The Immune System (Lyons)

Question 1

what are the formed elements in blood?

Answer 1

RBC, leukocytes, megakaryocyte fragments, platelets

Question 2

what are the organic/inorganic substances in blood

Answer 2

plasma proteins (albumin, fibrinogen, globulins)

AA, vitamins, hormones, nutrients, wastes, etc.

Question 3

structure of RBC

Answer 3

no nucleus
biconcave disk
8 micrometers in diameter

Question 4

what are platelets?

Answer 4

fragments of megakayocyte cells in bone marrow

Question 5

whats the function of platelets?

Answer 5

hemostasis. doesn’t leave the blood

Question 6

what are the granulocytes

Answer 6

neutrophils aka polymorphonuclear cell
eosinophils
basophils
monocytes
NK cells
lymphocytes

Question 7

Neutrophils: size, morphology, function

Answer 7

9-12 micrometers

segmented nucleus, 3-5 lobes

chemotactically attracted to inflammation sites; phagocytosis of bacteria

Question 8

Eosinophils: size, morphology, function

Answer 8

10-12 micrometers

bilobed nucleus, large cytoplasm, eosinophilic lysosomes

chemotactically attracted to inflammation sites by eosinophil chemotactic factor released by mast cells or parasites; neutralize histamine; inhibit mast cells; phagocytose Ag-Ab complex in allergic response

Question 9

Basophils: size, morphology, function

Answer 9

9-12 micrometers

lobed nucleus, masked by large basophilic granules in cytoplasm

similiar to mast cells (secrete same substances, same primary/secondary IgE response)

Question 10

Monocytes

Answer 10

12-30 micrometers

large, eccentric, horseshoe shaped nucleus

differentiate into macrophages in CT, dendritic cells, osteoclasts/blasts of bone/cartilage

Question 11

Natural Killer cell function

Answer 11

innate immune system lymphocytes that are cytolytic

Question 12

Lymphocytes: size, morphology, function

Answer 12

small (6-9 micrometers), medium (10-12 micrometers), large (12-18 micrometers)

round, dense heterochromatic nucleus; larger the cell, larger the nucleus and more cytoplasm

cell surface receptors facilitate cell migration, response to foreign and self Ag

Question 13

innate vs. adaptive immunity

Answer 13

innate - neutrophils/macrophages phagocytose Ag

adaptive - lymphocytes neutralize and destory Ag

Question 14

cell mediated immunity vs. antibody mediated immunity

Answer 14

CMI - t cells directly attack intracellular Ag

AMI - extracellular Ag destroyed by Ab secreted by B cell that helps destroy/neutralize Ab

Question 15

what are the primary lymphoid organs and where do B cells and T cells mature?

Answer 15

Thymus (T cells)
Bone marrow (B cells)

Question 16

what are the secondary lymphoid organs?

Answer 16

lymph nodes, spleen, diffuse lymphatic tissue

Question 17

how does the thymus development in comparison to the rest of the body?

Answer 17

greatest size during fetal stage, then grows more slowly. regresses and thymic tissue replaced by adipocytes

Question 18

what are the two lobules of the thymus and their morphology

Answer 18

cortex - dark staining, isolated compartment supported by reticular epithelia
medulla - light staining, continuous

Question 19

what surrounds the thymus?

Answer 19

loose CT that blends w/ surrounding CT

Question 20

what are trabeculae

Answer 20

connective tissue that is continuous with the capsule

separates lobules

Question 21

how are the 6 types of reticular epithelial cells distributed?

Answer 21

three in cortex

three in medulla

Question 22

what are the two main functions of reticular epithelia cells?

Answer 22

barrier - keeps Ag out while T cells mature

T cell maturation - releases hormones and expresses MHC molecules for selection

Question 23

what are hassall’s corpuscles, what substances do they release?

Answer 23

densely packed whorls of reticular epithelial cells

release IL-4, IL-7, cytokine thymic stromal lymphopoietin (TSLP)

Question 24

what does thymic stromal lymphopoietin (TSLP) do?

Answer 24

increases dendritic cell ability to convert naive thymocytes to regulatory T cell lineage

Question 25

what types of cells are in the thymus

Answer 25

macrophages
CT cells
small, medium, large T lymphocytes