a. The most important functions of the skin are:
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Protection − The skin provides protection to the body from mechanical injury, ultraviolet rays, from disease-causing microbes, and prevents desiccation.
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Temperature regulation − The skin helps in the maintenance of body temperature at a constant.
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The skin contains numerous sense receptors, which help in perceiving the surroundings.
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The skin is also involved in the synthesis of vitamins such as Vitamin D.
- The skin also helps in disposing off the excess water and salt by evaporation.
Ans b. The following things should be done in order to keep our bones healthy and strong:
- Have calcium rich foods like milk, yoghurt as calcium is an important component of bones.
- We need to take enough vtiamin D as it helps in the absorption of calcium present in foods.
- Some other important nutrients like potassium, vitamin K and magnesium also help the body to absorb and use calcium.
- Daily exercise is required to keep our bones in a state of good health.
Ans c. The skeletal system includes all of the bones and joints in the body. It performs the following functions:
- gives a definite shape to the body
- provides support and protection for the soft tissues that make up the rest of the body
- provides attachment points for muscles to allow movements at the joints
Ans d. Bones are structurs which are hard and non flexible. The chances of breaking of bones occurs, if the bones are weak. There are various reasons due to which bones may become weak and may break:
- certain diseases can result in weakening of the bones and cause them to break. For example, osteoporosis and arthirits are diseases which result in the weakening of bones
- defeciency of nutrients like calcium and vitamin D
- certain stress or injury may result into fracturing of bones
- bone loss also occurs with age and thus making them more fragile
- alcohol and smoking also have a negative impact on bones and bone density
Ans e. There are 4 types of bones:
1. Flat bones: They are thin shaped and, in some cases, provide mechanical protection to soft tissues beneath or enclosed by the flat bone.
2. Irregular bones: They have complicated shapes which cannot be classified as 'long', 'short' or 'flat'. Their shapes are due to the functions they fulfill within the body.
3. Long bones: These type of bones are longer than wider and they function to support the weight of the body and facilitate movement
4. Short bones: They are almost cube shaped bones as they are equal in their length and width.