Unit 5. In this unit we examine the respiratory system. So what is respiration? It is the process of supplying the cells of the body with oxygen and removing carbon dioxide and it involves inhalation and exhalation.
The structure of the respiratory system can be divided into two sections. Your upper respiratory tract consists of your nose, the pharynx, the larynx and the epiglottis and the lower respiratory tract which is contained within the thoracic cavity, involves the trachea, the bronchus, bronchioles, lungs, diaphragm and intercostal muscles. So the structure and function of the organs of the respiratory system. Firstly the nose.
The nose is made of cartilage and two nasal bones and lined with mucosal membranes lined with cilia. The two nostrils have two chambers which are divided by a septum. which is also made of cartilage. The nasal cavity connects to the sinus which are hollow spaces inside the bone filled with air.
As air enters the nostrils it is warmed and moistened and it filters dust particles. The pharynx is made of muscular and fibrous tissue and connects with the nose and its function is to act as an air passage and warm and moisten air. And then the larynx is a tube positioned between the tongue at the back of the mouth and the trachea. It is composed of cartilage rings attached by ligaments.
Its function is that it is a passageway for air between the pharynx and the trachea. As air passes it filters bacteria, helps with voice production and warms and moistens air. The trachea is 10 centimeters long and is continuous with the larynx.
It is a tubular pipe which runs from front of the neck to chest. where it divides into two bronchi. It is composed of cartilage rings lined with mucosal membranes and cilia.
Its function is to act as a passageway between the larynx and the bronchi and its mucosal membranes collect and trap foreign particles. The bronchi are the branches of the respiratory tube which transport oxygen and carbon dioxide in and out of the lungs. They are made of hyaline cartilage and they are involuntary and are lined with ciliated epithelium.
As they enter each lung, they subdivide into the broncholes. The broncholes are extensions of the bronchus and are made of muscular, fibrous, elastic tissue. As they go deeper into the lungs, they get smaller in size and their function is to take care of the alveoli of the lungs. Then the alveoli.
Here the exchange of gases in the lungs takes place, which are tiny and the alveoli are tiny sacs at the end of the bronchioles. They are surrounded by a network of capillaries and their function is to allow the exchange of gases between the circulatory and respiratory system. And then your lungs.
Your two lungs lie on either side of the thoracic cavity. They are cone shaped and composed of spongy tissue. bronchioles and alveoli, connective tissue, blood vessels, nerves and lymph vessels. Both lungs have an apex and a base. The right lung has three lobes which are known as superior, middle and inferior and the left lung has two lobes superior and inferior with each lobe subdivided into lobules.
The lungs are covered with a sac called the pleura which allows ease of movement during respiration. The lungs are protected by the ribcage, sternum and vertebrae. The space between the lungs is called the mediastinum, which contains your heart, aorta, pulmonary artery and vein, esophagus, nerves, lymph nodes and vessels. The functions of the lung is to take in oxygen for the body cells and remove carbon dioxide from the body cells.
The diaphragm and intercostal muscles The diaphragm is a large muscle positioned between the chest and the abdomen. It is made up of a central sheet of tendon and muscle fibres. And when relaxed, it is dome shaped.
And when contracted, it becomes a concave shape. The diaphragm assists in the breathing process. And during inhalation, the diaphragm contracts, pulling downwards to increase the volume of the chest. During exhalation of the diaphragm, The diaphragm relaxes moving upwards and decreases the volume of the chest cavity. The intercostal muscles lie between the ribs and during breathing they aid the diaphragm.
During inhalation the intercostal muscles contract at the same time as diaphragm, lifting the ribcage up and outwards, increasing the size of the chest cavity. During expiration the intercostal muscles relax allowing the ribs to fall down and inwards helping to decrease the size of chest casualty. In summary the steps in the breeding process are air is warmed moistened and filtered as it travels through the mouth and nasal passage air then passes through the trachea and bronchus on into the lungs and then passes through the bronchioles and then into the alveoli where gas exchange takes place. This concludes this video presentation on the respiratory system.
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