organ systems

1.Respiratory:
Easier - The lungs, airways, diaphragm, windpipe, throat, mouth, and nasal passages are all part of the respiratory system. Respiration is the process of breathing in and out through this system. Smoking and air pollution are two common causes of respiratory problems.
Harder - Oxygen is taken into the body through the airways, absorbed into the lungs, then transported through the body in the blood. The lungs also give out carbon dioxide into the atmosphere.

2.Lymphatic:Lymph organs include the bone marrow, lymph nodes, spleen, and thymus. Precursor cells in the bone marrow produce lymphocytes. B-lymphocytes (B-cells) mature in the bone marrow. T-lymphocytes (T-cells) mature in the thymus gland.

3.Muscular:The human body contains more than 650 individual muscles which are attached to the skeleton, which provides the pulling power for us to move around. The main job of the muscular system is to provide movement for the body. The muscular system consist of three different types of muscle tissues : skeletal, cardiac, smooth. Each of these different tissues has the ability to contract, which then allows body movements and functions. There are two types of muscles in the system and they are the involuntary muscles, and the voluntary muscles. The muscle in which we are allow to control by ourselves are called the voluntary muscles and the ones we can? control are the involuntary muscles. The heart, or the cardiac muscle, is an example of involuntary muscle.

4.SkeletaL: Skeletal system is the biological system providing support in living organisms. Skin, muscle and bones allow movement. Skin - pliable covering. Muscles do actual moving. Bones give anchor to move against. The skeleton functions not only as the support for the body but also in haematopoiesis, the manufacture of blood cells that takes place in bone marrow. This is why people who have cancer of the bone marrow almost always die. It is also necessary for protection of vital organs and is needed by the muscles for movement.

5.Endocrine:The nervous system sends electrical messages to control and coordinate the body. The endocrine system has a similar job, but uses chemicals to “communicate”. These chemicals are known as hormones. A hormone is a specific messenger molecule synthesized and secreted by a group of specialized cells called an endocrine gland. These glands are ductless, which means that their secretions (hormones) are released directly into the bloodstream and travel to elsewhere in the body to target organs, upon which they act. Note that this is in contrast to our digestive glands, which have ducts for releasing the digestive enzymes.