respiratory pathways. Pharyngeal muscles contract to force the bolus into the esophagus.
