PREPARED BY:

Saritha P, JNV Palakkad

NAVODAYA VIDYALAYA SAMITI, NOIDA

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E-CONTENT PREPARATION

CLASS – VII -SCIENCE

CHAPTER – 2

NUTRITION IN ANIMALS

CHAPTER 2

NUTRITION IN ANIMALS

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• Animal nutrition
• Ways of food intake
• Human digestive tract
• Steps in human digestion
• Important gland related to digestion
• Digestion in herbivores
• Nutrition and digestion in amoeba

TOPICS TO BE COVERED

• Students comes to know about the difference between animal nutrition and plant nutrition
• Students understand about the nutrition in starfish
• Students learn human digestive system
• Students analyze the various steps in human digestion
• Students know that the digestion of starch start from the mouth.
• Students can understand the glands associated with digestion inhuman beings and their functions
• Students can learn digestion in herbivores
• Students compare the mode of digestion and nutrition in amoeba and human being?

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OBJECTIVES

ANIMAL NUTRITION INCLUDES

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• NUTRITIONAL REQUIRMENT

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• MODE OF INTAKE

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• UTILIZATION BY THE BODY

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• CARBOHYDRATES
• FATS
• PROTEINS
• VITAMINS
• MINERALS

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DIGESTION

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BREAKING DOWN OF COMPLEX FOOD TO SIMPLE SUBSTANCES

THE MODE OF INTAKE OF FOOD VARY IN DIFFERENT ORGANISMS

NAME THE KIND OF FOOD AND THE MODE OF FEEDING BY DIFFERENT ANIMAL

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NUTRITION IN STAR FISH

• Feeds on animals covered by hard shells.
• Star fish pops out its stomach through its mouth to eat the soft animal inside the shell.
• Stomach then go backs into the body.
• The food is slowly digested.

STEPS IN ANIMAL NUTRITION

1. INGESTION: Method of obtaining food by an animal
2. DIGESTION: Breaking down of complex food into simpler molecules
3. ABSORPTION:Taking of digested food particles into blood
4. ASSIMILATION:Utilisation of digested food for energy and materials essential for the body
5. EGESTION:Removal of waste from the body

HUMAN DIGESTIVE SYSTEM

PARTS OF DIGESTIVE SYSTEM

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• The food passes through a continuous canal called digestive tract
• Digestive tract includes 1) mouth 2)buccal cavity 3)food pipe(oesophagus) 4)stomach 5)small intestine 6)large intestine 7)rectum 8)anus

THE GLANDS ASSOCIATED WITH THE ALIMENTARY CANAL ARE

• Salivary glands
• Liver
• Pancreas
• Gall bladder

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MOUTH

• WE INTAKE THE FOOD THROUGH MOUTH
• CHEW THE FOOD WITH TEETH AND BREAK THE FOOD MECHANICALY INTO SMALL PIECES

THERE ARE TWO SETS OF TEETH

1.MILK TEETH(20 IN NUMBER) THE FIRST SET OF TEETH

2.PERMANENT TEETH(32 IN NUMBER)

OUR TEETH

FUNCTIONS OF EACH TEETH

• INSCISORS TO CUT THE FOOD LIKE A SCISSOR
• CANINE TO TEAR THE FOOD LIKE A FORK
• PRE MOLARS AND MOLARS

TO GRIND THE FOOD

DENTAL FORMULA

ADULT 2,1,2,3/2,1,2,3*2

CHILD 2,1,0,2/2,1,0,2*2

TOOTH DECAY

STEPS OF TOOTH DECAY

• Left over food in the mouth
• Bacteria break down the sugars
• Produce acid
• These acids damage the enamel of our teeth
• Tooth decay start

TONGUE

• Muscular organ in the mouth
• Covered with moist, pink tissue –mucosa
• Tiny bumps called papillae present
• Thousand of taste buds cover papillae

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FUNCTIONS OF TONGUE

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• To know the taste
• Mix the food with saliva
• Help to swallow
• To talk

• Sweet- At the tip of the tongue
• Salt- At the either side of the front of the tongue
• Sour –Sour buds are behind the salty buds
• Bitter –Bitter buds are at the back

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TASTE BUDS

• Help to taste
• Replaced by every two weeks
• Average person has10000 taste buds
• Smoking reduce the number of taste buds

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TONGUE PROBLEMS

• SORES
• SWEKLLING
• TONGUE CANCER
• TONGUE ULCERS

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Most of the tongue problems can be prevent by good oral hygiene

OESOPHAGUS

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• From the mouth food enters to oesophagus

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• Its about 22-25cm long

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• It’s a muscular and tubular structure

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• Wave like movement which push the food is called PERISTALSIS

STOMACH

• Food enters the stomach through oesophagus
• It’s a ‘j’ shaped muscular bag
• Located at the left side of the upper abdomen
• Its about 30cm long and 15cm wide
• It can hold 2liters of food at a time

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SECRETIONS OF STOMACH

INNER LINING SECRETES

• Mucous-protect the inner lining
• Hydrochloric acid –kills bacteria helps in the digestion of protein
• Digestive juices –break down protein into simpler substances

SMALL INTESTINE

FROM THE STOMACH FOOD ENTERS TO IT

• Its highly coiled structure
• About 7.5 meters long
• Receives secretions from pancreas and liver
• Its walls also secretes some juices
• Digestion is completed in small intestine
• Small finger like structures called villi to increase the area of absorption

LARGE INTESTINE

From the small intestine the left over food enters to the large intestine.

• Its about 1.5 meters long.
• Shorter and wider than small intestine.
• Absorption of water takes place here.
• Undigested food is removed as faecal matter.

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RECTUM AND ANUS

RECTUM

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• Lying at the end of the large intestine.
• Muscular organ about 15 cm long.
• It opens through the anus.
• Stores the undigested food as faecal matter.

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ANUS

• Lies at the base of the abdomen.
• Through this solid waste substance leave the body.

GLANDS ASSOCIATED WITH DIGESTIVE SYSTEM

1)SALIVARY GLANDS:

• PRODUCES SALIVA THROUGH A SYSTEM OF DUCTS.
• SALIVA CONTAINS THE ENZYME AMYLASE WHICH DIGESTS STARCH.
• PREVENTS MICROBIAL GROWTH IN THE MOUTH.
• 0.5 TO 1.5 LITRES OF SALIVA PRODUCED EVERY DAY IN HUMANS.
• ENCOURAGES TISSUE REPAIR.
• ACT AS A SOLVENT FOR FOOD.

2)LIVER:

• Reddish –brown in colour.
• Situated on the right side in the upper part of the abdomen.
• Largest gland of the body.
• Secrete bile juice.
• Bile juice stored in a sac called gall bladder.
• Important role in the digestion of fat.
• Has the power of regeneration.

3)PANCREAS:

• It’s a cream coloured gland.
• Located just below the stomach.
• Produces pancreatic juice.
• It acts on carbohydrates and proteins and changes them into simpler forms.
• Produce insulin to regulate sugar level.

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• Series of reactions with food and digestive hormones and juices
• Digestion of starch starts from the oral cavity

Activity

• Take two test tubes
• Add boiled rice in one test tube
• Add teaspoon full of 4to 5 minutes chewed boiled rice in second testtube
• Add 10mi of water to both
• Add 5drops of iodine solutions to both the test tube
• Rice in first test tube turns blue black colour indicates the presence of starch
• Second test tube no change
• Saliva acts on starch and digest it

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PROCESS OF DIGESTION IN HUMAN BEINGS

ACTION OF SALIVA ON STARCH

• Food moves to the stomach through the esophagus by peristalsis movement
• By the secretions of stomach the food digested and proteins are converted into simpler form
• Partly digested food enters to small intestine as chyme
• Pancreatic juice acts on carbohydrates and fats
• Biles juice acts on fats
• CARBOHYDRATES TO GLUCOSE
• PROTEINS TO AMINOACIDS
• FATS TO FATTY ACIDS AND GLYCEROL
• Digestion will complete and absorption takes place in small intestine
• Villi helps to increase absorption area
• Food enters to large intestine for water absorption
• Waste materials will store in rectum
• Removed through anus as faecal matter

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WHOLE PROCESS OF DIGESTION CAN SUMMARIES AS FOLLOWS

RUMINANTS

Ruminants are the grass eating animals which has rumen. Example: cow.

The digestive tract consist of the following:

• MOUTH
• OESOPHAGUS
• A FOUR COMPARTMENT STOMACH

1)RUMEN

2)RETICULUM

3)OMASUM

4)ABOMASUM

• SMALL INTESTINE
• LARGE INTESTINE

Rumen consists of special bacteria which could digest cellulose.

RUMINATION

• Half chewed food swallowed and goes from mouth to the rumen.
• Bacteria acts on the food and digest cellulose.
• Then the food enter into the second muscular chamber called reticulum.
• This half digested food called cud.
• Send back to mouth to be chewed again .
• Chewing of the cud is called rumination.
• This type of animals are called ruminants.

NUTRITION IN AMOEBA

1)INGESTION:Obtains food by its pseudopodia surrounds and engulfs it.

2)DIGESTION:The food digested in the food vacuole by the digestive enzymes.

3)ABSORPTION:The digested food is absorbed into the cytoplasm.

4)ASSIMILATION:Absorbed nutrients utilised for releasing energy.

5)EGESTION:Waste materials are discharged into the surroundings by rupturing the food vacuoles.

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Answer the following questions?

1. What are villi? Write its location and function?
2. Name the largest gland of our body?
3. Sketch digestive system of human beings and label the parts?
4. Why the carnivorous animals have large and sharp canines?
5. What is assimilation? Write its importance?
6. Why do we taste food sweeter after chewing it for a longer time
7. Why we could not feel bitter guards taste at the tip of our tongue?
8. The ruminants can live by eating grasses but the human could not. Why?
9. What are pseudopodia ?
10. Write the importance of peristalsis?�

ASSIGNMENT

Write an assignment on the common digestive problems in human beings? How can we prevent it?

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