Different methods used by organisms to obtain food
Process of nutrition
1. Ingestion
2. Digestion
3. Absorption
4. Assimilation
5. Egestion
Parts of the human digestive system
Mouth
Oesophagus
Stomach
Smallintestine
Large intestine
Rectum
Anus
Digestive glands
Salivaryglands
Liver
Pancreas
Gall bladder
Assimilation
Process in which the absorbed food is used for producing energy and for growth
Plaque
Sticky layer containing food particles, saliva and bacteria
Alimentary canal
The digestive system from oesophagus to the anus
Faeces
Unabsorbed portion of the food that is thrown out of the body
Taste buds
Taste-sensitive locations on the surface of the tongue
Villi
Finger-like-projections on the inner wall of the small intestine
Cud
Partially digested food stored in a part of stomach called rumen
Ruminants
Plant/grass-eating animals that digest their food in two steps
Contractile vacuole
The point from where the undigested food is thrown out of the body by Amoeba
Modes of procuring food
Picking up food directly into mouth
Using hands to put food into mouth
Using false feet (pseudopodia) to engulf food
Using brush-like body structures (cilia) to sweep food
Using tongue to catch prey
Using feeding tube to suck nectar
Using tentacles with sting cells to kill prey and put it into body cavities
Weaving web to catch prey
Different organisms use different methods to procure food. Each animal has some special structures on its body to procure food.
The various steps involved in the process of nutrition are: Ingestion, Digestion, Absorption, Assimilation, and Egestion.
Ingestion
The acts of getting and eating food collectively
Digestion
The breakdown of food into simpler and soluble molecules inside the body
Absorption
The process by which soluble molecules present in the digested food passes into the body fluids like blood
Egestion
The process by which the undigested food materials are thrown out of the body
Mosquitoes, houseflies, and butterflies live on liquid food.
In human beings, ingestion takes place through the mouth.
In human beings, absorption takes place in the small intestine.
Types of teeth in humans
Incisors
Canines
Premolars
Molars
Milk teeth
First set of 20 teeth that appear by the age of 2 years
Permanent teeth
New set of 32 teeth that form by the age of 12
Incisors help in cutting or biting the food.
Canines help in tearing the food.
Premolars and molars help in chewing and grinding the food.
Root
The part of a tooth embedded into the jaw
Crown
The top part of the tooth outside the gums
Neck
The part between the root and the crown
Enamel
The white part of a tooth and the hardest substance in our body
Dentine
Hard bone-like structure inside the tooth
Pulp cavity
The soft inner part of the tooth containing blood vessels and nerves
Tooth enamel is the hardest material in our body and is also chemically the most stable tissue.
Teeth of ancient humans and animals have provided the most useful data for studying the process of evolution.
Plaque absorbs sugary and starchy food materials, and the bacteria in the plaque convert them into acids that dissolve the tooth enamel and lead to the formation of cavities.
Build-up of plaque at the place where teeth meet the gums leads to loosening of the teeth.
Suggestions for proper care of teeth and gums
Brush teeth everyday in the morning and before bed
Massage gums gently with a soft brush
Wash mouth thoroughly with water after eating
Eat self-cleaning foods like raw vegetables and fruits