Question

Can you paraphrase the following rationale, thank you!

1. Which function is carried out by all lymphoid tissues and organs?

a. Filtration of lymph

b. Filtration of blood
c. Extramedullary hemopoiesis
d. Production of lymphocytes
e. Destruction of old erythrocytes

Rationalization: Filtration of blood, extramedullary hemopoiesis, destruction of old erythrocytes occurs in spleen, but filtration of lymph occurs in lymph nodes. All of the lymphoid tissues and organs function in the production of lymphocytes

2. Which structure is partly encapsulated and covered by nonkeratinized stratified squamous epithelium?

a. Appendix

b. Lymph node

c. Palatine tonsil

d. Peyer’s patch

e. Thymic (Hassal’s) corpuscle

Rationalization: Palatine tonsil is located in the posterior lateral walls of the oral cavity, it means that it is prone to abrasion and stratified squamous forms thick layer of cells to protect against abrasion and acts as a mechanical barrier.

3. Which cell type gives rise to both memory and effector cells and is primarily associated with humoral immunity?

a. B lymphocyte

b. Nk cell

c. Macrophage

d. T lymphocyte

e. Reticular cell

Rationalization: Given with the clue “humoral immunity” B lymphocyte is known to be responsible for secreting antibodies (specifically Plasma B-cell)

4. Recycling of iron and heme, the major complex containing iron, occurs most actively in which lymphoid organ(s)/ tissue?

a. Lymph nodes

b. Peyer’s patch

c. Tonsils

d. Spleen

e. Lymphatic vessels

Rationalization: Spleen is responsible for filtration of blood

5. Which description is true of all secondary (peripheral) lymphoid organs?

a. Capable of antigen-independent lymphopoiesis

b. Contain crypts

c. Contain epithelial-reticular cells

d. Lack connective tissue capsules

e. Contain lymphoid nodules

Rationalization: Antigen-independent lymphopoiesis occurs in primarily in lymphoid organs, secondary lymphoid organs are surrounded by connective tissue

6. Which structure would be most heavily labeled by an immunohistochemical method targeting the CD8 surface antigen

a. Germinal centers

b. Paracortex

c. Peyer’s patch

d. Sheathed arterioles

e. Splenic cords

Rationalization: The paracortex of contains lymphoid tissue rich in T-cells distinguishable by immunohistochemistry.

7. A baby is born with a cleft palate and a condition called DiGeorge syndrome, which involves failure of third and fourth pharyngeal pouch derivatives to develop properly. The palate defect is corrected surgically, but regarding the pharyngeal pouch defect the parents are advised that the growing child may expect which of the following health problems?

a. Insufficient B-cell production by lymph nodes in the head and neck

b. Inability to secrete IgA

c. Excessive numbers of circulating but defective erythrocytes

d. Increased oral infections due lack of palatine and pharyngeal tonsils

e. Conditions related to autoimmunity

Rationalization: There are common problems that occur in DiGeorge syndrome such as heart defects, hypothyroidism, thymus gland dysfunction, cleft palate and developmental problem. Due to small or absence of thymus, may have increased risk of autoimmune diseases.

8. Many immune-related cellular activities are often impaired in aged patients. Which lymphoid organ(s) normally develop less functionality and increasing amounts of adipose tissue with age?

a. Axillary lymph nodes

b. Lingual tonsils

c. Thymus

d. Splenic white pulp

e. Splenic red pulp

Rationalization: Because as we grow old, thymus gland begins to deteriorate and less functional. Thymus is the site of T-lymphocyte differentiation and selection, it is most active during neonatal and pre-adolescent period.

9. A 12-year-old girl of African descent presents with anemia and a large percentage of her peripheral erythrocytes appear sickle-shaped. Genetic testing reveals homozygosity for sickle cell disease. In which of the following sites will the abnormal RBCs be removed from the circulation?

a. Thymic cortex

b. Periarteriolar lymphoid sheathes of splenic white pulp

c. Medullary sinuses of lymph nodes

d. Thymic medulla

e. Splenic cords (of Billroth)

Rationalization: Because the red pulp is composed almost entirely of splenic cord (of Billroth) and splenic sinusoids and it the site where the effete RBC in blood are removed.

10. A 6-year-old boy is brought to the clinic where his mother reports that he was bitten by a neighbor’s dog two days earlier. The child’s right hand is lacerated between the thumb and index finger and this area is inflamed but healing. The doctor’s examination reveals small but painless swellings beneath the skin inside the right elbow and armpit and he explains to the mother that these are active lymph nodes enlarged in response to infection in the hand. What has produced swelling?

a. Increased flow of lymph through the nodes’ afferent lymphatics

b. Formation of germinal centers for B-cell proliferation in each node’s cortex

c. Arrival of antigen-presenting cells in each node’s medulla

d. Enlargement and increased activity of the nodes’ high endothelial venules

e. Increased thickness of each node’s paracortex

Rationalization: It was the immune response of B-cell to invading pathogens. Antibodies are secreted by plasma cells that arise by terminal differentiation.

Answer 1

1.The main function of all the lymphoid tissues are production of lymphocytes.there are other functions also of lymphoid tissue such as filtration of blood and extramedullary hemopoiesis and destruction of old RBC done by spleen and filtration of lymph is done by lymph nodes.

2.Palatine tonsil is present on posterolateral walls of of oral cavity.During eating these tonsils can be abrased ,to prevent this and protect palatine tonsil from damage ,there is covering made by non keratinized stratified squamous epithelium.

3.B lymphocytes are the immune cell which form the memory cells as well as antibodies.

4.RBC contains the Hemoglobin and heme is the iron containing group in hemoglobin molecule , Recycling of Iron can take place by breakdown of RBC ,which takes place in the Spleen.

5.Secondary Lymphoid organs are surrounded by connective tissues,they does not contain crypts,and contains lymphatic nodules such as lymph nodes.

6.Lymph node contain paracortex,which have lymphoid tissue rich in T-cells,These T-cells cen be distinguished by immunohistochemistry test.

7.Third and fourth pharyngeal pouches Derivatives are thymus gland and parathyroid gland.As there is failure in development of Thymus gland ,there will be no Differentiation of T-Cells, which are involved in immune response .Thus there will be condition develop related to autoimmunity

8.Thymus gland is involved in the Differentiation of Immune cells .It begins to degenerate on aging and get replaced by adipose tissue .

9.Red pulp is involved in separation and destruction of abnormal RBC's from blood,Red pulp is formed by Splenic cords and sinusoids

10.Swelling arises due to formation of germinal centers for B-cell proliferation in each node's cortex as there immune response is activated by B cells for the pathogen.