Question 1

Anemia can be caused either by a low hematocrit, or by a low hemoglobin level even when the red blood cell count is normal.&#160;

Accepted Answer

This statement is true. Anemia can be caused by a low hematocrit, meaning a low percentage of red blood cells in the total blood volume, or by a low hemoglobin level, which is the protein in the red blood cells that carries oxygen. In some cases, the red blood cell count may be normal but the amount of hemoglobin in each cell is decreased, resulting in anemia.

Question 2

The primary determinating factor for total blood cholesterol level is&#10;A)heredity.&#10;B)obesity.&#10;C)lack of exercise.&#10;D)a high cholesterol diet.&#10;E)All of these factors contribute equally to the total blood cholesterol level.

Accepted Answer

Heredity is the primary determining factor for total blood cholesterol level. While other factors such as obesity, lack of exercise, and a high cholesterol diet can also contribute to high cholesterol levels, they do not have as large of an impact as genetics. People with a family history of high cholesterol are more likely to have high cholesterol themselves, regardless of lifestyle factors.

Question 3

A complete blood count (CBC)measures all of the following except&#10;A)the white blood cell count.&#10;B)the hematocrit.&#10;C)the hemoglobin concentration.&#10;D)the red blood cell count.&#10;E)the percentages of each type of white blood cell.

Accepted Answer

A complete blood count (CBC) measures the white blood cell count, hematocrit, hemoglobin concentration, and red blood cell count. However, it does not measure the percentages of each type of white blood cell, which is measured by a differential white blood cell count.

Question 4

Which of the following is not true of cholesterol?&#10;A)For the best health, it is recommended that the LDL and HDL levels in the blood should be as low as possible.&#10;B)A cholesterol level of greater than 200 mg/dl is associated with an increase in the likelihood of developing cardiovascular disease.&#10;C)LDLs are molecules that transport cholesterol to the tissues for use by the cells.&#10;D)HDLs are molecules that are transported to the liver for decomposition and removal from the body.&#10;E)All of these are true of cholesterol.

Accepted Answer

While it is important to keep LDL levels low, it is also important to maintain a healthy level of HDL cholesterol. HDL cholesterol can actually help remove LDL cholesterol from the bloodstream and lower the risk of cardiovascular disease.

Question 5

All of the following factors could cause decreased hematocrit except&#10;A)anemia.&#10;B)smoking or emphysema.&#10;C)kidney disease with a decline in erythropoietin production.&#10;D)a hemorrhage.&#10;E)All of these could cause decreased hematocrit.

Accepted Answer

Smoking or emphysema can actually lead to increased hematocrit due to chronic hypoxia stimulating erythropoietin production.

Question 6

Which of the following is not true of hemoglobin?&#10;A)It makes up about 1/3 of a red blood cell.&#10;B)Each hemoglobin molecule consists of 4 protein subunits.&#10;C)Oxyhemoglobin is bright red, and deoxyhemoglobin is dark red.&#10;D)Each hemoglobin molecule can bind to up to 20 oxygen molecules at a time.&#10;E)All of these are true of hemoglobin.

Accepted Answer

Each hemoglobin molecule can bind to a maximum of 4 oxygen molecules at a time. Therefore, choice D is not true of hemoglobin. The other choices are all true of hemoglobin.

Question 7

When a blood sample is spun down in a centrifuge tube, what is found in the buffy coat?&#10;A)Blood plasma&#10;B)Red blood cells&#10;C)Platelets&#10;D)Red blood cells and platelets&#10;E)White blood cells and platelets

Accepted Answer

The buffy coat is the thin, whitish layer that forms between the plasma and red blood cells after centrifugation of a blood sample. It is made up of white blood cells and platelets, which have a higher density than plasma but lower density than red blood cells. Therefore, the correct choice is E, which indicates white blood cells and platelets.

Question 8

The most important factor influencing the percent saturation of hemoglobin is&#10;A)the pH.&#10;B)the temperature.&#10;C)the partial pressure of oxygen.&#10;D)the carbon dioxide level.&#10;E)All of these factors are equally important in determining the percent saturation of hemoglobin.

Accepted Answer

The percent saturation of hemoglobin is primarily determined by the partial pressure of oxygen. As oxygen levels increase, hemoglobin binds more oxygen, resulting in an increased percent saturation. Other factors such as pH, temperature, and carbon dioxide levels can also influence the binding of oxygen to hemoglobin, but to a lesser extent than the partial pressure of oxygen.

Question 9

The binding site for oxygen molecules in red blood cells is the globin portion of the hemoglobin molecules.

Accepted Answer

The binding site for oxygen molecules in red blood cells is the heme portion of the hemoglobin molecules, not the globin portion. The heme contains an iron atom that binds oxygen.

Question 10

When a blood sample is spun down in a centrifuge tube, the blood plasma settles to the bottom, due it is high viscosity.

Accepted Answer

When a blood sample is spun down in a centrifuge tube, the heaviest components such as red blood cells settle to the bottom, while plasma - which is less dense than red blood cells - remains at the top of the tube. Therefore, plasma does not settle due to its high viscosity, but rather due to its lower density compared to other blood components.

Question 11

The blood clotting cascade is initiated by chemicals released by&#10;A)normal cells in the vicinity of the broken blood vessel.&#10;B)injured tissues and platelets.&#10;C)red blood cells in the area.&#10;D)fibroblasts in the vicinity of the broken blood vessel.&#10;E)pathogenic microorganisms in the area.

Accepted Answer

The answer of The blood clotting cascade is initiated by...

Question 12

On the average, males have a slightly higher hematocrit than females.

Accepted Answer

The answer of On the average, males have a slightly...

Question 13

During hemostasis, the final stage of blood coagulation involves&#10;A)the conversion of prothrombin to thrombin.&#10;B)the formation of a platelet plug.&#10;C)the conversion of fibrinogen to fibrin.&#10;D)blood vessel spasm.&#10;E)the secretion of serotonin.

Accepted Answer

The answer of During hemostasis, the final stage of blood...

Question 14

A normal average hematocrit in a male is about&#10;A)15%.&#10;B)45%.&#10;C)25%.&#10;D)<1%.&#10;E)55%.

Accepted Answer

The answer of A normal average hematocrit in a male...

Question 15

According to the oxygen dissociation curve for temperature, the higher the temperature, the higher the percent saturation of hemoglobin for any partial pressure of oxygen.

Accepted Answer

The answer of According to the oxygen dissociation curve for...

Deck 43: Blood Testing