Topic 10 Immune System: Type of WBC (leukocytes)

Question 1

• All WBC’s originate from stem cells in bone marrow, but some multiply and become non- naive in the lymph node. Lymph drainage acts as a sewer system of antigens: cell recognizes antigen, goes from naive → activated. Be sure to know the relative amounts of leukocytes in the blood: erythrocytes > platelets > leukocytes.

Answer 1

Note

Question 2

• Engulf foreign particles, bacteria, dead or dying cells via phagocytosis. Macrophages are the largest phagocytes

Answer 2

1. Phagocytes

Question 3

a. Neutrophils
b. Monocytes
c. Eosinophils
d. Dendritic Cells
e. Mast Cells

Answer 3

Types of Phagpocytes

Question 4

• Function in destruction of pathogens in infected tissues; are drawn to infected/injured areas by chemicals via the process of chemotaxis
• Neutrophils slip between endothelial cells of capillaries and into tissues via diapedesis.

Answer 4

a. Neutrophils

Question 5

• Circulate in blood until they move into tissues via diapedesis where they develop into macrophages, which are professional antigen-presenting cells that phagocytize cell debris and pathogens. Monocytes can also give rise to dendritic cells.

Answer 5

b. Monocytes

Question 6

• Work collectively to surround and destroy multicellular parasites.

Answer 6

c. Eosinophils

Question 7

• Responsible for the ingestion of pathogens and stimulate acquired immunity. The main role of dendritic cells is as an antigen-presenting cell that activates T-lymphocytes. Dendritic cells can also have myeloid (from monocyte) or lymphoid lineage

Answer 7

d. Dendritic Cells

Question 8

• Function in allergic response, inflammatory response (histamine release), and anaphylaxis. These reside in tissues

Answer 8

e. Mast Cells

Question 9

• Covered later; lymphocytes are WBC’s, but are not part of the non-specific second line of defense

Answer 9

2. Lymphocytes

Question 10

• Release histamines for inflammatory response, found circulating the blood, and are recruited into tissue when needed. Contain histamine and heparin (which works as an anticoagulant) and several cytokines

Answer 10

3. Basophils

Question 11

• Other WBCs are called natural killer cells (NK cells) and attach abnormal body cells such as tumors or pathogen-infected tissues
• After neutrophils and macrophages engulf necrotic tissue + bacteria, they die; these dead leukocytes + necrotic tissue = pus

Answer 11

4. Natural Killer Cells