The Building blocks…

–Karthik Gurumurthy

Animals’ bodies consist of many different parts, each with a special job. All the parts work together to carry out the necessary activities that enable an animal to function.

Think of an animal’s body as being like a sand castle made of tiny grains of sand. Similarly, animals are made of tiny building blocks called cells. The larger the animal, the more cells it has. To make a sand castle bigger, you add more sand. An animal gets bigger by creating more cells. Cells are alive, and as an animal lives and grows, the cells in its body divide to make new cells.

The cells in most animals are not all alike. Cells have different sizes and shapes depending on the work they do. Flat, wide skin cells cover and protect the body. Muscle cells are fibrous, that is made of long, slender pieces. They can lengthen and shorten themselves to help an animal move. Brain cells are long and narrow and send out brances that make contact with other brain cells.

Groups of the same kind of cells join together to make tissue. Muscles are tissues made from muscle cells. Skin tissue is made from skin cells. Certain tissues come together to form organs. Organs, such as the heart, lungs, kidneys, and lives, do the work of the body. An animal’s entire skin is considered an organ, too. It covers and protects everything inside the body.

Groups of organs and tissues are linked together in systems to carry out certain tasks, such as breathing or digesting food. These organ systems all work together to keep an animal alive and healthy.