Grass Anatomy: Roots & Stems. A grass plant is composed of a root, a stem, leaves and a seed head. The root is fibrous, or composed of many small roots that move out in all directions.The stem, or culm, starts out a single section but develops nodes and internodes that segment it along its length.eaves & Seed-heads. Grass leaves emerge from nodes on the stem, with the newest growing on the opposite side from an older leaf below it. A single leaf is composed of a blade, sheath, ligule, auricle and collar.
HIV is the cause of the spectrum of disease known as HIV/AIDS. HIV is a retrovirus that primarily infects components of the human immune system such as CD4+ T cells, macrophages and dendritic cells. It directly and indirectly destroys CD4+ T cells.
S â Syndrome. AIDS is a group of symptoms that can eventually result from an HIV infection. HIV can damage the bodyâs immune system over time, and cause ongoing inflammation in the body. When that happens, the body may not be able to fight off certain types of illnesses or cancer.