The insect equivalent of a platelet
(a blood cell which helps bring about blood clots). At a site of injury,
these cells will break down into threads around which plasma can gel, stopping
the flow of hemolymph
(the arthropod equivalent of blood) from the site.
Proteins on the
outer part of body cells that help fight illness. These proteins vary from
person to person. Scientists think that people with certain types of HLA
antigens are more
likely to develop insulin-dependent
diabetes. The HLA
antigens are also responsible for histocompatibility
that is able to stage an immune response.
A type of non-granular leukocyte
that mainly stays in lymphatic tissue (e.g., the lymph nodes) and is active
in immune responses, including the production of antibodies.
A type of large leukocyte
that travels in the blood but can leave the bloodstream and enter tissue;
like other leukocytes, it protects the body by digesting debris and foreign
A huge cell in the bone marrow that produces blood platelets.
A type of cell
which is found in the epidermis
of the skin and which produces the pigment melanin.
Melanocytes are transparent cells with dendrites.
A type of large, round leukocyte
that engulfs and breaks down debris and invading cells. Monocytes are formed
in bone marrow and have round or kidney-shaped nuclei.
A motile cell produced by and found in the bone marrow which develops
into granular leukocytes.
A developing female reproductive cell
which divides by meiosis
into four haploid
cells, forming one ovum
that goes on to potentially become fertilized by a sperm
cell and two to three polar bodies that subsequently degenerate.
A particle found in the bloodstream that binds to fibrinogen
at the site of a wound to begin the blood clotting process. Platelets are
formed in bone marrow, where they arise from cells called megakaryocytes.