lec 10: Functions of WBCs

Question 1

White blood cells are

Answer 1

large, nucleated, motile cells

Question 2

Total leukocytic count range is between………….

Answer 2

4000-11000 WBC /mm³

Question 3

Neutrophils

Answer 3

(60-70%).

Question 4

Eosinophils

Answer 4

(1-4%).

Question 5

Basophils

Answer 5

(0.25-0.5% )

Question 6

Lymphocytes

Answer 6

(25-33 %).

Question 7

Monocytes

Answer 7

(2-6%).

Question 8

It is the movement of leukocytes which starts by protrusion of
pseudopodium from one end, then movement of the remainder of
the cell towards this pseudopodium.

Answer 8

Ameboid motion

Question 9

Chemotaxis

Answer 9

A. Some of the bacterial or viral toxins.
B. Degenerative products of the inflamed tissues.
C. Leukotrienes and polypeptides from WBCs (lymphocytes,
mast cells and basophils).
D. Several components of the “complement complex (C5a).

Question 10

Diapedesis, amoeboid movement, chemotaxis and phagocytosis are evident in …………………and……………

Answer 10

NEUTROPHILS and MONOCYTES.

Question 11

Opsonization: It is the coating of the foreigner

(bacteria) by opsonins like

Answer 11

IGg , C3b

Question 12

……………from neutrophils protrude around the bacteria and fuse to form a phagosome

Answer 12

Pseudopodia

Question 13

the most numerous white blood cell in the circulation

Answer 13

Neutrophils

Question 14

increase in infection with pyogenic bacteria.

Answer 14

Neutrophils

Question 15

Average half life of the inactivated neutrophil in the circulation is

Answer 15

6 hours

Question 16

A single neutrophil can usually phagocytize ……………….. before the neutrophil itself becomes inactivated and dies

Answer 16

3 to 20 bacteria

Question 17

neutrophil can synthesize toxic oxygen metabolites like …………………………………………..

Answer 17

superoxide radical (O‾₂) and hydrogen peroxide (H₂O₂) and hypochlorous acid (HOCl).

Question 18

……………….exhibit diapedesis , chemotaxis and weak phagocytosis

Answer 18

Mature eosinophils

Question 19

the least common of granulocytes in peripheral blood

Answer 19

Basophils

Question 20

do not exhibit phagocytosis

Answer 20

Basophils

Question 21

They bear membrane receptors to IgE and are involved in allergic reactions

Answer 21

Basophils

Question 22

……………….. increase in parasitic and allergic conditions

Answer 22

Eosinophils

Question 23

functions of Basophils

Answer 23

• Release of HISTAMINE and other inflammatory mediators when activated . These mediators initiate INFLAMMATION
• Release of HEPARIN which prevents blood coagulation by acting as a cofactor for anti-thrombin III. Heparin may also exert anti-inflammatory effects

Question 24

Basophils are involved in…………………….which range from mild urticaria to severe anaphylactic shock.

Answer 24

type- I HYPERSENSITIVITY

Question 25

``` Ig E (the antibody that causes allergic reactions) become attached to basophlis and mast cells. Binding of IgE with its specific allergen→ to rupture of cytoplasmic granules of MAST CELLS and BASOPHILS with subsequent release of HEPARIN and ALLERGIC MEDIATORS which include: ```

Answer 25

1. Histamine 2. SRSA (Slow reacting substance of anaphylaxis), known now as LEUKOTRIENES 3. bradykinin 4. Lysosomal enzymes 5. Serotonin.

Question 26

the largest blood cells

Answer 26

Monocytes

Question 27

Its cytoplasm is rich in lysosomes and they are professional phagocytic cells.

Answer 27

Monocytes

Question 28

They circulate in the blood for 72 hours then migrate to the tissues where they change into tissue macrophages (large phagocytic cells), whose life span is unknown

Answer 28

Monocytes

Question 29

Tissue macrophages constitute the tissue macrophage system (Reticulo-endothelial system) which include :-

Answer 29

1. Kupffer cells in the liver. 2. Pulmonary alveolar macrophages (PAM). 3. Microglia in the brain. 4. Bone osteoclasts.

Question 30

...............................form the core of immune system in humans. They provide defense against targets to which they are programmed

Answer 30

Lymphocytes

Question 31

About...........................of body lymphocytes are found in the peripheral blood and the rest are in the lymphoid tissues.

Answer 31

2%

Question 32

.......................are responsible for humoral immunity. , produces immunoglobulins .

Answer 32

B-lymphocytes

Question 33

.................... are responsible for cell mediated immunity . They attack and kill virus- infected cells as well as malignant cells . They also facilitate antibody production by B-cells.

Answer 33

T-lymphocytes

Question 34

WBCs are activated by ................................

Answer 34

contact with the organism or its toxin.

Question 35

• Activated WBCs show ..............................

Answer 35

increased motor activity, phagocytosis and degranulation.

Question 36

The................. is stimulated by different cytokines to increase leukopoiesis.

Answer 36

bone marrow

Question 37

• Once the organism is eradicated, Immune cells undergo apoptosis except for..................

Answer 37

memory cells.

Question 38

prevent overactivity of the immune system

Answer 38

T-regulatory cells