1
Question
(a) Draw a labelled diagram of the human digestive system. With the help of this diagram, describe the process of digestion of food in man (humans).
(b) Describe one way in which the small intestine is adapted for the absorption of digested food.
(c) What is the special name of the contraction and expansion movement which pushes the food further in our digestive tract (or alimentary canal)?
(a) Draw a labelled diagram of the human digestive system. With the help of this diagram, describe the process of digestion of food in man (humans).
(b) Describe one way in which the small intestine is adapted for the absorption of digested food.
(c) What is the special name of the contraction and expansion movement which pushes the food further in our digestive tract (or alimentary canal)?
Open in App
Solution
a) Human digestive system
- Food is crushed and cut in the mouth with the help of teeth and is mixed with saliva that is secreted by three salivary glands(one below the tongue and two at the side of the jaw) to make it wet and slippery, this process is known as mastication.
- Saliva contains amylase that breaks down complex carbohydrates and the tongue helps in pushing the food to the next part of the alimentary canal.
- The soft food then passes through the esophagus in a wave-like movement known as a peristaltic movement.
- In the stomach, food mixes with gastric juices and dil. HCl. The food is broken down into simple substances with the help of digestive enzymes like pepsinogen, while mucus protects the walls of the stomach.
- From the stomach, the food moves into the small intestines with the help of ring-like muscles called pyloric sphincters which allow only a little food to pass through at a time.
- In the small intestine, carbohydrates, proteins, and fats are broken down with the help of juices secreted by the pancreas, liver, and the small intestine itself.
- Fat is converted into small globule-like forms with the help of bile juices from the liver. This process is known as emulsification.
- Pancreatic juices contain trypsin enzyme that breaks down proteins and lipase that breaks down fats.
- The later part of the small intestines is alkaline in nature and helps in the digestion of carbohydrates.
- The broken-down food is then absorbed by small projections present on the inside walls of the intestine called villi. Villi are surrounded by blood and lymph vessels that absorb the food and transport it to the rest of the body.
- Finally, the food moves into the large intestine where most of the water is removed from the food and is then passed out of the body through the anus.
b) Absorption of food in the intestine:
- The small intestine has small finger-like projections called villi (this increases the surface area for the absorption of food materials), which is highly supplied with blood vessels.
- As food passes through the small intestine, it is absorbed through the villi and enters the blood vessels, through which it is distributed to all parts of the body.
c) Peristalsis:
- Peristalsis is the specific name given to the food movement in the body.
- The peristaltic movement also called peristalsis refers to the contraction and relaxation of the food in the esophagus and the food pipe and the food is forced down the track to the stomach.
- This movement is involuntary and is necessary for the movement of food down the stomach and bowels down the anus.
a) Human digestive system
- Food is crushed and cut in the mouth with the help of teeth and is mixed with saliva that is secreted by three salivary glands(one below the tongue and two at the side of the jaw) to make it wet and slippery, this process is known as mastication.
- Saliva contains amylase that breaks down complex carbohydrates and the tongue helps in pushing the food to the next part of the alimentary canal.
- The soft food then passes through the esophagus in a wave-like movement known as a peristaltic movement.
- In the stomach, food mixes with gastric juices and dil. HCl. The food is broken down into simple substances with the help of digestive enzymes like pepsinogen, while mucus protects the walls of the stomach.
- From the stomach, the food moves into the small intestines with the help of ring-like muscles called pyloric sphincters which allow only a little food to pass through at a time.
- In the small intestine, carbohydrates, proteins, and fats are broken down with the help of juices secreted by the pancreas, liver, and the small intestine itself.
- Fat is converted into small globule-like forms with the help of bile juices from the liver. This process is known as emulsification.
- Pancreatic juices contain trypsin enzyme that breaks down proteins and lipase that breaks down fats.
- The later part of the small intestines is alkaline in nature and helps in the digestion of carbohydrates.
- The broken-down food is then absorbed by small projections present on the inside walls of the intestine called villi. Villi are surrounded by blood and lymph vessels that absorb the food and transport it to the rest of the body.
- Finally, the food moves into the large intestine where most of the water is removed from the food and is then passed out of the body through the anus.
b) Absorption of food in the intestine:
- The small intestine has small finger-like projections called villi (this increases the surface area for the absorption of food materials), which is highly supplied with blood vessels.
- As food passes through the small intestine, it is absorbed through the villi and enters the blood vessels, through which it is distributed to all parts of the body.
c) Peristalsis:
- Peristalsis is the specific name given to the food movement in the body.
- The peristaltic movement also called peristalsis refers to the contraction and relaxation of the food in the esophagus and the food pipe and the food is forced down the track to the stomach.
- This movement is involuntary and is necessary for the movement of food down the stomach and bowels down the anus.
Suggest Corrections
207
Similar questions