Digestive System

1. Odd one — Lipase
   Category of remaining — Sugars

2. Odd one — Gall bladder
   Category of remaining — Digestive glands

3. Odd one — Bile
   Category of remaining — Macronutrients

4. Odd one — Colon
   Category of remaining — Parts of the Small intestine

5. Odd one — Albumen
   Category of remaining — Digestive Enzymes

1. Canines
2. The mouth
3. finer crushing and grinding
4. biting, cutting
5. Canines
6. Premolars, Molars
7. 32
8. temporary teeth, 20

The process by which all organisms obtain or synthesize their food and convert it into simpler substances, so that it can be absorbed and utilized by the cells of the body is called nutrition.

Liver — The role of liver in the digestion of food is to produce a greenish yellow fluid called the bile that helps in emulsification (breaking down fats into tiny droplets).

Pancreas — It secretes the pancreatic juice that contains enzymes namely amylase, trypsin and lipase. This pancreatic juice acts on carbohydrates, proteins and fats and converts them into simpler units called glucose, amino acids and fatty acids respectively.

Digestive juice secreted by the stomach is the Gastric juice. The gastric juice contains water, hydrochloric acid and an enzyme pepsin. Its functions are:

1. Hydrochloric acid kills the germs preventing rotting of food during its long stay in stomach. It activates the enzyme pepsin.
2. Pepsin converts proteins into a simpler compound called peptones.

(i) Four types of teeth present in humans are:

1. Incisors
2. Canines
3. Premolars
4. Molars

(ii) Small intestine is a long coiled tube of about 7 metres. The food remains in it for about 3-5 hours for digestion and absorption. Small intestine has Duodenum and Ileum. Duodenum receives bile from liver and pancreatic juice from pancreas that help in the digestion of carbohydrates, proteins and fats. Semi-digested food is completely digested in the Ileum by the intestinal juices secreted by the intestinal glands present in the inner lining of Ileum. Villi are tiny finger-like projections present in the inner lining of the small intestine that greatly increase the inner surface area for absorption of the digested food. They absorb the amino acids and glucose. Vitamins and minerals salts are mostly soluble in water and are directly absorbed through the walls of the intestine.

(iii) Absorption of food means passing the digested food into the blood system and lymph vessels to be supplied to the rest of the body. Major portion of the digested food is absorbed by the villi present in the small intestine. It absorbs the amino acids and glucose to pass them into the blood system, whereas the fatty acids pass into the lymph vessels. Vitamins and minerals are soluble in water and are mostly absorbed through the walls of the intestine.

Egestion — The process of eliminating the undigested food through the anus is called Egestion.

Digestion — The process by which the complex chemical compounds present in the food are broken down into simpler substances that are readily absorbed and utilized by the body is called Digestion.

Assimilation — The utilization of the digested food and nutrients by the body cells is called Assimilation.

Oesophagus, Stomach, Small intestine, Large intestine.

Our body stores excess glucose as glycogen. During fasting or vigorous exercise, glycogen is rapidly broken down again to form a glucose unit.

The process by which the complex chemical compounds present in the food are broken down into simpler substances that are readily absorbed and utilized by the body is called digestion.

The four ways in which saliva is useful to us are:

1. It moistens and lubricates the mouth cavity and the tongue to make speaking and swallowing easy.
2. It cleans the mouth and destroys germs.
3. The saliva binds the food particles and makes it into a mass called the bolus.
4. Digestion begins in the mouth. Saliva contains an enzyme (amylase) which helps in the breakdown of starch to simple sugars (maltose).

The three groups into which the foods are classified are:

1. Energy-giving foods — They are made up of carbohydrates and fats. Carbohydrates provide us with instant energy, while fats are stored as energy resources. Its sources are:
   1. Rice
   2. Potato
   3. Fats
2. Body-Building foods — Proteins are considered to be body building food. Such foods help in the growth and repair of damaged cells and tissues. Its sources are:
   1. Pulses
   2. Milk
3. Protective foods — They are mainly vitamins and minerals. Minerals are needed for their specific roles in the body. Vitamins are needed for the normal functioning of various body processes. Its sources are
   1. Fruits and Vegetables
   2. Dairy products

Diagram of "vertical section of a grinding tooth"

(i) Enamel

(ii) Dentine

(iii) Cement

(iv) The acid produced by the bacteria slowly corrodes the enamel of the teeth and forms cavities known as caries

(v) Sometimes the sugary or starchy foods that we eat get stuck to the teeth. This along with bacteria on the teeth's surface form a yellow coloured film called plaque.

Canines

Reason — Canines are one on either side of the incisors in each jaw. They are pointed for tearing the food.

Wisdom tooth

Reason — The last molar in each side in each jaw is called the wisdom tooth.The wisdom tooth appears at the age of 17-20 years.

Enamel

Reason — Enamel is the hardest substance of the human body. It is the white visible part of the tooth and serves as the first line of defense against plaque and cavities.

Maltose

Reason — Saliva contains an enzymes (amylase) which helps in the break down of starch to simple sugars (maltose).

Rennin

Reason — The protein Casein present in the milk is converted into curd by the help of another enzyme, the Renin.

Liver

Reason — Bile juice is produced by the Liver and stored in the Gall Bladder.

Amylase

Reason — Saliva contains an enzyme amylase which helps in the breakdown of starch to simple sugars (maltose).

Gall bladder

Reason — The liver produces a greenish yellow fluid - the bile which is stored in the gall bladder, an organ found just below the liver.

Amino acids

Reason — The end product of protein is Amino acids.

Jejunum

Reason — No digestion takes place in the second part of the small intestine called Jejunum.

1. Glucose
2. Stomach
3. Duodenum
4. Lipase
5. Glucose
6. Large intestine
7. Amino acid
8. Carbohydrates, Proteins, Fats, Minerals, and Vitamins
9. Ingestion, Digestion, Absorption, Assimilation, and Egestion
10. Salivary glands, Liver, and Pancreas
11. Incisors, Canines, Premolars, and Molars
12. Duodenum, Jejunum, and Ileum
13. Caecum, Colon, and Rectum
14. Amylase, Maltase, and Lactase
15. Pepsin, Trypsin, and Rennin

The four types of teeth shown in the figure are listed below along with their functions:

• A → Incisors
  Function — Incisors are used for biting and cutting.
• B → Canines
  Function — Canines are used for tearing the food.
• C → Premolars
  Function — Premolars help in crushing and grinding the food.
• D → Molar
  Function — Molars help in finer crushing and grinding of food.

(i) Bile juice.

(ii) Gall Bladder

(iii) Bile juice breaks down the fats into tiny droplets and this process is called emulsification.

Three enzymes found in the pancreatic juice and their functions are given below:

1. Amylase — It acts on the starch converting it into maltose.
2. Trypsin — It converts proteins and peptones into peptides.
3. Lipase — It converts emulsified fats into fatty acids and glycerol.

The three regions of the large intestine are:

1. Caecum
2. Colon
3. Rectum

(i) The parts are

1. Stomach
2. Bile duct
3. Pancreas
4. Large intestine
5. Small intestine
6. Rectum
7. Appendix
8. Duodenum
9. Gall bladder
10. Liver
11. Anus

(ii) The juice secreted by part (1) is the Gastric juice.Gastric juice being acidic in nature kills the germs and activates pepsin.

(iii) The function of the three enzymes found in the gastric juice are

1. Amylase enzyme digest starch into maltose.
2. Trypsin enzyme digest proteins into peptides.
3. Lipase enzyme digest emulsified fats into fatty acids anf glycerols.

1. Nutrients — A nutrient can be defined as "a constituent of food that helps one way or the other in the body's functions".

2. Nutrition — The process by which all organisms obtain or synthesize their food and convert it into simpler substances, so that it can be absorbed and utilized by the cells of the body is called nutrition.

3. Wisdom teeth — The last molar on each side in each jaw is called the Wisdom Tooth. The wisdom tooth appears at the age of 17-20 years. In some people, however, wisdom teeth may not come out of the gums at all.

4. Emulsification — The bile juice breaks down fats into tiny droplets and this process is called emulsification.

5. Egestion — The process of eliminating the undigested food through the anus is called egestion.

1. False
   Reason — Molars help in finer crushing and grinding the food.

2. True
   Reason — The end products of carbohydrate digestion are simple sugars (glucose & fructose) which can easily be absorbed in our blood system.

3. False
   Reason — Proteins are digested into amino acid.

4. False
   Reason — The wisdom tooth appears at the age of 17-20 years. In some people, however, wisdom teeth may not come out of the gums at all.

5. False
   Reason — The temporary teeth consist of 20 teeth (8 incisors, 4 canines and 8 molars only).

6. False
   Reason — The ducts from the salivary glands open into the mouth.

7. True
   Reason — Saliva contains an enzyme called amylase which converts starch into maltose.