16-3: Leukocytes Flashcards
Leukocyte
larger cells that lack Hg, but do contain a nucleus; not nearly as numerous as RBCs, making up <1% of blood volume
What is the function of leukocytes?
protect the body from damage by bacteria, viruses, parasites, toxins, and tumor cells
diapedesis
WBCs are able to slip out of the blood vessels and enter the damaged or diseased tissues
What two cells make up the buffy coat?
WBCs and platelets
leukopenia
(“white deficiency”) a WBC count less than normal (under 4000/mm^3 - often cause by drugs like glucocorticoids
leukocytosis
(“white cell condidition”) a WBC count of over 11000/mm^3 (larger than normal); thisi s the body’s homeostatic response to a bacterial or viral invasion fo the body
What is the body’s homeostatic response to a bacterial or viral invasion?
leukocytosis
What is a white blood cell deficiency called?
leukopenia
WBCs have a ___ life span.
short, due to eating bacteria and debris - only a few days (during infections, may only live a few hours)
What are the two major categories of leukocytes?
grouped on basis of structural and chemical characteristics:
granulocytes - contain visible granules in cytoplasm
agranulocytes - lack obvious granules
leukopoiesis
the production of WBCs
granulocytes and monocytes arise from ___, and lymphocytes arise from ___.
myeloblasts; lymphoblasts
What are the three types of granulocyte?
neutrophils, eosinophils, and basophils
What are the two types of agranulocyte?
monocytes and lymphocytes
neutrophils
most numerous WBC, cytoplasm stains pale purple with barely visible granules; nuclei have 3-6 lobes
What is the function of a neutrophil?
phagocytize bacteria - good for short term infections since they have a short lifespan
High neutrophils can indicate:
an acute bacterial infection
Eosinophils
2-4% of WBCs, cytoplasm has coarse red granules, nucleus has 2 lobes
What is the function of an eosinophil?
kill paracitic worms, complex role in allergies
High eosinophils can indicate:
parasitic worms or allergies
Basophils
rarest WBC, cytoplasm contains large dark bluish-purple granules that make the purple, U-shaped nucleus hard to see
What is the function of a basophil?
release histamines (inflammatories) and contain heparin (anticoagulent)
High basophils can indicate:
inflammatory disease or allergy
Granulocytes
all are spherical in shape and larger than RBCs, they have lobed nuclei and their cytoplasmic granules stain specifically with Wright’s stain
Agranulocytes
lack visible granules and have spherical or kidney-shaped nuclei
monocytes
largest WBC, pale blue cytoplasm, Kidney or U-shaped purple nuclei
What is the function of a monocyte?
phagocytosis - migrate to infected tissue, leaving the blood, and become wandering macrophages (arrive later but stay longer - better for chronic infections)
High monocytes may indicate:
viral infection or chronic bacterial infection (eg. TB)
lymphocytes
2nd most numerous WBC (smallest); round purple nucleus with a thin rim of light blue cytoplasm around it. Most are found in lymph tissue, where they play a critical role in immunity
What are the two types of lymphocytes?
B-cells and T-cells
B-cells
when a foreign substance (antigen) enters the body, the B-cells become plasma cells, which then produce antibodies (proteins that attach to the antigen and neutralize them)
T-cells
function in the immune response by acting directly against virus-infected cells and tumor cells
