Respiratory+Physiology

Chapter 16

Chapter review- In chapter we learned about the respiratory system. The respiratory system is divided into a respiratory zone and a conducting zone. The respiratory zone is the site of gas exchange between air and blood. Respiration includes ventilation, gas exchange and oxygen utilization. Ventilation is breathing, gas exchange occurs between teh ari and blood in the lungs and between the blood and other tissues or the body. The structure of the respiratory system and the thoracic cavity (diaphragm) Alveoli- Air sacs: type I and type II alveolar cells.

Ventilation is influenced by compliance, elasticity and surface tension.

=Boyle's Law= The pressure of a given quantity of gas is inversely proportional to its volume. An increase in lung volume during inspiration decreases intrapulmonary pressure above that of the atmosphere, expelling air from the lungs.



Law of Laplace
The pressure created by surface tension should be greater in the smaller alveolus than in the larger alveolus. Without surfactant the smaller alveoli would collapse and empty their air into larger alveoli. A surfactant reduces surface tension. Surfactant becomes interspersed between water molecules at teh water-air interface, this reduces the hydrogen bonds between water molecules at the surface and thereby reduces the surface tension. Surfactant begins to be produced in late fetal life. Premature babies are sometimes born with lungs that lack sufficient surfactant. This condition is called RDS or respiratory distress syndrome.

Mechanics of Breathing
http://www.colorado.edu/intphys/Class/IPHY3430-200/image/17-1.jpg

Pulmonary ventilation consists of Inspiration and expiration. This is done by increasing and decreasing the volumes of the thorax and lungs. Normal breathing- contraction of the diaphragm and external intercostal muscles. Forced ventilation is aided by the scalenes and sternocleidomastoid. Normal expiration- relaxation of the daiphragm and external intercostals plus recoil of the lungs. Forced expiration is aided by contraction of abdominal muscles and internal intercostal muscles.

Pulmonary Function Tests
http://www.som.tulane.edu/classware/pathology/medical_pathology/renal-lung_cases/nl_lung_volumes.gif

Pulmonary disorders include asthma, emphysema, chronic obstructive pulmonary disease, and pulmonary fibrosis.

Next we learned about gas exchange in the lungs. According to Dalton's law, the total pressure of a gas mixture is equal to the sum of the pressure that each gas in the mixture would exert independently. The pressure that a particular gas exerts in partial pressure of that gas. We then learned about partial pressures of blood and how to measure the blood gas.

Regulation of breathing is controlled by the medulla Oblongata and the Pons in the brain. Automatic breathing is influenced by input from the chemoreceptors in the brain. There are two groups of chemoreceptors. They are the central and peripheral chemoreceptors. The peripheral chemoreceptors include aortic bodies and coraotid bodies.

Next we learned about hemoglobin and oxygen transport. Hemoglobin bonds with oxygen to carry it to the body. The oxygen-carrying capacity of whole blood is determined by its concentration of hemoglobin. Carbon dioxide is transported in the blood primarily in the form of bicarbonate, which is released when carbonic acid dissociates. Carbonic acid is produced mostly in the red blood cells as blood passes through systemic capillaries.

Lastly we learned about ventilation during exercise and acclimation to altitude.

Personal Application: The last section of this chapter is what I have had the most experience with as a personal trainer and that is the effects of ventilation while exercising or during a change in altitude. I ran a running club and some people really get nervous and do not understand how to slow their breathing down to be able to continue exercising.

References: I have sites the websites that I used and the rest of the information was taken from our text book. Human Physiology by Stuart Ira Fox