Case Study Questions Class 11 Biology Chapter 16 Digestion and Absorption
CBSE Class 11 Case Study Questions Biology Digestion and Absorption. Important Case Study Questions for Class 11 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Digestion and Absorption.
At Case Study Questions there will given a Paragraph. In where some Important Questions will made on that respective Case Based Study. There will various types of marks will given 1 marks, 2 marks, 3 marks, 4 marks.
CBSE Case Study Questions Class 11 Biology Digestion and Absorption
CASE 1
The process of conversion of complex food substances to simple absorbable forms is called digestion and is carried out by our digestive system by mechanical and biochemical methods.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 mouth leads to the buccal cavity or oral cavity. The oral cavity has a number of teeth and a muscular tongue. Each tooth is embedded in a socket of jaw bone. This type of attachment is called thecodont. Majority of mammals including human being forms two sets of teeth during their life, a set of temporary milk or deciduous teeth replaced by a set of permanent or adult teeth. This type of dentition is called diphyodont. An adult human has 32 permanent teeth which are of four different types (Heterodont dentition), namely, incisors (I), canine (C), premolars (PM) and molars (M). Arrangement of teeth in each half of the upper and lower jaw in the order I, C, PM, M is represented by a dental formula which in human is 2123/2123. The hard chewing surface of the teeth, made up of enamel, helps in the mastication of food. 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.
The oral cavity leads into a short pharynx which serves as a common passage for food and air. The oesophagus and the trachea (wind pipe) open into the pharynx. A cartilaginous flap called epiglottis prevents the entry of food into the glottis – opening of the wind pipe – during swallowing. 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 stomach. A muscular sphincter (gastro-oesophageal) regulates the opening of oesophagus into the stomach.
1.) Identify the correct statement
Statement 1 – Digestion is conversion of complex food substances to simple absorbable forms.
Statement 2 –Human digestive system consists alimentary canal and the associated glands.
Statement 3 –alimentary canal’s anterior opening begins with mouth.
Statement 4 – alimentary canal opens out posteriorly through the anus.
a) Statement 1 iscorrect
b) Statement 2 iscorrect
c) Statement 3 is incorrect
d) All statement are correct
2.) ________________ is the arrangement of tooth in which the base of the tooth is completely enclosed in a deep socket of bone.
a.) Heterodont
b) Thecodont
c) Diphyodont
d) Canine
3.) Explain diphyodont dentition type?
4.) What is the main function of muscular sphincter?
5.) What prevents the entry of food into opening of the wind pipe during swallowing?
Answer key
1.) d
2.) b
3.) Diphyodont dentition is one of the type of dentition in which forms two sets of teeth during lifetime, a set of temporary milk or deciduous teeth replaced by a set of permanent or adult teeth. This type of dentition is called diphyodont.
4.) Muscular sphincter i.e. gastro-oesophageal regulates the opening of oesophagus into the stomach.
5.) A cartilaginous flap called epiglottis prevents the entry of food into the opening of the wind pipe i.e. glottis during swallowing.
CASE 2
The digestive glands associated with the alimentary canal include the salivary glands, the liver and the pancreas. Saliva is mainly produced by three pairs of salivary glands, the parotids (cheek), the sub-maxillary/sub-mandibular (lower jaw) and the sub-lingual (below the tongue). These glands situated just outside the buccal cavity secrete salivary juice into the buccal cavity. Liver is the largest gland of the body weighing about 1.2 to 1.5 kg in an adult human. It is situated in the abdominal cavity, just below the diaphragm and has two lobes. The hepatic lobules are the structural and functional units of liver containing hepatic cells arranged in the form of cords. Each lobule is covered by a thin connective tissue sheath called the Glisson’s capsule. The bile secreted by the hepatic cells passes through the hepatic ducts and is stored and concentrated in a thin muscular sac called the gall bladder. The duct of gall bladder (cystic duct) along with the hepatic duct from the liver forms the common bile duct. The bile duct and the pancreatic duct open together into the duodenum as the common hepato-pancreatic duct which is guarded by a sphincter called the sphincter of Oddi. The pancreas is a compound (both exocrine and endocrine) elongated organ situated between the limbs of the ‘C’ shaped duodenum. The exocrine portion secretes an alkaline pancreatic juice containing enzymes and the endocrine portion secretes hormones, insulin and glucagon.
1.) _______________ is the salivary gland which present below the tongue
a) Parotids
b) Sub-maxillary
c) Sub-lingual
d) Sub-mandibular
2.) Identify the incorrect statement
Statement 1 – Hepatic lobules are structural and functional unit of the liver.
Statement 2 –Duct of gall bladder is known as Glisson’s capsule.
Statement 3 – Liver is the largest gland of the body in humans.
Statement 4 – Sub-mandibular is the salivary gland which present below the tongue.
a) Statement 1 and 2 are incorrect
b) Statement 2 and 3 are incorrect
c) Statement 3 and 4 are incorrect
d) Statement 4 and 2 are incorrect
3.) What is Glisson’s capsule?
4.) Name the location/organ at which bile duct and the pancreatic duct open together as common duct.
5.) Name the hormones secreted by exocrine and endocrine portion of pancreas.
Answer key
1.) c
2.) d
3.) Glisson’s capsule – it is thin connective tissue sheath protective covering present on hepatic lobules of liver.
4.) The bile duct and the pancreatic duct open together into the duodenum as the common hepato-pancreatic duct
5.) The exocrine portion secretes an alkaline pancreatic juice containing enzymes and the endocrine portion secretes hormones, insulin and glucagon.
CASE 3
The inflammation of the intestinal tract is the most common ailment due to bacterial or viral infections. The infections are also caused by the parasites of the intestine like tapeworm, roundworm, threadworm, hookworm, pin worm, etc.
Jaundice – The liver is affected, skin and eyes turn yellow due to the deposit of bile pigments.
Vomiting – It is the ejection of stomach contents through the mouth. This reflex action is controlled by the vomit centre in the medulla. A feeling of nausea precedes vomiting. Diarrhoea – The abnormal frequency of bowel movement and increased liquidity of the faecal discharge is known as diarrhoea. It reduces the absorption of food.
Constipation – In constipation, the faeces are retained within the colon as the bowel movements occur irregularly.
Indigestion – In this condition, the food is not properly digested leading to a feeling of fullness. The causes of indigestion are inadequate enzyme secretion, anxiety, food poisoning, over eating, and spicy food.
PEM – Dietary deficiencies of proteins and total food calories are widespread in many underdeveloped countries of South and South-east Asia, South America, and West and Central Africa. Protein-energy malnutrition (PEM) may affect large sections of the population during drought, famine and political turmoil. PEM affects infants and children to produce Marasmus and Kwashiorkar. Marasmus is produced by a simultaneous deficiency of proteins and calories. It is found in infants less than a year in age, if mother’s milk is replaced too early by other foods which are poor in both proteins and caloric value. This often happens if the mother has second pregnancy or childbirth when the older infant is still too young. In Marasmus, protein deficiency impairs growth and replacement of tissue proteins; extreme emaciation of the body and thinning of limbs results, the skin becomes dry, thin and wrinkled. Growth rate and body weight decline considerably. Even growth and development of brain and mental faculties are impaired. Kwashiorkar is produced by protein deficiency unaccompanied by calorie deficiency. It results from the replacement of mother’s milk by a high calorie low protein diet in a child more than one year in age. Like marasmus, kwashiorkor shows wasting of muscles, thinning of limbs, failure of growth and brain development. But unlike marasmus, some fat is still left under the skin; moreover, extensive oedema and swelling of body parts are seen.
1.) Identify the correct statement
Statement 1 – Jaundice cause skin and eyes turn yellow due to the deposit of bile.
Statement 2 – Diarrhoea reduces the absorption of food.
Statement 3 – In constipation bowel movements occur irregularly.
Statement 4 – Inadequate enzyme secretion, is one of the cause of indigestion.
a) Statement 1 and 2 are correct
b) Statement 2 and 3 are correct
c) Statement 3 and 4 are correct
d) All statement are correct
2.) The reflex actions of vomiting are controlled by the vomit centre present in the
a) Hypothalamus
b) Hepatic lobules
c) Medulla
d) Pancreas
3.) Name any two protein energy malnutrition condition.
4.) Explain Marasmus disorder with suitable example.
5.) Give an account of adverse effects of protein energy malnutrition.
Answer key
1) d
2) c
3) Protein energy malnutrition leads to produce Marasmus and Kwashiorkar.
4) Marasmus is condition which is developed by a simultaneous deficiency of proteins and calories. It is found in infants less than a year in age, if mother’s milk is replaced too early by other foods which are poor in both proteins and caloric value there is high possibility of developing Marasmus.
5) Adverse effects of PEM
- Marasmus protein deficiency impairs growth and replacement of tissue proteins; extreme emaciation of the body and thinning of limbs results, the skin becomes dry, thin and wrinkled. Growth rate and body weight decline considerably. Even growth and development of brain and mental faculties are impaired.
- Kwashiorkor shows wasting of muscles, thinning of limbs, failure of growth and brain development. Unlike marasmus, some fat is still left under the skin; moreover, extensive oedema and swelling of body parts are seen.
CASE 4
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. Small amounts of monosaccharaides like glucose, amino acids and some electrolytes like chloride ions are generally absorbed by simple diffusion. The passage of these substances into the blood depends upon the concentration gradients. However, some substances like glucose and amino acids are absorbed with the help of carrier proteins. This mechanism is called the facilitated transport. Transport of water depends upon the osmotic gradient. Active transport occurs against the concentration gradient and hence requires energy. Various nutrients like amino acids, monosaccharides like glucose and electrolytes like Na+ are absorbed into the blood by this mechanism. Fatty acids and glycerol being insoluble, cannot be absorbed into the blood. They are first incorporated into small droplets called micelles which move into the intestinal mucosa. They are re-formed into very small protein coated fat globules called the chylomicrons which are transported into the lymph vessels (lacteals) in the villi. These lymph vessels ultimately release the absorbed substances into the blood stream. Absorption of substances takes place in different parts of the alimentary canal, like mouth, stomach, small intestine and large intestine. However, maximum absorption occurs in the small intestine. The absorbed substances finally reach the tissues which utilise them for their activities. This process is called assimilation. The digestive wastes, solidified into coherent faeces in the rectum initiate a neural reflex causing an urge or desire for its removal. The egestion of faeces to the outside through the anal opening (defaecation) is a voluntary process and is carried out by a mass peristaltic movement.
1.) The end products of digestion pass through ____________ and then into blood.
oesophagus
intestinal mucus
intestinal mucosa
none of the above
2.) Identify the incorrect statement
Statement 1 – The end products of digestion pass through the intestinal mucosa into the blood.
Statement 2 – Absorption is carried out by passive, active or facilitated transport mechanisms.
Statement 3 –Active transport occurs against the concentration gradient.
Statement 4 – Active transport doesn’trequires energy.
a) Statement 1 is incorrect
b) Statement 2 is incorrect
c) Statement 3 is incorrect
d) Statement 4 is incorrect
3.) Explain what is assimilation in case of reabsorption?
4.) Define Micelles and Chylomicrons?
5) Name the organ at which digestive wastes solidifies?
Answer key
1.) c
2.) d
3.) Assimilation – When the end product of digestion pass through the intestinal mucosa and absorbed into blood and these substances finally reach the tissues which utilise them for their activities. This process is called assimilation.
4.) Fatty acids and glycerol being insoluble, cannot be absorbed directly into the blood. They are first incorporated into small droplets called micelles which move into the intestinal mucosa. They are re-formed into very small protein coated fat globules called the chylomicrons which are transported into the lymph vessels (lacteals) in the villi.
5.) The digestive wastes solidified into coherent faeces in the rectum.
CASE 5
The process of digestion is accomplished by mechanical and chemical processes. The buccal cavity performs two major functions, mastication of food and facilitation of swallowing. The teeth and the tongue with the help of saliva masticate and mix up the food thoroughly. Mucus in saliva helps in lubricating and adhering the masticated food particles into a bolus. The bolus is then conveyed into the pharynx and then into the oesophagus by swallowing or deglutition. The bolus further passes down through the oesophagus by successive waves of muscular contractions called peristalsis. The gastro-oesophageal sphincter controls the passage of food into the stomach. The saliva secreted into the oral cavity contains electrolytes and enzymes, salivary amylase and lysozyme. The chemical process of digestion is initiated in the oral cavity by the hydrolytic action of the carbohydrate splitting enzyme, the salivary amylase. About 30 per cent of starch is hydrolysed here by this enzyme (optimum pH 6.8) into a disaccharide – maltose. Lysozyme present in saliva acts as an antibacterial agent that prevents infections.
The stomach stores the food for 4-5 hours. The food mixes thoroughly with the acidic gastric juice of the stomach by the churning movements of its muscular wall and is called the chyme. The proenzyme pepsinogen, on exposure to hydrochloric acid gets converted into the active enzyme pepsin, the proteolytic enzyme of the stomach. Pepsin converts proteins into proteoses and peptones (peptides). The mucus and bicarbonates present in the gastric juice play an important role in lubrication and protection of the mucosal epithelium from excoriation by the highly concentrated hydrochloric acid. HCl provides the acidic pH (pH 1.8) optimal for pepsins. Rennin is a proteolytic enzyme found in gastric juice of infants which helps in the digestion of milk proteins. Small amounts of lipases are also secreted by gastric glands.
1.) The functions such as mastication of food and facilitation of swallowing are facilitated by
a) Teeth
b) Tongue
c) Buccal cavity
d) Pharynx
2.) ________________ is the carbohydrate splitting enzyme
a) Lysozyme
b) Pepsinogen
c) Hydrochloric acid
d) Salivary amylase
3.) Name the enzyme present in the saliva.
4.) Give the functions of hydrochloric acid in digestion process.
5.) Give the function of salivary amylase and lysozyme.
Answer key
1.) c
2.) d
3.) The saliva secreted into the oral cavity contains electrolytes and enzymes, salivary amylase and lysozyme.
4.) Functions of hydrochloric acid in digestion process are as follows,
- Plays important role in enzyme activation, such as proenzyme pepsinogen, on exposure to hydrochloric acid gets converted into the active enzyme pepsin.
- HCl provides the acidic pH (pH 1.8) optimal for pepsins
5.) Function of salivary amylase and lysozyme
Function of salivary amylase,
- It acts as carbohydrate splitting enzyme.
- It shows hydrolytic action of the carbohydrate splitting enzyme.
6.) Function of lysozyme,
- Lysozyme present in saliva acts as an antibacterial agent
- It prevents infections.