Transport of gas - Coursework Example

Transport of gas TASK 3 a) The difference in percentage saturation between the hemoglobin of the fetus and the mother at partial pressures of oxygen (P02) of 4kPa is 14%.b) The oxygen dissociation curve of fetal hemoglobin is to the left of the mother’s adult hemoglobin. This confers some advantages to the fetus. The affinity of fetal hemoglobin for oxygen is greater than the maternal hemoglobin (Hall, 2010, p.56). This facilitates the movement of oxygen from the mother to the fetus. Therefore, at low partial pressures the oxygen saturation for the fetal hemoglobin is higher than the maternal hemoglobin facilitating transfer of oxygen to the fetus (Sherwood, 2015, p. 76). Moreover, the P50 value of the fetal hemoglobin has a lower value as compared to maternal hemoglobin (Ganong, 2005, p. 89). This further buttresses the high affinity for oxygen of the fetal hemoglobin.

Additionally, fetal hemoglobin lacks the interaction with 2,3-BPG. Due to a change on a single amino acid on the binding pocket of 2,3-BPG, it binds less to fetal hemoglobin (Hall, 2010, p.58). This phenomenon explains the high affinity of fetal hemoglobin for oxygen as compared to maternal adult hemoglobin.c) After birth, the fetal hemoglobin is replaced with adult hemoglobin. Therefore, the oxygen-dissociation curve shifts to the right. It confers advantage to the infant after birth because the adult hemoglobin readily gives out oxygen to the tissues as compared to fetal hemoglobin, despite the fact that fetal hemoglobin has a higher affinity for oxygen.

It would prevent tissue ischemia (Maryland Department of Health and Mental Hygiene, 2013)Maintenance of carbon dioxide concentration between active muscle tissue and lung (Hall, 2010).Maintenance of oxygen concentration between active muscle tissue and lung (Hall, 2010).TASK 4 a)b) An increase in the partial pressures of carbon dioxide will shift the curve to the right. Carbon dioxide reduces intracellular pH as a result of the formation of bicarbonate ion. Formation of bicarbonate releases a proton into plasma, therefore reducing pH which has an effect of shifting the curve to the right (Ganong, 2005, p. 90). Similarly, pH affects the oxygen-dissociation curve.

A decrease in pH shifts the curve to the right. At molecular level, a high H+ concentration, some amino acids such as Histidine 164 exist in their protonated form predominantly. They; therefore, form ion pairs which maintains deoxyhaemoglobin in the T state. The T state of hemoglobin has a lower affinity for oxygen; therefore, with increased acidity levels, hemoglobin binds less oxygen. This phenomenon is known as the Bohr Effect(Hall, 2010, p.57).. ReferencesGanong, W. (2005) Review of Medical Physiology.

London: McGraw Hill Professional.Hall, J. ( 2010) Guyton and Hall Textbook of Medical Physiology. London: Elsevier Health Sciences.Maryland Department of Health and Mental Hygiene. Fetal Hemoglobin (Hemoglobin F) Fact Sheet. Available from from Maryland Department of Health and Mental Hygiene: http://phpa.dhmh.maryland.gov/genetics/SitePages/hemo_f.aspx [Accessed: January 31st, 2015].Sherwood, L. (2015) Human Physiology: From Cells to Systems. Cambridge: Cengage Learning.