Anatomy of the Respiratory Tract PDF

Anatomy of the Respiratory Tract Respiration is, generally spoken, the absorption (intake) of oxygen and the elimination of carbon dioxide as a waste product of the cells´metabolism. Every single cell in the mammalian organism is vitally dependant on this gas exchange that is the genuine function o...

Anatomy of the Respiratory Tract Respiration is, generally spoken, the absorption (intake) of oxygen and the elimination of carbon dioxide as a waste product of the cells´metabolism. Every single cell in the mammalian organism is vitally dependant on this gas exchange that is the genuine function of our cardio-respiratory system..  Nasal Cavity The nasal cavity is divided by the septum into two halves that are never really symmetric. The palate ( hard and soft palate) separates the nasal from the oral cavity. Towards posterior the nasal cavity opens into the upper pharynx ( nasopharynx). Functions: Heating, cleansing, and mosturization of the air Boost the voice and enable self-hearing Phonation During exspiration, air passes through the gap between the vocal folds that act like a violin´s strings. The tune depends on two parameters: 1. The loudness is a function of the air pressure 2. The frequency is a function of the vocal rim´s width. The vocal rim is closed The vocal rim is open Swallowing The tongue´s root pushes the epiglottis backwards, thus closing the entrance of the larynx. The food glides along the epiglottis down into the esophagus. In addition, the vocal rim is closed as an extra safety mechanism. During coughing, the vocal rim is first closed and then bursts open, when the pressure of the exspiratory air exceeds the laryngeal closing force,  The lower airways Air tube and bronchi The air tube is an elastic ( Movements of head and neck!!) tube of approx. 12 cm in length. It consists of horse-shoe- like cartilages that are connected to each others by elastic membranes. At the level of the fourth thoracic vertebra the air tube divides into the two main bronchi. As the right lung consists of three and the left lung consists of two lobes, the right main bronchus divides into three, the left one into two lobar bronchi. These further divide into segmental bronchi, and so on. They behave like braches of a tree, i.e. the bronchial tree. The Air-Blood- Barrier Physiology of Breathing: When the lungs are filled with air, this air is not pumped into the lungs from outside but sucked into the lungs due to a negative intrapulmonary pressure. This suction results from an active extension of the chest. The expansion of the chest is performed by the following muscles; The diaphragm: It flattens during contraction The muscles between the ribs: They “lift” the lower ribs towards anterior. Auxiliary respiratory muscles: Muscles descending from cervical ( and upper thoracic) spine to the ribs.  Components of the Air Inhaled Air Exhaled Air Nitrogen 78 % 79 % Oxygen 21 % 16 % Carbon 0,03 % 4% dioxide Noble gases 1% 1%