RESPI SYSTEM

• The Respiratory System consists of the nose, pharynx (throat), larynx (voice box), trachea (windpipe), bronchi, and lungs.
• The function of the Respiratory System is to provide for gas exchange and help regulate blood pH.
• The Respiratory System contains receptors for the sense of smell, filters inspired air, produces vocal sounds (phonation), and excretes small amounts of water and heat.
• Pulmonary Ventilation is the process of supplying the body with O2 and removing CO2.
• According to structure, the Respiratory System consists of the Nose, Nasal Cavity, Pharynx, Associated Structures, Larynx, Trachea, Bronchi, and Lungs.
• The Nose is a specialized organ at the entrance of the respiratory system that consists of a visible external portion and an internal portion inside the skull called the Nasal Cavity.
• The External Nose consists of the Frontal bone, nasal bones, and maxillae.
• The Internal Nose (Nasal Cavity) is a large space in the anterior aspect of the skull that lies inferior to the nasal bone and superior to the oral cavity, and is lined with muscle and mucous membrane.
• Aging results in decreases in vital capacity, blood O2 level, alveolar macrophage activity, ciliary action of respiratory epithelia, and consequently, elderly people are more susceptible to pneumonia, bronchitis, emphysema, and other issues.
• Disorders of the respiratory system include asthma, chronic obstructive pulmonary disease, emphysema, chronic bronchitis, lung cancer, malignant mesothelioma, pneumonia, tuberculosis, pulmonary edema, sudden infant death syndrome, and severe acute respiratory syndrome.
• The O2 diffusing capacity may increase threefold during maximal exercise so there is a greater surface area available for O2 diffusion.
• The respiratory and cardiovascular systems make adjustments in response to both the intensity and duration of exercise.
• As cardiac output increases, the blood flow to the lungs (pulmonary perfusion) increases as well.
• The Inflation Reflex prevents the collapse of the lung by sending nerve impulses along the vagus (X) nerves to the dorsal respiratory group (DRG) in the medullary respiratory center when baroreceptors become stretched during overinflation of the lungs.
• The Nasal Cavity divides into right and left sides, with the anterior portion primarily hyaline cartilage and the remainder formed by the Perpendicular plate of the Frontal, Sphenoid, and Ethmoid bones.
• The Pharynx, or Throat, is a funnel-shaped tube about 13 cm (5 in.) long that starts at the internal nares and extends to the level of the cricoid cartilage (larynx).
• The wall of the Pharynx is composed of skeletal muscles and is lined with a mucous membrane.
• The Pharynx has an outer circular layer and an inner longitudinal layer.
• Lungs receive blood via two sets of arteries: the pulmonary arteries and the bronchial arteries.
• The exchange of O2 and CO2 between the air spaces in the lungs and the blood takes place by diffusion across the alveolar and capillary walls.
• Air moves into the lungs when the air pressure inside the lungs is less than the air pressure in the atmosphere, and for inhalation to occur, lungs must expand, which increases lung volume and thus lowers lung P° to below atmospheric P°.
• Type II Alveolar cells, also known as "Septal Cells", produce "Alveolar Fluid" which keeps the surface between the cells and the air moist and lowers surface tension of alveoli, reducing the tendency of alveoli to collapse.
• Eupnea, Apnea, Dyspnea, Tachypnea are types of breathing patterns.
• The "Law of Partial Pressures" states that the total pressure in a gas mixture is equal to the sum of the partial pressures of its constituent gases.
• Type I Alveolar Cells are the main sites of gas exchange.
• Perfusion (blood flow) to each area of the lungs matches the extent of ventilation (airflow) to alveoli in that area.
• Pulmonary ventilation is affected by factors such as the volume of alveolar fluid, the compliance of the lungs, and the pressure changes in the lungs.
• Layers of respiratory membrane include the alveolar wall, an epithelial basement membrane, a capillary basement membrane, and the capillary endothelium.
• Lung volumes include tidal volume (VT), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), residual volume (RV), and functional residual capacity (FRC).
• Alveolar macrophages are phagocytes that remove fine dust particles and other debris from the alveolar spaces.
• Lung capacities include inspiratory capacity (IC), functional residual capacity (FRC), vital capacity (VC), and total lung capacity (TLC).
• The oxygen–hemoglobin dissociation curve is a graphical representation of the relationship between the amount of oxygen bound to Hb and partial pressure of oxygen in the blood.
• Carbon dioxide transport involves 7% of the CO being dissolved in the plasma, 23% of the CO being carried by Hb inside RBCs as carbaminohemoglobin, and 70% of the CO being transported as bicarbonate ions (HCO3).
• External respiration, also known as gas exchange, involves Oxygen diffusing from the alveoli to the pulmonary capillaries and CO2 moving in the opposite direction.
• As temperature increases, so does the amount of O2 released from hemoglobin.
• Increase in BPG decreases the affinity of Hb for O2 and thus helps unload O2 from hemoglobin.
• The medullary respiratory center (medulla oblongata) and the pontine respiratory group (pons) are the respiratory centers.
• The lower the amount of oxyhemoglobin (Hb–O2), the higher the CO2-carrying capacity of the blood.
• Central and peripheral chemoreceptors monitor levels of O2 and CO2 and provide input to the respiratory center.
• Cortical influences allow conscious control of respiration to avoid inhaling noxious gases or water.