Leukocytes

Question 1

What is the importance of leukocytes in the body?

Answer 1

It plays an important role in defense and immunity.

Question 2

WBCs are the _______ blood cells but they account for only ____ of the blood volume.

Answer 2

largest ; 1%

Question 3

WBCs contain ______ and have some ________ in their cytoplasm.

Answer 3

nuclei ; granules

Question 4

What does an increase in number of WBCs numbers in the bloodstream tell us?

Answer 4

That it is a sign of physiological problem, like infection, trauma or malignancy.

Question 5

What are the two main type of leukocytes?

Answer 5

Granulocytes

Agranulocytes

Question 6

List the granular leukocytes?

Answer 6

Basophil
Neutrophil
Eosinophil

Question 7

List the agranular leukocytes?

Answer 7

Lymphocyte

Monocyte

Question 8

What kind of nucleus does granulocytes have?

Answer 8

They have multilobed nuclei in their cytoplasm.

Question 9

What dye colour does eosinophil take when it is stained and seen under a microscope?

Answer 9

Red acid dye(eosin)

Question 10

What dye colour does basophil take when it is stained and seen under a microscope?

Answer 10

Alkaline methylene blue

Question 11

What dye colour does neutrophil take when it is stained and seen under a microscope?

Answer 11

Purple because they take up both dyes.

Question 12

Which cell among WBCs are the most numerous?

Answer 12

Neutrophil

Note: They account for 50-70% of the WBC population.

Question 13

Why are neutrophils said to be chemically neutral?

Answer 13

Because their granules take up both basic (blue) and acidic (red) dyes when stained.

Question 14

Describe the nucleus of a neutrophil?

Answer 14

The nucleus has two to five lobes, connected by very thin strands of chromatin resembling bead of a string.(multi-lobed nucleus)

Question 15

Describe the granules found in the cytoplasm of a neutrophil and their content?

Answer 15

Their cytoplasm is packed with very fine pale granules containing lysosomal enzymes and bactericidal (bacteria-killing agent).

Question 16

What is the diameter of a neutrophil?

Answer 16

12 microns

Question 17

What are the main functions of neutrophil?

Answer 17

• To protect against any foreign material that gains entry to the body mainly microbes. Hence, they are the first of the WBCs to arrive at the site of an infection.
• They remove waste materials(e.g cell debris)

Question 18

Neutrophil ingest and kill microbes by ___________.

Answer 18

phagocytosis

Question 19

What is the lifespan of a neutrophil in the bloodstream?

Answer 19

About 10hrs.

Note: When they are actively engulfing debris or pathogens,they may last for 30 mins or less.

Question 20

Describe the nucleus of an eosinophil?

Answer 20

It has two lobes connected by a thick strand of chromatin(bi-lobed nucleus).

Question 21

Describe the granules found in the cytoplasm of an eosinophil and their content ?

Answer 21

• The cytoplasm is packed with large, coarse granules that stain from brick red to crimson with acid (eosin) dyes.
• The granules are lysosome-like.

Question 22

What are the functions of eosinophil?

Answer 22

• It neutralises histamine that are released during allergic reactions.
• It protects the body against parasites and roundworms by releasing toxic compounds.
• It also reduces degree of inflammation when there is injury.

Question 23

Eosinophil account for ______ of all leukocytes.

Answer 23

2-4%

Question 24

What is the diameter of an eosinophil?

Answer 24

10-17 microns

Question 25

Describe the nucleus of a basophil?

Answer 25

The nucleus has two lobes which commonly obscured by the granules.

Question 26

Describe the granules found in the cytoplasm of a basophil and their content ?

Answer 26

Its cytoplasm contains large, coarse, histamine and heparin granules that have an affinity for the basic dyes.

Question 27

What are the functions of basophil?

Answer 27

- They migrate to injury sites and across the capillary endothelium to accumulate on damaged tissues where they release their granules in the interstitial fluids. - They increase the permeability of the capillaries to allow phagocytic cells in the tissue space.

Question 28

What is the diameter of a basophil?

Answer 28

8-10 microns.

Question 29

Basophil account for ______ of all leukocytes.

Answer 29

0.5-1% Note: They are the rarest of white blood cells.

Question 30

Give the order of formation of granulocytes?

Answer 30

After a hemocytoblast we get a common myloid stem cell after which we get a myeloblast followed by neutrophilic, basophilic and eosinophilic promyelocyte which then result in basophil, neutrophil and eosinophil.

Question 31

List the characteristics of agranulocytes?

Answer 31

- They no granules in their cytoplasm. | - They have a single layer round slightly indented nucleus.

Question 32

What are the two types of agranulocytes?

Answer 32

Monocyte | Lymphocyte

Question 33

Monocyte account for ______ of all leukocytes.

Answer 33

5-8%

Question 34

Lymphocyte account for ______ of all leukocytes.

Answer 34

~ 20% Note: They are the second most leukocytes in the blood.

Question 35

Monocytes are large __________ cells which engulf ______ and __________.

Answer 35

mononuclear(monster); debris; pathogens

Question 36

What is the diameter of a monocyte?

Answer 36

15 microns

Question 37

Describe the nucleus of a monocyte?

Answer 37

It has a large nucleus that tends to be oval or kidney-shaped rather than lobed.

Question 38

What are the functions of a monocyte?

Answer 38

- They are crucial in the body's defense against viruses, certain intracellular bacterial parasites, and chronic infections such as tuberculosis. - When they are phagocytically active, they release chemicals that attracts and stimulates neutrophils and other monocytes to the sites.

Question 39

What type of cell is a monocyte?

Answer 39

It is a very aggressive phagocyte, that attempt to engulf items as large as or larger than themselves.

Question 40

When does a monocyte becomes a tissue macrophage?

Answer 40

When it leaves the bloodstream and enter the peripheral tissues.

Question 41

What is the lifespan of a monocyte?

Answer 41

Several months.

Question 42

Give the order of formation of monocytes?

Answer 42

Hemocytoblast /Myeloid stem cell/Monoblast/Promonocyte/Monocytes(Mature macrophage)

Question 43

Describe the nucleus of lymphocytes?

Answer 43

- They have large nucleus that occupies most of the cell volume. - The nucleus is usually spherical but may be slightly indented, and it is surrounded by a thin rim of pale-blue cytoplasm.

Question 44

Where are lymphocytes located?

Answer 44

Blood Lymphatic tissues Spleen Lymph nodes

Question 45

Give the order of formation of lymphocytes?

Answer 45

Hemocytoblast/Lymphoid stem cell/Lymphoblast/Prolymphocyte/Lymphocytes

Question 46

What are the 3 main types of cells found in lymph?

Answer 46

Natural killer cells B-cells T-cells

Question 47

What are the function of T-cells?

Answer 47

- They are responsible for cell mediated immunity (cellular immunity). - They have a specific defence mechanism against invading foreign cells and tissues. - T-cells enter peripheral tissues and attack foreign cells directly. Note: They migrate to their targets.

Question 48

What are the functions of B cells?

Answer 48

- They are responsible for humoral immunity. - It is a specific defence mechanism that involves the production of antibodies ;they attack the foreign antigens throughout the body.

Question 49

How does B cells travel?

Answer 49

-They travel by blood, lymph and interstitial fluid.

Question 50

What are the functions of Natural killer cells?

Answer 50

- They are responsible for immune surveillance. - They play a role in the detection and subsequent destruction of abnormal cells. - They are important in preventing cancer.