Digestive system
It digests food which means food is broken down into usable decomposed form known as
nutrients and nutrients are absorbed in the bloodstream and transported to different part
of the body
Living organisms ingest food to satisfy their need for energy. Green plants manufacture
their own food through photosynthesis. Humans and animals ingest food to ensure
survival. They eat plants or meat of other animals
A nutrient is an ingredient of food used by the body
Steps in the digestive system:
1. Ingestion: intake of food
2. Mastication: chewing of food
3. Digestion: food is broken into small particles to be absorbed
4. Absorption: nutrients are absorbed in bloodstream
5. Transportation of food into different parts of the body for digestion
6. Assimilation: absorbed food molecules used in the process of growth, tissue repair and
reproduction
7. Egestion of waste that have not been absorbed
Types of digestion
There are 2 types of digestion
® Mechanical digestion
® Chemical digestion
Mechanical digestion
A physical process where food is broken into smaller parts by tearing, pushing, mixing and
grinding/crushing
® Food is broken down into smaller pieces
Chemical digestion
A chemical process where crushed food is mixed with gastric juices- enzymes and
hydrochloric acid. Food is converted into liquid to form easy absorption
® Food is broken into its simplest form
Mechanical and chemical digestion take place simultaneously
, Organs
The digestive tract consists of the following:
® Mouth
® Oesophagus
® Stomach
® Liver
® Pancreas
® Small intestine
® Large intestine
® Colon
® Rectum
® Anus
The digestive tract is also called the gut or gastrointestinal tract- G.I tract
Functions of the organs
The digestive system consists of different parts that have adapted to fit in the digestive
tract for a specific function
The mouth
Lips and cheeks
® Cover the mouth in the front and sides
® Prevent food from falling out
Jaws and Teeth
® Teeth on upper and lower jaw. Lower jaw moves to enable chewing
® Bite, chew and mince food to a bolus
Bolus is food mixed with saliva that’s been rolled into a little ball
Tongue
® Muscular organ connected to back and bottom of mouth and contains taste buds
® Grinds food against plate and teeth
® Mixes food with saliva
® Rolls food into bolus
® Pushes food to back of mouth
® Organ used to taste
It digests food which means food is broken down into usable decomposed form known as
nutrients and nutrients are absorbed in the bloodstream and transported to different part
of the body
Living organisms ingest food to satisfy their need for energy. Green plants manufacture
their own food through photosynthesis. Humans and animals ingest food to ensure
survival. They eat plants or meat of other animals
A nutrient is an ingredient of food used by the body
Steps in the digestive system:
1. Ingestion: intake of food
2. Mastication: chewing of food
3. Digestion: food is broken into small particles to be absorbed
4. Absorption: nutrients are absorbed in bloodstream
5. Transportation of food into different parts of the body for digestion
6. Assimilation: absorbed food molecules used in the process of growth, tissue repair and
reproduction
7. Egestion of waste that have not been absorbed
Types of digestion
There are 2 types of digestion
® Mechanical digestion
® Chemical digestion
Mechanical digestion
A physical process where food is broken into smaller parts by tearing, pushing, mixing and
grinding/crushing
® Food is broken down into smaller pieces
Chemical digestion
A chemical process where crushed food is mixed with gastric juices- enzymes and
hydrochloric acid. Food is converted into liquid to form easy absorption
® Food is broken into its simplest form
Mechanical and chemical digestion take place simultaneously
, Organs
The digestive tract consists of the following:
® Mouth
® Oesophagus
® Stomach
® Liver
® Pancreas
® Small intestine
® Large intestine
® Colon
® Rectum
® Anus
The digestive tract is also called the gut or gastrointestinal tract- G.I tract
Functions of the organs
The digestive system consists of different parts that have adapted to fit in the digestive
tract for a specific function
The mouth
Lips and cheeks
® Cover the mouth in the front and sides
® Prevent food from falling out
Jaws and Teeth
® Teeth on upper and lower jaw. Lower jaw moves to enable chewing
® Bite, chew and mince food to a bolus
Bolus is food mixed with saliva that’s been rolled into a little ball
Tongue
® Muscular organ connected to back and bottom of mouth and contains taste buds
® Grinds food against plate and teeth
® Mixes food with saliva
® Rolls food into bolus
® Pushes food to back of mouth
® Organ used to taste
