Human Digestive System and Teeth for Class 5 Science

The food we ingest is a complex material and is of no use to our body until it is digested.
The process of digestion is a complex process that involves the human digestive system.
The human digestive system starts from the buccal cavity and ends at the anus.
The food which we eat takes 6 to 8 hours to get digested. After that, it is converted into a form that can be used by our body to produce energy.

Types of Teeth

Question 1:

What Keeps Your Teeth Fixed in Place?

Answers:

Teeth are fixed in socket-like structures present in the upper and lower jaw.
This fixation is not superficial; rather, the teeth are fixed deep inside the boxes of the upper jaw and lower jaw called maxilla and mandible, respectively.
The jaw bones are the skull's strongest bones, and only the lower jaw, i.e., the mandible, is movable.

Question 2:

What Do You Understand by Dental Formula of Human?

Answers:

The formula used to calculate the number and types of teeth present in both jaws is called the dental formula.
The dental formula for humans is—

Here, 2 stands for incisors, 1 for canines, 2 for premolars, and 3 for molars.

Question 3:

How Are Teeth Different From Bones?

Answers:

Teeth are different from bones in the following aspects—

Teeth are covered by a layer called enamel, which makes them stronger than bones.
Bones are protected by layers of muscles and skin, but teeth are not.
Bones can produce new red blood cells in their central cavity, called bone marrow, but teeth cannot.

Question 4:

What Does a Healthy Tooth Look Like? Which Substance Is Responsible for That Appearance?

Answers:

Healthy teeth appear bright white, and shiny.
Calcium phosphate present in the enamel gives the characteristic colour to the teeth.

Question 5:

Do Your Teeth Resemble Your Parents or Siblings?

Answers:

Every person has different shapes and arrangements of teeth.
Like no two people can have the same DNA and fingerprints; similarly, no two people can have the same shape and arrangement of teeth.

Digestion Process

Question 1:

How Does the Food We Eat Change After Getting Digested?

Answers:

After digestion is over, the food gets converted into simple nutrients, which are absorbed into the bloodstream through the walls of the small intestine.
Carbohydrates, fats, and proteins change into glucose, glycerol, and amino acids, respectively.

Question 2:

Our Stomach Secretes an Acid Called Hydrochloric Acid, Which Is Highly Corrosive, but Our Stomach Is Not Affected by It. Can You Explain Why?

Answers:

The mucous layer covers the wall of our stomach.
It secrets mucous, a slimy liquid that lubricates the walls of the stomach, thereby protecting the stomach from the action of hydrochloric acid.

Question 3:

Once the Food Is Digested in the Stomach, It Is Delivered Slowly and in Small Quantities to the Small Intestine. Why Do You Think This Arrangement Is Adapted?

Answers:

After the digestion process is partially completed in the stomach, the food is further passed in small quantities to the small intestine for complete digestion.
The completely digested food then passes slowly through the walls of the small intestine for its complete absorption into the bloodstream.

Process of Digestion and Digestive Disorders

Question 1:

Why Does the Stomach in Ruminant Animals Have an Additional Chamber?

Answers:

Ruminants are herbivores that eat plants or plant parts.
Their food is rich in cellulose, a type of carbohydrate.
This cellulose takes a longer time to digest.
Hence, ruminants have adapted to consuming this type of food by developing an additional chamber in the stomach.

Question 2:

What Is an Antacid? Give One Example. How Does It Help in Curing Acidity?

Answers:

An antacid is a preparation that is basic in nature and meant to counteract the action of excess acid produced in the stomach.
ENO and Digene are examples of antacids.
The action of an antacid neutralises the hydrochloric acid produced by the stomach.

Question 3:

Certain Bacteria in Our Alimentary Canal Are Good for Our Health. Explain How They Are Beneficial.

Answers:

The bacteria found in our alimentary canal help in the following ways—

They aid in the process of digestion by digesting dietary fibres and complex sugars.
Also, bacteria produce certain enzymes that are good for our alimentary canal.

Question 4:

Amoeba Is a Protozoan. It Undergoes a Holozoic Mode of Nutrition Like Humans. Explain.

Answers:

Amoeba belongs to the group of Protozoa, which comprises animal-like microorganisms.
It is a unicellular organism with a simple level of body organisation.
The mode of nutrition constitutes ingestion, digestion, absorption, assimilation, and egestion. Collectively, it is called the holozoic mode of nutrition.
In the case of amoeba, nutrition comprises the steps mentioned above and hence, is considered a holozoic mode of nutrition.

Question 5:

What Is Peristalsis? Explain Shortly.

Answers:

Peristalsis is an involuntary movement of the alimentary canal.
Involuntary movements are those we cannot control, like peristalsis, the beating of our heart, etc.
Peristalsis is the regular contraction and relaxation of muscles of the alimentary canal. It helps in the movement of food through the alimentary canal during the process of digestion.

Question 6:

Among the All Digestive Glands in the Human, the Pancreas Is the Second-Largest Digestive Gland. How Does It Help in Controlling the Blood Sugar Level of Our Bodies?

Answers:

The pancreas plays a vital role in the digestion of fats and proteins by secreting enzymes required for their digestion.
Apart from that, specific cells in the pancreas release the hormone called insulin.
The secretion of insulin is triggered as soon as the blood sugar level rises so that insulin can act and bring back the blood sugar level to normal. Thus, the pancreas helps in maintaining the blood sugar level in our bodies.

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