ANAT 025HUMAN ANATOMY(DIGESTIVE SYSTEM)
SCHOOL: OXFORD UNIVERSITY
DIGESTIVE SYSTEM
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Animal
nutrition &
Digestive system
Concept of nutrition: It is the scientific study of food and various modes of
nutrition of living organisms.
- Nutrition is needed for:
Food materials are the source of energy for all vital processes.
Food materials are needed for growth and repair of worn out tissues.
Types of nutrition:
1. Autotrophic nutrition: Autotrophs are living organisms which can
manufacture their food by themselves e.g. green plants. They can synthesize
inside their cells high energy food stuffs as carbohydrates, fats and proteins
out of simple inorganic and low energy materials as CO2 and H2O in
addition to minerals salts and light energy by a process called
Photosynthesis.
2. Heterotrophic nutrition: Living organisms obtain food from other
organisms either plants or animals that were previously feeding on
plants.
Types of Heterotrophiк Nutrition
In nature, organisms exhibit various types of heterotrophic nutrition. They are as
follows:
Holozoic Nutrition
Saprophytic Nutrition
Parasitic Nutrition
,Holozoic Nutrition
Holozoic nutrition involves the ingestion and internal processing of solid and
liquid food in an organism. This involves the steps of ingestion, digestion,
absorption, assimilation and excretion.
Ingestion is the intake of food, which is
broken down into simpler organic matters by
a process called digestion. After extraction of
useful components, the unwanted and
undigested particles are excreted out.
Examples of animals that exhibit holozoic
nutrition include all vertebrates. Even some
unicellular organisms such as amoeba also
exhibit holozoic nutrition.
Types of Holozoic Organisms:
Holozoic organisms can be divided into three types:
Herbivores- These organisms depend upon plants for their food. Cows,
buffaloes, deer, elephants are herbivores.
Carnivores- These animals feed on other animals for their food. Lions,
tigers and leopards are carnivores.
Omnivores- These animals can survive on both plants and animals for
their food. Cockroach, pig, chimpanzees, raccoons and ant are some
examples of omnivores.
Saprophytic Nutrition
Saprophytes (animals which follow saprophytic nutrition) feed on dead and
decayed organisms for energy. They are an important part of the ecosystem as
they help to keep our environment clean and recycle nutrient back into the
ecosystem.
Some examples of saprophytes are fungi and certain types of bacteria. These are
also responsible for the staling of bread and other similar food products.
Saprophytes release certain enzymes to act on the complex organic matter. It works
by breaking it down into its constituents, which can be easily consumed by them.
, 2|Page
SCHOOL: OXFORD UNIVERSITY
DIGESTIVE SYSTEM
,1|Page
Animal
nutrition &
Digestive system
Concept of nutrition: It is the scientific study of food and various modes of
nutrition of living organisms.
- Nutrition is needed for:
Food materials are the source of energy for all vital processes.
Food materials are needed for growth and repair of worn out tissues.
Types of nutrition:
1. Autotrophic nutrition: Autotrophs are living organisms which can
manufacture their food by themselves e.g. green plants. They can synthesize
inside their cells high energy food stuffs as carbohydrates, fats and proteins
out of simple inorganic and low energy materials as CO2 and H2O in
addition to minerals salts and light energy by a process called
Photosynthesis.
2. Heterotrophic nutrition: Living organisms obtain food from other
organisms either plants or animals that were previously feeding on
plants.
Types of Heterotrophiк Nutrition
In nature, organisms exhibit various types of heterotrophic nutrition. They are as
follows:
Holozoic Nutrition
Saprophytic Nutrition
Parasitic Nutrition
,Holozoic Nutrition
Holozoic nutrition involves the ingestion and internal processing of solid and
liquid food in an organism. This involves the steps of ingestion, digestion,
absorption, assimilation and excretion.
Ingestion is the intake of food, which is
broken down into simpler organic matters by
a process called digestion. After extraction of
useful components, the unwanted and
undigested particles are excreted out.
Examples of animals that exhibit holozoic
nutrition include all vertebrates. Even some
unicellular organisms such as amoeba also
exhibit holozoic nutrition.
Types of Holozoic Organisms:
Holozoic organisms can be divided into three types:
Herbivores- These organisms depend upon plants for their food. Cows,
buffaloes, deer, elephants are herbivores.
Carnivores- These animals feed on other animals for their food. Lions,
tigers and leopards are carnivores.
Omnivores- These animals can survive on both plants and animals for
their food. Cockroach, pig, chimpanzees, raccoons and ant are some
examples of omnivores.
Saprophytic Nutrition
Saprophytes (animals which follow saprophytic nutrition) feed on dead and
decayed organisms for energy. They are an important part of the ecosystem as
they help to keep our environment clean and recycle nutrient back into the
ecosystem.
Some examples of saprophytes are fungi and certain types of bacteria. These are
also responsible for the staling of bread and other similar food products.
Saprophytes release certain enzymes to act on the complex organic matter. It works
by breaking it down into its constituents, which can be easily consumed by them.
, 2|Page
