Wednesday, October 29, 2008

Human Respiratory Organs

By Don Bethune

Human being have lungs for respiration. So respiration in human beings is know as pulmonary respiration.Respiratory organs are well developed in human being.The respiratory system consists of repiratory tract and respiratory organs.The repiratory tract is passage along whcih air travels from the atmosphere in order to reach lungs.

The Nasal Cavity. The Nasal Cavity is situated above the mouth, and accesses the external atmosphere through the nostrils, and internally it accessed the pharynx with the internal nostrils. The nasal cavity helps filter out dust particles from the outside environment with the cilia and with mucus.

The Pharynx. After entering through the nasal cavity, air next goes to the pharynx. There, the pharynx opens into the larynx or voice box through the glottis. The pharynx is actually shared by the respiratory system with the digestive tract. Luckily, the glottis is usually covered by the cartilage epiglottis when we swallow food, so we donat choke.

The Larynx: This is a cartilagious, box-like structure that is situated at the tracheal opening. The larynx will move up or down when we swallow to allow the passage of air or food, safely. It also is responsible for human speech, as it contains two vocal chords that vibrate to produce sound.

The Trachea. After the larynx, thereas the trachea, which is a tube leading to the bronchi. This tube is eleven centimeters in length and twenty five in diameter. The trachea has an incomplete C-shape cartiligious ring within its wall, which prevents it from collapsing so we can keep breathing.

The Bronchi and Bronchioles. The next stop for air is the two primary bronchi that split off from the trachea. These serve the function of carrying the air into the next organ, the lungs. The right bronchus divides into three bronchi, each extending respectively into the three lobes of the right lung. On the other side, the left bronchi divides into two bronchi that extend into the two lobes of the left lung.

Lungs:- There are two lungs in the thoracic cavity.The thoracic cavaty is bounded by vertebral coloumn arrives sternum and diaphragm.The lungs are highly elastic hollow dark coloured spongi bag like structure. The lungs rest on a sheet of muscle called the diaphragm which forms the floor of the thoracic.

As mentioned before, the right lung is separated into three lobes, whereas the left long is only separated into two lobes. The lungs are also surrounded by a narrowly shaped pleural cavity, which is in turn surrounded by two membranes. These membranes secrete an oily substance called pleural fluid, which fills the Pleural cavity.

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