leukocytes- agranulocytes Flashcards
agranulocytes
-leukocytes that only contain primary granules; these granules are so small they are often overlooked
-have a round or indented nucleus
what mechanism do leukocytes use to enter the connective tissue?
homing mechanism
what are the steps of the homing mechanism?
- rolling & attachment (reversible binding)
- adhesion (strong interaction b/w leukocyte & endothelial cell)
- transendothelial migration AKA diapedesis (migrate across endothelium)
what are the 2 types of agranulocytes?
monocytes & lymphocytes
“Never Let Monkeys Eat Bananas”
relative concentrations of WBCs
neutrophils –> lymphocytes –> monocytes –> eosinophils –> basophils
complete blood count (CBC)
total number of RBCs & WBCs
differential cell count
relative percentages of WBCs
what is occurring if there is high number of WBCs?
infection or tumor
what are the suffixes that relate to high amounts of something?
-philia
-osis
what causes high number of neutrophils?
acute inflammation, bacteria
what causes high number of lymphocytes & monocytes?
subacute inflammation, viral
what causes high number of eosinophils?
allergies, parasites
what is occuring if there is a low number of WBCs?
immune supression or tumor
what are the suffixes that relate to low amounts of something?
-penia
neutropenia
transient reduction in number of neutrophils can occur due to cytokines in early viral infections
cytopenia
-continued reduction in number of WBCs
-demand > supply
thrombocytopenia
low number of platelets
How big are monocytes compared to RBC?
3x diameter
Relative amount of monocytes compared to other leukocytes:
3-8%
Shape of nucleus of monocytes:
kidney/U/mickey mouse (Alli) shaped
How long to monocytes stay in the blood stream?
12-100 hours
Activity of monocytes:
lysosomal and phagocytic
After monocytes enter the CT, what do they become?
macrophages
How long can macrophages survive in the tissues?
several months
What do macrophages do in the tissues?
bacterial phagocytosis, antigen presentation, and clean up of old cell debris
Examples of macrophages in tissues
Kupfer cells in liver, microglial in CNS, Langerhans cells in skin, dust cells in lungs, and osteoclasts in bones
In what type of infections are monocytes active?
subacute to chronic infections
What is it called when monocytes fuse together?
epithelioid giant cells in chronic granulomas
Where do lymphocytes develop?
bone marrow
What are the two types of lymphocytes?
T and B lymphocytes
What do T lymphocytes do?
manage and direct an immune response and some directly attack foreign cells and virus infected cells
What do B lymphocytes do?
they are stimulated to become plasma cells and make antibodies
Relative amount of lymphocytes compared to all WBC:
either 20-45% or 20-25%
What type of infections are lymphocytes active in ?
subacute to chronic infections
What is the life span of lymphocytes?
days to years
Size of small lymphocytes:
6-9um
size of large lymphocytes
9-16um
Percentage of lymphocytes that are B cells:
4-10%
Percentage of lymphocytes that are T cells:
90%
Where are most lymphocytes found?
lymphatic tissue
Where are B cells formed and become immunocompetent?
in the bone marrow
What is the process that B cells go through after encountering an antigen?
amplification/clonal expansion
B and T cells that do not replicate by remain:
memory or effector cells
What is present on B cell membranes that allow them to function as Ag presenting cells?
HLA type II surface markers and surface immunoglobulins
Responses that B and T cells are active in:
anamnestic response of humoral immunity
Where are T cells formed?
bone marrow
Where do T cells become immunocompetent?
thymus
Type of immunity T cells are involved in:
Cell mediated immunity
Receptors on T cells that present antibodies:
paratopes
Receptors on T cells that recognized foreign proteins on antigens:
epitopes
What do CD molecules on T cells do?
recognized HLA receptors on other cells
-help to avoid any “self” destruction
Three types of T cells
cytotoxic, suppressor, and helper
What do cytotoxic/killer T cells do?
recognize cells with foreign surface antigens or receptors and kill them
-punch holes in the plasma membrane
What do helper T cells do?
recognize Ag and secrete lymphokines that will stimulate B cells to make antibodies or Tk cells to kill the pathogen
What do suppressor T cells do?
suppress the activity of B cells
-dampen immune response so the body does not just kill everything, including self
What are Null cells?
lymphocytes that do not have the markers of T or B cells
Example of a null cell:
Natural killer cell
What are null cells responsible for?
nonspecific cytotoxicity against virus infected and tumor cells
-function in Ab-dependent, cell-mediated cytotoxicity
Leukocyte adhesion deficiency
defect in wound healing, recurrent infections, and marked leukocytosis
