{"id":88279,"date":"2021-06-23T17:49:01","date_gmt":"2021-06-23T12:19:01","guid":{"rendered":"https:\/\/kseebsolutions.guru\/?p=88279"},"modified":"2021-07-01T20:45:21","modified_gmt":"2021-07-01T15:15:21","slug":"1st-puc-biology-question-bank-chapter-16","status":"publish","type":"post","link":"https:\/\/kseebsolutions.guru\/1st-puc-biology-question-bank-chapter-16\/","title":{"rendered":"1st PUC Biology Question Bank Chapter 16 Digestion and Absorption"},"content":{"rendered":"

Karnataka 1st PUC Biology Question Bank Chapter 16\u00a0Digestion and Absorption<\/h2>\n

1st PUC Biology Digestion and Absorption One Marks Questions and Answers<\/h3>\n

Question 1.
\nWhat is succus entericus?
\nAnswer:
\nIt is the intestinal juice.<\/p>\n

\"1st<\/p>\n

Question 2.
\nWhat is hyperacidity?
\nAnswer:
\nHyperacidity is a condition where there is an over-secretion of HCl in the stomach.<\/p>\n

Question 3.
\nName any two associated glands of the human alimentary canal.
\nAnswer:
\nSalivary gland, Liver \/ Pancreas.<\/p>\n

Question 4.
\nWhat is Chyme?
\nAnswer:
\nThe acidic semisolid food entering into the intestine from stomach, is called as chyme.<\/p>\n

Question 5.
\nMention the function of steapsin.
\nAnswer:
\nSteapsin hydrolyses fat emulsion, into fatty acids, and glycerol.<\/p>\n

\"1st<\/p>\n

Question 6.
\nWhat is the function of caecum in the human body?
\nAnswer:
\nCaecum is present at the junction of small and large intestines, and it connects the small and large intestines.<\/p>\n

Question 7.
\nWhat is mastication?
\nAnswer:
\nMastication is the process of chewing of food. Teeth plays an important role.<\/p>\n

Question 8.
\nWhat is bolus?
\nAnswer:
\nBolus is the soft mass of the semi – masticated food along with the addition of saliva in the mouth.<\/p>\n

\"1st<\/p>\n

Question 9.
\nWhere is the bile stored?
\nAnswer:
\nIn the gall bladder.<\/p>\n

Question 10.
\nMention the position of the liver.
\nAnswer:
\nIt is located below the diaphragm towards the right side of the abdominal cavity.<\/p>\n

Question 11.
\nChoose the correct answer among the following:
\n(a) Gastric juice contains.
\n(i) pepsin, lipase and rennin.
\n(ii) trypsin, lipase and rennin.
\n(iii) trypsin, pepsin and lipase.
\n(iv) trypsin, pepsin and rennin.
\nAnswer:
\n(i) pepsin, lipase and rennin.<\/p>\n

(b) Succus entericus is the name given to,
\n(i) a junction between the ileum and large intestine.
\n(ii) intestinal juice.
\n(iii) swelling in the gut.
\n(iv) appendix.
\nAnswer:
\n(ii) intestinal juice.<\/p>\n

\"1st<\/p>\n

1st PUC Biology Digestion and Absorption Two Marks Questions and Answers<\/h3>\n

Question 1.
\nExplain the role of saliva indigestion.
\nAnswer:
\nSalivary amylase acts on starch and glycogen and converts them into maltose units.
\n\\(\\text { Starch, Glycogen + Water } \\frac{\\text { Salivary amylase }}{\\mathrm{pH} 6.8 \\mathrm{to} 7.2}{\\longrightarrow} \\text { Maltose units. }\\)
\nThe water and mucin soften the food particles. The lysozyme destroys the bacteria.<\/p>\n

Question 2.
\nDistinguish between mechanical digestion from chemical digestion.
\nAnswer:<\/p>\n\n\n\n\n
Mechanical digestion<\/strong><\/td>\nChemical digestion<\/strong><\/td>\n<\/tr>\n
1.\u00a0\u00a0 It is a process in which there is cutting, chewing by teeth, and churning of food in alimentary canal.
\n2.\u00a0 Enzymes are not involved.<\/td>\n		1.\u00a0\u00a0 It is a process in which hydrolysis of the enzymes takes part in the breaking of the food molecules.
\n2.\u00a0\u00a0 Enzymes are involved.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Question 3.
\nWhat is Dentition? Write the dental formula of human beings.
\nAnswer:
\nDentition is the arrangement of teeth in the oral cavity. The human dentition is defined as.
\nThecodont : Teeth are located within the sockets of jaw bone.
\nDiphyodont: Humans develop two sets of teeth in his life time, i.e., milk teeth, and permanent teeth set.
\nHeterodont: Teeth are of different types like incisors, canines, molars, and premolars.
\nThe dental formula of man is
\n\"1st<\/p>\n

\"1st<\/p>\n

Question 4.
\nWhat is Jaundice? Mention the types.
\nAnswer:
\nJaundice is the yellowing of the skin and sclera of the eyes, due to excess bilirubin in the blood. The different types of jaundice are:
\na. Haemolytic jaundice
\nb. Obstructive jaundice
\nc. Viral jaundice<\/p>\n

Question 5.
\nMention the role of HCl in digestion.
\nAnswer:
\na. It activates inactive pepsinogen into active pepsin.
\nb. It converts inactive prorenin into active renin.
\nc. It provides acidic medium (pH 1.5 – 2.5) for the action of both pepsin, and renin.
\nd. HCl kills harmful bacteria, and loosens fibrous food.
\ne. It inactivates the ptyalin.<\/p>\n

Question 6.
\nName the various parts of human alimentary canal in the proper sequence.
\nAnswer:
\nThe various parts of human alimentary canal are mouth buccal cavity, pharynx, oesophagus, stomach, small intestine, large intestine and anus.<\/p>\n

Question 7.
\nMatch column I with column II
\nColumn I — column II
\n(a) Bilirubin and biliverdin — (i) Parotid
\n(b) Hydrolysis of starch — (ii) Bile
\n(c) Digestion of fat — (iii) Lipases
\n(d) Salivary gland — (iv) Amylases
\nAnswer:
\n(a) (ii), (b) (iv), (c) (iii), (d) (i).<\/p>\n

Question 8.
\nGive the dental formula of human beings.
\nAnswer:
\nThe dental formula of human
\n\"1st<\/p>\n

Question 9.
\nBile juice contains no digestive enzymes, yet it is important for digestion. Why?
\nAnswer:
\nBile salts help in the emulsification of fats.<\/p>\n

Question 10.
\nDescribe the digestive role of chymotrypsin. Which two other digestive enzymes of the same category are secreted by its source gland?
\nAnswer:
\nIntestinal Glands :
\nThese are present in the inner mucosa of small intestine. There are 4 types of intestinal glands.
\nthey are:
\n1. Glands of crypts of lieberkuhn.
\n2. Payer\u2019s glands.
\n3. Brunner\u2019s glands.
\n4. Solitaiy. glands.
\nOut of these glands, crypts of lieberkuhn secretes intestinal juice (Succus entericus), While others secrete an alkaline secretion which protects the intestinal lining from bacterial infection.<\/p>\n

\"1st<\/p>\n

Components of Food (Concept of Balanced Diet):
\nA balanced diet is one which contains the right proportion of the seven nutrients namely carbohydrates, fats, proteins, vitamins, minerals, water, and roughage (Fibrous component)
\nrequired to maintain good health.<\/p>\n

Carbohydrates and lipids (fats) provide energy for the body. Proteins are required for growth, maintenance and repair of worn out tissues. Water, minerals, and vitamins are essential for
\nmaintaining normal metabolism.<\/p>\n

The correct and recommended proportion of balanced diet is represented as follows.
\nCarbohydrates – 64%, Proteins – 14%, Lipids-2 1%, Vitamins, and minerals -. 1%.
\nIn addition, large amount of roughage consisting of mainly fibrous cellulose is also important.<\/p>\n

Question 11.
\nHow are polysaccharides, and disaccharides digested?
\nAnswer:
\n(a) Digestion in the mouth : The salivary amylase or ptyalin converts starch and glycogen into maltose units.
\n\\(\\text { Starch the Glycogen }+\\text { Water } \\frac{\\text { Salivary amylase }}{\\mathrm{pH} 6.8 \\mathrm{to} 7.2}{\\longrightarrow} \\text { Maltose units }\\)<\/p>\n

b. Digestion in intestine :
\nPancreatic juice : Carbohydrase secreted by pancreas is called pancreatic amylase. It converts starch and glycogen into maltose units.
\n\\(\\text { Starch Glycogen } \\frac{\\text { Pancreaticamylase }}{\\mathrm{pH} 7.1-8.2} \\rightarrow \\text { Maltose units. }\\)<\/p>\n

Intestinal juice : It consists of three types of carbohydrases.
\nMaltase : Maltase catalyses hydrolysis of maltose (disaccharide) into glucose units (monosaccharides).
\n\\(\\text { Maltose } \\frac{\\text { Maltase }}{\\mathrm{pH} 7 . \\mathrm{to8} .2} \\text { Glucose }+\\text { Glucose. }\\)<\/p>\n

Sucrase : Sucrase catalyses the splitting of sucrose (disaccharide) into glucose, and fructose units (monosaccharides).
\n\"1st<\/p>\n

\"1st<\/p>\n

Lactase : Lactase acts on milk sugar lactose (disaccharide), and splits lactose into galactose, and glucose units (monosaccharides).
\n\\(\\text { Lactose } \\frac{\\text { Lactase }}{p H^{7.11082}} \\text { Glucose }+\\text { Galactose. }\\)<\/p>\n

Question 12.
\nWhat would happen if HCl were not secreted in the stomach?
\nAnswer:
\nNon-secretion of HCl in the stomach will result in the following.
\n(i) Food will not become soft, and so it will not be easily broken in stomach.
\n(ii) Microbes will grow in stomach, and cause fermentation.
\n(iii) Milk will not be curdled.
\n(iv) Pepsinogen will not be changed into pepsin.
\n(v) Pepsin will not be able to bring about digestion of proteins.<\/p>\n

Question 13.
\nHow does butter in your food get digested and absorbed in the body?
\nAnswer:
\nFirst emulsification takes place by bile juice and digestion by steapsin to are absorbed by.<\/p>\n

\"1st<\/p>\n

Question 14.
\nExplain the term the codont and diphyodont.
\nAnswer:
\nThe human teeth are Diphyodont because 2 sets of teeth (Milk teeth, and Permanent teeth) are formed during the life time. Human teeth are thecodont because all the teeth are inserted in the sockets. The arrangement of teeth on the jaws is called Dentition. The dental formula of human
\n\"1st<\/p>\n

Question 15.
\nName different types of teeth and their number in an adult human.
\nAnswer:
\nThe tongue is attached to the buccal cavity by a soft ligamentous structure called Frenum or Frenulum. Tongue helps in ingestion of food substance, mixing the food with saliva, tasting, and also for speech. Both upper and lower jaw contain teeth. In Humans, teeth are heterodont because 4 different types of teeth are present. They are.
\n(1) Incisors (Cutting teeth)
\n(2) Canines (Tearing teeth)
\n(3) Premolars and
\n(4) Molars (Grinders).<\/p>\n

\"1st<\/p>\n

Question 16.
\nWhat are the functions of liver?
\nAnswer:
\nIt is an accessory gland that is situated outside the Alimentary canal. It is situated just below the diaphragm and attached slightly towards the right side partly covering the stomach. Liver
\nis the largest gland in the human body, weighing about 1.5 Kg (in adults).
\nIt consists of 4 lobes namely:
\n1. Right lobe (largest lobe).
\n2. Left lobe (Smallest lobe).
\n3. Caudale lobe and
\n4. Quadrate tobe.
\nLiver is an exocrine gland because it secretes. Its secretion called bile juice is passed through the bile duct. The bile juice is stored in gall blabber.<\/p>\n

Question 17.
\nDescribe the enzymatic action on fats in the duodenum.
\nAnswer:
\nIn duodenum, pancreatic lipase or steapsin is available for digestion of fats. However, digestion is incomplete due to the brief stay of food.<\/p>\n

1st PUC Biology Digestion and Absorption Three Marks Questions and Answers<\/h3>\n

Question 1.
\nDescribe how carbohydrates are digested in the human alimentary canal.
\nAnswer:<\/p>\n

(a) Digestion in the mouth : The salivary amylase or ptyalin converts starch and glycogen into maltose units.
\n\\(\\text { Starch the Glycogen }+\\text { Water } \\frac{\\text { Salivary amylase }}{\\mathrm{pH} 6.8 \\mathrm{to} 7.2}{\\longrightarrow} \\text { Maltose units }\\)<\/p>\n

b. Digestion in intestine :
\nPancreatic juice : Carbohydrase secreted by pancreas is called pancreatic amylase. It converts starch and glycogen into maltose units.
\n\\(\\text { Starch Glycogen } \\frac{\\text { Pancreaticamylase }}{\\mathrm{pH} 7.1-8.2} \\rightarrow \\text { Maltose units. }\\)<\/p>\n

Intestinal juice : It consists of three types of carbohydrases.
\nMaltase : Maltase catalyses hydrolysis of maltose (disaccharide) into glucose units (monosaccharides).
\n\\(\\text { Maltose } \\frac{\\text { Maltase }}{\\mathrm{pH} 7 . \\mathrm{to8} .2} \\text { Glucose }+\\text { Glucose. }\\)<\/p>\n

Sucrase : Sucrase catalyses the splitting of sucrose (disaccharide) into glucose, and fructose units (monosaccharides).
\n\"1st<\/p>\n

Lactase : Lactase acts on milk sugar lactose (disaccharide), and splits lactose into galactose, and glucose units (monosaccharides).
\n\\(\\text { Lactose } \\frac{\\text { Lactase }}{p H^{7.11082}} \\text { Glucose }+\\text { Galactose. }\\)<\/p>\n

\"1st<\/p>\n

Question 2.
\nAnswer briefly:
\n(a) Why are villi present in the intestine, and not in the stomach?
\n(b) How does pepsinogen changes into its active form?
\n(c) What are the basic layers the wall of the alimentary canal?
\n(d) How does bile help in the digestion of fats?
\nAnswer:
\n(a) To increase surface area for absorption
\n(b) By HCl action
\n(c) Serosa, muscular is external, Sub mucosa and mucosa
\n(d) By the emulsification of fats<\/p>\n

Question 3.
\nState the role of pancreatic juice in digestion of proteins.
\nAnswer:
\nThe Pancreatic juice is secreted from acinar cells (Exocrine part) of the pancreas. it contains the following digestive enzymes namely Trypsin, Carboxypeptidase, Chymotrypsin, Amylopsin (Pancreatic amylase), Steapsin etc.<\/p>\n

Trypsin:
\nIt is secreted in an inactive form called Trysinogen. It is activated by non-digestive intestinal enzyme called Enterokinase. Trypsin acts on whole proteins or semi digested, ones and convert them into polypeptides.
\n\"1st<\/p>\n

Chymotrypsin:
\nIt is secreted in an inactive form called chymotrypsinogen. It is activated by an enzyme called trypsin. Chymotrypsinogen acts on peptones, proteoses, and convert them into polypeptides
\n\"1st<\/p>\n

Question 4.
\nWhat are the three major types of cells found in gastric glands? Name their secretions.
\nAnswer:
\n(i) Peptic or Chief Cells: Pepsinogen, Prorennin and Gastric lipase (in infants).
\n(ii) Oxyntic or Parietal Cells: HCl.
\n(iii) Goblet Cells: Mucus.<\/p>\n

\"1st<\/p>\n

1st PUC Biology Digestion and Absorption Five Marks Questions and Answers<\/h3>\n

Question 1.
\nExplain the physiology of protein digestion in a human body.
\nAnswer:
\nDigestion in Stomach:
\nGastric juice: Pepsin, and Renin are the proteases present in gastric juice
\n(i) Pepsin : It is an enzyme produced in an inactive form called pepsinogen. Pepsinogen is activated by HCl. Pepsin is an endopeptidase and it breaks inner peptide bonds of the protein molecule to form proteoses, peptones, and polypeptides.
\n\"1st<\/p>\n

(ii) Renin : Renin is also secreted in an inactive form called prorenin. It is activated by HCl. Renin acts on the milk protein called casein, and converts it into paracasein. Paracasein in turn combines with calcium salts, and forms calcium paracaseinate (curdy precipitate).
\n\"1st<\/p>\n

\"1st<\/p>\n

This process of conversion into calcium paracaseinate is called curdling of milk.
\nPancreatic juice : Trypsin, Chymotrypsin and Carboxypeptidase are the proteases secreted by the pancreas.<\/p>\n

(i) Trypsin : It is secreted as an inactive trypsinogen. Later gets activated by enterokinase of the intestinal juice. Trypsin is a endopeptidase. It acts on proteins and converts them into Proteoses, Peptones and Polypeptides.
\n\"1st<\/p>\n

(ii) Chymotrypsin : It is secreted as an inactive chymotrypsin and later gets activated by trypsin. Chymotrypsin is also an endopeptidase and converts Protein into Polypeptides.
\n\"1st<\/p>\n

(iii) Carboxypeptidase: It converts polypeptides into Tripeptides, Dipeptides and Amino acids.
\n\"1st<\/p>\n

Intestinal juice : The four proteases forming the intenstinal juice are Aminopeptidase. Dipeptidase, Tripeptidase and Erepsin.
\n(i) Aminopeptidase: It is a exopeptidase which acts on the terminal ends of the polypeptides and convert them into Tripeptides, Dipeptides and Amino acids.
\n\"1st<\/p>\n

(ii) Tripeptidase : It acts on the Tripeptide units and converts them into amino acids.
\n\"1st<\/p>\n

(iii) Dipeptidase : It acts on Dipeptide units and converts them into Amino acids.
\n\"1st<\/p>\n

(iv) Erepsin : It is a powerful protease of the intestine. It convert polypeptides, and other short chain Amino acids into free Amino acids.
\n\"1st<\/p>\n

\"1st<\/p>\n

Question 2.
\nDescribe the process of digestion of protein in the stomach.
\nAnswer:
\nProcess of Digestion :
\nDuring this process, the complex food. molecules such as proteins, carbohydrates, and lipids are converted into smaller molecules such as ammo acid, monosaccharide, fatty acids, and
\nglycerol respectively.<\/p>\n

Digestion in Buccal Cavity:
\nAs soon as the food enters into the buccal cavity, both mechanical and chemical digestion takes place. Mechanical digestion is brought about by the cutting and chewing action of the
\nteeth. During this pr\u00f2cess the complex food molecules are converted into smaller molecules. In the mean time, saliva is secreted and mixes with the food.<\/p>\n

Question 3.
\nDiscuss the main steps in the digestion of proteins as the food passes through different parts of the alimentary canal.
\nAnswer:<\/p>\n

Digestion in Stomach:
\nGastric juice: Pepsin, and Renin are the proteases present in gastric juice
\n(i) Pepsin : It is an enzyme produced in an inactive form called pepsinogen. Pepsinogen is activated by HCl. Pepsin is an endopeptidase and it breaks inner peptide bonds of the protein molecule to form proteoses, peptones, and polypeptides.
\n\"1st<\/p>\n

(ii) Renin : Renin is also secreted in an inactive form called prorenin. It is activated by HCl. Renin acts on the milk protein called casein, and converts it into paracasein. Paracasein in turn combines with calcium salts, and forms calcium paracaseinate (curdy precipitate).
\n\"1st<\/p>\n

This process of conversion into calcium paracaseinate is called curdling of milk.<\/p>\n

\"1st<\/p>\n

Question 4.
\nDraw a neat labelled diagram of the digestive system of the human body.
\nAnswer:
\n\"1st<\/p>\n

Question 5.
\nExplain the role of pancreatic juice in digestion.
\nAnswer:
\nPancreatic juice :
\nThe exocrine part of pancreas (acini) secretes an alkaline fluid called pancreatic juice. Pancreatic juice contains water, mineral salts and a variety of enzymes, such as one carbohydrase, three types of proteases, one lipase and one nuclease.<\/p>\n

a. Carbohydrase : Carbohydrase acts on the carbohydrate molecules. Carbohydrase secreted by pancreas is called pancreatic amylase (amylopsin). It is a powerful enzyme, due to which polysaccharides are converted into disaccharides.<\/p>\n

b. Proteases : Proteases are enzymes which act on proteins. Trypsin, Chymotrypsin and Carboxypeptidase are the proteases secreted by the pancreas.<\/p>\n

(i) Trypsin : It is secreted as the inactive Trypsinogen. Later gets activated by enterokinase of the intestinal juice. Trypsin is a endopeptidase. It acts on proteins and convert them into Proteoses, Peptones and Polypeptides.
\n\"1st<\/p>\n

(ii) Chymotrypsin : It is secreted as the inactive chymotrypsin and later gets activated by Trypsin. Chymotrypsin is also an endopeptidase and converts Protein into Polypeptides.
\n\"1st<\/p>\n

(iii) Carboxypeptidase : It is an exopeptidase, acting on the terminal peptide bonds of the polypeptide chain. It converts Polypeptides into Tripeptides, Dipeptides and Amino acids.
\n\"1st<\/p>\n

\"1st<\/p>\n

c. Lipase : It is an enzyme which acts on lipids. Lipase secreted by pancreas is called pancreatic lipase or steapsin. It is secreted in an inactive form, and is activated by enterokinase. Pancreatic Lipase is a powerful enzyme and it hydrolyses fat emulsion into Fatty acids and Glycerol.
\n\"1st<\/p>\n

d. Nuclease : Nuclease splits Nucleic acids into Nucleotides
\n\"1st<\/p>\n

1st PUC Biology Digestion and Absorption Text Book Questions and Answers<\/h3>\n

Definition:
\nThe physiological process of breaking up of complex insoluble food materials into simple, soluble substances is called Digestion.
\nor
\nDigestion is a catabolic process involving the enzymatic hydrolysis of food materials.<\/p>\n

Human Digestive System:
\nThe human digestive system can be distinguished into two components:<\/p>\n

    \n
  • The Alimentary canal<\/li>\n
  • Associated organs (Glands)<\/li>\n<\/ul>\n

    \"1st<\/p>\n

    Alimentary canal
    \nThe Alimentary canal is a hollow tube of about 9 meters length with two openings. An anterior mouth and a posterior Anus. There are several organs in between these regions, which perform specialized functions. The different regions are.<\/p>\n

    (a) Oral cavity: It is also called the Buccal cavity. It is totally bound by the muscular cheeks. The anterior portion terminates into a pair of fleshy lobes called lips. Internally it is lined by stratified squamous epithelium.<\/p>\n

    The roof of the buccal cavity is formed by a hard structure called Palate. The anterior part is known as hard palate and the posterior part is called soft palate. The fleshy projection seen at the full end, which prevents the entry of food into the nasal cavity is called Uvula.<\/p>\n

    The tongue is present on the floor of the buccal cavity. Its upper surface is covered by papillae with taste buds. There are 3 types of papillae present on the tongue namely:<\/p>\n

      \n
    • Filiform.<\/li>\n
    • Fungiform.<\/li>\n
    • Circumvallate.<\/li>\n<\/ul>\n

      The tongue is attached to the buccal cavity by a soft ligamentous structure called Fremim or Frenulum. Tongue helps in ingestion of food substance, mixing the food with saliva, tasting, and also for speech. Both upper and lower jaw contains teeth. In Humans, teeth are heterodont because 4 different types of teeth are present. They are.<\/p>\n

        \n
      • Incisors (Cutting teeth)<\/li>\n
      • Canines (Tearing teeth)<\/li>\n
      • Premolars and<\/li>\n
      • Molars (Grinders).<\/li>\n<\/ul>\n

        \"1st<\/p>\n

        The human teeth are Diphyodont because 2 sets of teeth (Milk teeth, and Permanent teeth) are formed during the life time. Human teeth are thecodont because all the teeth are inserted in the sockets. The arrangement of teeth on the jaws is called Dentition. The dental formula This formula indicates half of the upper jaw and half of the lower jaw.<\/p>\n

        (b) Pharynx : It is a short narrow passage common for both digestive and respiratory systems. It is divisible into anterior nasopharynx, a middle oropharynx and a lower laryngo pharynx. A small cartilage flap called epiglottis is present, which prevents the food from entering the trachea while it is swallowed.<\/p>\n

        (c) Oesophagus : It is commonly called as food pipe. It is about 25 cm in length. It opens into stomach. It helps in pushing the food to the stomach by the peristaltic contractions of the body wall. The place where Oesophagus enters the diaphragm is called as Oesophageal Hiatus.<\/p>\n

        (d) Stomach : It is a \u201cJ\u201d shaped muscular sac like organ present below the slightly towards the side. It can be distinguished into four regions. They are cardiac, fundus, body, and pylorus. Stomach is the organ of storage and digestion. Pylorus stomach is the digestive organ, and leads info small intestine.<\/p>\n

        Small intestine :
        \nIt is the longest part of the Alimentary canal. It is about 7 meters in length. It can be distinguished into a Duodenum, jejunum and ileum, with a length of 1 meter, 2.5 meter, and 3.5 meter respectively. The small intestine is characterized by the presence of small finger shaped projections called villi, which help in the absorption of food. Duodenum is involved in digestion and absorption whereas jejunum and ileum are involved only in absorption.<\/p>\n

        Large intestine :
        \nIt is about 2 meters long, and broader than small intestine! The large intestine can be distinguished into colon, and Rectum. The large intestine shows ascending colon, transverse colon, descending colon and sigmoid colon.<\/p>\n

        \"1st<\/p>\n

        Rectum is the terminal part, about 20 cm in length. It opens out through the Anus. At the junction of ileum and colon, there is a blind pouch called caecum. A attached to this is a finger shaped structure called vermiform appendix, which is a vestigial organ. Large intestine helps in absorption of water, vitamins and elimination of faeces. Faeces becomes semisolid due to the absorption of water, and also gets coated with mucous.<\/p>\n

        Salivary Glands :
        \nThese are exocrine glands present in buccal cavity. There are 3 pairs of salivary glands opening into the buccal cavity through their respective ducts (Tube like structures). The 3 pairs of salivary glands are:
        \n(1) A pair of parotid glands : Present in front of the ears and opens into the buccal cavity through the cheeks.
        \n(2) A pair of sub-maxillary glands : Present below the lower jaw on either side at the angles of the jaw.
        \n(3) A pair of Sub-lingual glands : Present below the tongue.
        \nAll these glands secrete saliva. The saliva contains water, mucin lyzozyme and an enzyme called Salivary amylase or Ptyalin.<\/p>\n

        Functions of Saliva :
        \n(1) It moistens the dry food and helps in swallowing by a lubricating action.
        \n(2) The salivary amylase or ptyalin acts on starch, and converts it into maltose.
        \n(3) It dissolves soluble substances like salts and sugar and helps in tasting.
        \n(4) It helps in the movement of tongue and lips, by keeping them moist.<\/p>\n

        Gastric Glands :
        \nThese are present in the inner wall of the stomach. There are 3 types of Gastric glands.
        \n(1) Cardiac glands : Present in the cardiac region of the stomach, and they secrete mucus.
        \n(2) Fundic glands : Present in the fimdus region of the stomach. They contain 3 types of cells.
        \n(a) Oxyntic cells or Parietal cells – Secrete HCl.
        \n(b) Chief cells or peptic cells – Secretes pepsinogen, pro rennin and Gastric lipase enzyme.
        \n(c) Mucus cells-Secrete Mucus.
        \n(3) Pyloric glands : Present in the pyloric region of stomach and secrete mucus. All these glands secrete gastric juice. It contains HCl, Mucus, and enzymes like pepsin, rennin, and gastric lipase, the pH of gastric juice is 1.5-2.0.<\/p>\n

        \"1st<\/p>\n

        Functions of Gastric juice :
        \n(1) HCl present in the gastric juice gives acidic PH for the action of enzymes and also kills harmful bacteria.
        \n(2) HCl activates and converts pepsinogen into pepsin, and prorennin into rennin.
        \n(3) Pepsin acts on proteins, and converts them into Peptones, and proteoses.
        \n(4) Rennin acts on the milk protein casein, and converts it into solid casein or curd.<\/p>\n

        Liver:
        \nIt is an accessory gland that is situated outside the Alimentary canal. It is situated just below the diaphragm and attached slightly towards the right side partly covering the stomach. Liver is the largest gland in the human body, weighing about 1.5 Kg (in adults).
        \nIt consists of 4 lobes namely:
        \n1. Right lobe (largest lobe).
        \n2. Left lobe (Smallest lobe).
        \n3. Caudate lobe and
        \n4. Quadrate lobe.<\/p>\n

        Liver is an exocrine gland because it secretes. Its secretion called bile juice is passed through the bile duct. The bile juice is stored in gall blabber.<\/p>\n

        Bile juice contains bile salts sodium glycocholate and sodium taurocholate, and pigments such as bilirubin, and biliviridin. Each liver lobe is made up of large number of hexagonal shaped units called Hepatic lobules.<\/p>\n

        \"1st<\/p>\n

        Functions :
        \n1. ft is a store house for glycogen, and some vitamins.
        \n2. It secrets bile juice, which helps in emulsification of fats.
        \n3. It is responsible for detoxification of the digested food.
        \n4. It provides proteins like fibrinogen and prothrombin, that are involved in clotting of blood.
        \n5. It is responsible for the maturation of RBC\u2019s.
        \n6. It converts ammonia, the nitrogenous waste, into a less toxic form called urea.
        \n7. Breaking down of worn out RBC\u2019s.
        \n8. It is a site of alcohol metabolism.
        \n9. Kupffer cells helps in phagocytosis.
        \n10. It stores blood, and regulates blood volume in the body.<\/p>\n

        Pancrease :
        \nIt is the second largest gland in human beings. It is a heterocrine gland since it contains both exo and endocrine parts. It is present below the stomach at the region of Duodenum. It is a pale yellowish compound tubular gland and measures about 12.5 cm long, and 2.5 cm in diameter. The exocrine part of pancreas is known as pancreatic acini which secretes pancreatic juice into the duodenum through pancreatic duct (Wrsung duct).\u00a0 The endocrine part of the pancreas is known as Islets of Langerhans which secretes the hormones called insulin (P cells) and glucagon (cells).<\/p>\n

        \"1st<\/p>\n

        Functions of Pancreas :
        \n1. Pancreas secretes pancreatic juice. It is rich in bicarbonates, and neutralizes the acidic food.
        \n2. Pancreatic juice contains several enzymes such as Trypsin, Chymotrypsin etc., which help indigestion.
        \n3. The hormones secreted by the islets of Langerhans play an important role in glucose metabolism.
        \n4. Insulin converts excess of blood sugar into glycogen, and glucagon converts stored glycogen into glucose when there is a scarcity of blood sugar.<\/p>\n

        1st PUC Biology Digestion and Absorption Text Book Questions and Answers<\/h3>\n

        Definition:
        \nThe physiological process of breaking up of complex insoluble food materials into simple , soluble substances is called Digestion.
        \nor
        \nDigestion is a catabolic process involving the enzymatic hydrolysis of food materials.
        \nHuman Digestive System
        \nThe human digestive system can be distinguished into two components:
        \n1. The Alimentary canal
        \n2. Associated organs (Glands)<\/p>\n

        Alimentary canal
        \nThe Alimentary canal is a hollow tube of about 9 meters length with two openings. An anterior mouth and a posterior Anus. There are several organs in between these regions, which perform specialized functions. The different regions are.<\/p>\n

        (a) Oral cavity: It is also called Buccal cavity. It is totally bound by the muscular cheeks. The anterior portion terminates into a pair of fleshy lobes called lips. Internally it is lined by stratified squamous epithelium.
        \nThe roof of the buccal cavity is formed by a hard structure called Palate. The anterior part is known as hard palate and the posterior part is called soft palate. The fleshy projection seen at the full end, which prevents the entry of food into the nasal cavity is called Uvula.<\/p>\n

        \"1st<\/p>\n

        The tongue is present on the floor of the buccal cavity. Its upper surface is covered by papillae with taste buds. There are 3 types of papillae present on the tongue namely:
        \n(1) Filiform.
        \n(2) Fungiform.
        \n(3) Circumvallate.<\/p>\n

        The tongue is attached to the buccal cavity by a soft ligamentous structure called Fremim or Frenulum. Tongue helps in ingestion of food substance, mixing the food with saliva, tasting, and also for speech. Both upper and lower jaw contain teeth. In Humans, teeth are heterodont because 4 different types of teeth are present. They are.
        \n(1) Incisors (Cutting teeth)
        \n(2) Canines (Tearing teeth)
        \n(3) Premolars and
        \n(4) Molars (Grinders).<\/p>\n

        (a) The human teeth are Diphyodont because 2 sets of teeth (Milk teeth, and Permanent teeth) are formed during the life time. Human teeth are thecodont because all the teeth are inserted in the sockets. The arrangement of teeth on the jaws is called Dentition. The dental formula
        \n\"1st
        \nThis formula indicates half of the upper jaw and half of the lower jaw.<\/p>\n

        (b) Pharynx : It is a short narrow passage common for both digestive and respiratory systems. It is divisible into anterior nasopharynx, a middle oropharynx and a lower laryngo pharynx. A small cartilage flap called epiglottis is present, which prevents the food from entering the trachea while it is swallowed.<\/p>\n

        (c) Oesophagus : It is commonly called as food pipe. It is about 25 cm in length. It opens into stomach. It helps in pushing the food to the stomach by the peristaltic contractions of the body wall. The place where Oesophagus enters the diaphragm is called as Oesophageal Hiatus.<\/p>\n

        \"1st<\/p>\n

        (d) Stomach : It is a \u201cJ\u201d shaped muscular sac like organ present below the slightly towards the side. It can be distinguished into four regions. They are cardiac, fundus, body, and pylorus. Stomach is the organ of storage and digestion. Pylorus stomach is the digestive organ, and leads info small intestine.<\/p>\n

        Small intestine :
        \nIt is the longest part of the Alimentary canal. It is about 7 meters in length. It can be distinguished into a Duodenum, jejunum and ileum, with a length of 1 meter, 2.5 meter, and 3.5 meter respectively. The small intestine is characterized by the presence of small finger shaped projections called villi, which help in the absorption of food. Duodenum is involved in digestion and absorption whereas the jejunum and ileum are involved only in absorption.<\/p>\n

        Large intestine :
        \nIt is about 2 meters long, and broader than small intestine! The large intestine can be distinguished into colon, and Rectum. The large intestine shows ascending colon, transverse colon, descending colon and sigmoid colon.<\/p>\n

        Rectum is the terminal part, about 20 cm in length. It opens out through the Anus.<\/p>\n

        At the junction of ileum and colon, there is a blind pouch called caecum. A attached to this is a finger shaped structure called vermiform appendix, which is a vestigial organ. Large intestine helps in absorption of water, vitamins and elimination of faeces. Faeces becomes semisolid due to the absorption of water, and also gets coated with mucous.<\/p>\n

        Salivary Glands :
        \nThese are exocrine glands present in buccal cavity. There are 3 pairs of salivary glands opening into the buccal cavity through their respective ducts (Tube like structures). The 3 pairs of salivary glands are:<\/p>\n

          \n
        • A pair of parotid glands : Present in front of the ears and opens into the buccal cavity through the cheeks.<\/li>\n
        • A pair of sub-maxillary glands : Present below the lower jaw on either side at the angles of the jaw.<\/li>\n
        • A pair of Sub-lingual glands : Present below the tongue.<\/li>\n<\/ul>\n

          All these glands secrete saliva. The saliva contains water, mucin lyzozyme and an enzyme called Salivary amylase or Ptyalin.<\/p>\n

          \"1st<\/p>\n

          Functions of Saliva :
          \n(1) It moistens the dry food and helps in swallowing by a lubricating action.
          \n(2) The salivary amylase or ptyalin acts on starch, and converts it into maltose.
          \n(3) It dissolves soluble substances like salts and sugar and helps in tasting.
          \n(4) It helps in the movement of tongue and lips, by keeping them moist.<\/p>\n

          Gastric Glands :
          \nThese are present in the inner wall of the stomach. There are 3 types of Gastric glands.
          \n(1) Cardiac glands : Present in the cardiac region of the stomach, and they secrete mucus.
          \n(2) Fundic glands : Present in the famous region of the stomach. They contain 3 types of cells.
          \n(a) Oxyntic cells or Parietal cells – Secrete HCl.
          \n(b) Chief cells or peptic cells – Secretes pepsinogen, pro rennin and Gastric lipase enzyme.
          \n(c) Mucus cells-Secrete Mucus.
          \n(3) Pyloric glands : Present in the pyloric region of stomach and secrete mucus. All these glands secrete gastric juice. It contains HCl, Mucus, and enzymes like pepsin, rennin, and gastric lipase, the pH of gastric juice is 1.5-2.0.<\/p>\n

          Functions of Gastric juice :
          \n(1) HCl present in the gastric juice gives acidic PH for the action of enzymes and also kills harmful bacteria.
          \n(2) HCl activates and converts pepsinogen into pepsin, and prorennin into rennin.
          \n(3) Pepsin acts on proteins, and converts them into Peptones, and proteoses.
          \n(4) Rennin acts on the milk protein casein, and converts it into solid casein or curd.<\/p>\n

          Liver:
          \nIt is an accessory gland that is situated outside the Alimentary canal. It is situated just below the diaphragm and attached slightly towards the right side partly covering the stomach. Liver is the largest gland in the human body, weighing about 1.5 Kg (in adults).
          \nIt consists of 4 lobes namely:
          \n1. Right lobe (largest lobe).
          \n2. Left lobe (Smallest lobe).
          \n3. Caudate lobe and
          \n4. Quadrate lobe.<\/p>\n

          Liver is an exocrine gland because it secretes. Its secretion called bile juice is passed through the bile duct. The bile juice is stored in gall blabber.<\/p>\n

          \"1st<\/p>\n

          Bile juice contains bile salts sodium glycocholate and sodium taurocholate, and pigments such as bilirubin, and biliviridin. Each liver lobe is made up of large number of hexagonal shaped units called Hepatic lobules.<\/p>\n

          Functions :
          \n1. ft is a store house for glycogen, and some vitamins.
          \n2. It secrets bile juice, which helps in emulsification of fats.
          \n3. It is responsible for detoxification of the digested food.
          \n4. It provides proteins like fibrinogen and prothrombin, that are involved in clotting of blood.
          \n5. It is responsible for the maturation of RBC\u2019s.
          \n6. It converts ammonia, the nitrogenous waste, into a less toxic form called urea.
          \n7. Breaking down of worn out RBC\u2019s.
          \n8. It is a site of alcohol metabolism.
          \n9. Kupffer cells helps in phagocytosis.
          \n10. It stores blood, and regulates blood volume in the body.<\/p>\n

          Pancrease :
          \nIt is the second largest gland in human beings. It is a heterocrine gland since it contains both exo and endocrine parts. It is present below the stomach at the region of Duodenum. It is a pale yellowish compound tubular gland and measures about 12.5 cm long, and 2.5 cm in diameter. The exocrine part of pancreas is known as pancreatic acini which secretes pancreatic juice into the duodenum through pancreatic duct (Wrsung duct).
          \nThe endocrine part of the pancreas is known as Islets of Langerhans which secretes the hormones called insulin (P cells) and glucagon (a cells).<\/p>\n

          Functions of Pancreas :
          \n1. Pancreas secretes pancreatic juice. It is rich in bicarbonates, and neutralizes the acidic food.
          \n2. Pancreatic juice contains several enzymes stich as Trypsin, Chymotrypsin etc., which help in digestion.
          \n3. The hormones secreted by the islets of Langerhans play an important role in glucose metabolism.
          \n4. Insulin converts excess of blood sugar into glycogen, and glucagon converts stored glycogen into glucose when there is a scarcity of blood sugar.<\/p>\n

          \"1st<\/p>\n

          Intestinal Glands :
          \nThese are present in the inner mucosa of small intestine. There are 4 types of intestinal glands, they are:-
          \n1. Glands of crypts of lieberkuhn.
          \n2. Payer\u2019s glands.
          \n3. Brunner\u2019s glands.
          \n4. Solitary glands.<\/p>\n

          Out of these glands, crypts of lieberkuhn secretes intestinal juice (Succus entericus), While others secrete an alkaline secretion which protects the intestinal lining from bacterial infection. Components of Food (Concept of Balanced Diet):<\/p>\n

          A balanced diet is one which contains the right proportion of the seven nutrients namely carbohydrates, fats, proteins, vitamins, minerals, water, and roughage (Fibrous component) required to maintain good health.
          \nCarbohydrates and lipids (fats) provide energy for the body. Proteins are required for growth, maintenance and repair of worn-out tissues. Water, minerals, and vitamins are essential for maintaining normal metabolism.<\/p>\n

          The correct and recommended proportion of balanced diet is represented as follows. Carbohydrates – 64%, Proteins – 14%, Lipids-21%, Vitamins, and minerals – 1%.
          \nIn addition, large amount of roughage consisting of mainly fibrous cellulose is also important.<\/p>\n

          Process of Digestion :
          \nDuring this process, the complex food molecules such as proteins, carbohydrates, and lipids are converted into smaller molecules such as amino acid, monosaccharide, fatty acids, and glycerol respectively.<\/p>\n

          \"1st<\/p>\n

          Digestion in Buccal Cavity :
          \nAs soon as the food enters into the buccal cavity, both mechanical and chemical digestion takes place. Mechanical digestion is brought about by the cutting and chewing action of the teeth. During this process the complex food molecules are converted into smaller molecules. In the mean time, saliva is secreted and mixes with the food.<\/p>\n

          Role of Saliva :
          \nSaliva is an alkaline digestive juice containing water, mucin, lysozyme, and an enzyme salivary amylase (Ptyalin). Water dissolves the soluble food substances, mucin lubricates the food, and ptyalin acts on the starch part of food and finally converts it into maltose.
          \n\\(\\text { Starch } \\frac{\\text { Ptyalin,pH6:7 }}{\\longrightarrow} \\text { Soluble starch } \\stackrel{+\\mathrm{H}_{2} \\mathrm{O}}{\\longrightarrow} \\text { Dextrin } \\stackrel{+\\mathrm{H}_{2} \\mathrm{O}}{\\longrightarrow} \\text { Maltose }\\)<\/p>\n

          The process of grinding the food with the help of the teeth is called as mastication. After the partial digestion of food in the buccal cavity, the food is shaped into a spherical mass called Bolus. The bolus is swallowed into the stomach through the Oesophagus.<\/p>\n

          \"1st<\/p>\n

          Digestion in Stomach :
          \nAs soon as the food Bolus enters the stomach, the gastric mucosa secretes a hormone called gastrin. It stimulates the gastric glands to secrete gastric juice.<\/p>\n

          Role of Gastric juice :
          \nGastric juice contains HCl, mucus, and enzymes like pepsin, Rennin, and Gastric lipase. HCl\u00a0gives acidic pH, dissolves insoluble minerals, and fibrous proteins, and converts inactive form of pepsinogen, and prorennin into active form of pepsin, and rennin respectively.<\/p>\n

          Role of Pepsin :
          \nIt is secreted in an inactive form called Pepsinogen. It is converted into active form of Pepsin by HCl.
          \n\\(\\text { Pepsinogen } \\stackrel{\\mathrm{HCl}}{\\longrightarrow} \\text { Pepsin }\\)
          \nPepsin acts on proteins, and converts them into peptones, proteoses and polypeptides.
          \n\\(\\text { Proteins } \\stackrel{\\text { pepsin }^{\\circ}}{\\longrightarrow} \\text { Peptones }+\\text { Proteoses }+\\text { Polypeptides }\\)<\/p>\n

          Role of Rennin :
          \nIt is secreted in an inactive form called prorennin. It is activated into rennin by HCl.
          \n\\(\\text { Prorennin } \\stackrel{\\mathrm{HCl}}{\\longrightarrow} \\text { Rennin }\\)<\/p>\n

          Rennin acts on the milk protein casein, and converts it into Para casein.
          \n\\(\\text { Casein } \\stackrel{\\text { Rennin }}{\\longrightarrow} \\text { Para casein }\\)<\/p>\n

          Para casein combines with calcium ions to form solid casein or curd.
          \nPara casein +Ca2+<\/span><\/sup><\/span>\u2192 Calcium paracaseinate (Solid Casein).<\/p>\n

          Calcium paracaseinate is acted upon by pepsin, and converted into proteoses, peptones and polypeptides
          \n\\(\\text { Calcium paracaseinate } \\stackrel{\\text { pepsin }}{\\longrightarrow} \\text { Peptones + Proteoses + Polypeptides }\\)<\/p>\n

          Role of Gastric lipase :
          \nIt is inactive in the adult stomach because of more acidic pH, but in children it acts on butter fat. After the partial digestion of food in the stomach, it is converted into semisolid substance known as Chyme.<\/p>\n

          Digestion in Small Intestine:
          \nWhen partially digested acidic chyme enters into the duodenum of small intestine, the intestinal mucosa secretes 4 types of gastro intestinal hormones.
          \n1. Enterocrinin : Stimulates the secretion of intestinal juice from intestinal glands.
          \n2. Secretin : Stimulates the secretion of pancreatic juice.
          \n3. Cholecystokinin (CCK): Stimulates the contraction of gall bladder to secrete bile juice
          \n4. Enterogastrin : Inhibits the secretion of gastric juice by gastric glands.<\/p>\n

          Role of Bile juice :
          \nBile juice is secreted by the hepatic cells of liver, and stored in the gall bladder. It is released into the duodenum through the bile duct. Bile juice doesn\u2019t contain any digestive enzymes. But it contains the digestive components in the form of bile salts Sodium Glycocholate, and Sodium taurocholate, Bile salts emulsify the fats by lowering their surface tension, and convert them into numerous tiny droplets. Bile is rich in sodium bicarbonate; hence it neutralizes the acidic chyme. It also helps in absorption of fat soluble vitamin K.
          \n\\(\\text { Fats } \\stackrel{\\text { Bile }}{\\longrightarrow} \\text { Emulsified fats. }\\)<\/p>\n

          Role of Pancreatic juice :
          \nThe Pancreatic juice is secreted from acinar cells (Exocrine part) of the pancreas. It contains the following digestive enzymes namely Trypsin, Carboxypeptidase, Chymotrypsin, Amylopsin (Pancreatic amylase), Steapsin etc.<\/p>\n

          \"1st<\/p>\n

          Trypsin :
          \nIt is secreted in an inactive form called Trysinogen. It is activated by non-digestive intestinal enzyme called Enterokinase. Trypsin acts on whole proteins or semi digested, ones and convert them into polypeptides.
          \n\"1st<\/p>\n

          Chymotrypsin :
          \nIt is secreted in an inactive form called chymotrypsinogen. It is activated by an enzyme called trypsin. Chymotrypsinogen acts on peptones, proteoses, and convert them into polypeptides.
          \n\"1st<\/p>\n

          Carboxypeptidase :
          \nIt is secreted in an inactive form called procarboxypeptidase. It is activated by an enzyme called trypsin. Carboxypeptidase acts on whole are semi digested proteins, and hydrolyzes carboxyl terminal bonds. .The products are poly peptides, dipeptides, and amino acids.
          \n\"1st<\/p>\n

          Amylopsin :
          \nIt is also known as pancreatic amylase. It acts on starch and glycogen, and converts them into maltose.
          \n\"1st<\/p>\n

          Steapsin :
          \nIt is also known as pancreatic lipase. It acts on emulsified fats, and convert them into fatty acids, and glycerol.<\/p>\n

          \"1st<\/p>\n

          Nucleic acids:
          \n\"1st<\/p>\n

          Role of Intestinal Juice :
          \nIntestinal juice is secreted by the intestinal glands. It is also called succus entericus. It contains enzymes like- Enterokinase, amino peptidase and dipeptidase, Sucrase, Maltase, Lactase, Phospholipase, and nuclease.<\/p>\n

          Nucleases are of three types:
          \n1. Nucleotidase.
          \n2. Phosphotase.
          \n3. Nucleosidase.<\/p>\n

          Enterokinase:
          \nIt is a non digestive intestinal enzyme and acts as an activator. It activates the inactive form trypsinogen of pancreatic juice into trypsin.
          \n\"1st<\/p>\n

          Amino peptidase and Dipeptidase :
          \nThey generally act on fragments of protein, and not on whole proteins hence, they are commonly called peptidases.
          \n\"1st<\/p>\n

          Sucrase:
          \nIt converts sucrose into glucose and fructose.
          \n\"1st<\/p>\n

          Maltase :
          \nIt converts maltose into glucose and glucose.
          \n\"1st<\/p>\n

          Lactase :
          \nIt converts Lactose into Glucose and Galactose.
          \n\"1st<\/p>\n

          \"1st<\/p>\n

          Phospholipase:
          \nIf acts on Phospholipids and converts them into phosphoric acid, fatty acid and glycerol. Phospholipids \"1st<\/p>\n

          Nucleases :
          \n(a) Nucleotidase : It acts on nucleic acids and converts them into nucleotides.
          \nDNA on Nuclear Tides.<\/p>\n

          (b) Phosphotase : It acts on Nucleotides, and converts them into Inorganic Phosphates
          \n\"1st<\/p>\n

          (c) Nucleosidase : It acts on Nucleosides and converts them into Nitrogen base and pentose Sugar.
          \n\"1st<\/p>\n

          Thus the intestinal juice plays an important role in the digestion of proteins’; carbohydrates, lipids and nucleic acids. As a result, the food in the small intestine is converted into a watery emulsion called Chyle.
          \nAfter the digestion of all these components in the small intestine, the nutrient food substances such as amino acids, monosaccharides, fatty acids and glycerol are absorbed by the villi present in the wall of the small intestine, by active and passive mechanisms. After the absorption, the undigested food and the cellulose part of food enters into large intestine.<\/p>\n

          \"1st<\/p>\n

          Digestion in large intestine [colon]:
          \nThere is not much digestion carried out in the large intestine. The intestiral contents are decomposed by symbiotic bacteria (E.coli). The cellulose part of the diet provides roughage for the movement of intestinal content. The wall of the large intestine also absorbs water and electrolytes.<\/p>\n

          Absorption of digestive food:
          \nSmall intestine is involved in absorption of major part of the nutrients through diffusion, osmosis, facilitated diffusion and active transport.<\/p>\n

          Carbohydrates are absorbed in the form of monosaccharides, lipids are mainly absorbed in the form of fatty acids, and monoglycerides proteins are absorbed in the form of amino acids.<\/p>\n

          Assimilation:
          \nThe amino acids and sugars are transported to the liver, the through hepatic portal vein. Amino acids are used for synthesis of cell organelles, enzymes and hormones. Glucose is utilised by the cells for obtaining energy by its breakdown. Excess glucose is converted into glycogen, and stored in the liver and muscles. A part of the excess glucose is converted into fats for storage in the adipose tissue. Ribose, and deoxyribose sugars are utilised for synthesis of ATP, RNA and DNA.<\/p>\n

          Regulation Of Digestion:
          \nThe functioning of the digestive system is under the control of Nervous system and hormones.<\/p>\n

          \"1st<\/p>\n

          Neural Control:
          \n1. Sight, smell or taste of food can stimulate the secretion of saliva.
          \n2. Neural signals control the gastric and intestinal secretions, and hormones.
          \n3. Muscular activities of the different parts of the alimentary canal are regulated by nerves.<\/p>\n

          Mormonal Control:
          \nThe following hormones control the activities of alimentary canal:
          \n(a) Gastric – controls secretion of gastric juice.
          \n(b) Secreting – stimulates the secretion of water, and bicarbonate ions
          \n(c) Chorley – stimulates pancreas to release pancreatic juice and gall bladder to release bile juice.<\/p>\n

          Digestive Disorers :
          \nJaundice [Icterus]:
          \nIt is the most common digestive disorder. Jaundice relates to the yellow appearance of skin, urine, nails and cornea of the eye due to an increased Bilirubin pigment (Bile pigment).<\/p>\n

          Jaundice is of three types:
          \n1. Haemolytic Jaundice or Neonatal Jaundice or Prehepatic Jaundice : It is commonly found in newly born babies up to one week of age. It is due to the excessive haemolysis (Destruction of RBC\u2019s).<\/p>\n

          2. Infective or Hepatocellular Jaundice : It is due to the infection of hepatitis virus of the liver. So, the liver becomes unable to process Bilirubin. It results in heavy accumulation of Bilirubin which leads to Hepatocellular Jaundice.<\/p>\n

          3. Obstructive Jaundice or Extra Hepatic jaundice : It occurs due to the obstruction in the Bile duct. The obstruction of Bile duct is due to gallstone formation. The bile duct is thus blocked, and bile juice cannot enter into duodenum.<\/p>\n

          \"1st<\/p>\n

          Causes:
          \n1. Liver damage due to viral infection, and consumption of alcohol.
          \n2. Increased Bilirubin pigment in the body.
          \n3. Excessive haemolysis.
          \n4. Blockage of bile duct due to gallstone.
          \n5. Presence of tumors in the bile duct.<\/p>\n

          Effects:
          \n1. Yellow colouration of the skin, eyes and urine.
          \n2. Fever, loss of appetite, nausea, vomiting and headache.
          \n3. Infective jaundice leads to bleeding, and shrinkage of liver [Cirrhosis]
          \n4. Unconsciousness and finally it may lead to death.<\/p>\n

          Prevention:
          \nIt can be prevented by avoiding the consumption of alcohol, and also by avoiding the consumption of contaminated food and water.
          \nTreatment :
          \n1. Vaccines, and anti-viral drugs are used against infective jaundice.
          \n2. Obstructive jaundice can be treated by surgery.<\/p>\n

          Hepatitis :
          \nHepatitis is the inflammation of the liver. Here the cells are either damaged or destroyed. Types of Hepatitis
          \n1. Viral hepatiti
          \n2. Toxic hepatitis
          \n3. Alcoholic hepatitis Viral hepatitis:
          \nOccurs due to the infection of different strains of viruses namely A, B, C, D, and E.
          \nOf these, Hepatitis A virus (HAV) is a DNA virus. Its infection is through contamination of food, and water.
          \nHepatitis B virus (HBV) is a RNA virus, and its transmission is through contact body fluids such as sexual contact, Blood transfusion, use of improperly sterilized ‘ surgical instruments, needles etc.<\/p>\n

          \"1st<\/p>\n

          Toxic hepatitis:
          \nIt is caused by the toxic effect of drugs on the liver. Some of the drugs known to cause toxicity in susceptible individuals are Paracetamol, Aspirin, heavy metals, mushroom poisoning, etc.
          \nAlcoholic hepatitis:
          \nIt is due to excessive consumption of alcohol over a period of time.<\/p>\n

          Symptoms:
          \nThe most common symptoms are : Loss of appetite, fatigue (tiredness), mild fever, muscle, and joint aches.
          \nPrevention and Treatment:
          \n1. Consumption of boiled water, and cooked food.
          \n2. Using anti bacterial, and antiviral drugs as prescribed by a doctor.
          \n3. Undergoing vaccination for Hepatitis – B.
          \n4. Avoiding sexual contact with infected persons, and blood transfusion from infected persons.
          \n5. Using disposable, and sterilized needles.<\/p>\n

          Vomiting:
          \nVomiting is a forceful expulsion of part or all the contents of the stomach through mouth. It is due to reverse peristalsis of stomach and oesophagus.<\/p>\n

          \"1st<\/p>\n

          Causes:
          \n1. Harmful food substances, certain drugs or chemicals.
          \n2. Head injury.
          \n3. Irritation of stomach and duodenum.
          \n4. Morning sickness seen during early pregnancy.
          \n5. Emotional factors like nauseating sights and odours may be.<\/p>\n

          Effects
          \nExcessive vomiting can lead to loss of salts, and fluids from the body causing dehydration and low BP.<\/p>\n

          Diarrhoea :
          \nIt is a condition where the watery faeces move through the large intestine uncontrollably and rapidly.<\/p>\n

          Causes:
          \n1. Viral, bacterial or protozoan infection.
          \n2. Inflammation of colon.<\/p>\n

          \"1st<\/p>\n

          Effects
          \nDiarrhoea results in dehydration, and electrolyte imbalance. Severe diarrhoea is dangerous.<\/p>\n

          Constipation :
          \nIt is improper, infrequent or difficult defaecation. It arises when the contents are retained in the large intestine for a longer duration than the normal. More water is absorbed from the feces making it hard and dry.<\/p>\n

          Causes:
          \n1. Ignoring the urge to defecate.
          \n2. Decreased mobility in colon due to low bulk diet or aging.
          \n3. Blockage due to tumour in the colon.
          \n4. Injury to nerve pathway which relaxes the muscles for defaecation.<\/p>\n

          \"1st<\/p>\n

          Effects:
          \nIt causes abdominal discomfort, dull headache, loss of appetite and mental depression. The symptoms may disappear after defaecation.<\/p>\n

          Indigestion.
          \nInability to digest food is called indigestion. Symptoms include feeling of fullness in the stomach, discomfort in the upper abdomen, burping, and heartburn.<\/p>\n

          Causes:
          \n1. Insufficient production of digestive enzymes.
          \n2. Overeating or eating fatty or fried foods.
          \n3. Less likely causes include gallstones, ulcer of stomach or duodenum.
          \nLoss of appetite and vomiting.<\/p>\n

          Protein Energy Malnutrition (Pem) :
          \nDecreased intake of proteins in the food results in PEM. Clinically two types of PEM are recognised namely. Kwashiorkor, and Marasmus.<\/p>\n

          Kwashiorkor :
          \nIn this disease protein intake is inadequate but the calorie requirement of the body is met. It results in protein malnutrition characterised by edema of the abdomen, decreased blood pressure, loss of appetite, enlarged liver, excessive pigmentation of the skin and mental retardness.<\/p>\n

          Marasmus :
          \nThis disease is due to inadequate intake of proteins, and calories. It is characterised by low weight, wasting of muscles, dry skin and a thin body.<\/p>\n

          1st PUC Biology Question Bank with Answers<\/a><\/h4>\n","protected":false},"excerpt":{"rendered":"

          Karnataka 1st PUC Biology Question Bank Chapter 16\u00a0Digestion and Absorption 1st PUC Biology Digestion and Absorption One Marks Questions and Answers Question 1. What is succus entericus? Answer: It is the intestinal juice. Question 2. What is hyperacidity? Answer: Hyperacidity is a condition where there is an over-secretion of HCl in the stomach. Question 3. …<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[81],"tags":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/88279"}],"collection":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/comments?post=88279"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/88279\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=88279"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=88279"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=88279"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}