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Digestion and Absorption

Digestion and AbsorptionNEET Zoology · Class 11 · NCERT Chapter 16

3 interactive concept widgets for Digestion and Absorption. Drag any slider, change any number, and watch the formula and the answer update live. Built so you understand how each NEET problem actually works, not just the final number.

Alimentary canal explorer

Click any part of the human digestive system to see its role and the NEET fact tested about it.

Alimentary canal

Human alimentary canal: click any part

A labelled diagram of the human digestive system. Click any pin or chip to see the role of that part and the NEET fact tested about it.

MOUTHLIVERPANCREAS
Mouth and Buccal Cavity
Oesophagus
Stomach
Small Intestine
Large Intestine
Liver and Gall Bladder
Pancreas

Mouth and Buccal Cavity

The entry point of the alimentary canal. Contains teeth (dental formula 2123/2123), tongue and openings of three pairs of salivary glands. Salivary amylase begins starch digestion. Chewing increases surface area. Food is formed into a bolus.

NEET fact

Dental formula is 2123/2123. Human teeth are thecodont, diphyodont and heterodont.

Try this

  • Click on the pancreas. Why is it called a mixed gland? What two types of secretion does it produce?
  • Click on the liver. What does bile contain, and what does it do to fats?
  • Compare the small intestine and large intestine. What does each one mainly absorb?

Digestion enzyme tracker

Pick a food type and trace its digestion through the mouth, stomach and small intestine, with the enzyme and end product at each site.

Digestive enzymes

Digestion enzyme tracker: trace any food type step by step

Pick a food type (carbohydrate, protein, fat or nucleic acid) and trace what enzyme acts at each site, what the substrate is and what the end product becomes.

Pick a food type

Carbohydrate
Protein
Fat
Nucleic Acid

Starts as

Starch (polysaccharide)

Ends as

Monosaccharides (glucose, fructose, galactose)

1. Mouth

2. Stomach

3. Small

Mouth

Enzyme

Salivary amylase (ptyalin)

Secreted by

Salivary glands

Substrate

Starch

Product

Maltose + dextrins

NEET note

About 30% of starch is digested here. Salivary amylase is inactivated by stomach acid.

Try this

  • Select Fat. Notice that bile salts emulsify fats but are not enzymes. Which enzyme then breaks the emulsified fat?
  • Select Carbohydrate. In which two sites does amylase act, and what are the enzymes at each site?
  • Select Protein. Which inactive enzyme in the stomach is activated by HCl, and what activates trypsinogen in the duodenum?

Digestive disorders explorer

Explore the common digestive disorders and protein energy malnutrition, with cause and key features for each.

Disorders

Digestive disorders and protein energy malnutrition explorer

Click any disorder or PEM condition to see its cause and key features. Use the filter to focus on digestive disorders or protein energy malnutrition (marasmus and kwashiorkor).

All
Digestive Disorders
Protein Energy Malnutrition
Jaundice
Vomiting (Emesis)
Diarrhoea
Constipation
Indigestion (Dyspepsia)
Marasmus
Kwashiorkor

Jaundice

Disorder

Cause

Excess bilirubin in the blood. Bilirubin is a pigment from the breakdown of haemoglobin in old red blood cells. It is normally processed and excreted by the liver in bile. Jaundice occurs when the liver is diseased (hepatitis, cirrhosis), the bile duct is blocked (obstructive jaundice) or red blood cells are destroyed faster than the liver can clear bilirubin (haemolytic jaundice).

Key features

Yellow skin and whites of eyes (scleral icterus)
Dark urine (bilirubin spills into urine)
Pale stools (less bilirubin reaching the gut)
Itching in some cases

NEET fact

Jaundice is caused by excess bilirubin in blood. The liver is the main site for bilirubin processing.

Try this

  • Compare marasmus and kwashiorkor. Which one has oedema, and why does oedema occur in that condition?
  • Click on Jaundice. What is bilirubin and where does it come from?
  • Compare diarrhoea and constipation in terms of how much water the colon absorbs in each case.

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