Ch 11.3 -- Leukocytes -- VTPP 435

Ch 11.3 -- Leukocytes -- VTPP 435

Leukocytes (WBCs)

mobile units of immune system

Immune System

-involves WBCs and a variety of plasma proteins
-defends against invading microorganisms
-clean up crew to remove worn-out cells and tissue debris
-paves the way for wound healing and tissue repair
-identifies and destroys cancer cells that arise in body

Leukocytes Transport

-WBCs wriggle through capillary pores to crawl thru assaulted areas
-are circulating in the blood

5 Types of Leukocytes

-colorless, vary in structure
1) Neutrophils
2) Eosinophils
3) Basophils
4) Monocytes
5) Lymphocytes

Two Categories of Leukocytes

-depend on appearance of nuclei and presence or absence of granules in cytoplasm
1) Polymorphonuclear Granulocytes
2) Mononuclear Agranulocytes

Polymorphonuclear Granulocytes

-contain granules
-Neutrophils, Eosinophils, Basophils
-Ncueli segmented into several lobes of varying shapes
-3 types based on stored chemicals: Eosinophils, Basophils, Neutrophils

Mononuclear Agranulocytes

-leukocytes that do not have granules or very few
-monocytes and lymphocytes
-single, large, non-segmented nucleus

Neutrophils

-phagocytic specialists
-needed for inflammatory responses
-first defenders on bacterial invasion
-use Neutrophil Extracellular Traps (NETs)
-scavenge to clean up debris
-release chemicals from granules to kill

Neutrophilia

-an increase in circulating neutrophils
-happens during bacterial infections

Eosinohpils

-needed for allergic responses
-combat internal parasite infections
-attach to parasitic worm and secrete substances to kill it

Eosinophilia

-associated with allergic conditions and internal parasite infestations

Basophils

-make, store, and release histamine and heparin
-least numerous WBC
-similar to mast cells

Heparin

-hastens the removal of fat particles from blood
-can help prevent clotting of blood samples drawn

Monocytes

-emigrate from blood, enlarge, and become tissue macrophages
-are immature when released from bone marrow
-live for months-years
-has a limit to how much material it can ingest

Lymphocytes

-WBCs that provide immune defense against targets for which they are specifically programmed
-live for 100-300 days
-2 types: B Cells and T Cells

B Lymphocytes (B Cells)

-produce antibodies against specific targets to which they have been exposed
-circulate thru body
-mark antigen to have it destroyed

T Lymphocytes (T Cells)

-directly destroy their specific target cells by releasing chemical to punch holes into victim cell
-target viruses & cancer cells

Lymphoid Tissues

-tissues that produce and store lymphocytes like lymph nodes and tonsils

Granulocyte Colony-Stimulating Factor

-a messenger that directs differentiation and proliferation of cell types
-stimulates replication and release of granulocytes from bone marrow
-bolsters defense and reduces infection

Leukemia

-cancer condition
-uncontrolled proliferation of WBCs
-WBCs produced are abnormal and numerous
-anemia also occurs