Basis of Immune Response

Question 1

What is haematopoiesis and What is the function of the thymus, liver and bone marrow

Answer 1

Haematopoiesis is the process of creating and replenishing blood and bone marrow cells.

The thymus and spleen create specific types of immune cells.

The liver and bone marrow are responsible for cell production.

Question 2

How are Plasma, T and NK cells created (4)

Answer 2

1. Pluripotent haematopoietic stem cell differentiates into common lymphoid progenitors in the bone marrow.
2. This then goes into the blood where they become B, T or NK cells
3. B cells are checked in the bone marrow and T cells are checked in the thymus.
4. They then enter the lymph nodes, where they travel to the effector cells, where they are activated and become plasma cells, activated T cells and activated NK cells, respectively.

Question 3

How are dendritic cells created (3)

Answer 3

1. Pluripotent haematopoietic stem cell → common lymphoid progenitor in the bone marrow.
2. common lymphoid progenitor → immature dendritic cell in the blood.
3. An immature dendritic cell travels to the tissue, where it becomes a mature dendritic cell and travels to the lymph nodes.

Question 4

How are macrophages and mast cells created (4)

Answer 4

1. Pluripotent hematopoietic stem cell → common myeloid progenitor in bone marrow.
2. Common myeloid progenitor splits into two, one becoming a granulocyte/macrophage progenitor in bone marrow.
3. they are then taken into the blood where they are made into neutrophils, eosinophils, basophils, unknown precursors of mast cells and monocytes.
4. Precursors of mast cells and monocytes are then taken into tissues, where they become mast cells and macrophages.

Question 5

How are Erythrocytes (red blood cells) created (3)

Answer 5

1. Pluripotent hematopoietic stem cell → common myeloid progenitor in bone marrow.
2. Common myeloid progenitor splits into two, one becoming a megakaryocyte/erythrocyte progenitor in bone marrow.
3. The megakaryocyte/erythrocyte progenitors become megakaryocytes and erythrocytes in the bone marrow where they go into the blood and become platelets and erythrocytes (red blood cells).

Question 6

What are monocytes/macrophages, and what is their function

Answer 6

Antigen presenting mononuclear phagocyte

phagocytosis and activation of bacterial mechanisms.

Question 7

What are Cytokines, and what is their function

Answer 7

phagocyte

mediate further inflammatory response.

Question 8

What are dendritic cells, and what is their function

Answer 8

phagocyte

antigen uptake in peripheral sites and antigen presentation in lymph nodes & express major histocompatibility complex ii.

Question 9

What are neutrophils, and what is their function

Answer 9

polymorphonuclear granulocytes - phagocyte

1st to arrive at inflammation site and phagocytose bacteria.

Question 10

What are Eosinophils, and what is their function

Answer 10

polymorphonuclear granulocytes - phagocyte

granules stain with basic eosin red. Removal of parasitic organisms and role is asthma pathology.

Question 11

What are Basophils, and what is their function

Answer 11

polymorphonuclear granulocytes - not phagocytic

Granules stain with acid dye methylene blue and contain heparin and histamine. Role in allergic response

Question 12

What are Mast cells, and what is their function

Answer 12

release histamine and other pharmacologically active substances from their granules. Play a major role in the development of allergic disease.

Question 13

What are Natural Killer cells, and what is their function

Answer 13

do not express T or B cell receptors. Recognise and destroy virus-infected cells and certain tumour cells. Detection via lack of MHC I and Fc receptors.

Question 14

What are Gamma-Delta cells, and what is their function

Answer 14

Intraepithelial cells a part of the innate and adaptive system which lacks diversity.

Question 15

What are Natural Killer T cells, and what is their function

Answer 15

Share NK and T cell characteristics with ab antigen receptors but lack diversity. Suppress or activate innate and adaptive responses.

Question 16

What are B lymphocytes, and what is their function

Answer 16

Produce antibodies of unique specificity. B cell receptor binding of antigen results in B cell differentiation into plasma cells.

Question 17

What are Plasma cells, and what is their function

Answer 17

When activated secretes antibodies.

Question 18

What are T helper cells, and what is their function

Answer 18

express cytokines to coordinate the immune response. And express T cell receptor and CD4 co-receptor.

Question 19

What are cytotoxic T lymphocytes and what is their function

Answer 19

Express T cell receptor and CD8 co-receptor and destroy infected cells directly.