Complete the following exercises about the human digestive system and teeth.

here are the answers for this section:

B. Fill in the blanks:

1. Teeth and bones give proper shape to our face.
2. Enamel is the hardest substance in the human body.
3. Smaller pieces are easier to chew and digest food.
4. We should always eat healthy and nutritious food.

C. Write 'T' for True and 'F' for False:

1. Teeth help us to bite, chew and grind our food. $\rightarrow$ T
2. Human beings have four sets of teeth. $\rightarrow$ F (They have two sets: milk teeth and permanent teeth)
3. Incisors are at the back of each jaw. $\rightarrow$ F (Incisors are at the front)
4. Premolars and molars are flat teeth. $\rightarrow$ T
5. Muscles of the food pipe push food down into the stomach. $\rightarrow$ T

D. Answer the following questions:

1. To draw a well-labelled diagram of the digestive system, you should include the mouth, esophagus (food pipe), stomach, small intestine, large intestine, rectum, and anus. Also, label accessory organs like the liver, gallbladder, and pancreas.

2. In the stomach, food is mixed with gastric juices containing acids and enzymes. These juices break down proteins, and the stomach muscles churn the food, turning it into a semi-liquid paste called chyme.

3. The function of the tongue is to help in tasting food, mixing food with saliva, swallowing, and speaking.

4. In the small intestine, most of the digestion and absorption of nutrients (carbohydrates, proteins, fats, vitamins, minerals) occur. In the large intestine, water and electrolytes are absorbed from the remaining indigestible food matter, and waste material is formed into feces.

5. We should chew our food properly because it breaks down food into smaller pieces, which increases the surface area for digestive enzymes to act upon, making digestion more efficient. It also helps prevent choking.

6. Temporary teeth (also known as milk teeth or deciduous teeth) are the first set of teeth that erupt in childhood, typically 20 in number. They eventually fall out. Permanent teeth are the second set of teeth that replace the milk teeth, typically 32 in number, and are meant to last a lifetime.

7. A tooth consists of a crown (the visible part above the gum) and a root (embedded in the jawbone).

   • The outermost layer of the crown is enamel, the hardest substance in the body.
   • Beneath the enamel is dentin, a bone-like material.
   • The innermost part is the pulp, which contains nerves and blood vessels.
   • The root is covered by cementum, which helps anchor the tooth to the jawbone.

8. a) Molars:

   • Number: There are typically 8 molars in adults (two on each side of both jaws), plus 4 wisdom teeth (third molars) which may or may not erupt. So, 8-12 in total.
   • Function: They have broad, flat surfaces used for grinding and crushing food.
   • b) Incisors:
   • Number: There are 8 incisors in adults (four in the upper jaw and four in the lower jaw).
   • Function: They are sharp, chisel-shaped teeth used for biting and cutting food.

9. A few ways to protect teeth from decaying are:

   • Brushing teeth twice a day with fluoride toothpaste.
   • Flossing daily to remove food particles between teeth.
   • Limiting sugary foods and drinks.
   • Rinsing the mouth after meals.
   • Regular dental check-ups and cleanings.

HOTS (Critical Thinking)

No, another set of teeth will not grow if permanent teeth fall off. Permanent teeth are the final set of teeth a human develops.

PROJECT WORK (Collaboration)

These are activities for you to complete, not questions for me to answer.

Life Skill

This is an activity for you to complete, not a question for me to answer.