19.5 WBCs Flashcards
WBCs AKA
leukocytes
two groups of leukocytes:
- granulocytes (neutrophils, eosinophils, basophils)
2. agranulocytes (monocytes, lymphocytes)
4 characteristics of WBCs
- can migrate out of bloodstream
- capable of amoeboid movement
- attracted to specific chemical stimuli
- neutrophils, eosinophils, and monocytes are capable of phagocytosis
margination
adhering to vessel wall
emigration/diapedesis
squeezing between epithelial cells into surrounding tissue
positive chemotaxis
attraction to specific chemical stimuli
-guides WBCs to pathogens, damaged tissue, and other active WBCs
microphages
neutrophils & eosinophils
macrophages
monocytes that have moved out of bloodstream and become actively phagocytic
nonspecific defenses
granulocytes (neutrophils, eosinophils, and basophils).. respond to variety of stimuli
specific defenses
lymphocytes.. attacks against specific types of invading pathogens or foreign proteins
neutrophils
-% of WBCs, AKA, appearance, characteristics, lifespan
70% of WBCs, AKA polymorphonuclear leukocytes (PMNs)
- dense, segmented nuc w/ 2-5 lobes; pale granular cytoplasm
- mobile, first to injury site, attack & digest “marked” bacteria
- life span: 10 hours, dies after engulfing 1-2 dozen bacteria
neutrophil activity
- engulfs bacteria, experiences “respiratory burst,” produces H2O2 and superoxide ions that kill bacteria
- lysosomes: defensins kill, digestive enzymes break down
- release of prostaglandins and leukotrienes
leukotrienes
attract more phagocytes
prostaglandins
increase permeability, contributing to inflammation, restricting spread of injury
eosinophils
-% of WBCs, AKA, appearance, characteristics
2-4% of WBCs, AKA acidophils
- granules stain deep red, bilobed nuclei
- attack objects coated in antibodies, primarily toxic compounds.. effective against parasites!!
- sensitive to allergens, reduce inflammation
basophils
-% of WBCs, appearance, characteristics
- 1% of WBCs
- granules stain dark, smaller than neutrophils & eosinophils
- discharge granules (contain histamine & heparin) at injury sites, enhance inflammation initiated by mast cells
- release chems to attract eosinophils & basophils
heparin
prevents blood clotting
histamine
dilates blood vessels
monocyte
-% of WBCs, appearance, characteristics
- 2-8% WBCs
- large! nearly 2x diameter of RBC. large kidney-shaped nucleus
- becomes macrophage when it enters tissues. while active, release chems that attract neutrophils, monocytes, & other phagocytes. draw fibroblasts to area.
lymphocytes
-% of WBCs, appearance, characteristics, classes
- 20-30% WBCs
- slightly larger than RBC, large round nuc w/ halo of cytoplasm
- most are in connective tissues & lymphatic organs.. 3 classes: T cells, B cells, NK cells
T cells
cell-mediated immunity (defense mechanism against invading foreign cells)
B cells
humoral immunity (defense mechanism involving production of antibodies) -differentiate into Plasma cells when activated
plasma cells
synthesize & secrete antibodies
Natural Killer (NK) Cells
immune surveillance (detection & destruction of abnormal cells) -sometimes known as "large granular lymphocytes" ..important in preventing cancer
differential count
number of each type of cell in a sample of 100 WBCs
leukopenia
inadequate numbers of WBCs
-penia = “poverty”
leukocytosis
excessive number of WBCs
-osis = too many
leukemia
indicated by extreme leukocytosis
progenitor cells
give rise to all formed elements except lymphocytes
Which WBCs complete development in the red bone marrow?
granulocytes!
blast cells –> myelocytes –> band cells –> mature WBCs
which WBC enters bloodstream before completing development?
monocytes (complete development when they become macrophages in peripheral tissues
lymphocyte development
derived from lymphoid stem cells
- in red blood marrow (or peripheral lymphatic tissue in spleen or lymph nodes), differentiate into B or NK cells
- migrating to thymus, differentiate into T cells
lymphopoiesis
process of lymphocyte production
production of B and T cells in adults is regulated primarily by
exposure to antigens
colony-stimulating factors
M-CSF: monocyte production
G-CSF: granulocyte production
GM-CSF: granulocyte & monocyte production
Multi-CSF: accelerates production of granulocytes, monocytes, platelets, and RBCs
