The structure of the respiratory system, related to the process of ventilation

The structure of the respiratory system consists of the Nose, Pharynx, larynx and trachea, bronchi and bronchioles.
The respiratory system consists of a series of air passages to take air into and out of the alveoli. The passages are formed by the nose and nasal cavity, the throat and mouth the trachea, the two bronchi (singular bronchus) and many tiny bronchioles. Most of these passages are lined by a membrane that contains some special cells.

We need to breathe because. all of the cells in the body require oxygen. If your body didn't have oxygen it wouldn't be able to move. The way that oxygen gets into your body is from breathing in, the oxygen then goes to your blood, which then circulates through your entire body. When you breathe it is done with the help of your diaphragm and other muscles in your chest. When your diaphragm is pulling down, your diaphragm is doing this to make more room for your lungs to expand.
Air is usually breathed in through the nose, except during heavy exercise. Once the air is breathed in it takes the following journey to the lungs.

The Nasal Cavity

The structure of the nasal cavity is two air passages lined with goblet cells and cilia and lets air through.

The Nasal cavity are immediately inside the nostrils. It is covered with mucus, the mucus is there to stop infection by trapping any foreign bodies.The nasal cavity serve as a moistener, filter to warm up the air before it reaches the lungs. The Hairs within the nostrils prevent many foreign particles from entering. Different air passages and the nasal passages are covered with mucus membrane. Many of the cells that produce the cells that make up the membrane contain cilia. Other secrete a type of sticky fluid called mucus. The mucus and cilia collect dust, bacteria and other particles in the air. The mucus also helps in moistening the air.

The pharynx

The pharynx is shaped like a funnel. The pharynx carries air towards the lungs and food to the digestive tract. When the air leaves the pharynx it passes into the larynx. The larynx (voice box) is the opening of the trachea. The larynx is protected by a piece of cartilage called the epiglottis which is a flexible connective tissue. Food and liquids are blocked from entering the opening of the larynx by the epiglottis to prevent choking during swallowing.

Around the center of the chest, the trachea divides into two cartilage ringed tubes called bronchi. The bronchi enter the lungs and spread into smaller tubes called bronchial tubes.

Each bronchiole ends in a tiny air chamber that looks like a bunch of grapes, each chamber contains cavities known as alveoli. The walls of the alveoli which are only one cell thick are the respiratory surface. they are thin moist and surrounded by several number of capillaries. The exchange of oxygen and carbon dioxide between and air occurs through these walls.

www.cdli.ca/~dpowers/resp/struct#1.htm

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