Anatomy of immune system - lymph node focus

Question 1

Where do superficial lymphatic vessels drain from?

Answer 1

Subcutaneous and mucous membranes

Question 2

Where do deep lymphatic vessels drain from?

Answer 2

Deep territories (accompany the arteries and deep veins)

Question 3

What does the superficial and deep lymphatic vessels form when they converge?

Answer 3

Lymphatic trunks

Question 4

What does the lymphatic trunk converge to?

Answer 4

Thoracic duct
Right lymphatic duct

Question 5

Where does the thoracic duct collect lymph from?

Answer 5

Subdiaphragmatic regions and left supradiaphragmatic half

Question 6

What does the thoracic duct flow into?

Answer 6

The junction between the left subclavian vein and the left jugular vein (base of neck)

Question 7

What does the right lymphatic duct drain?

Answer 7

The right half of the body above the diaphragm

Question 8

Where does the right lymphatic duct exit?

Answer 8

At the right jugular junction

Question 9

What is the process of homing?

Answer 9

Mature naive lymphocytes entering different secondary lymphoid organs randomly from the blood

Question 10

If not activated (or quiescent) through where do the lymphocytes leave?

Answer 10

The efferent lymphatic vessel

Question 11

What does the lymph node promote?

Answer 11

Passage of lymphocytes from blood to lymph
Encounter between lymphocyte and antigen
Activation, proliferation and differentiation of B and T cells
Cooperation between T and B cells

Question 12

3 regions of lymph nodes

Answer 12

Cortical region/B area
Paracortical region/T area
Medullary zone

Question 13

Where are the germinal center of the lymph node found?

Answer 13

Secondary follicle of cortical region

Question 14

Cells found in the cortical region of lymph nodes and their function there

Answer 14

B cells - inactive in primary follicles and active in secondary follicle
FDC - germinal centers, APC to B cell
Macrophages - APC to lymphocytes

Question 15

How do FDC bind immune complexes?

Answer 15

Have receptors like CR1 (complement receptor 1) that binds C3b and FC receptor that binds antibody

Question 16

Where in the lymph node are T cells activated?

Answer 16

Paracortical region

Question 17

Cells found in the paracortical region of lymph nodes and their function there

Answer 17

T cells - mostly CD4+ but also some CD8+, activated by APC
DC- APC for T cells
Macrophages

Question 18

In which region are the High Endothelial Venules (HEV) located?

Answer 18

Paracortical region

Question 19

What is the function of HEV?

Answer 19

Allow for naive lymphocytes to leave the blood stream and enter the lymph node

Question 20

Where in the lymph node are plasma cells found?

Answer 20

Medullary zone

Question 21

Life span of plasma cell

Answer 21

1 month before undergoing apoptosis

Question 22

Cells found in the medullary zone of lymph nodes and their function there

Answer 22

Plasma cells - medullary cords, secrete antibodies
Macrophages - medullary sinuses, phagocytosis and APC
DC - medullary sinuses, APC to T cells
Lymphocytes, mainly B cells - medullary cords
Neutrophils (sometimes) - medullary sinuses, fight bacteria via phagocytosis and degranulation

Question 23

How many efferent and blood vessels in lymph node?

Answer 23

1 of each

Question 24

How does the venues of the lymph node allow for the passage of lymphocytes?

Answer 24

It is modified to be isoprismatic

Question 25

How does the antigen get to the lymph nodes?

Answer 25

It is transported as a soluble protein from lymph or carried by DC

Question 26

2 zones of the germinal centers

Answer 26

Dark zone Light zone

Question 27

What is the dark zone occupied by?

Answer 27

Centroblasts

Question 28

What happens to the centroblasts in the dark zones?

Answer 28

They proliferate and move into the light zone, transforming into centrocytes

Question 29

What is the light zone occupied by?

Answer 29

Centrocytes that have migrated from the dark zone

Question 30

What do the centrocytes in the light zone give rise tp?

Answer 30

B lymphocytes (both memory and plasma)

Question 31

How many of the of the B cells stay in the lymph node and how many migrate to the bone marrow?

Answer 31

10% stay in the lymph-node 90% migrate to the boned marrow

Question 32

What do reticular cells/reticular fibroblasts do?

Answer 32

Form a specialized network of fibers (FRC conduits or ducts) that structure the lymph node and facilitate immune function.

Question 33

Where in the lymph node are FRC ducts found?

Answer 33

Primarily in paracortical region and also regions involved in antigen transport

Question 34

Which form does the B cell recognize antigen in?

Answer 34

Native form

Question 35

How many lymphocytes pass through the lymph nodes every day?

Answer 35

25x10^9 lymphocytes (each lymphocyte passes through a lymph node at least once a day)

Question 36

When do naive T cells encounter antigens?

Answer 36

During passage through secondary lymphoid organs

Question 37

How does the T cells reenter the blood stream?

Answer 37

They leave the lymph node through the efferent lymphatic and thoracic duct which empties into the superior vena cava which enter the heart

Question 38

What regulates the exit of T cells from lymph nodes?

Answer 38

Interaction between S1P (sphingosine-1-phosphate, gradient of it as it is in low levels in lymphnode) and S1P1 (the receptor)

Question 39

2 main zones of the spleen

Answer 39

Red pulp Whte pulp

Question 40

What is the red pulp?

Answer 40

Complex system of blood vessels that facilitate removal of old or damaged blood cells from circulation (emocateresis)

Question 41

What is emocatersis?

Answer 41

Removal of old or damaged blood cells from circulation

Question 42

What is the white pulp?

Answer 42

Region that contain T cells, B cells and accessory cells Builds immunological response to blood antigens