Vascular system regions, blood vessels

HSA is the single most abundant protein in blood (Table 12.7). Its normal concentration is approximately 42 g 1 1, representing 60 per cent of total plasma protein. The vascular system of an average adult thus contains in the region of 150 g of albumin. HSA is responsible for over 80 per cent of the colloidal osmotic pressure of human blood. More than any other plasma constituent, HSA is thus responsible for retaining sufficient fluid within blood vessels. It has been aptly described as the protein that makes blood thicker than water. 

P. falciparum is the most dangerous of the four malaria strains, and can kill a healthy adult in 48 hours. This type is so dangerous because the parasitized red blood cells become sequestered in the deep vascular beds of the brain—Whence the term cerebral malaria for infection with this strain. Sequestration happens because parasite-derived proteins on the surface of infected red blood cells cause them to stick to each other and to the cells lining the host s venules and capillaries (two types of small blood vessel), especially in the brain and heart. This has the effect of keeping the parasite away from the host s natural defense system. It also means that the progress of the disease can be hidden from a health practitioner who draws blood from a peripheral body region (for example, the arm) such blood will not reveal the true extent of the infection. Delirium, convulsions, and coma are features of falciparum malaria, which is associated with a 20% mortality rate in adults. 

In the region of the root each hair follicle is surrounded by a system of capillary blood vessels that maintains a constant information exchange between the root and the rest of the body. The narrowing of a capillary can be a threat to the life of the hair-follicle when the arterial supply to the vascular loop of the papilla breaks down the hair follicle begins to die off, but remains anchored in the scalp for some months. After certain intoxications the dead hair root exhibits substance-specific alterations (Figs. 5 and 6). 

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