Digestion Flashcards
Which enzymes are present in the saliva? Is there any difference between animal species?
the enzymes a-amylase and the complex
lysozyme. However, horses, cats and dogs lack salivary a-amylase. In pigs, the activity of this enzyme is low.
Which of the following: glycogen, polysaccharides, oligosaccharides and amylopectin can be attacked by a-amylase in the saliva?
Yes: starch. glycogen, polysaccharides, oligosaccharides
no: amylopectin
What are the parts of the stomach of a monogastric animal?
oesophageal area (with a-amylase activity) cardia (entrance), gastric gland region (secretion of glycoprotein and fucolipid mucus -> hydrochloric acid and pepsinogen) and pylorus (protective mucus)
Which factors lead to a stimulation of the glands to secrete gastric juice in monogastric animals?
in the cephalic phase, stimuli such as the sight and smell of food act via the vagus nerve.
Then, in the gastric phase, secretion is maintained by chemical sensors and distension of the stomach.
Finally, the presence of digesta in the duodenum elicits secretion by neural and hormonal messages.
Where is the majority of the digestion and absorption occur in monogastrics?
Small intestine, the duodenal area being the site for mixing digesta and secretions and the jejunal area being the site of absorption.
What is the function of bile salts in the digestion?
The bile salts play an important part in digestion by activating pancreatic lipase and emulsifying fats.
what are the secretory functions of the pancreas?
the endocrine process for the production of insulin and the exocrine process for the production of digestive enzymes (from the acinar cells), water and electrolytes (from the duct cells), which together form the pancreatic juice, which is secreted into the duodenum through the pancreatic duct.
Which factors induce the pancreas to secrete its juice into the duodenum?
Secretin (acid response)
Cholecystokinin (peptides)
Trypsin activation (enterokinase)
Trypsin specificity (lysine, arginine)
Chymotrypsin activation
Carboxypeptidase conversion
Endopeptidases (trypsin, chymotrypsin)
Which enzyme breaks down fats?
pancreatic lipase
What is the major role of the large intestines?
The large intestine plays an important role in the retrieval of nutrients, electrolytes and water in the digesta.
Extensive microbial activity occurs in the large intestine, especially the caecum.
what are the products of microbial breakdown of polysaccharides in pigs?
volatile fatty acids
What are the major products of fermentation in the fowl (chicken)?
The major products of fermentation are lactic and acetic acids.
What are some differences between the digestive system in horses, monogastric animals and ruminants?
The horse is a non-ruminant herbivore, having a simple monogastric digestive tract
similar to that of the pig but with a much-enlarged hindgut (especially the caecum),
which contains a microbial population.
The small intestine is the main site for digesting non-fibrous carbohydrates, protein and fat, and the microbes in the large intestine ferment fibrous materials, as in the ruminant. However, unlike the ruminant, the horse has enzymic digestion before microbial fermentation, and it falls between the pig and the ruminant in its ability to digest fibrous foods.
What is the end product of microbial fermentation in the oesophagal and fundic regions of the stomach of horses?
lactic acid
Which type of food encourages the development of the rumen?
a combination of fibrous and starchy foods encourages the development of the rumen and assists the weaning process.
The consumption of fibrous foods, such as straw and hay, stimulates the enlargement of the reticulum. The fermentation of food by microbes in the rumen produces volatile fatty acids and these, particularly butyric acid from the fermentation of concentrates such as cereals, encourage the formation of papillae on the rumen wall.
