Solution-Class-11-Science-Biology-Chapter-14-Human Nutrition-Maharashtra Board

Human Nutrition

Maharashtra Board-Class-11-Science-Biology-Chapter-14


Question 1.

Choose correct option

(A) Acinar cells are present in ...........

(a) liver

(b) pancreas

(c) gastric glands

(d) intestinal glands

Answer :

(b) pancreas

(B)  Which type of teeth are maximum in number in human buccal cavity?

(a)  Incisors

(b)  Canines

(c)  Premolars

(d)  Molars

Answer :

(d)  Molars

(C)  Select odd one out on the basis of digestive functions of tongue.

(a)  Taste

(b)  Swallowing

(c)  Talking

(d)  Mixing of saliva in food

Answer :

(c)  Talking

(D)  Complete the analogy: Ptyalin: Amylase : : Pepsin : ................. .

(a)  Lipase

(b)  Galactose

(c)  Proenzyme

(d)  Protease

Answer :

(d)  Protease

Question 2.

Answer the following questions

(A) For the school athletic meet, Shriya was advised to consume either Glucon-D or fruit juice but no sugarcane juice. Why it must be so?

Answer :

  • Sugarcane juice contains Policosanol. Consuming this compound causes loose motion, spinning of head.
  • Policosanol is also a blood thinner compound which disables the blood to make clots on excessive bleeding.
  • So, consumption of sugarcane must be avoided during school athletic meet.

(B) Alcoholic people may suffer from liver disorder. Do you agree? Explain your answer.

Answer :

  • Alcoholism causes different disorders of liver like steatosis (fatty liver), alcoholic hepatitis, fibrosis and cirrhosis.
  • Most of the alcohol in the body is broken down in the liver by an enzyme called alcohol dehydrogenase, which transforms ethanol into a toxic compound called acetaldehyde (CH3CHO).
  • Over consumption of alcohol leads to cirrhosis (distorted or scarred liver) and eventually to liver failure.
  • Therefore, alcoholic people may suffer from liver disorder.

(C) Digestive action of pepsin comes to a stop when food reaches small intestine. Justify.

Answer :

Pepsin acts in acidic medium thus it is active in stomach. There is alkaline condition in the small intestine. pH of small intestine is very high for pepsin to work. Therefore, pepsin gets denatured in the small intestine.

(D) Small intestine is very long and coiled. Even if we jump and run, why it does not get twisted? What can happen if it gets twisted?

Answer :

  • Mesentery is a tissue found in the abdomen. It links the small intestine to the abdominal wall and holds it in place, preventing twisting while running and jumping.
  • If the small intestine twists, the affected area may obstruct the passage of food and drink. If the twist is particularly severe, it can potentially cut off the blood flow. If this occurs, the surrounding tissue may kill, causing major complications.

Question 3.

Write down the explanation

(A) Digestive enzymes are secreted at appropriate time in our body. How does it happen?

Answer :

  • It is essential that the digestive enzymes and juices are produced in sequential manner and at a proper time.
  • These secretions are under neurohormonal control. Sight, smell and even thought of food trigger saliva secretion.
  • Tenth cranial nerve stimulates secretion of gastric juice in stomach.
  • Even the hormone gastrin brings about the same effect.

(B) Explain the structure of tooth. Explain why human dentition is considered as thecodont, diphydont and heterodont.

Answer :

Structure of tooth:

  • A tooth consists of the portion that projects above the gum called crown and the root that is made up of two or three projections which are embedded in gum.
  • A short neck connects the crown with the root.
  • The crown is covered by the hardest substance of the body called enamel which is made up of calcium phosphate and calcium carbonate.
  • Basic shape of tooth is derived from dentin which is a calcified connective tissue.
  • The dentin encloses the pulp cavity. It is filled with connective tissue pulp. It contains blood vessels and nerves.

  • Pulp cavity has extension in the root of the tooth called root canal.
  • The dentin of the root of tooth is covered by cementum which is a bone like substance that attaches the root to the surrounding socket in the gum.

Human dentition :

  • Human dentition is described as thecodont, diphyodont and heterodont. .
  • It is called thecodont type because each tooth is fixed in a separate socket present in the jaw bones by gomphosis type 0f joint.
  • It is called diphyodont type because we get only tow sets of teeth, milk teeth and permanent teeth.
  • It is called heterodont type because humans have four different type of teeth like incisors, canines, premolars and molars.

(C) Explain heterocrine nature of pancreas with the help of histological structure.

Answer :

  • Pancreas is a leaf shaped heterocrine gland present in the gap formed by bend of duodenum under the stomach.
  • Exocrine part of pancreas is made up of acini, the acinar cells secrete alkaline pancreatic juice that contains various digestive enzymes.
  • Pancreatic juice is collected and carried to duodenum by pancreatic duct.
  • The common bile duct joins pancreatic duct to fonn hepato-pancreatic duct. It opens into duodenum.
  • Opening of hepato-pancreatic duct is guarded by sphincter of Oddi.
  • Endocrine part of pancreas is made up of islets of Langerhans situated between the acini.
  • It contains three types of cells alpha-cells which secrete glucagon, Beta-cells which secretes insulin and delta cells secrete somatostatin hormone.
  • Glucagon and insulin together control the blood-sugar level.
  • Somatostatin hormone inhibits glucagon and insulin secretion.

Question 4.

Write short note on

(A) Position and function of salivary glands.

Answer :

  • There are three pairs of salivary glands which open in buccal cavity.
  • Parotid glands are present in front of the ear.
  • The submandibular glands are present below the lower jaw.
  • The glands present below the tongue are called sublingual.
  • Salivary glands are made up of two types of cells.
  • Serous cells secrete a fluid containing digestive enzyme called salivary amylase.
  • Mucous cells produce mucus that lubricates food and helps swallowing.

(B) Jaundice

Answer :

  • Jaundice is a disorder characterized by yellowness of conjunctiva of eyes and skin and whitish stool.
  • It is a sign of abnormal bilirubin metabolism and excretion.
  • Jaundice develops if excessive break down of red blood cells takes place along with increased bilirubin level than the liver can handle or there is obstruction in the flow of bile from liver to duodenum.
  • Bilirubin produced from breakdown of haemoglobin is either water soluble or fat soluble.
  • Fat soluble bilirubin is toxic to brain cells.
  • There is no specific treatment to jaundice.
  • Supportive care, proper rest are the treatments given to the patient.

Question 5.

Observe the diagram. This is histological structure of stomach. Identify and comment on significance of the layer marked by arrow.

Answer :

The layer marked in the diagram represents glandular epithelium of mucosa

Significance of the glandular epithelium of mucosa :

Globlet cells of the epithelial layer of a mucous membrane secrete mucus which lubricates the lumen 0f the elementary canal. This helps in movement of food through the gastrointestinal tract.

Question 6.

Find out pH maxima for salivary amylase, trypsin, nucleotidase and pepsin and place on the given pH scale

Answer :

Salivaxy amylase = 6.8

Trypsin = 8

Nucleotidase = 7.5

Pepsin = 2

Question 7.

Write the name of a protein deficiency disorder and write symptoms of it

Answer :

  • Kwashiorkor is a protein deficiency disorder.
  • This protein deficiency disorder is found generally in children between one to three years of age.
  • Children suffering from Kwashiorkor are underweight and show stunted growth, poor brain development, loss of appetite, anaemia, protruding belly, slender legs, bulging eye, oedema of lower legs and face, change in skin and hair colour.

Question 8.

Observe the diagram given below label the A, B, C, D, E and write the function of A, C in detail.

Answer :

A- Bile duct, B- Stomach, C- Common hepatic duct, D- Pancreas, E- Gall Bladder


  • Bile duct: It carries bile from the gall bladder and empties it into the intestine.
  • Common hepatic duct: It drains bile from the liver. It helps in transportation of waste from liver and helps in digestion by releasing bile.

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