Respiration Circulation Free Essay Example, 1250 words

The diaphragm flattens and contracts. The pressure in the lungs decreases because of the change of the diaphragm and the contraction of the intercostal muscles that lead to increase in volume of the pleural cavity. The above changes lead to movement of air to the lungs. However, during the process of exhalation, the inverse happens. There is a movement of ribs downwards and inwards. This happens because of relaxation of internal intercostal muscles. The diaphragm forms a shape of a done and relaxes. All this leads to less volume in the pleural cavity leading to increase in pressure. In the end, the gases from the lungs are forced out. Ventilation on human lungs takes place when there is a complete elimination of CO2 from the body and diffusion of oxygen to the blood. The mechanism allows gaseous exchange in the alveoli; oxygen diffuses in the blood vessels while carbon dioxide diffuses out. The ventilation that takes place in the lungs on a human can be analysed using a spirometer ( Letts Educational 2008). The instrument measures the volume exchange of air per minute. We will write a custom essay sample on Respiration & Circulation or any topic specifically for you Only $17.96 $11.86/pageorder now The number of breaths per minute can also be measured with the instrument. The instrument gives information of the volume of lungs use during breathing during exercise or resting, The diagram below shows change in volume and pressure on lungs during exhalation and inhalation. Respiration (n. d.) Diffusion Gradient for Gas Exchange in the Lungs Ventilation stated above give a continuous supply of oxygen to the lungs and elimination of carbon dioxide. Blood circulate throughout the body losing oxygen and picking up carbon dioxide. The blood with less oxygen and more carbon dioxide are brought to the lungs to be oxygenated. Oxygenation of blood takes place through a process of gaseous exchange. However, gaseous exchange happens through diffusion. Diffusion means a net change of particles in the area of high concentration to area of high concentration. However, diffusion of gases happens in the alveoli. This is because air in the alveoli is highly concentrated with oxygen with high partial pressure. Conversely, blood in the capillaries around the alveoli contains more CO2 than oxygen. CO2 also has high partial pressure (Starr and McMillan 2013). Diffusion will take place because of the pressure gradient. Oxygen will move towards the blood in the capillaries because of lower concentration in it. Carbon Dioxide on other hand m oves towards the alveoli because of high concentration in the blood than the alveoli.