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Correct ANSWER is (b) Ca^2+

To elaborate: The SALIVA secreted into the oral cavity contains electrolytes which contain NA^+, K^+, Cl^–, HCO3 and enzymes like salivary amylase. Saliva ALSO contains an antibacterial, lysozyme.

The CORRECT OPTION is (a) Inflammation

Explanation: The inflammation of the alimentary canal is the most common ailment due to bacterial or viral INFECTIONS. The infections are also caused by parasites of the intestine like tapeworm, ROUNDWORM, etc.

The correct option is (C) Rennin

Easy explanation: Rennin is a proteolytic enzyme found in the gastric juice of infants which helps in the DIGESTION of milk proteins. Small amounts of LIPASES are also secreted by gastric GLANDS.

Right option is (d) Six

To explain I would SAY: Saliva is MAINLY produced by three pairs of SALIVARY GLANDS which are the parotids, the sub-maxillary or sub-mandibular, and the sub-lingual.

The CORRECT OPTION is (c) Frenulum

To explain: The tongue is a freely MOVABLE muscular ORGAN attached to the floor of the oral cavity by the frenulum. The upper surface of the tongue has small projections called PAPILLAE, some of which bear taste buds.

Right ANSWER is (a) Alimentary CANAL and associated glands

To EXPLAIN I would say: The human DIGESTIVE system CONSISTS of the alimentary canal and the associated glands. The alimentary canal begins with an anterior opening-the mouth, and it opens out posteriorly through the anus.

The correct choice is (B) Enterokinase

To explain I would SAY: Trypsinogen is activated by an enzyme, enterokinase, secreted by the INTESTINAL mucosa into ACTIVE trypsin, which in turn activates the other enzymes in the pancreatic JUICE.

Right option is (a) Ileo-caecal VALVE

The explanation: The undigested, unabsorbed SUBSTANCES are called faeces which enter into the caecum of the large intestine through the ileocaecal valve, which PREVENTS the BACKFLOW of the faecal matter.

Right answer is (b) False

Best explanation: Bio-macromolecules in food cannot be utilised by our body in their original form as they are too big to be absorbed by our blood CAPILLARIES or the lacteals, therefore they have to be BROKEN down into very small SUBSTANCES so that they can get EASILY absorbed.

Correct answer is (d) Overpopulation

To EXPLAIN I would say: PEM may affect large sections of the population during DROUGHT, famine, and political TURMOIL. This HAPPENED in Bangladesh during the liberation war.

The correct choice is (a) The actual amount of energy COMBUSTION of 1 g of food

To explain I would say: The actual amount of energy combustion of 1 g of food is the physiologic VALUE of food. Physiologic value of fats and carbohydrates is 9 kcal/g and 4 kcal/g respectively.

Correct choice is (C) HYDROCHLORIC acid

Best explanation: The PROENZYME pepsinogen on exposure to hydrochloric acid gets converted into the active enzyme pepsin which is the proteolytic enzyme of the stomach. Pepsin converts PROTEINS into proteoses and peptones.

Right option is (a) Neural signals

For explanation: GASTRIC and intestinal SECRETIONS are STIMULATED by neural signals. The muscular ACTIVITIES of different parts of the alimentary canal can also be moderated by neural MECHANISM, both local and through CNS.

The CORRECT answer is (B) Testis

To EXPLAIN: The digestive glands associated with the alimentary canal INCLUDE the SALIVARY glands, the liver, and the pancreas. The testis is not a digestive gland.

Right CHOICE is (b) False

To explain: The serosa is the outermost LAYER of the ALIMENTARY canal. The alimentary canal is made up of FOUR different layers namely-serosa, muscularis, sub-MUCOSA and mucosa. Mucosa is the innermost layer of the alimentary canal.

Right choice is (b) False

Easy explanation: Humans have thecodont TYPE of dentition. In this type, each tooth is embedded in the socket of jaw bone. Acrodont type of dentition is found in fish and AMPHIBIANS. In this FORM of dentition teeth are ATTACHED to the top surface of the jaw bone.

Right answer is (C) Swelling of body parts

Easy explanation: In marasmus, protein deficiency IMPAIRS growth, and replacement of tissue proteins, EXTREME emaciation of the body, and THINNING of limbs are also OBSERVED. The skin also becomes dry, thin, and wrinkled.

The correct option is (C) ABNORMAL frequency of bowel movement

Easiest explanation: The abnormal frequency of bowel movement and increased liquidity of the faecal discharge is known as diarrhoea. It reduces the ABSORPTION of FOOD.

The correct option is (a) Heat

Easy EXPLANATION: Heat is the ultimate FORM of ENERGY and that is why the energy requirements of ANIMALS, and the energy content of food, are expressed in terms of a measure of heat energy.

Correct choice is (B) Mucosa

To explain: The mucosa LAYER of the ALIMENTARY canal forms gastric glands in the stomach and crypts in between the BASES of villi in the intestine which are also KNOWN as Crypts of Lieberkuhn.

Right choice is (b) Duodenum-J shape

The explanation is: Small INTESTINE is distinguishable into THREE regions, a ‘C’ SHAPED duodenum, a long coiled middle portion JEJUNUM, and highly coiled ileum.

The correct choice is (d) FOUR

The explanation is: The stomach is divided into four major portions namely-Fundus, Cardiac, BODY, and Pyloric. The given FIGURE represents the anatomical REGIONS of the HUMAN stomach:

The correct OPTION is (c) Oral cavity

The BEST I can EXPLAIN: The MOUTH leads to the buccal cavity of the alimentary canal. The buccal cavity is also known as the oral cavity. The oral cavity has a number of teeth and a muscular TONGUE.

Right choice is (a) Sub-mucosa

Easiest explanation: In the duodenum, GLANDS are present in the sub-mucosa. The sub-mucosal LAYER is FORMED of LOOSE connective tissue CONTAINING nerves, blood, and lymph vessels.

Correct option is (a) Infants

For explanation I would say: Marasmus is found in infants of less than one year in age. Marasmus OFTEN happens when the MOTHER has a second pregnancy or childbirth when the OLDER infant is still too YOUNG.

Correct choice is (B) False

For EXPLANATION: Transport of water depends upon the osmotic gradient. However, some substances like glucose and amino acids are absorbed with the HELP of carrier PROTEINS. This MECHANISM is called facilitated transport.

The CORRECT CHOICE is (d) Secretions of brush border cells and goblet cells

The best EXPLANATION: The intestinal mucosal epithelium has goblet cells which secrete mucus. The secretions of the brush border cells of the mucosa ALONG with the secretions of the goblet cells CONSTITUTE the intestinal juice or succus entericus.

Correct answer is (b) Vitamin D

Easiest EXPLANATION: Vitamin D is also known as a poor man’s vitamin or sunshine vitamin. Vitamin D is GOOD for MAINTAINING healthy bones as vitamin D acts as a hormone and helps in the absorption of Calcium from the INTESTINE.

Right answer is (c) SODIUM ions

To explain I would say: Sodium ions are not absorbed by simple diffusion. Glucose, amino acids and some ELECTROLYTES like chloride ions are GENERALLY absorbed by simple diffusion. The rate or passage of these ions depends upon the CONCENTRATION gradients.

Right answer is (d) End products of digestion are PASSED through the intestinal mucosa

The best I can explain: Absorption is the process by which the end products of digestion pass through the intestinal mucosa into the blood or LYMPH. It is carried out by PASSIVE, active or facilitated transport mechanisms.

The correct option is (a) Sodium ions

The explanation: Active TRANSPORT occurs against the concentration gradient and hence requires ENERGY. VARIOUS nutrients like amino ACIDS, monosaccharides like glucose and electrolytes like sodium ions are absorbed into the BLOOD by this mechanism.

Correct choice is (b) Disaccharides

Easiest explanation: In the small intestine, carbohydrates in the CHYME are hydrolysed by PANCREATIC amylase into disaccharides. FATS are broken down by lipases with the help of bile into DI and MONOGLYCERIDES.

The CORRECT CHOICE is (d) Nuclease

The best I can explain: Nucleases are not PRESENT in the bile as this ENZYME is the secretion of the pancreas. The bile released into the duodenum contains bile pigments like bilirubin and BILIVERDIN, bile salts, cholesterol and phospholipids. No enzyme is present in the bile juice.

Correct CHOICE is (a) Hepatic lobules

For explanation: The hepatic lobules are the STRUCTURAL and functional units of the liver containing hepatic cells arranged in the FORM of cords. Each lobule is covered by a THIN CONNECTIVE tissue sheath called as Glisson’s capsule.

Right CHOICE is (B) False

To elaborate: Pharynx SERVES as a common passage for food and air. Oral cavity leads to short pharynx followed by esophagus which is the food pipe. Trachea is the wind pipe.

The correct answer is (d) Two sets of teeth during life

The explanation: Diphyodont is a TYPE of dentition which consists of two sets of teeth during the entire life cycle of the organism. Majority of MAMMALS including human BEINGS form two sets of teeth during their life. One set which is the MILKY teeth GET replaced by the new set of teeth by the age of 12-13 years.

The correct choice is (a) Endocrine part

Best explanation: Pancreas is a compound or heterocrine GLAND which CONSISTS of both endocrine and exocrine parts. Endocrine part PRODUCES the hormones like insulin and glucagon while the exocrine part is responsible for secreting PANCREATIC juices and enzymes.

Correct option is (a) Thick

Explanation: The oesophagus is a THIN, long tube which extends POSTERIORLY passing through the NECK, thorax and diaphragm and leads to a ‘J’ SHAPED bag-like structure CALLED a stomach.

The correct answer is (d) Amount of heat ENERGY REQUIRED to raise the temperature of 1 G water

The explanation: Heat energy is often measured as CALORIE (cal) or joule (J), which is the amount of heat energy required to raise the temperature of 1 g of water by 1° C.

The correct choice is (b) Facilitation of swallowing and mastication of food

The best explanation: The buccal cavity PERFORMS two major FUNCTIONS which are mastication of food and facilitation of swallowing. The TEETH and the TONGUE with the help of saliva masticate and mix the food thoroughly.

The correct option is (d) 1.2-1.5 KG

For EXPLANATION I would say: The liver is the largest gland of the human body and weighs about 1.2-1.4 kg in an adult human. It is SITUATED in the abdominal CAVITY, just below the DIAPHRAGM, and has two lobes.

The correct answer is (c) Glycerol

To explain: The nucleases in the pancreatic JUICE acts in nucleic acids to form nucleotides and NUCLEOSIDES which are further BROKEN down by nucleosidases to sugars and nitrogen BASES.

Right option is (C) Very SMALL protein-coated fat molecules

For EXPLANATION I would say: Fatty ACIDS and glycerol being insoluble, cannot be absorbed into the BLOOD. They are first incorporated into micelles and then are reformed into very small protein-coated fat molecules called chylomicrons.