Test: Digestion & Absorption - 1 (Old NCERT) - JAMB MCQ

• Human being forms two sets of teeth during their life: temporary milk or deciduous teeth replaced by a set of permanent or adult teeth called diphyodont.
• An adult human has 32 permanent teeth which are of four different types called heterodont.
• Each tooth is embedded in a socket of jaw bone called thecodont.
  

Amylase catalyzes the breakdown of starch. When amylase reacts with starch, it cuts off the disaccharide maltose (two glucose molecules linked together). Its function is to catalyze the hydrolysis of starch into glucose.
It is commonly found in saliva and germinating seeds. 

I. Myenteric plexus controls peristaltic waves in the Gastrointestinal tract but does not regulate glandular secretions.

II. Neurons of Meissner's plexus controls both exocrine and endocrine secretion in the Gastrointestinal tract but does not regulate peristaltic waves.

Hence, both statements in the question are wrong.

(1) Maltose is made up of two molecules of glucose.

(2) Lactose is a disaccharide, a type of sugar composed of two simple sugars, glucose and galactose. 

(3) Sucrose is made up of glucose and fructose molecules. When sucrose is consumed, the enzyme separates sucrose into its individual sugar units of glucose and fructose.

The wall of alimentary canal possesses four layers- serosa, muscularis, sub mucosa, and mucosa:

• Sub-mucosa layer is formed of loose connective tissues containing nerves, blood, and lymph vessels. Glands are also present in sub-mucosa of duodenum.
• Serosa is the outermost layer and is made up of a thin mesothelium and connective tissue.
• Muscularis is formed by smooth muscles usually arranged into an inner circular and an outer longitudinal layer.
• Mucosa is the innermost layer lining the lumen of the alimentary canal. Mucosa forms irregular folds (rugae) in the stomach and villi in the small intestine.
  

(a) - (iv): Constipation occurs when bowel movements become less frequent and stools become difficult to pass. It happens most often due to changes in diet or routine, or due to inadequate intake of fiber. You should call your doctor if you have severe pain, blood in your stools, or constipation that lasts longer than three weeks.

(b) - (i): You can get jaundice if a gallstone passes out of the gallbladder into the bile duct and blocks the flow of bile. Symptoms of jaundice include: yellowing of the skin and eyes. dark brown urine.

(c) - (ii): Stress and anxiety may provoke acid reflux or make the symptoms worse. For instance, a 2018 study involving more than 19,000 people found that those with anxiety were more likely to experience GERD symptoms.

(d) - (iii) : Classic symptoms of chronic mesenteric ischemia include postprandial abdominal pain associated with significant weight loss, food fear, nausea, vomiting, or diarrhea. The abdominal pain classically starts 15 to 30 minutes after a meal and typically lasts for ∼30 minutes.

Hence, the correct option is Option C.

Food material consists of plant or animal cells. Each cell contain DNA in their nucleus. Digestion of DNA takes place in small intestine by the action of enzyme present in succus entericus and pancreatic juice.

Malnutrition is the condition of having less than the required amount of food or more than the required amount of food. Both conditions are harmful to health. So, malnutrition covers both undernutrition and overnutrition.

The deficiency of proteins within the body is responsible for a disease,  known as kwashiorkor. So, a kwashiorkor diseased patient is generally advised to specially, consume more meat, lentils, milk and eggs because these are rich sources of protein.

Trypsinogen is activated by an enzyme, enterokinase, secreted by the intestinal mucosa into active trypsin.
Enterokinase → Trypsinogen → Trypsin

Enteropeptidase (also called enterokinase) is an enzyme produced by cells of the duodenum and is involved in digestion in humans and other animals. Enteropeptidase converts trypsinogen (a zymogen) into its active form trypsin, resulting in the subsequent activation of pancreatic digestive enzymes.

simple diffusion, facilitated transport, active transport.
Correct answer is D.

Chronic gastritis involves swelling or inflammation of the stomach lining. This is caused by bacteria Helicobacter pylori.

1. Brunner's glands (or duodenal glands) are compound tubular submucosal glands found in that portion of the duodenum which is above the hepatopancreatic sphincter (Sphincter of Oddi).
2. The main function of these glands is to produce a mucus-rich alkaline secretion (containing bicarbonate) in order to protect the duodenum from the acidic content of chyme (which is introduced into the duodenum from the stomach); provide an alkaline condition for the intestinal enzymes to be active, thus enabling absorption to take place, lubricate the intestinal walls. They are the distinguishing feature of the duodenum.

The figure shows the 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 small intestine is the most important part of the gastrointestinal tract between the stomach and the large intestine where much of the digestion and absorption of food takes place due to the finger-like projection. The small intestine has three distinct regions the duodenum, jejunum, and ileum. It is the part of the digestive tract where approx 90% of the digestion and absorption of food occurs, the other 10% taking place in the stomach and large intestine. Most of the absorption part of the digestive process occurs in the jejunum and the ileum.

Regurgitation is the expulsion of material from the pharynx or esophagus. Regurgitation is more common in infants than adults because cardiac sphincter is much less effective in infants.

(a) - (ii) : Goblet cells secrete mucus which helps to neutralise the stomach acidity.

(b) - (iii) : Oxyntic cells secrete HCl and Castle's intrinsic factor so they are acidic.

(c) - (iv) : Chief cells also called peptic cells secretes proenzymes like pepsinogen.

(d) - (i) : Intestinal gland cells also called Brunner's gland secretes intestinal juice or succus entericus.

Hence, the correct option is Option A.

• Various types of movements are generated by the muscularis layer of the small intestine. These movements help in a thorough mixing up of the food with various secretions in the intestine and thereby facilitate digestion.
• The bile, pancreatic juice and the intestinal juice are the secretions released into the small intestine. Pancreatic juice and bile are released through the hepato-pancreatic duct.
• 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.

The correct answer is (a).

Bolus from pharynx is conveyed into oesophagus by deglutition.

Bolus is the semisolid chewed food mixed with saliva in mouth. The food from pharynx passed to oesophagus by swallowing.

The oesophagus and the trachea (wind pipe) open into the pharynx.

• All the four basic layers (serosa, muscularis, sub-mucosa and mucosa) in the wall of gut show modifications in different parts of the alimentary canal.
  Example: mucosal epithelium has goblet cells which secrete mucus.
• Mucosa also forms glands in the stomach and crypts in between the bases of villi in the intestine.

• Lymph are the extracellular fluids that constitute the lymphatic system in the human body.
• Absorption of fats takes place through lymphatic ducts. As fats cannot be carried through narrow capillaries.

CCK acts on both the pancreas and gall bladder and stimulates the secretion of pancreatic enzymes and bile juice respectively.

The accessory digestive glands include the salivary glands, the liver (with gall bladder) and the pancreas.

• Digestive glands which are not part of the digestive tract but have a role in digestion are called accessory digestive glands.
• Salivary glands, liver and pancreas are the various accessory digestive glands which are associated with the alimentary canal but are not within the alimentary canal.
• These glands release their secretions into the alimentary canal through ducts.