animal nutrition Flashcards
what is the purpose of mastication
It increases the surface area that comes into contact with the enzymes
Food is mixed with saliva to allow for easy swallowing and passage through the oesophagus.
What is mechanical digestion
It is a physical process also known as mastication where food is crushed and grinded by the teeth
what happens during mechanical digestion
large pieces of food is broken dowwn into smaller pieces of food
what is ingestion
the intake of food in large complex substances
What is assimilation?
the transportation to and the use of absorbed nutrients in various cells for repair , growth and energy
what is chemical digestion
the chemical breakdown of food where large insoluble nutrients are broken down into smaller soluble nutrients through the process of hydrolysis
define hydrolysis
the process whereby large insoluble nutrients are broken down into smaller soluble nutrients with the chemical addition of water.
importance of food
1) brings about growth by providing substances required by cells
2) serves as a energy source
3) it is a source of regulating substances that are required for functioning of the body. E.g minerals and vitamins
herbivores
organisms that eat plants only
carnivores
organisms that eat meat only ( other animals)
omnivores
organisms that eat both plants and animals
type of teeth that herbivores have
incisors- broad and flattened for clipping of blades of grass
premolars and molars- large and flattened for grinding grass
cliastema(a gap)- occurs between incisors and premolars to enable tongue to move around during chewing.
the role of water in digestion
1) makes food more liquid so it can move around more freely around the alimentary canal
2) keeps surrounding tissues of the alimentary canal soft and pliable.This also allows free movement
Peristalsis
the rythmical contraction and relaxation of the muscles of the oesophagus
describe the process of peristalsis
the circular muscles above the bolus contracts and this narrows the oesophageal tube
the circular muscles below the oesophagus relax, this causes the oesophagus to widen and the bolus is moved forward
What substances are absorbed by the small intestine
glucose ,amino acids, fatty acids and glycerol, vitamins , minerals, water , undigested and indigestable material
what is the difference between undigested and indigestable material
undigested material is food that can be digested by the body but was not digested because it was not needed whereas indigested material is food that cannot be digested because the body does not have the ability to do so
peristalsis in the stomach
food enters stomach through cardiac sphincter , cardiac sphincter controls movement of bolus in the stomach, in the stomach peristalsis occurs in many different ways, this ensures that food is broken down into smaller pieces and it is thoroughly mixed with digestive juices
The food is then moved into the large intestine through peristalsis
importance of saliva
contains water to soften food and helps with chewing
contains mucous to lubricate food and helps with chewing
creates a slightly alkaline medium for the enzymes that are found in the mouth
The enzyme carbohydrase is part of the saliva. Plays a role in digesting carbohydrates
what enzymes are required for hydrolysis
proteases - breakdown[hydrolyse] proteins into amino acids
carbohydrases- hydrolyse carbohydrates into simple sugars
lipases - hydrolyse fats [lipids] into fatty acids and glycerol [produced in the pancreas]
need for digestion
food contain large amounts of energy so that food must be broken down , absorbed and transported so that the energy can be released so the food we eat is made up of large complex molecules that are insoluble in water, digestion must occur so that the large molecules can be broken down into small soluble substances so that these smaller substances can be absorbed and transported
how are gastric juices formed
when the stomach detects protein it secretes a hormone called gastin through the stomach walls into the blood vessels , the blood passes the stomach lining and the gastin stimulate the stomach cells to secrete gastric juices
How do gastric juices assist in digestion
1) contain enzyme protease, which plays a role in the digestion of protein
2) contains water to keep food fluid to allow for easy movement along alimentary canal
3) contains mucin ,mucin combines with water to form a protective lining inside the stomach that protects the stomach from the action of enzymes
4) hydrochloric acid is present to provide an acid medium for the enzymes found the stomach and it acts as an antiseptic as well , it destroys germs that may come in with the food
digestive juices in the small intestine
pancreatic juices