Content Summary:
The respiratory system works with the cardiovascular system to provide oxygen from the lungs to the cells and then remove carbon dioxide from them and return it to the lungs. There are two zones within the respiratory system: the respiratory zone where gas exchange occurs and the conducting zone.which provides the passageway for air to reach the respiratory zone and filters, cleans, warms and humidifies the air. External respiration is the ventilation and exchange of oxygen and carbon dioxide between the blood and air. Internal respiration is the exchange of oxygen and carbon dioxide between the blood and other tissues, and the utilization of oxygen within tissues.

Summary #1
Boyle's law states that the pressure of a given quantity of gas is inversely proportional to its volume. During inspiration, there is an increase in gas volume in the lungs, so intrapulmonary pressure decreases. During expiration, there is a decrease in gas volume in the lungs, so intrapulmonary pressure increases.


Summary #2
Myoglobin is a red (heme) pigmented globin protein molecule that is found in striated muscle such as cardiac muscle and skeletal fibers. Myoglobin has one subunit of heme where hemoglobin has four. Myoglobin has a higher affinity for oxygen than does hemoglobin, so these molecules store oxygen and release it when the Pco2 becomes low. It is thought that myoglobin acts as a connection between the transfer of oxygen from blood to the mitochondria located in muscle cells. During diastole, the myoglobin take up more oxygen and then release it during systole.

Summary #3
There are several pulmonary disorders, and a common symptom is dyspnea which is shortness of breath. Asthma is characterized by an obstruction of air flow through the bronchioles and causes the person to have attacks of dyspnea, wheezing and other symptoms. The obstruction is caused by inflammation of the airway, mucous secretion, and bronchoconstriction that makes breathing difficult. Asthma is treated with glucocorticoid drugs that inhibit inflammation. Emphysema is a chronic and progressive condition in which alveolar tissue is destroyed. The loss of alveoli reduces the ability of the bronchioles to remain open during expiration. Bronchioles can also collapse because of compression of the lungs during expiration, and this leads to an added decrease in gas exchange. Emphysema's most common cause is cigarette smoking. Chronic obstructive pulmonary disease (COPD) is another disease caused by cigarette smoking. It's symptoms are chronic inflammation with narrowing of the airways and destruction of the alveolar walls which causes difficulty in breathing. Persons with COPD may also contract pneumonia, pulmonary emboli (traveling blood clots), and suffer from heart failure. It is currently the fifth leading cause of death in the US. Pulmonary fibrosis is a condition where the lungs accumulate fibrous connective tissue proteins. This can happen from inhalation of particles, one of which is coal dust.







Pulmonary Fibrosis:


Breathing is such a fundamental process and it is important to understand how our bodies function within that system. Studying this chapter has helped me with that and even though I do not understand all the concepts completely, I have gained so much knowledge! One of the things that really interested me was the section on acclimatization to high altitude. Both my daughters lived in Colorado for a time and their bodies made changes to the higher altitude. On a short visit there, I found it much harder to breathe when we went climbing and on one adventure, I had to let them go ahead of me while I went back to our vehicle as I was breathing hard and it continued to get worse. I know now that I was hyperventilating.

Professionally, understanding how our respiratory system works has given me insight as to the challenges my patients may face in completing ADL with a pulmonary disorder. I would research their diagnosis so that I can function in a better capacity to treat them, as well as understand any challenges that they encounter daily.

Essential questions:
Pulmonary ventilation (breathing) is accomplished through an exchange of air from the atmosphere and the alveoli within the lungs. It consists of two phases: 1) inspiration (inhalation) and 2) expiration ( exhalation). Inspiration requires contraction of the diaphragm, the external intercostals and the parasternal intercostals. This process increases thoracic volume vertically and laterally. When deep inspiration is needed, the scalenes, pectoralis minor and sternaocleidomastoid muscles may help. Atmospheric air flows into the lungs which increases thoracic volume and decreases intrapulmonary pressure. The thorax and lungs become stretched, then recoil from the elastic tension when the respiratory muscles relax. The lung volume decreases and raises pressure within the alveoli which is higher than the atmospheric pressure. This causes air to be pushed out of the lungs, and this process is expiration. Abdominal muscles also contract and force abdominal organs up and against the diaphragm. This also decreases the volume within the thorax.

Boyle's Law states that the pressure of a given quantity of gas is inversely proportional to its volume. When pressure increases, volume decreases and when pressure decreases, volume increases.

Pressure changes in normal quiet breathing:
Inspiration Expiration
Intrapulmonary pressure (mmHg) -3 +3
Intrapleural pressure (mmHg) -6 -3
Transpulmonary pressure (mmHg) +3 +6

Lung volumes:
  • Tidal volume---the volume of gas inspired or expired in an unforced respiratory cycle
  • Inspiratory reserve volume---the maximum volume of gas that can be inspired during forced breathing in addition to tidal volume
  • Expiratory reserve volume---the maximum volume of gas that can be expired during forced breathing in addition to tidal volume
  • Residual volume---the volume of gas remaining in the lungs after a maximum expiration

References: Human Physiology by Stuart Ira Fox, Anatomy and Physiology by Stanley E Gunstream