(3)	Respiratory+system+structure

====The Respiratory System Structure is responsible for the process of respiration, which is vital for all living organisms. This system's main function is to facilitate the diffusion of Oxygen in the blood stream by transporting air to the lungs. In return waste (Carbon Dioxide) is released from the blood. ====



 * Diagram to show the different parts of the human respiratory system**



__Mouth/Nasal Cavity: __
====This part of the system brings oxygen into our body. It is responsible for warming, filtering and moistening the incoming air before it travels down the pharynx. ====

__Pharynx: __
====This is where the throat divides into two parts: the trachea (wind pipe) and oesophagus (food pipe). The trachea is guarded by a small flap of cartilage, a particular structure amde of this tissue called the epiglottis, a flap of cartilage at the root of the tongue, which is depressed during swallowing to cover the opening of the windpipe (not on diagram) preventing food from travelling into the wind pipe. ==== []

__Larynx: __
====This is the part of the body where sound is generated- the voice box. The larynx produces a strong 'cough' reflex to protect the trachae in the event of solid objects passing the epiglottis (cartilage flap). ====

__Trachea: __
====This windpipe connects the throat to the lungs and is used to transport air. This part of the system is also responsible for removing dust particles that have been inhaled by cilia - tiny hairs that cover the inner membrane of the trachea. We dispose of these particles by coughing. ==== ====The sizes differ in each person, ranging from 20-25mm diameter, and 10-16cm length. 15-20 C-shape cartilage rings surround the front and sides of the of the trachea protecting it and keeping it open. Sometimes it is necessary for the trachea to partially collapse because the oesophagus (sitting behind the trachea) expands when swallowing large food particles ====

__Bronchi: __
====The bronchi are the two tubes extending from the trachea going into the right and left lung. They are surrounded by irregular rings of cartilage and walls that consist of smooth muscle. One they are inside the lungs they divide into several tertiary bronchi.

__Bronchioles: __
====These are tertiary bronchi that have continued to divide. They are extremely narrow tubes, close to 1mm diameter. At the end of the tubes are alveolar sacs. ====

__Alveoli (Alvioli): __
====<span style="font-family: Arial,Helvetica,sans-serif;">These hollow cavities are in charge of permitting gas exchange Oxygen - Carbon Dioxide. They have very thin walls, contained within alveolar ducts, and are surrounding by a network of capillaries. The stimulated gasses pass throught these capillaries. ==== = = = =

<span style="font-family: Arial,Helvetica,sans-serif;">This muscle sits beneath the lungs; connecting to the lower ribs, sternum, lumbar spine and forming a solid base for the thoracic cavity.
This video shows how the respiratory system works.

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