The 10 major systems of the body are groups of organs that allow our body to move, think, protect itself and continue functioning. The major systems are grouped by structure and function, but all are interdependent, and some work more closely than others. For example, the muscular system is a vital part of the circulatory system because smooth muscle tissue is needed to make the heart beat. Similarly, the muscular system relies on the skeletal system as a point of resistance and support.
Skeletal and Muscular Systems
The skeletal system is composed of bones, cartilage, tendons and ligaments. The skeletal system serves as the body's physical support and also serves to protect the inner organs and give them structure to attach to. The skeletal system is the framework for muscles to attach to and is a necessary component of movement.
The muscular system is composed of skeletal muscles and smooth muscles and is used to produce voluntary and involuntary movement. Skeletal muscles are used to produce voluntary movement, and smooth muscles are used by the body organs such as blood vessels, the bladder and the heart to produce involuntary movement.
Circulatory, Lymphatic and Respiratory Systems
The circulatory system includes the heart, blood vessels and arteries and is used to circulate nutrients, hormones, oxygen and waste to the entire body.
The lymphatic system is used to produce immunity from diseases, toxins and foreign proteins from the body. The lymphatic system includes lymph nodes, lymph vessels, T cells and B cells.
The respiratory system includes the lungs, the trachea and the nose, and it is used to collect oxygen from the air and to dispel wastes from the body.
Digestive and Excretory Systems
The digestive system is used to break down food and to absorb needed nutrients and sustenance from foods. The digestive system includes the mouth, the esophagus, the stomach and the large and small intestines.
The excretory system is used to dispel extra water, toxins and cellular wastes from the body. The excretory system includes the bladder, the kidneys, the ureters and the urethra.
Nervous and Reproductive Systems
The nervous system includes the brain, the spinal cord and the nerves and is used to transmit electrical impulses to the entire body. The nervous system is used to produce thought, to initiate voluntary and involuntary movement and to chemically coordinate processes of all the other body systems.
The reproductive system is used to reproduce human life. Male organs include the penis, testes and seminal vesicles. and female organs include mammary glands, ovaries, oviducts, the uterus and the vagina.
The endocrine system is used to carry out messages throughout the body by use of various glands and hormones. The endocrine system can control complex mental processes like sexual drive and physical effects throughout the entire body, such as increased heart rate or hair growth. The endocrine system includes organs such as the pituitary gland, the adrenal gland, the hypothalamus, the thyroid and the pancreas.