Definitions [17]
Define with examples: Carnivores
The organisms which feed upon other animals and animal products.
Examples - tiger, lion, cat, etc.
Define digestion.
It is the breaking down of complex insoluble food components into simple soluble substances.
Define with examples: Omnivores
The organisms which feed on all kinds of plant and animal food are called omnivores.
Examples - Cockroach and human beings.
Define with examples: Autotrophs
These are the organisms which prepare organic food in their body from simple inorganic materials like carbon dioxide, water, etc.
Example - green plants and certain protests.
Define with examples: Herbivores
The organisms that feed on plants only are termed as herbivores.
Examples - sheep, cow, goat, etc.
Define the following term:
Peristalsis
Peristalsis is the rhythmic contraction and relaxation of the muscles of the alimentary canal that pushes the food along the gut.
Write short answers
Define homodont dentition.
A homodont dentition all the teeth in the jaws are similar in shape and structures,
E.g. in frogs and fish.
Define the following term :
Pylorus
Pylorus is the passage at the lower end of the stomach that opens into the duodenum.
Define the following term :
Omnivore
Omnivores are organisms that consume both plants and animals.
Define the following term:
Assimilation
Absorption of substances which are built into other compounds in the organisms.
Define the following term:
Kilocalorie
A kilocalorie is a unit of energy. It is the energy required to raise the temperature of 1 kg of water by 1 Celsius.
Define the following term:
Egestion
Egestion — The process of removal of the undigested food from the body is defined as egestion.
Define the following term:
Digestion
Digestion — The process of breaking the food into smaller and simpler substances so that they can be easily used by the body is called digestion.
Define the term nutrition.
The process by which living beings receive food and utilise it to grow and become healthy is called nutrition.
On the basis of nutrition, living beings can be classified into the following types:
- Holozoites
- Parasites
- Saprophytes
- Symbionts
Holozoits can be further classified into
- herbivores
- carnivores
- ommivores
Define the following term:
assimilation
Assimilation — The process of using the digested food by the body is called assimilation.
Define the term ‘digestion’.
The process of converting complex food substances into simpler and smaller units so that they can be easily utilised by the body is defined as digestion.
E.g. proteins are converted to amino acids.
Define with examples: Heterotrophs
The organisms which cannot prepare their own food and depends on ready-made food synthesized by green plants are called heterotrophs.
Examples - animals and human beings.
Key Points
- Digestion is the conversion of complex food into soluble forms that can be absorbed into the blood.
- The digestive system has two main components: the alimentary canal (mouth to anus) and associated digestive glands.
- The alimentary canal is a long muscular tube about 9 m in adults, including mouth, pharynx, oesophagus, stomach, small intestine, large intestine, rectum and anus.
- Salivary glands, liver and pancreas are accessory digestive glands that open into this canal and secrete juices needed for digestion.
- Different organs of the digestive system act in sequence; each stage of digestion occurs in a specific organ that performs a specialised mechanical or chemical role.
