Digestive system Flashcards
What is animal nutrition?
Process by which food is taken into the body to make use of it in different body functions
What is heterotrophic nutrition?
Type of nutrition in which organisms obtain organic food molecules by ingesting other organisms or substances derived by them
What is ingestion?
First stage of holozoic nutrition. in which the act of feeding or eating occurs.
Factors that affect the mechanisms of feeding in an organism
The diet and the environment
What is digestion?
the process of breaking down food molecules into smaller molecules that can be taken up by the cells of the organism through the plasma membrane.
What is mechanical digestion?
Digestion in which food pieces are broken down into smaller fragments to increase the surface area to make chem digestion more efficient.
What is chem digestion?
Digestion in which digestive enzymes are used to break down large food molecules into smaller molecules by breaking bonds, which can then be taken up by animal cells.
Feeding mechanism of oysters. explain.
They have gills with cilia. traps food particles that move over the gills, and the cilia sweep the food particles into the alimentary canal in a film of mucus.
How is mechanical digestion done in the mouth
Different types of teeth with varying shapes - molars, premolars, canines and incisors. they cut mash and grind food to smaller pieces increasing the surface area for chem digestion.
What steps of holozoic nutrition occur in the mouth?
Ingestion and first steps of digestion
What is saliva?
Mixture containing water, salivary amylase, antimicrobial substances, buffers and mucus ( a viscous mixture of cells, salts and slipper glycoprotein called mucin)
Functions of water in saliva
Liquifies food. Provides watery medium for chem digestion, aids in taste reception
How is saliva released into the mouth?
From salivary glands through ducts. due to reflex action when food enters the mouth or in response to stimuli like sight and smell of food.
Function of salivary amylase
Catalyses the breakdown of polysaccharides into smaller polysaccharides, and the disaccharide maltose.
Function of antimicrobial substances. examples.
Immunoglobulins and lysosymes. provides protection from bacteria entering the mouth.
