Immunology - Lymphoid Structures

Question 1

What are the functions of the lymph node?

Answer 1

Filtration of lymph by macrophages; storage and activation of B and T cells; production of antibodies

Question 2

Does a lymph node have more afferent or efferent lymph vessels?

Answer 2

It has many afferent vessels and few efferent vessels

Question 3

Within a lymph node, what is the site of B-cell localization and proliferation?

Answer 3

The follicle

Question 4

In lymph nodes, _____ (primary/secondary) follicles have pale central germinal centers and are active, while _____ (primary/secondary) follicles are dense and dormant.

Answer 4

Secondary; primary

Question 5

Which lymph node area contains cords of closely packed lymphocytes, plasma cells, and sinuses?

Answer 5

The medulla

Question 6

Which lymph node structures communicate with efferent lymphatics and contain reticular cells and macrophages?

Answer 6

Medullary sinuses

Question 7

Which lymph node area houses T cells?

Answer 7

The paracortex, which is located between the follicles and the medulla

Question 8

In lymph nodes, what is the name of the region that contains high endothelial venules through which T and B cells enter the lymph node from the blood?

Answer 8

The paracortex

Question 9

Which part of the lymph node contains B cells?

Answer 9

Follicles, which are located in the outer cortex

Question 10

In which genetic syndrome would a lymph node biopsy show an underdeveloped paracortex?

Answer 10

DiGeorge syndrome, due to thymic aplasia and lack of functional T cells

Question 11

In what part of the lymph node are the follicles (ie, the sites of B cell localization and proliferation) located?

Answer 11

The outer cortex

Question 12

In lymph nodes, what area becomes greatly enlarged during an extreme cellular immune response and contains high endothelial venules?

Answer 12

The paracortex

Question 13

Into which lymph vessel does lymph from the right arm and right half of the head drain? What is the lymph drainage for the rest of the body?

Answer 13

Right lymphatic duct; the rest of the body drains to the thoracic duct

Question 14

What are the primary lymph nodes in the lymphatic drainage of the stomach?

Answer 14

The celiac nodes

Question 15

What are the primary lymph nodes in the lymphatic drainage of the duodenum, jejunum, and sigmoid colon?

Answer 15

The duodenum and jejunum drain to the superior mesenteric lymph nodes; the primary drainage sites for the sigmoid colon are the inferior mesenteric lymph nodes

Question 16

Which lymph nodes serve as the primary lymph drainage site for the lower rectum and anal canal (above the pectinate line)?

Answer 16

Internal iliac

Question 17

What is the primary lymph node drainage site for the scrotum, thigh, and anal canal (below the pectinate line)?

Answer 17

Superficial inguinal nodes

Question 18

Where does lymph from the testes drain?

Answer 18

The superficial and deep plexuses

Question 19

Where does the lymph from the lateral side of the dorsum of the foot drain?

Answer 19

Popliteal lymph nodes

Question 20

In the spleen, what is the name of the long, vascular channels located in the red pulp that contains the fenestrated barrel hoop basement membrane?

Answer 20

The sinusoids

Question 21

In the spleen, what type of cells are found in the periarterial lymphatic sheath and in the red pulp?

Answer 21

T cells

Question 22

In the spleen, what type of cells are found in the follicles within the white pulp?

Answer 22

B cells

Question 23

In a patient with Streptococcus pneumoniae bacteremia, what important immunologic function does the spleen serve?

Answer 23

Macrophages found within the spleen remove encapsulated bacteria from the blood

Question 24

Name three findings seen on peripheral smear in asplenic patients.

Answer 24

Howell-Jolly bodies, target cells, thrombocytosis

Question 25

What is the major consequence of asplenia?

Answer 25

Increased susceptibility to infection by encapsulated organisms

Question 26

Why are asplenic patients more susceptible to encapsulated bacteria?

Answer 26

Asplenic patients have decreased immunoglobulin M secretion, leading to poor complement activation and therefore inhibited phagocytosis

Question 27

In which encapsulated organ do T cells mature?

Answer 27

The thymus

Question 28

From which branchial pouch is the thymus derived?

Answer 28

Third branchial pouch

Question 29

What is the purpose of negative selection of T cells? Positive selection?

Answer 29

Negative selection ensures that T cells are nonreactive to self, and positive selection ensures that T cells are able to recognize major histocompatibility complex molecules

Question 30

In the thymus, the ______ (cortex/medulla) is dense with immature T cells, whereas the ______ (cortex/medulla) is pale with mature T cells and epithelial reticular cells.

Answer 30

Cortex; medulla