Nutrition in Animals with notes (हिंदी में) || Class 7 Chapter 2 Science ||

Nutrition in Animals with notes (हिंदी में) || Class 7 Chapter 2 Science ||


Class 7, Chapter 2
Nutrition in Animals
1.       Nutrients – Substance that provides nourishment (खाना) needed for growth & maintenance of life.
2.       It contains carbohydrates, vitamins, proteins, minerals & fats.
3.       Animals get their food from plants, either directly by eating plants or indirectly by eating animals that eat plants.
4.       The components of food like carbohydrates are complex substances & they are broken down into simpler substances, it is called digestion.
DIFFERENT WAYS OF TAKING FOOD
1.       Bees (मधु-मक्खी) and humming-birds suck (चूसना) the nectar (पराग or रस) of plants.
2.       Infants (शिशु) of human and many other animals feed on mother’s milk.
3.       Snakes like the python (अजगर) swallow (निगल लेना) the animals they prey upon (शिकार करना).
4.       Some aquatic animals filter tiny food particles floating nearby and feed upon them.
DIGESTION IN HUMANS
1.       We take in food through the mouth, digest and utilise (उपयोग करना) it.
2.       The unused parts of the food are defecated (मलत्याग करना).
3.       The food passes through a continuous canal which begins at the buccal cavity and ends at the anus (मलद्वार).
4.       The canal can be divided into various compartments: (1) The buccal cavity, (2) foodpipe or oesophagus, (3) stomach, (4) small intestine, (5) large intestine ending in the rectum (6) the anus
5.       These parts together form the alimentary canal (पोषण नली ) (digestive tract).
6.       Alimentary canal is 9m long structure extending from mouth to anus.
7.    The digestive tract and the associated glands (ग्रन्थि) together constitute the digestive system.
           
   
The mouth and buccal cavity
Food is taken into the body through the mouth and this process is called ingestion (अंतरग्रहण).
In Buccal cavity teeth, tongue & saliva (थूक or लार) are present
Teeth – we chew (चबाना) the food with the teeth and break it down into small pieces.
Each tooth is rooted (धंसना) in a separate socket in the gums (मसूड़ा)
Our teeth vary in appearance (दिखावट) and perform different functions.
Saliva – Food is moistened (गीला करना) & made it softer
Saliva contains enzyme (called salivary amylase) & converts starch (complex form of carbohydrates) to sugar (simple form of carbohydrates)
Tongue - We use our tongue for talking, mix saliva with the food during chewing and help in swallowing (निगल लेना) food & also taste food with our tongue due to has taste buds (स्वाद-कलिका) that detect different tastes of food
Primary/Milk and Permanent teeth
Milk teeth
1.       Temporary teeth
2.       Later replaced with permanent teeth
3.       Fall off (गिरना) at the age between 6 - 8 years
4.       Total 20 in number – Incisors – 8, canine – 4, Molar- 8
Permanent Teeth
1.       Never get replaced
2.       Total 32 in number
3.       It may last throughout life or fall off during old age or due to some dental disease
4.       Incisors (help in biting (काटना) food) – 8
5.       canine (sharpest, help in tearing (काट कर अलग करना) food) – 4
6.       Molar (broad (चौड़ा) chewing surface with multiple cusps (नोक), three types of it and 3rd molar [at last position] teeth are called wisdom (बुद्धि) teeth)- 12
7.       premolar (help in grinding (पिसना)) – 12
             
                 
Note
1.       Normally bacteria are present in our mouth but they are not harmful (हानिकारक) to us.
2.       However, if we do not clean our teeth and mouth after eating, many harmful bacteria also begin to live and grow in it.
3.       These bacteria break down the sugars present from the leftover food and release acids.
4.       The acids gradually damage (नष्ट करना) the teeth

Subscribe My You Tube channel- Competitive World Knowledge

To get the videos FOR UPSC, State PCS, SSC CGL, Bank PO, RBI,...
Class 6th to 12th Politics, History, Geography, Economy
Class 7th to 10th Science……Spoken English Videos

The Pharynx and the foodpipe/oesophagus
Pharynx
1.       Common passage of food and air
2.       It connects both food pipe & wind pipe.
3.       No digestion happen here

Subscribe My You Tube channel- Competitive World Knowledge

To get the videos FOR UPSC, State PCS, SSC CGL, Bank PO, RBI,...
Class 6th to 12th Politics, History, Geography, Economy
Class 7th to 10th Science……Spoken English Videos

Food pipe/Oesophagus
1.       The swallowed (निगलना) food passes into the foodpipe or oesophagus.
2.       The foodpipe runs along the neck and the chest.
3.       Food is pushed down by movement of the wall of the foodpipe.
4.       At times the food is not accepted by our stomach and is vomited out (निकाल देना or उल्टी करना).
5.       No digestion happen here
                   
                     
The stomach
1.       The stomach is a thick-walled bag.
2.       Its shape is like J and it is the widest (चौड़ा) part of the alimentary canal.
3.       It receives food from the food pipe at one end and opens into the small intestine at the other.
4.       The inner lining of the stomach secretes (निकालना) mucous (बलगम or चिपचिपा), hydrochloric acid and digestive juices/Enzymes (pepsin).
5.       The mucous protects the lining of the stomach.
6.       The acid kills many bacteria that enter along with the food and makes the medium in the stomach acidic and helps the digestive juices to act.
7.       The digestive juices break down the proteins into simpler substances.
8.       Digestion happens here with the help of gastric (पेट का) enzymes.
Subscribe My You Tube channel- Competitive World Knowledge

To get the videos FOR UPSC, State PCS, SSC CGL, Bank PO, RBI,...
Class 6th to 12th Politics, History, Geography, Economy
Class 7th to 10th Science……Spoken English Videos

             

Digestive glands – Liver & Pancreas
Liver
1.       It is the largest gland (ग्रंथि).
2.       It is a reddish brown gland situated in the upper part of the abdomen (पेट) on the right side
3.       It secretes (निकालना) bile juice stored in gall bladder
4.       This bile juice digests the fats.
5.       This juice makes the medium alkaline (Basic in nature)
6.       In the basic environment, it activates the action of pancreatic & intestinal enzymes
Subscribe My You Tube channel- Competitive World Knowledge

To get the videos FOR UPSC, State PCS, SSC CGL, Bank PO, RBI,...
Class 6th to 12th Politics, History, Geography, Economy
Class 7th to 10th Science……Spoken English Videos

Pancreas
1.       It is the second largest gland
2.       It is a large cream coloured gland located just below the stomach
3.       The pancreatic juice acts on carbohydrates, fats and proteins and changes them into simpler forms


The small intestine
1.       The small intestine is highly coiled and is about 7.5 metres long.
2.       It receives secretions from the liver and the pancreas.
3.       Besides (इसके अलावा), its wall also secretes (निकालना) juices.
4.       The partly (कुछ) digested food now reaches the lower part of the small intestine where the intestinal juice completes the digestion of all components of the food.
5.       Like the carbohydrates get broken into simple sugars such as glucose, fats into fatty acids and glycerol (चरबी से निकाला हुआ एक सत्त्व), and proteins into amino acids.
Subscribe My You Tube channel- Competitive World Knowledge

To get the videos FOR UPSC, State PCS, SSC CGL, Bank PO, RBI,...
Class 6th to 12th Politics, History, Geography, Economy
Class 7th to 10th Science……Spoken English Videos

Absorption in the small intestine
1.       The digested food can now pass into the blood vessels (नाड़ी) in the wall of the intestine.
2.       This process is called absorption.
3.       The inner walls of the small intestine have thousands of finger-like structure.
4.       These are called villi.
5.       The villi increase the surface area for absorption of the digested food.
6.       Each villus has a network of thin and small blood vessels close to its surface.
7.       The surface of the villi absorbs the digested food materials.
8.       The absorbed substances are transported via the blood vessels to different organs of the body where they are used to build complex substances such as the proteins required by the body.
9.       This is called assimilation.
10.   In the cells, glucose breaks down with the help of oxygen into carbon dioxide and water, and energy is released.
Sugar/Glucose + Oxygen → carbon dioxide + water + energy
C6H12O6 + 6O2 → 6CO2 + 6H2O
11.   The food that remains undigested and unabsorbed enters into the large intestine.
Large intestine
1.       The large intestine is wider and shorter than small intestine.
2.       It is about 1.5 metre in length.
3.       Its function is to absorb water and some salts from the undigested food material.
4.       The remaining waste passes into the rectum (मलाद्धार) and remains there as semi-solid faeces (मल).
5.       The faecal matter is removed through the anus (मलद्वार) from time-to-time.
6.       This is called egestion.
Subscribe My You Tube channel- Competitive World Knowledge

To get the videos FOR UPSC, State PCS, SSC CGL, Bank PO, RBI,...
Class 6th to 12th Politics, History, Geography, Economy
Class 7th to 10th Science……Spoken English Videos

DIGESTION IN GRASS-EATING ANIMALS
1.       Have you observed cows, buffaloes and other grass-eating animals chewing (जुगाली करना) continuously even when they are not eating?
2.       Actually, they quickly swallow (निगलना) the grass and store it in a part of the stomach called rumen.
3.       Here the food gets partially digested and is called cud.
4.       But later the cud returns to the mouth in small lumps (ढेर) and the animal chews (जुगाली करना) it.
5.       This process is called rumination and these animals are called ruminants.
6.       The grass is rich in cellulose, a type of carbohydrate.
7.       In ruminants like cattle, deer, etc., bacteria present in rumen helps in digestion of cellulose.
8.       Many animals, including humans, cannot digest cellulose.
9.       Animals like horses, rabbit, etc., have a large sac (थैली)-like structure called Caecum between the oesophagus and the small intestine.
10.   The cellulose of the food is digested here by the action of certain bacteria which are not present in humans.
                    
      
FEEDING AND DIGESTION IN AMOEBA
1.       Amoeba is a microscopic single-celled organism found in pond water.
2.       Amoeba has a cell membrane, a rounded, dense nucleus and many small bubble-like vacuoles in its cytoplasm (कोशिका द्रव्य).
3.       Amoeba constantly changes its shape and position.
4.       It pushes out one, or more finger-like projections, called pseudopodia or false feet for movement and capture of food.
5.       Amoeba feeds on some microscopic organisms.
6.       When it senses food, it pushes out pseudopodia around the food particle and absorbs (निगलना) it.
7.       The food becomes trapped in a food vacuole.
8.       Digestive juices are secreted (निकालना) into the food vacuole.
9.       They act on the food and break it down into simpler substances.
10.   Gradually the digested food is absorbed.
11.   The absorbed substances are used for growth, maintenance and multiplication.
12.   The undigested residue of the food is expelled (निकाल देना) outside by the vacuole.
                                     


Comments

Popular posts from this blog