Blood is a connective tissue with a fluid matrix called plasma. Three basic types of cells are found suspended in plasma:The Erythrocytes (red blood cells) are pink with a light center (where the cell is thinner and the light shines through).onnective tissue fibers, blood vessels, and sweat glands can be seen embedded in the adipose tissue. As the photomicrograph illustrates this tissue consists of adipocytes that contain lipid droplets. Adipose Tissue: 1  Description: Resembles a chicken-wire fence.
It is possible that hypofunctional 5-HTP cells (reflecting TPH1 dysfunction) in the periphery, leading to deficient 5-HTP, low 5-HT, and concomitant compensatory TPH2 activation in the brain, may cause endogenous depression.
Causes of Depression. Unfortunately, it is not fully known what exactly causes clinical depression for a particular individual. There are many theories about causes such as biological and genetic factors, environmental influences, and childhood or developmental events. However, it is generally believed that clinical depression is most often caused by the influence of more than just one or two factors. For instance, a person whose mother had recurrent major depression may have inherited a vulnerability to developing clinical depression (genetic influence).