Anatomy and Physiology of the Immune system

Question 1

What is the immune system comprised of?

Answer 1

-Primary lymphoid tissues (central)
-Bone marrow - thymus

Question 2

Maturation of lymphocytes

Answer 2

-B cells in bone marrow
-T cells in the thymus

Question 3

Leukocytes maturation

Answer 3

Mature in the blood and/or non lymphoid organs

Question 4

Secondary lymphoid organs - peripheral

Answer 4

The site of antigen capture and initiation of adaptive immune response

Question 5

BONE MARROW

Answer 5

-Major hematopoietic site in humans
-Haematopoiesis is facilitated by a mixture of cells and extra matrix components
-All blood cell types except mature T cells are found in its cavities
-Growth factors, cytokines, and reticular stroma (extracellular matrix molecules, macrophages and adipocytes) are all important in B cell development

Question 6

HAEMATOPOIESIS

Answer 6

-Generation of leukocytes and blood cells - occur within adult bone marrow
-Haematopoietic stem cells (HSCs) are multipotent and self renewing
-HSCs are maintained by contact-dependent signals with stromal cells and soluble factors (growth factors & cytokines)
-Activated T cells and macrophages can contribute to the process during infection
-HSCs give rise to the common lymphoid and myeloid progenitor cells

Question 7

THYMUS

Answer 7

-T cell precursors from the BM migrate to the thymus
-Site of T cell maturation & development
-Only mature T cells exit the thymus and enter the blood and peripheral lymphoid tissues

Question 8

DiGeorge Syndrome

Answer 8

T cell deficiency caused by mutations in the genes required for thymus development
-22q11 deletion complex

Question 9

SPLEEN

Answer 9

-Acts as a filter of blood removing aged or abnormal red blood cells and other extraneous particles including microbes
-Microbes that enter the bloodstream stimulate an immune response within the spleen
-Source of B cells that response in the absence of T cells
Lymphoid function occurs within the white pulp and filtration in the red pulp

Question 10

Identification of Immune cells

Answer 10

-Leukocyte subsets can be identified using a combination of histological stain or monoclonal to label glycoproteins differentiation antigens expressed on the their cell surface
-Cell phenotype determining antigens are assigned cluster of differentiation CD numbers (more than 350)

Question 11

CD MARKERS

Answer 11

-CD3+ - T cells
-CD19+/CD20+ - B cells
-CD14+ - monocyte/macrophage
-CD3+/CD4+ - T helper cells
CD3+/CD8+ - Cytotoxic T cells
CD3-/CD16+/CD56+ - NK cells

Question 12

Leukocytes

Answer 12

White blood cells that provide either innate or specific adaptive immunity
myeloid cells - first line of defence, non-specific innate immunity (neutrophils, eosinophils, basophils/mast cells, monocytes/macrophages/dendritic cells)
lymphoid cells - non-specific immunity (natural killer cells)
lymphoid cells - humoral and cell mediated specific immunity ( B lymphocytes)