Structure and Function of Monocytes: Topic 1 Flashcards
what are monocytes?
WBC that transform into powerful cells called macrophages once they leave the bloodstream and enter tissues
what percent of the total WBC count are monocytes?
5%
how big are monocytes?
they’re the biggest WBC
12 μm
what shape is a monocyte nucleus?
horseshoe-shape
what do monocytes look like?
monocyte chromatin is less condensed and lighter-staining
largest WBC
nucleus looks “raked”
are monocytes granulocytes or agranulocytes?
agranulocytes
they don’t have specific granules!
what kind of granules are in monocytes? what do they do?
when present, are small and purple-staining (azurophilic) and look like cytoplasmic dust
contain lysosomal enzymes that help digest foreign material
what organelles do monocytes have?
a well-developed Golgi apparatus, some ribosomes and polysomes, mitochondria, and a little rough endoplasmic reticulum
only visible with an electromicroscope
What’s in the cytoplasm of a monocyte?
Monocytes often (but not always) have tiny, purple granules and vacuoles in their cytoplasm
What happens to monocytes when they leave the circulation?
They transform into powerful immune cells called macrophages.
what are dendritic cells?
a a type of macrophage that lives in the skin and under other epithelial tissues, waiting for foreign intruders, like microbes, to enter the body
once a microbe makes it into the tissue, the dendritic cell ingests it, travels to lymph nodes, and presents little bits of the microbe (called antigens) to lymphocyte
a chain of events follows, resulting in the formation of an army of lymphocytes directed specifically against that particular antigen (and microbe)
what is the main function of monocytes?
phagocytosis
what best describes the nucleus of a monocyte?
Large and indented, with fine, “raked” chromatin
when a monocyte encounters a microbe, what does it do to get rid of it?
Ingest (phagocytose) the microbe
what are macrophages in the liver called?
Kupffer cells
