White cells

Question 1

What are white blood cells derived from?

Answer 1

Lymphoid-myeloid stem cells

Question 2

What are 3 types derived from lymphoid stem cells?

Answer 2

T, B, NK (natural killer)

Question 3

What times of WBCs are derived from myeloblasts?

Answer 3

Eosinophils, neutrophils, basophils, monocytes

Question 4

What does M-CSF do?

Answer 4

Stimulates monocyte proliferation

Question 5

What does G-CSF do?

Answer 5

Stimulates granulocyte proliferation

Question 6

What does GM-CSF do?

Answer 6

Stimulates both monocyte and granulocyte proliferation

Question 7

How do neutrophils migrate into tissues? (5 steps)

Answer 7

1. Neutrophils migrate through blood vessels into tissues following specific chemicals such as interleukin-8 or hydrogen peroxide by a process called chemotaxis.
2. At the site of acute inflammation, neutrophils line up along the vessel wall (margination). This leads to an accumulation of neutrophils along the vessel wall near the site of inflammation.
3. The neutrophils then roll along the vessel wall until it securely binds to the vessel wall by firm adhesion.
4. The neutrophil then begins to squeeze through the vessel wall by diapedeses.
5. The neutrophil continues to follow along the concentration gradient of specific chemicals until reaching a pathogen which can then be destroyed by phagocytosis.

Question 8

Function of eosinophils?

Answer 8

Eosinophils defend against parasitic infection and spend less time in blood circulation than neutrophils.

Question 9

Function of basophils?

Answer 9

Involved in a variety of immune and inflammatory responses. Its granules contain stores of histamine and heparin as well as proteolytic enzymes (protease enzymes).

Question 10

Function of monocytes?

Answer 10

Monocytes spend several days in circulation where they can carry out phagocytosis in the blood and present the antigens on their cell surface membrane to activate lymphoid cells. When they migrate into tissues, they differentiate into macrophages that can release cytokines and carry out a large amount of phagocytosis.

Question 11

Function of b lymphocytes?

Answer 11

Differentiate into plasma cells that produce monoclonal antibodies.

Question 12

Function of t lymphocytes?

Answer 12

These are involved in cell-mediated immunity and activate B cells.

Question 13

Function of NK

Answer 13

These are part of the innate immune system and can kill tumour cells as well as virus infected cells.

Question 14

Causes of neutrophilia

Answer 14

1. Bacterial infection, inflammation, infarction/tissue damage, chronic myeloid leukaemia
2. Pregnancy, exercise and corticosteroids
3. Accompanied by left shift which means more neutrophil precursors in blood
4. Neutrophil hyper segmentation caused by a lack of b12 or folic acid

Question 15

Cause of lymphocytosis

Answer 15

Usually a response to viral infection. Can result from leukaemia.

Question 16

Cause of lymphopenia

Answer 16

Reduction in lymphocytes caused by:

1. HIV
2. Chemotherapy
3. Radiotherapy
4. Corticosteroids

Question 17

Cause of monocytosis

Answer 17

Caused by infection or chronic inflammation.

Question 18

Cause of eosinophilia

Answer 18

Usually due to allergy or parasitic infection.

Question 19

Cause of basophilia

Answer 19

Uncommon. Found in leukaemia.