Histology Testbank: Lymphatic System 3a

Instructions: For each histology question, pick the one best answer. This histology test bank is also useful for the histology questions on the USMLE (USMLE step 1).

1.
What are the large aggregates of lymphatic tissue in the ileum?
a. Lymph follicles
b. White pulp
c. Peyer's patches
d. Lymph node
e. Diffuse lymphatic tissue

Answer: c

The localized concentrations of lymphocytes that are seen in the respiratory tract, genitourinary tract, and gastrointestinal tract are lymph follicles. They are also called lymphatic nodules.

The lymphatic tissue in the spleen is called white pulp.

The large aggregates of lymphatic tissue in the ileum are called Peyer's patches.

A lymph node is an encapsulated lymphatic organ.

The random distribution of lymphocytes seen in the lamina propria of the respiratory tract, genitourinary tract, and gastrointestinal tract is called diffuse lymphatic tissue. Difuse lymphatic tissue in not encapsulated.

2.
Where is diffuse lymphatic tissue NOT found?
a. Gastrointestinal tract
b. Central nervous system
c. Genito-urinary tract
d. Respiratory tract
e. None of the above-diffuse lymphatic tissue is found in all of these regions

Answer: b

Diffuse lymphatic tissue is non-encapsulated lymphatic tissue. It is found in the gastrointestinal tract, the genito-urinary tract, and the respiratory tract. In the gastrointestinal tract it is referred to as GALT (gut associated lymphatic tissue). In the respiratory tract it is referred to as BALT (bronchi associated lymphatic tissue). Diffuse lymphatic tissue is not found in the central nervous system.

3.
Where are the splenic sinuses?
a. Malpighian corpuscle
b. Trabeculae
c. White pulp
d. Red pulp
e. Cords of Billroth

Answer: d

The spleen has a connective tissue capsule. The invaginations of the capsule into the splenic parenchyma are trabeculae.

The parenchyma of the spleen can be divided into the white pulp and the red pulp. The white pulp of the spleen is the lymphatic portion of the spleen. Within the white pulp, splenic nodules are found. Splenic nodules are also called Malpighian corpuscles.

The red pulp is made up of the splenic sinuses and splenic cords. The splenic cords are also called the cords of Billroth.

4.
What does the acronym PALS stand for?
a. Papillary layer sinus
b. Peyer's lymphatic sheath
c. Periarterial lymphatic sheath
d. Peripheral lymphatic sinus
e. Parenchymal lymphatic sheath

Answer: c

PALS stands for periarterial lymphatic sheath. Periarterial lymphatic sheaths are the lymphocytes which surround the central artery in the spleen.

5.
Which of the following is an encapsulated lymphatic organ?
a. Lymph follicles
b. White pulp
c. Peyer's patches
d. Lymph node
e. Diffuse lymphatic tissue

Answer: d

The localized concentrations of lymphocytes that are seen in the respiratory tract, genitourinary tract, and gastrointestinal tract are lymph follicles. They are also called lymphatic nodules.

The lymphatic tissue in the spleen is called white pulp.

The large aggregates of lymphatic tissue in the ileum are called Peyer's patches.

A lymph node is an encapsulated lymphatic organ.

The random distribution of lymphocytes seen in the lamina propria of the respiratory tract, genitourinary tract, and gastrointestinal tract is called diffuse lymphatic tissue. Difuse lymphatic tissue in not encapsulated.