398 



APPLIED PHYSIOLOGY 



dead cells, or even such substances as stitches left in the 

 body by a surgeon. The excess of white blood cells causes 

 more swelling, and some pain. This is an aggravated form of 

 congestion, and is called inflammation. Some of the white 

 ^_ ___ blood cells grow in place 





Beginning of inflammation (x 400). 



a white blood cells adhering to the wall of a 

 capillary and passing through it. 



b white blood cells which have passed outside 

 of the capillary in order to repair an 

 injury. 



c red blood cells passing through the capil- 

 lary. 



d wall of capillary. 



of the removed cells and 

 so fill in the gap. Each 

 cell becomes long and 

 branched and finally de- 

 velops into a connective 

 tissue cell. If the new 

 cells are in great amount, 

 they have a different ap- 

 pearance from the origi- 

 nal cells and are then 

 called a scar. 



702. Repair of cuts. 

 When a cut is made in 

 a tissue, the same proc- 



ess takes place, but in addition new blood tubes sprout 

 from each side of the wound and interlace in the middle. 

 The white blood cells grow about the new tubes and 

 become connective tissue and so bind the edges of the 

 cut together. 



When the skin is injured, the white blood cells form 

 new tissue upon the surface while the epithelium spreads 

 over it from the edges, stopping the growth and complet- 

 ing the healing process. Sometimes the new connective 

 tissue grows faster than the epithelium and forms soft 

 tufts, which project above the healthy flesh. These tufts 

 are called proud flesh. If they are scraped off, or cauter- 

 ized, the epithelium is enabled to cover the wound, and 

 to complete the healing. 



