07+Respiratory+Physiology

Respiratory Physiology Chapter 16

__//**Content Summary **//__ //The respiratory system is divided into two sections. First is the respiratory zone, which is the zone where the gases of the body are exchanged. Next is the conducting zone, which is where the transfer of gas into the blood occurs across the walls of the respiratory alveoli. These walls promote a rapid rate of gas diffusion. This chapter covers a plethora of topics on the respiratory system. The three most important topics in this chapter to me were the physical aspects of ventilation, mechanics of breathing, and the gas exchange in the lungs. // Source (Physiology Book)

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//Intrapulmonary and intrapleural pressures range while the body is engaging in ventilation. Although the intrapleural pressure may change, it always remains below the atmospheric pressure. Intrapulomonary pressure on the other hand stays below atmospheric pressure during inspiration, and is increased to an amount that is greater than atmospheric pressure during expiration. Lung volume causes the difference in the pressures in the lungs, as stated by Boyle’s Law. The lungs also have physical properties that influence the mechanics of ventilation. There are three main physical properties that can affect these mechanics. The first of these properties is the ease at which the lungs are able to expand. This mainly refers to the difference in the intrapulmonary and intrapleural pressures. Next is the elasticity of the lungs. The main aspect of this is the availability of the lungs to be able to return to their regular form after expansion. The last is the tension in the surface cause by the fluid in the aveoli. This force is exerted to counter the effects of distension. // Source (Physiology Book)

//Simply put, the mechanics of breathing refer to inspiration and expiration. These two rely heavily on the contraction and relaxation of striated muscles. Of these striated muscles, the diaphragm and the intercostals muscles play the largest roles. The diaphragm and the external intercostals contract and increase the volume of the thorax during quiet inspiration. The decrease in thoracic volume in expiration is caused by the relaxation of these muscles, and the elasticity of the lungs and the diaphragm cause the decrease in volume. The only time that there are extra muscles involved, is when there is forced expiration or inspiration. Diseases that affect the expiration and inspiration can be deadly. Pulmonary disorders are often identified with the help of spirometry. There are two main classifications of disorders that affect the respiratory system. Pulmonary fibrosis is an example of a restrictive disease. This disorder decreases the capacity of the lungs and/or airways. Asthma is an example of an obstructive disease. Obstruction of the airways causes forced expiratory volume to decrease. // Source (Physiology Book)

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//The muscles that are directly responsible for respiration can be traced back to the medulla oblongata. Since breathing is an automatic action, it is obvious that the inspiratory and the expiratory processes are reciprocal in order to form a cycle. Part of what is interpreted by the brain for these processes is responses to a feedback loop. The others come from apneustic and pneumotaxic centers that are located in the pons. Automatic breathing is different than that of someone who is consciously thinking about the process. The conscious thoughts about breathing come from the cerebral cortex instead of the medulla oblongata. Breathing and its processes are affected by the certain elements in the blood. Pco₂, pH, and P0₂ are these elements that really matter. However, these are not all equal and some carry heavier weight and importance than the others. Each chemoreceptor for each individual element are located in different areas. // Source (Physiology Book)

__//**Application **//__ //The respiratory system is an intriguing system to study, and applies to everyone whether they really like it or not. A nurse, or anyone in the medical profession, should really have a superior understanding of the system. It is a scary thought to think about, but what if someone were to go into cardiac arrest while you are on call? In order to be able to feel comfortable in doing your job to revive them, you have to know everything there is to know about the respiratory system. Being to prepared is never a bad idea, and knowing to much can never hurt you in an instance like this. CPR is not only used by health officials and can often be used by a pedestrian to save a victims life when there is no time to wait for an emergency official. Life guards and EMTs should also know at least the basics of the respiratory system, again knowing a little extra can always make you feel more comfortable should a stressful situation arise. //

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__//**Essential Questions **//__ //Ventilation is accomplished by the simple contraction of a few muscles in the thoracic cavity. The main muscles involves in ventilation are the diaphragm and the external intercostals. When these muscles contract they cause the lungs to shrink in volume, and inversely when they relax they allow the lungs to use their elasticity to return to form. This increase and decrease in pressure can be described best by Boyle’s Law. Pressure changes in the lungs are directly a result of the available volume of the lungs. The intrapulmonary pressure is greater than the atmospheric pressure when the process of expiration is occurring, and the opposite is true for inspiration. //