IMPORTANT FOODSTUFFS, IMPORTANT TISSUES 141 



Plasma (the fluid portion) 60 - 70% 



Corpuscles 30 - 40% 



Plasma 



Water 90-92% 

 Solids 8 - 10% 

 Proteins 5.5 

 Carbohydrates 0.1 - 0.2 



Cholesterol, fat, extractives 

 Inorganic subst. 1.0 - 2.0% 

 Red Corpuscles 



Water 59.2 - 68.7% 

 Solids 40.8 - 31.3% 



Hemoglobin 31.7% 

 Stroma 



Protein 5.7-6.4% 

 Phospholipin 0.37 - 0.39% 

 Cholesterol 0.14-0.17% 

 Inorg. (excl. Fe) 0.09% 



The important constituent of the red corpuscles is hemoglobin. 

 This substance already has been discussed in the chapter on 

 proteins (q.v.). It carries oxygen to the cells, and assists in 

 carrying away C0 2 . In the transportation of C0 2 , other factors 

 are important, for this substance is carried to a considerable 

 extent also in the plasma, as sodium bicarbonate, carbonate and 

 combined with plasma proteins. When C0 2 passes from the 

 tissues into the blood it makes the blood less alkaline. This 

 favors the liberation of 2 from oxyhemoglobin. The reverse 

 case occurs in the lungs. 



The transference of 2 into, and of C0 2 out of the blood dur- 

 ing its passage through the lungs has been much studied to de- 

 termine whether it is a process of simple diffusion, or depend- 

 ent upon secretory activities of the cells of the alveolar epithe- 

 lium. It is now believed that under ordinary conditions dif- 

 fusion is the principal, if not the sole cause of the passage of 

 gases to and from the blood. It is probable, however that in 

 times of stress there may be an active secretion of gases by the 

 cells to supplement the ordinary diffusion. 



The white corpuscles are true cells, and possess a nucleus. 



