Blood 2 Flashcards
How do leukocytes differ from erythrocytes?
- far less numerous
- shorter lifespans when active
- complete cells (organelles and nucleus)
- many types of leukocytes
What are leukocytes?
WBCS
What is the most distinct characteristic of leukocytes?
Their movement
They continuously leave the bloodstream to perform their defensive functions in the body’s tissues
Granular leukocytes
Containing vesicles that appear when cells are stained
- neutrophils, eosinophils, basophils
Agranular leukocytes
Contain no granules
- lymphocytes, monocytes
Agranular leukocytes
Contain no granules
- lymphocytes, monocytes
What are the first leukocytes to the site of infection?
Neutrophils
What type of infection do neutrophils have a preference for?
Bacteria
What leukocytes are capable of phagocytosis during parasitic infections?
Eosinophils
What leukocytes contain antihistamine molecules?
Eosinophils
Definition: Basophils
Intensify the inflammatory response through the release of histamine and heparin
Where are lymphocytes formed?
In the lymphoid cells
What are the 3 major groups of lymphocytes?
- Natural killer cells
- B cells
- T cells
Definition: Provide generalized, nonspecific immunity to cells containing foreign or abnormal markers.
Natural Killer (NK) cells
Definition: B cells
Produce antibodies which bind to specific foreign or abnormal components of plasma membranes
Definition: T Cells
Provide cellular-level immunity by physically attacking foreign or diseased cells
Definition: Variety of B and T cells which form after exposure to a pathogen, enabling rapid responses upon subsequent exposures
Memory cells
Definition: form macrophages when they leave the blood vessels and function to release antimicrobial and chemotactic signals to attract other leukocytes to the site of infection
Monocyte
What does an elevation in white blood cell count usually indicate?
An infection or inflammation
Definition: Fragment of the cytoplasms of a cell called a megakaryocyte that is surrounded by a plasma membrane
Platelet
What happens when platelets enter into circulation?
About 1/3 migrate to the spleen for storage for later release in response to any ruptured blood vessels
When do platelets become activated?
When blood vessels are damaged as their primary function is to limit blood loss
How long do platelets remain once activated?
10 days, then they are phagocytized by macrophages
