Question

1. Gas Exchange and Transport

(1C) Discuss the effect of bicarbonate on oxygen transport. With more explanation

Answer 1

Gas exchange means the exchange of oxygen and carbon di oxide.From the lungs oxygen is passed to the blood stream and from the blood stream carbon di oxide is eliminated to the lungs.In lungs between the alveoli and the capillaries exchange of gas takes place.Depend on the thickness of biological membrane the rate of diffusion takes place.

Gas exchange in blood and tissues are carried out by simple diffusion,Simple diffusion is based on pressure gradient.There is a concentration/pressure gradient for oxygen from the alveoli to the blood and blood to the tissues.The rate of diffusion of carbon di oxide is higher than oxygen .

Transport of oxygen and carbon di oxide happens through blood.Oxygen binds to hemoglobin in blood to give oxyhaemoglobin.The primary factor that affects binding is partial pressure of oxygen.Otherb factors involved are partial pressure of carbon di oxide,hydrogen ion concentration,temperature.For the formation of oxyhaemoglobin low PO2,HIGH pco2 ,high temperature and H+ HIGH is required.Every 100 ml of oxygenated blood gives 5 ml of O2 to the tissues.

Hemoglobin also carries about 25% of carbon di oxide as carbaminohemoglobin.This binding depends up on the partial pressure of CO2.When partial carbon di oxide is low and PO2 is high in the alveoli,CO2 seperated from carbamino heamoglobin and is released in the alveoli.

2 . The carbon di oxide in the blood is transported as dissolved CO2 or as bicarbonate.Bicarbonate diffuses out of the red blood cells .From teh red blood cells they pass in to the  plasma in venous blood and vise versa in arterial blood