Pith, or medulla, is a tissue in the stems of vascular plants. Pith is composed of soft, spongy parenchyma cells, which store and transport nutrients throughout the plant. In eudicots, pith is located in the center of the stem. In monocots, it extends also into flowering stems and roots. The pith is encircled by a ring of xylem; the xylem, in turn, is encircled by a ring of phloem.
Throughout the lymph node's interior are a series of street-like channels called sinuses that help guide the flow of lymph from the afferent lymphatic vessels, through the cortex and medulla, and finally to the efferent lymphatic vessels at the hilum.ach lymph node chain is responsible for draining a particular body region or structure. For example, the lymph node chains in your armpits drain your arms and upper chest, while the chains in your groin are responsible for filtering lymph from your feet, legs, genitals, and lower abdominal wall.
Your lymphatic system comprises a network of organs, vessels and numerous lymph nodes situated throughout your body. Most of your lymph nodes are located in your head and neck region. Lymph nodes that frequently swell are in this area, as well as in your armpits and groin area.our lymphatic system comprises a network of organs, vessels and numerous lymph nodes situated throughout your body. Most of your lymph nodes are located in your head and neck region. Lymph nodes that frequently swell are in this area, as well as in your armpits and groin area.