Animal Nutrition I Flashcards
What is the definition of nutrition?
Nutrition is the process by which organisms obtain food [1] and energy [2] for growth [3], repair [4], and maintenance of body [5].
What is the function of the digestive system?
To break down large and complex food substances into smaller and simple food substances
What is the difference between physical digestion and chemical digestion?
1) The identities of food substance remains unchanged in physical digestion. However, in chemical digestion, the identities of the food substance change, and new products are formed.
2) Physical digestion often increases the surface area to volume ratio. Chemical digestion is to allow food substances to enter the bloodstream through intestinal walls.
Is emulsification physical digestion?
yes. As there are no new products formed during the process.
What is the function of the mucus along the gut?
1) The mucus protects the stomach wall from being damaged by HCL
2) Prevents digestion by pepsin since the stomach wall is made of protein.
3) Provides lubrication as food is churned in stomach
What is ingestion?
Ingestion is food taken into the body.
What is digestion?
Digestion is large food substances broken down into small soluble substances.
What is absorption?
It is the process at which small, soluble substances is being absorbed into the cell
What is assimilation?
Assimilation is the process at which substances are used to provide new energy/ make new protoplasm.
What is egestion?
It is undigested food removed from the body as waste product.
Where does ingestion occur?
Mouth
What is the function of the salivary gland and tongue in mouth?
Salivary gland - produce saliva
tongue - aids to mix food with saliva
What does saliva consist?
salivary amylase, mucus and water
Why does salivary amylase function effectively in the mouth?
This is due to saliva, which provides a neutral environment for it to function properly.
Why must food be chewed?
By doing so, food is cut and grind into smaller pieces. This increases surface area to volume ratio and allows enzymes to digest them faster.
What is starch digested into by salivary amylase?
Maltose
What is peristalsis?
It is the rhythmic- wave- like contraction of muscles of the wall.
How is food being pushed down into the stomach in the oesophagus?
The 2 muscles (circular and longitudinal) work antagonistically to bring about the movement of food along the oesophagus via peristalsis, pushing the food along the canal down the stomach with gravity.
Is there digestion of carbohydrates in the stomach? Explain.
No.
1) Salivary amylase are denatured in the stomach due to it’s acidic environment.
2) The stomach does not produce any suitable form of amylase for digestion of starch.
3) May cause hydrolysis of salivary amylase protein.
Where does protein digestion occur?
Stomach and small intestine.
What is the function of the strong muscular walls in the stomach?
The stomach muscular wall contract and relax, causing the peristaltic action (churn) to bring food into close contact with gastric juice.
Why does the mucous lining in the stomach have numerous pits?
It is to bear mucous secreting epithelial cells which secretes mucous.
what do gastric juice contain?
Hydrochloric acid.
Rennin and Pepsin (enzymes)
What is the function of hydrochloric acid in the stomach?
1) HCl converts inactive prorennin and pepsinogen into active pepsin and rennin.
2) Provides acidic environment in stomach such that protease can function efficiently in this optimum condition.
3) kill germs and parasites
4) stop the action of salivary amylase
Describe the physical digestion in the stomach.
The churning action [1] by the muscular wall of the stomach causes food to break further into smaller pieces. It also helps food mix with gastric juice which increases surface area to volume ratio[1] to act more efficiently.
what does pepsin convert proteins into in the stomach?
polypeptides
What does rennin convert caseinogen(soluble) into in the stomach?
casein (insoluble)
Why is milk proteins in the form of soluble caseinogen not beneficial?
When milk proteins are in the form of caseinogen, they would pass through the stomach to the small intestine very quickly [1]. This prevents pepsin digestion to take place [1]. Thus, rennin changes caseinogen into an insoluble form to give pepsin sufficient time to digest it. [1]
Why is the nature of juices from intestinal glands, pancreatic juice and gall bladder alkaline?
1) Being alkaline, it provides suitable alkaline medium for optimum action of all the enzymes.
2) It neutralises acidic chyme
Why is the small intestine 7m long?
This is to allow for maximum absorption [1] and allow time for digestion [1].
Where does digestion occur in the small intestine?
Duodenum
Where does emulsification occur?
small intestine.
Where is bile produced and stored at?
Bile is produced by the liver, and stored at gall bladder
Is bile an enzyme? explain.
Bile is not an enzyme as it breaks up fat molecules into fat globules.
What is the function of emulsification?
It increases surface area to volume ratio of the fat molecules so that they can be digested by lipase faster, increasing efficiency.
Which organ secretes pancreatic juice into duodenum?
pancreas
How is pancreatic juice transported to the small intestine?
via the pancreatic duct
What does pancreatic juice contain?
Pancreatic amylase, lipase and trypsinogen.
What are the end products of carbohydrate digestion?
Simple sugar [glucose, fructose and galactose]
What are the 6 enzymes that intestinal juice contain?
Maltase, surcease, lactase, lipase, erepsin and enterokinase.
What are the 3 organs associated with the alimentary gut?
pancreas, liver and gall bladder.
Name the organs that are responsible for the secretion and production of bile?
Liver - produce bile
Bile duct- transport bile to duodenum
Gall bladder- stores bile
