Hematology

Question 1

What is the main function of RBCs?

Answer 1

To carry oxygen via hemoglobin molecules

Question 2

Blood is a body fluid with 4 main functional components…

Answer 2

1. Plasma
2. Red blood cells (erythrocytes)
3. White blood cells (leukocytes)
4. Platelets (thrombocytes)

Question 3

Describe RBC shape

Answer 3

biconcave disk

Question 4

Describe RBC nucleus

Answer 4

Anucleate (no nucleus) - not alive

Question 5

What blood component contributes to blood viscosity?

Answer 5

RBCs

Question 6

Which is more numerous in the blood? RBCs or WBCs?

Answer 6

RBCs

Question 7

Briefly describe erythropoiesis

Answer 7

Process of RBC production
- Multipotent stem cell differentiates into myeloid stem cell
- Myeloid stem cell differentiates into an erythrocyte (stimulated by erythropoietin produced by the kidneys)
- Erythrocyte differentiates into a reticulocyte (newborn RBC)

Question 8

Reticulocyte

Answer 8

Immature RBCs, still contain some ribosomal RNA (producing hemoglobin)

Question 9

Erythropoiesis begins in the…

Answer 9

bone marrow

Question 10

Reticulocytes do not normally circulate in the peripheral blood except in states of…

Answer 10

anemia

Question 11

Erythropoietin

Answer 11

Hormone produced by renal tubule cells in response to blood O2 levels - stimulates erythropoiesis

Question 12

When the need for oxygen is significant and acute (eg. in a state of anemia), the bone marrow might push out …

Answer 12

immature RBC precursors or reticulocytes into the bloodstream

Question 13

RBC oxygenation happens in …

Answer 13

lungs

Question 14

RBCs pick up oxygen molecules via … from the lung alveoli

Answer 14

diffusion

Question 15

Hemoglobin is comprised of …

Answer 15

4 globulin subunits (2 alpha, 2 beta)

Question 16

Hemoglobin

Answer 16

Oxygen carrying molecule in the blood. Heme (iron-containing molecule) bound to globin proteins.

Question 17

Alterations in hemoglobin sructure will alter its ability to…

Answer 17

carry oxygen

Question 18

Describe carbon monoxide poisoning

Answer 18

Carbon monoxide poisoning causes hemoglobin to bind more tightly to oxygen, causing oxygenated blood to flow through the body but without dropping oxygen off to the tissues.

Question 19

Why does carbon monoxide not cause cyanosis?

Answer 19

Cyanosis (bluish color in skin due to oxygen shortage) does not occur because the blood circulating is rich in oxygen (however, it is not distributing that oxygen to tissues).

Question 20

When O2 binds hemoglobin, it induces…

Answer 20

a conformational change in the structure that makes it more receptive to more oxygen binding

Question 21

One molecule of hemoglobin can carry…

Answer 21

4 oxygen molecules

Question 22

Name the 5 different types of WBC

Answer 22

1. Neutrophil
2. Eosinophil
3. Basophil
4. Monocyte
5. Lymphocyte

Question 23

During WBC development, hematopoietic stem cells differentiate into two major progenitor cells…

Answer 23

• Myeloid stem cells
• Lymphoid stem cells

Question 24

Platelets arise from…

Answer 24

multinucleated megakaryocytes in bone marrow

Question 25

Describe the nucleus of platelets

Answer 25

Platelets are small, anuclear cells

Question 26

What is the role of platelets?

Answer 26

Platelets interact with proteins from the coagulation cascade and lead to blood clotting

Question 27

What is plasma?

Answer 27

Liquid component of blood, mostly water and proteins, electrolytes

Question 28

Plasmapheresis

Answer 28

Separation of plasma from the cellular blood components

Question 29

What is a CBC test?

Answer 29

A complete blood count test (CBC) is a common blood test that measures the levels of the different components of blood to evaluate overall health and detect conditions like anemia.

Question 30

MCV

Answer 30

Mean corpuscular volume: measure of the average size or volume of RBCs, key component of the CBC

Question 31

Hematocrit

Answer 31

Measures proportion of RBCs in the blood (key component of CBC) [RBC volume]/[Total blood volume] *100

Question 32

RDW

Answer 32

Red cell distribution width: measure of the variation in size of RBCs in a blood sample (component of the CBC)

Question 33

MCH

Answer 33

Mean corpuscular hemoglobin: measure of the average amount of hemoglobin contained in each red blood cell

Question 34

MCHC

Answer 34

Mean corpuscular hemoglobin concentration: measure of the average concentration of hemoglobin within a given volume of RBCs

Question 35

MPV

Answer 35

Mean platelet volume

Question 36

Would having large RBCs affect your hematocrit?

Answer 36

Yes, if you have large RBCs your hematocrit would be higher despite having the same number of RBCs as another person with smaller RBCs.

Question 37

Microcytosis

Answer 37

RBCs are smaller than average (less than 80fl)

Question 38

Macrocytosis

Answer 38

RBCs are larger than average (more than 95fl)

Question 39

The RDW increases when...

Answer 39

a population of abnormal RBCs (microcytic or macrocytic) suddenly starts circulating in the blood

Question 40

The MCHC decreases when...

Answer 40

there are issues in hemoglobin synthesis

Question 41

What is the purpose of a peripheral blood smear?

Answer 41

It is used to examine the appearance, size and shape of RBCs under the microscope. It can provide more info about the reason for any abnormal values observed in the CBC.

Question 42

What are some examples of abnormal RBC morphologies that can be detected in a peripheral blood smear? (5)

Answer 42

1. Spherocyte (spherical rather than biconcave disk) 2. Sickle cell (crescent rather than biconcave disk) 3. Red cell fragment 4. Acanthocyte (spiky or irregular projections) 5. Elliptocyte (oval or elongated shape)

Question 43

Define anemia

Answer 43

Decreased ability of blood to carry oxygen to the cells due to decreased overall hemoglobin

Question 44

What are the potential causes for decreased overall hemoglobin?

Answer 44

1. Decreased RBC number 2. Decrease in the body's ability to make hemoglobin 3. Decreased hemoglobin function

Question 45

Symptoms of anemia

Answer 45

Fatigue, pallor, weakness

Question 46

Why is cyanosis not a symptom of anemia?

Answer 46

Cyanosis happens when hemoglobin cannot be saturated properly. It is usually due to a lack of oxygen rather than a lack of hemoglobin.