Respiratory system
The Respiratory System
The respiratory system is the system that deals with breathing and supplying the blood with oxygen, but also has many other functions, including:
- filtering and cleaning the air we breathe
- adding resonance to our voice.
The respiratory system consists of many organs that work together to allow gas exchange to take place. This system works in conjunction with the circulatory system.
The respiratory system consists of the:
- Nose
- Larynx
- Pharynx (throat)
- Trachea
- Lungs
- Bronchi
- Bronchioles
- Alveoli
- Diaphragm.
Air is sucked into the body via the nose or mouth, where it is cleaned of unwanted dust. It is then passed to the back of the pharynx and into the trachea, where it travels into the divided bronchi, which lead to the alveoli via the bronchioles. Here, in the alveoli, gas exchange takes place.
The Lymphatic System
The lymphatic system consists of organs, ducts, and nodes. It transports a clear watery fluid called lymph. This fluid distributes immune cells and other factors throughout the body. It also interacts with the blood circulatory system to drain fluid from cells and tissues. The lymphatic system contains immune cells called lymphocytes, which protect the body against antigens (viruses, bacteria, etc.) that invade the body.
The main functions are:
- to collect and return interstitial fluid, including plasma protein, to the blood and thus help maintain fluid balance.
- to defend the body against disease by producing lymphocytes.
- to absorb lipids from the intestine and transport them to the blood.
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.
Besides providing a home for lymphocytes (B-cells and T-cells), the ducts of the lymphatic system provide transportation for proteins, fats, and other substances in a medium called lymph.
Lymph nodes are bean-shaped and range in size from a few millimetres to about 1-2 cm in their normal state. They may become enlarged due to a tumour or infection. White blood cells are located within the honeycomb structures of the lymph nodes. Lymph nodes are enlarged when the body is infected.
Lymph means clear water, and it is basically the fluid and protein that has been squeezed out of the blood (i.e. blood plasma). The lymph is drained from the tissue in microscopic blind-ended vessels called lymph capillaries.