HSF II Histology Leukocytes

Question 1

Role of chemotaxis and cytokines for WBCs

Answer 1

WBCs are attracted to infection sites by chemical signals, specifically cytokines from dead/damaged cells or pathogens

Question 2

How do leukocytes leave the bloodstream?

Adhesion is strong with ICAMs

Answer 2

Margination, (tethering before) pavementing (rolling/adhesion), diapedesis

Question 3

What is the extravasation and homing mechanism?

Answer 3

Extravasation is the process of WBC moving out of the capillary into tissue. The homing mechanism is how WBCs get where they need to go

Question 4

Describe primary granules

Answer 4

Azurophilic
Present in all WBCs
Contain lysosomal enzymes (hydrolases)

Question 5

Describe secondary granules

Answer 5

Lysozyme and alkaline phosphatases
Variable staining

Question 6

Acquired immunity consists of…

Answer 6

B cell lymphocytes for germs
T cell lymphocytes for compromised cells in the body
APCs to alert lymphocytes to foreign agents

Question 7

Describe neutrophils for acute inflammation (w/in a week)

note:
Cardinal signs of inflammation:
pain, swelling, redness, heat

Answer 7

PMN (polymorphonuclear)
Pale-colored granules
Eliminate bacteria/ limit inflammatory extent
Phagocytotic primarily, phagolysosome, respiratory burst (H2O2, HOCL)

Elastase, myeloperoxidase in pr1mary

Lysozyme, proteases, defensins, lactoferrin in 2ndary (all antibacterial stuff)

Gelatinase in 3rtiary to break down collagen

Question 8

Homing and neutrophils

Answer 8

Have receptors for integrins (to bind to iCAMs) to enable antibacterial fxn and homing of neutrophils

Question 9

What are stab cells or band cells?

Answer 9

Immature neutrophils (do not appear multilobed)
Deeply indented (>1/2) nucleus

Increased numbers of these = left shift

Question 10

Describe eosinophils

Answer 10

IgE surface receptors
Parasitic infection role
Reduce allergy severity (inhibit basophils)
Triggers bronchial asthma

Histaminase, Eosinophil peroxidase, Lysosomal enzymes, Major basic protein (against heparin + parasites)

Use eosinophilic chemotactic factor to go to basophils and mast cells to ameliorate histamine

Releases eosinophil-derived inhibitor to inhibit basophil and mast cells

Antiparasitic against helminth and affinity for Ag-Ab complexes (destroyed by major basic protein, phagocytosis)

Question 11

Describe basophils

Answer 11

Least numerous granulocyte
Many BV granules in cytoplasm
May resemble mast cells in leaving circulation

Hydrolytic enzymes, heparin sulfate (anticoagulant), histamine (increases vasodilation and permeability)
Leukotrienes–> slow reacting anaphylaxis
Degranulated for Type 1 hypersensitivity (asthma, allergy), and can escalate to anaphylaxis

Question 12

Describe mast cells

Answer 12

Resident cell in CT w/ histamine and heparin

Part of immune and neuroimmune lines

Allergy, anaphylaxis, wound healing, angiogenesis, pathogen defense

Question 13

In the bone marrow, monoblasts…

Answer 13

turn into promonocytes in vascular niche and exit via venous sinuses to become macrophages (filled w/ hydrolytic enzymes) that will phagocytose bacteria, present antigens, and clean up debris

Question 14

Macrophages and lymphocytes are active in…

Answer 14

subacute to chronic infections

Question 15

Macrophages can fuse and…

Answer 15

become multinucleate epitheloid granulomas (chronic)

Question 16

B-cells come from ___ _____ in mammals and function in…

Answer 16

bone marrow;
humorally mediated immune response and produce antibodies

they encounter Ag and undergo clonal expansion to produce Ab-producing plasma cells

Question 17

B-cells also function in the anamnestic response of humoral immunity, which means…

Answer 17

renewed rapid production of antibodies following the second contact with antigen (vaccine stuff)

Question 18

B-cells also can…

Answer 18

present Ag and have HLA type 2 surface markers and surface immunoglobulins

Question 19

Plasma cells have a ____ nucleus and are…

Answer 19

Cartwheel; activated B cells that make large amts. of a specific antibody

Question 20

T-cells are also formed in bone marrow but migrate to…

Answer 20

Thymus to become immunocompetent. Cell-mediated immunity with paratopes (receptors like Ab) and recognize epitopes on Ags

Have CD (cluster of differentiation) markers/molecules on surface to recognize HLA (human leukocyte antigen) receptors to prevent self-destruction

Question 21

What are the types of T-cells?

Answer 21

Cytotoxic - kill cells w/ foreign surface Ags
Helper - sound chemical alarm (usually presented by macrophage/b-cell) by secreting cytokines to stimulate B-cells to make AB or Tk to kill
Suppressor - suppress B-cells to dampen immune response (to self molecules)

Question 22

What are null cells?

Note- FC receptor is found on cells that protect the immune system. They bind to FC part of antibodies attached to pathogens.

Answer 22

Neither B or T cells, they have Fc receptors without markers

Include natural killer cells and pluripotent stem cells that can be cytotoxic and help in AB-dependent cytotoxicity (ADCC)

Question 23

Lymphocyte maturation process

Answer 23

Lymphoblast->Prolymphocyte->Lymphocyte

Question 24

Mature B-/T-Cells leave bone marrow and thymus to establish lymphocyte colonies in…

Answer 24

the spleen, gut, and lymph nodes