What is the Respiratory System?
The Respiratory System exchanges oxygen from the air with carbon dioxide in the body. This exchange of gases takes place in the lungs as air is drawn in when a person inhales air through the nose or mouth. This exchange process occurs in the alveolar region of the lungs. Basically it's a system of tubes that deliver air to the lungs, where oxygen is diffused into the blood and where carbon dioxide is diffused out.
The major function of the respiratory system is gas exchange between our external environment and our circulatory system.
Once in the lungs, the oxygen is transferred into the blood, when the oxygen-rich blood in the lungs leaves through capillaries and enters cells in the body. This oxygen is used by the cells for cellular respiration. During cellular respiration, the oxygen in cells is utilized along with glucose and O2 and makes ATP (adenosine triphosphate, aka, energy currency). ATP is the energy that our cells require to maintain our growth and bodily functions. Without oxygen, our cells would not be able to produce the energy they need to survive.
The Respiratory System Pathway:
Air -> Nostrils/Mouth -> Pharynx ->
Glottis -> Trachea -> Left and Right Bronchi -> Bronchioles -> Alveoli
What is the Pleural cavity?
The pleural cavity is the potential space between the two pleura (visceral and parietal) of the lungs. The pleura is a serous membrane which folds back onto itself to form a two-layered membrane structure. The thin space between the two pleural layers is known as the pleural cavity and normally contains a small amount of pleural fluid. The outer pleura (parietal pleura) is attached to the chest wall. The inner pleura (visceral pleura) covers the lungs and adjoining structures, via. blood vessels, bronchi and nerves. The parietal pleura is highly sensitive to pain, while the visceral pleura is not, due to its lack of sensory innervation.
The pleural cavity aids optimal functioning of the lungs during respiration. The pleural cavity also contains pleural fluid, which allows the pleurae to slide effortlessly against each other during ventilation. The pleural cavity transmits movements of the chest wall to the lungs, particularly during heavy breathing. This occurs because the closely apposed chest wall transmits pressures to the visceral pleural surface and hence to the lung itself.
What is breathing?
Breathing is the process that moves air in and out of the lungs. Aerobic organisms, which we are — require oxygen to release energy via respiration, in the form of the metabolism of energy-rich molecules such as glucose. Breathing is only one process that delivers oxygen to where it is needed in the body and removes carbon dioxide. Another important process involves the movement of blood by the circulatory system. Gas exchange occurs in the pulmonary alveoli by passive diffusion of gases between the alveolar gas and the blood in lung capillaries. Once these dissolved gases are in the blood, the heart powers their flow around the body (via the circulatory system). The medical term for normal relaxed breathing is eupnea.
The primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body. The respiratory system does this through breathing. When we breathe, we inhale oxygen and exhale carbon dioxide. This exchange of gases is the respiratory system's means of getting oxygen to the blood.
In addition to removing carbon dioxide, breathing results in loss of water from the body. Exhaled air has a relative humidity of 100% because of water diffusing across the moist surface of breathing passages and alveoli.
The Thoracic Cavity
The thoracic cavity/chest cavity is the chamber of the human body protected by the thoracic wall (thoracic cage/associated skin/muscle/fascia) and includes the tendons as well as the cardiovascular system which could be damaged from injury to the back, spine or the neck.
It contains three potential spaces lined with mesothelium: the paired pleural cavities and the pericardial cavity. The mediastinum comprises those organs which lie in the center of the chest between the lungs.
The principle contents of the Thoracic cavity are the lungs and heart and the membranous lining includes the pericardium and the pleural cavity.
The two Pleural cavities are lined by parietal pleura (lines the thoracic wall, covers the superior surface of the diaphragm and separates the pleural cavity from the mediastinum). Each lung is covered by visceral pleura (portion of the serous membrane that covers the surface of the lung and dips into the fissures between its lobes;called the pulmonary pleura/visceral pleura. The visceral pleura is derived from mesoderm). The diaphragm, a dome-shaped muscle, is the principle muscle of respiration.
3 Phases of Respiration
Muscles for Inhaling and Exhaling (Inspiration and Expiration)
The Respiratory Membrane
Four Gas Laws
Lung/Breathing Conditions & Illness