Histology Testbank: Blood 1a

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.
Which of the four basic tissue types does blood belong to?
a. Epithelium
b. Connective tissue
c. Muscle
d. Nervous tissue
e. Blood

Answer: b

There are four basic tissue types: epithelium, connective tissue, muscle and nervous tissue. Connective tissue is the most diverse. Blood is considered a type of connective tissue.

2.
Which of the following formed elements do not contain a nucleus?
a. Platelets
b. Erythrocytes
c. Leukocytes
d. Monocytes
e. Both a and b

Answer: e

Blood is composed of the formed elements and plasma. Plasma is the liquid portion of blood. The formed elements consist of the cells and cell fragments. The erythrocytes (red blood cells), platelets, and leukocytes (white blood cells) are all considered formed elements.

Erythrocytes do not contain a nucleus. During their development within the bone marrow, they have a nucleus. However, prior to their entering into the blood stream, the nucleus is ejected.

Platelets are cell fragments. Platelets also do not contain a nucleus. They are fragments from megakaryocytes within the bone marrow. Leukocytes, which include monocytes, are cells with a nucleus.

3.
What comes from a megakaryocyte?
a. Lymphocytes
b. Basophils
c. Erythrocytes
d. Monocytes
e. Platelets

Answer: e

Platelets are cell fragments. They are fragments from megakaryocytes within the bone marrow.

Histology hint from Sarah Bellham: The prefix "mega" is from the Greek "megas" which means great or big. For example: megaphone, megalomaniac, megabyte, and megakaryocyte.

4.
Which leukocyte is the most abundant in a peripheral smear of blood?
a. Lymphocytes
b. Basophils
c. Neutrophil
d. Monocytes
e. Eosinophils

Answer: c

Neutrophils are the most abundant leukocyte.

Leukocytes are the white blood cells. The order of frequency of the leukocytes is: neutrophil, lymphocyte, monocyte, eosinophil, basophil.

Histology hint from Sarah Bellham: The order of frequency of the leukocytes can be remembered by the mnemonic: "Never Let Monkeys Eat Bananas".

5.
Which of the following is not a granulocyte?
a. Lymphocytes
b. Neutrophil
c. PMN
d. Eosinophils
e. Basophils

Answer: a

The granulocytes are named because of the presence of visible cytoplasmic granules. The granulocytes consist of neutrophils, eosinophils, and basophils. "PMN" is an abbreviation for polymorphonuclear neutrophil. Thus, it is a neutrophil, which is a granulocyte. The non-granulocytes are lymphocytes and monocytes.

Histology hint from Sarah Bellham: Poly is from the Greek "polys", which means many. "Poly" is also sometimes used as a nickname for polymorphonuclear leukocyte.

6.
Which of the following is a granulocyte?
a. Thrombocyte
b. Lymphocyte
c. Eosinophil
d. Monocyte
e. Erythrocyte

Answer: c

The granulocytes are named because of the presence of visible cytoplasmic granules. The granulocytes consist of neutrophils, eosinophils, and basophils. The non-granulocytes are lymphocytes and monocytes. Erythrocytes are red blood cells. A thrombocyte is a platelet.

Note from Sarah Bellham: The suffix (or prefix) "phil" comes from the Greek word meaning love. It is used to specify an attraction or affinity towards something. It is seen in such words as philosophy, philanthropy and bibliophile.

This suffix is used in naming the three granulocytes: eosinophils, basophils, and neutrophils. Eosinophils "love" or are attracted to the eosin dye; thus the granules in an eosinophil are orange/pink. Basophils "love" or are attracted to the basophilic dye; thus the granules in a basophil are blue. Neutrophils "love" or are attracted to the neutral dye; thus the granules in a neutrophil are neutral colored.

7.
Which of the following is NOT a term used for a neutrophil?
a. Polymorphonuclear neutrophils
b. Poly's
c. PMN
d. NP
e. Polymorph

Answer: d

Neutrophils are granulocytes. Neutrophils have a multi-lobed nucleus. The lobes are separated by a thin strand. Because of the shape of the nucleus, neutrophils are also called "polymorphonuclear neutrophils", "poly's", "PMN", or "polymorph".

8.
Which leukocyte has a multi-lobed (3-5 lobes) nucleus?
a. Neutrophil
b. Lymphocytes
c. Monocytes
d. Eosinophil
e. Basophils

Answer: a

The leukocytes consist of neutrophils, lymphocytes, monocytes, eosinophils, and basophils.

Lymphocytes are agranulocytes. Lymphocytes can be categorized by three sizes: small, medium, and large. The small lymphocytes are the smallest leukocyte, being only slightly larger than an erythrocyte.

Monocytes are agranulocytes. They are the largest leukocyte.

Eosinophils are granulocytes. Eosinophils have prominent orange pink granules. The nucleus of eosinophils is usually bi-lobed.

Basophils are granulocytes. Basophils have large blue granules, which often obscure the nucleus. The granules are basophilic, therefore they are blue.

9.
Which cell has large blue granules, often obscuring the nucleus?
a. Neutrophil
b. Lymphocytes
c. Monocytes
d. Eosinophil
e. Basophils

Answer: e

The leukocytes consist of neutrophils, lymphocytes, monocytes, eosinophils, and basophils.

Monocytes are agranulocytes. They are the largest leukocyte.

Eosinophils are granulocytes. Eosinophils have prominent orange pink granules. The nucleus of eosinophils is usually bi-lobed.

Basophils are granulocytes. Basophils have large blue granules, which often obscure the nucleus. The granules are basophilic, therefore they are blue.

10.
Which of the following is not considered a "formed element"?
a. Plasma
b. Erythrocytes
c. Platelets
d. Leukocytes
e. Red blood cells

Answer: a