There are ten important systems in the human body: the skeletal, muscular, nervous, circulatory, respiratory, digestive, reproductive, endocrine, urinary and lymphatic system. The first six are described below.
The Skeletal & Muscular Systems
The skeletal system provides the body with support and protection of its vital organs and the muscular system enables us to move. The adult human skeleton is composed of 206 bones that are bound together by tough bands of tissue called ligaments.
The places where bones join together are known as joints. Movement depends on the contraction or tightening of the skeletal muscles, which are attached to the bones by tendons. The bones are filled with bone marrow, a fatty substance, and this is where red and white blood corpuscles or cells are produced.