Body's Response to Infection

Question 1

What is another name for white blood cells?

Answer 1

Leukocytes

Question 2

Give two ways in which white blood cells can be categorised.

Answer 2

Categorised according to their developmental origin from stem cells in the bone marrow (myeloid and lymphoid) or by their morphology (granulocytes/polymorphonuclear leukocytes and mononuclear cells)

Question 3

What are PAMPs?

Answer 3

. Pathogen-associated molecular patterns

. Chemical structures found in many pathogens (e.g. viral double stranded RNA)

Question 4

How are antigens carried from the site of infection to lymphoid tissues?

Answer 4

. Some carried free in lymph

. Some carried by dendritic cells

Question 5

Name the cells that arise from myeloid progenitors.

Answer 5

. Erythrocytes, mast cells, myeloblasts (unipotent stem cell)
. Myeloblasts give rise to basophils, eosinophils, neutrophils, and monocytes
. Monocytes give rise to macrophages

Question 6

Name the cells that arise from lymphoid progenitors.

Answer 6

. Natural killers, small lymphocytes
. Small lymphocytes give rise to T-cells and B-cells
. B-cells give rise to plasma cells

Question 7

Which cells are granulocytes (PMNs) and which are mononuclear (PBMCs)

Answer 7

. All the myeloid progenitor cells are granulocytes except erythrocytes (no nucleus), monocytes and macrophages which are mononuclear
. From the lymphoid progenitors, NKs, T-cells and B-cells are mononuclear

Question 8

How do lymphocytes move from lymph nodes to the bloodstream?

Answer 8

Move from lymph nodes via efferent lymphatics then enter blood via thoracic duct