Nutrition in Animals NCERT CBSE Class 7 Chapter 2 Summary Note

                   Nutrition in Animals
NCERT Class VII (Chapter-2) - Note


*Nutrient- Components of food.
                - Such as Carbohydrates,
                                 proteins,
                                 fats,
                                 vitamins,
                                 minerals


*Nutrition- Intake of food
                 - Its utilisation by body.


*Nutrition includes-          Ingestion, Digestion,
             Absorption, Assimilation, and Egestion


*We take food because
- Food contains nutrients.
- Nutrients help us as follows:
    Carbohydrates- Give energy
    Proteins- Body growth
    Fats- Give more energy
    Vitamins- Protect from diseases
    Minerals- Metabolism
                    (processes take place in  body)


*Simpler components- Smaller components.
         - These can be used directly.
         - Formed from complex components.
        - Example- Glucose, amino acids etc.


*Complex components-
         - Larger components.
         - These can't be used directly.
       - Break down to form simpler components.
         - Example- Carbohydrates proteins etc.


*Alimentary canal- A continuous canal that
       begins at buccal cavity and ends at anus.


* Compartments of alimentary canal-
             buccal cavity
             Food pipe or oesophagus
             stomach
             small intestine
             large intestine
            anus


*Digestive system-
    Alimentary canal + Digestive glands                                          (salivary  glands, liver, pancreas)


* Gland- Any organ that secret juice.
                Example-Salivary gland


* Buccal cavity contains-
            Teeth
            Tongue
            salivary glands


* Teeth- 32 in number.
             - Chew and masticate food.
            - Types( based on appearance and function)
             Incisor, Canine, Premolar, Molar
           - Types (based on origin)
               Milk teeth, Permanent teeth


* Tongue- Fleshy muscular organ.
                - Attached at back to the floor of                              buccal cavity.
               - Front end is free(not attached)
              - Front end can be moved in all   
                direction.
            - Function- Taste food.
                             - Mix food with saliva.
                            - help in food swallowing


* Salivary glands- 3pairs in number.
                              - Secret saliva.
                             - Saliva digest carbohydrates 
                                (starch) into glucose.


* Food is pushed down by movement of wall of
   alimentary canal.


* Stomach- Thick walled bag.
                   - Flattened J shaped.
                  - Widest part of alimentary canal.


* Inner lining of stomach (gastric gland)secret-
           - mucous( cover stomach)
           - Hydrochloric acid(kills bacteria,
                                               activate pepsin)
          - Pepsin (Digest proteins)


* Liver- Reddish brown gland.
           - location- Upper right of abdomen
          - Largest gland in body.
          - Function- Secret bile juice (digest fats)


* Gall bladder- a sac that store bile juice.


* Pancreas- large cream colour gland
                   - located just below stomach.
                  - Function- secret pancreatic juice
            (digest carbohydrates,proteins and fats.)


* Small intestine
         - 7.5m highly coiled pipe.
         - It receives secretions from liver and   
            pancreas.
        - It secrets intestinal juice (digest
         carbohydrates,proteins and fats.)



* Results of digestion
Carbohydrates   -   Glucose
Proteins              - Amino acids
Fats                    - Fatty acids and glycerol


* Villi - Thousands of finger like outgrowth.
          - Present in inner surface of small     
             intestine.
          - Function- Increases surface area of
                               small intestine.
                           - Increases absorption of
                             digested food.


* Large intestine- 1.5meter long pipe.
                               - Wider and shorter than
                                  small intestine.
             - Function- Absorb water and minerals
                                 from undigested food.


* Anus- The faecal matter is removed through
               anus.


* Ingestion- Intake of food by body.


* Digestion- Break down of comple components
                      into simpler components.


* Absorption- Passing of digested food into
       blood vessels in the wall of small intestine.


* Assimilation- Transportation of absorbed
                             substances.
                        - And their utilisation.


* Egestion- Removal of faecal matter through
                     anus.


* Ruminants- Grass eating animals.
                      - These have rumen.


* Cellulose- A carbohydrate present in grass.


* Ruminants quickly swallow grass.
   - Store it in rumen( present between
      oesophagus and intestine)
  - Rumen have bacteria.
   - Bacteria digest cellulose.( Now food is     
     called   cud)
   - Cud return to mouth. They chew it. (This is
       rumination)


* Amoeba- Very very small organism.
                  - Single celled organism.
                  - Found in pond water.
                  - It has cell membrane, a rounded
                   and dense nucleus, many vacuoles


* Amoeba constantly change its shape and position.


* Pseudopodia- False feet of amoeba.
                         - Function- help in movement,   
                                             food capture


* Nutrition in Amoeba
- It feeds on very very small organism.
- it capture food with help of pseudopodia.
- Engulf the food into food vacuole.
- Digestive juices are secreted into food
   vacuole.
- Juices digest food.
- Undigested food is expelled outside by
   vacuole.