It protects the body against disease-causing organisms and toxic substances inhaled with air". (Encarta 2005)
Using several instruments and random sampling method for smokers, non-smokers and asthmatic person, the respondents are being measured with their adult lung volumes using a spirometer. The peak expiratory flow rate is also measures as well as the respondents vital capacity using a vitalograph.
The aim of this practical is to introduce the student to measuring human lung volumes, together with observing the control of respiration. Respiration refers to the overall gaseous exchange between the atmosphere, blood and body cells. In this context, respiration is taken to mean the movement of air into (inspiration) and out of (expiration) of the lungs. More accurately, inspiration and expiration is termed ventilation. An inspiration followed by expiration is called one respiration. The number of respirations per minute gives the respiratory rate (RR). A healthy adult averages a respiratory rate of between 12 to 18 respirations per minute. During this respiratory process, various amounts of air are exchanged between the lungs and the atmosphere. These amounts of air are referred to as lung volumes, which can be recorded using a spirometer, or a peak flow meter which is a measuring instrument used to know the vital capacity of lungs.
Respiration is controlled by the levels of carbon dioxide (CO2) in the blood. Chemoreceptors within the arterial system detect CO2 levels and this information is relayed via afferent nerves to the central nervous system. High CO2 levels in the blood (hypercapnia) leads to increased respiratory rates (hyperventilation). Low CO2 levels (hypocapnia) leads to respiration rates which are slow and shallow. This is termed hypoventilation.
Spirometric tests and peak expiratory flow are the tests used primarily to assess lung function (Laszlo 1991, p311). There are many other tests involved in assessing lung function, some of which will be undertaken during this practical session, along with consideration of the homeostatic control of respiration.
This study is conducted randomly by examining smokers, non smokers and asthmatics. Vitalograph and spirometer are the instruments used to measure the Forced vital capacity, Forced expiratory volume and Peak Expiratory Flow and Vital capacity of the respondents.
RESULTS AND DISCUSSION
Effects on smokers and non smokers:
It was observed that both women who are non smokers have low readings in Forced vital capacity, Forced expiratory volume and Peak Expiratory Flow.
In checking the inspiratory reserve volume and expiratory reserve volume, normally, the volume of air that comes out is almost similar to what a person exhales.
Table 3 shows the result of each person's Predicted PEF, Vitalograph PEF and Peak flow rate. Rob being the youngest attained the highest measurement of the three key result areas.
When the respondents were checked with regards to the amount of poison that they are carrying from their blood, it was expected and observed that non smokers have lesser findings compared to smokers. Significantly, the presence of poison that is