Question 1

The formed elements in the blood are

Accepted Answer

The formed elements in the blood are mostly red blood cells (erythrocytes), which make up about 45% of blood volume, while white blood cells (leukocytes) and platelets (thrombocytes) are much less abundant.

Question 2

"Formed elements" are

Accepted Answer

Formed elements refer to the cellular components of blood, including red blood cells, white blood cells, and platelets. Sodium and potassium are electrolytes, which are dissolved in the plasma portion of blood. Serum and plasma are components of blood, but do not refer specifically to the cellular elements. Lymph is a fluid found in lymphatic vessels, separate from blood.

Question 3

Heme released from hemoglobin in aged red blood cells is decomposed in the liver into

Accepted Answer

Heme released from hemoglobin in aged red blood cells is decomposed in the liver into iron and the bile pigment biliverdin, which is eventually converted to bilirubin.

Question 4

A condition occurs where the number of basophils in the blood drastically decreases. Which of the following would directly result from the loss of basophils?

Accepted Answer

Basophils are involved in the inflammatory response, releasing histamine and other mediators that attract other immune cells to areas of tissue damage or infection. The loss of basophils would result in a reduced inflammatory response and a decreased attraction of defensive leukocytes such as neutrophils and macrophages to these areas.

Question 5

The familiar brown color of human feces comes primarily from the orange-colored product of red blood cell breakdown that has been secreted in the bile and has become brown as it travels through the intestines. Which product contributes to this color?

Accepted Answer

Bilirubin is the orange-yellow pigment that is formed from the breakdown of heme in red blood cells. It is secreted in the bile by the liver and travels through the intestines, where it is metabolized by bacteria into urobilinogen and then into stercobilin, which gives feces its characteristic brown color. Biliverdin is also involved in the breakdown of heme but contributes to the green color of bile, not feces. Degraded platelets and ferritin are not directly related to fecal color.

Question 6

The biconcave cells in blood that lack nuclei when they are mature are the

Accepted Answer

Red blood cells, also known as erythrocytes, are biconcave cells in blood that lack nuclei when they are mature. White blood cells, platelets, and macrophages all have nuclei.

Question 7

The normal white blood cell count is ________ cells per microliter of blood.

Accepted Answer

The normal white blood cell count ranges between 4,500 to 11,000 cells per microliter of blood. Choice A is too low, choice C is too high, and choice D is in the millions, which is not a normal range for white blood cells.

Question 8

Vitamin B₁₂ is poorly absorbed in the absence of

Accepted Answer

Vitamin B12 requires intrinsic factor (IF), a protein secreted by the parietal cells of the stomach, for absorption in the small intestine. Without IF, vitamin B12 cannot be absorbed and will be excreted. This is why people with pernicious anemia, who have an autoimmune disease that attacks the parietal cells and inhibits IF production, require B12 injections to ensure sufficient absorption.

Question 9

A primary function of lymphocytes is to

Accepted Answer

Lymphocytes are a type of white blood cell that plays a crucial role in the immune system. They are responsible for recognizing and attacking foreign substances, such as viruses and bacteria, in the body. This is achieved through the production of specific antibodies, which target and neutralize the invading pathogens. Therefore, option D, act against foreign substances, is the correct answer.

Question 10

Leukopenia is a disorder resulting from conditions like HIV and aplastic anemia that causes levels of white blood cells to drop below the normal standard. Which of the following white blood cell counts suggests leukopenia?

Accepted Answer

Leukopenia is defined as a white blood cell count less than 4,000 cells per microliter of blood. Option B, with a WBC count of 3,000 cells per microliter of blood, indicates leukopenia. The other options are within the normal range of WBC counts.

Question 11

Hematocrit is

Accepted Answer

Hematocrit is defined as the percentage of red blood cells in a blood sample. It is commonly used as a diagnostic tool to assess the patient's overall health status, as it can indicate the presence of anemia or dehydration, among other conditions. It is a standard part of a complete blood count (CBC) test.

Question 12

The percentage of red blood cells in a sample of human blood is normally about

Accepted Answer

The percentage of red blood cells in a sample of human blood is known as hematocrit. In adult males, the normal range for hematocrit is between 40% and 52%, while in adult females, it is between 35% and 47%. Therefore, the closest answer choice to the normal range is C, 45%.

Question 13

Blood volume varies with

Accepted Answer

Blood volume is directly proportional to body fat content. This is because adipose tissue contains more blood vessels per unit tissue than other tissues such as muscle, bone, and nerves. Therefore, people with higher body fat content tend to have higher blood volumes. Bone density, muscle mass, and strength of nervous signals do not have a direct correlation with blood volume.

Question 14

Biliverdin and bilirubin are pigments that result from the breakdown of red blood cells. Biliverdin is ________ in color and bilirubin is ________ in color.

Accepted Answer

Biliverdin is indeed greenish in color, but bilirubin is orange in color. This is why jaundice, which is caused by an excess of bilirubin in the blood, can cause the skin and eyes to appear yellow.

Question 15

Which two mature blood cell types descend from myeloblasts?

Accepted Answer

Myeloblasts give rise to granulocytes, which include neutrophils, basophils, and eosinophils. Therefore, the correct answer is C, as neutrophils and basophils are two mature blood cell types that descend from myeloblasts. A is incorrect because T cells and B cells are lymphocytes, which come from lymphoid precursor cells. B is incorrect because erythrocytes (red blood cells) and platelets (thrombocytes) come from precursor cells in the bone marrow known as megakaryocytes and erythroblasts, respectively. D is incorrect because monocytes come from monoblasts and lymphocytes come from lymphoblasts.

Question 16

While looking at a sample of blood in a microscope, you see a purple-stained cell that is markedly larger than a red blood cell (about two to three times larger). It has a large kidney-shaped nucleus. What type of blood cell is this?

Accepted Answer

The description of a purple-stained cell that is larger than a red blood cell and has a large kidney-shaped nucleus is consistent with a monocyte. Monocytes are a type of white blood cell that are larger than red blood cells and have a large horseshoe-shaped nucleus. They are stained purple in standard blood smears. Eosinophils, basophils, and neutrophils are types of white blood cells, but they do not have the specific characteristics that were described.

Question 17

Which is the correct sequence for differentiation of a red blood cell?

Accepted Answer

The correct sequence for differentiation of a red blood cell is hematopoietic stem cell, erythroblast, reticulocyte, erythrocyte. The hemocytoblast in choice C is not a valid term for red blood cell differentiation, and choice B has the order of erythroblast and erythrocyte reversed.

Question 18

Which of the following are agranulocytes?

Accepted Answer

Monocytes are agranulocytes, meaning they do not have visible granules in their cytoplasm. Basophils, eosinophils, and neutrophils are all types of granulocytes, which have visible granules in their cytoplasm.

Question 19

Platelets are best described as

Accepted Answer

Platelets are not complete cells, but rather fragments of larger cells called megakaryocytes. These fragments contain granules that are important for blood clotting.

Question 20

A patient comes to the hospital with a suspected case of MRSA (a dangerous bacterial infection). Which of the following blood components would you expect to show elevated numbers in a blood test?

Accepted Answer

Neutrophils are a type of white blood cell that are responsible for fighting off bacterial infections. In the case of a suspected MRSA infection, it is likely that the body would be producing an elevated number of neutrophils to combat the bacteria.

Quiz 14: Blood