Blood Cells

Question 1

Volume of blood (adult male)?

Answer 1

5.5L

Question 2

Haemocrit (packed cell volume) in males and females?

Answer 2

0. 47 males

0. 42 females

Question 3

What is the order of abundance of cells in the blood (with power of 10 per microlitre)?

Answer 3

RBC (10^6) most

platelets (10^5)

WBC (10^3) least

Question 4

Diameter of a red blood cell?

Answer 4

7 microns/micrometres

Question 5

Shape of red blood cell?

Answer 5

Biconcave disc

Question 6

Lifespan of red blood cell?

Answer 6

120 days

Question 7

Do red blood cells respire aerobically or anaerobically?

Answer 7

Anaerobically

Question 8

What organs remove old red blood cells from the blood?

Answer 8

Liver, spleen

Question 9

What are old red blood cells replaced by and at what rate?

Answer 9

Erythroid precursor cells

10^10 cells/hour

Question 10

What is the penultimate precursor of red blood cells, how big are they, what do they contain?

Answer 10

Normoblast

8-10 microns/micrometres

Nucleus, haemoglobin, mitochondria and ribosomes

Question 11

What is the final precursor of a red blood cell and how can they be distinguished?

Answer 11

Reticulocyte

Staining with brilliant cresyl blue = remaining RNA forms a blue, reticular precipitate

Question 12

Shape of platelets?

Answer 12

Biconvex disc

Question 13

Fancy name of platelets?

Answer 13

Thrombocytes

Question 14

Size of platelets?

Answer 14

2-3 microns/micrometres

Question 15

What are the main functions of platelets?

Answer 15

Haemostasis, maintenance of blood vessels

Question 16

What is contained in platelet alpha granules?

Answer 16

Clotting factors

Platelet factor 4 - chemotaxis of neutrophils and monocytes, vascular permeability

Platelet-derived growth factor - promote deposition of fibrin

Question 17

What is contained in platelet dense granules?

Answer 17

Serotonin

Question 18

What is meant by a “granule”?

Answer 18

Secretory vesicle

Question 19

Lifespan of platelets?

Answer 19

8-10 days

Question 20

What is the precursor of platelets? What is the size of this cell and describe its nucleus?

Answer 20

Megakaryocyte

50-75 microns/micrometres (giant)

Large irregular nucleus

Question 21

What are the two types of white blood cell and describe their nuclei?

Answer 21

Granulocytes - polymorphonuclear

Agranulocytes - mononuclear

Question 22

Which white blood cells are in each of the two main divisions? Give their order of abundance

Answer 22

Granulocytes: neutrophils (40-70%), eosinophils (1-6%), basophils (<1%)

Agranulocytes: lymphocytes (20-40%), monocytes (2-6%)

Question 23

What does myeloid mean and what cells does it describe?

Answer 23

“Bone marrow derived”

Granulocytes and monocytes and their precursors

Question 24

What does lymphoid mean and what cells does it describe?

Answer 24

Originate in bone marrow and mature in tissues such as the thymus

Lymphocytes and their precursors

Question 25

Size and nucleus of a neutrophil?

Answer 25

12-14 microns/micrometres Highly lobulated nucleus

Question 26

What do neutrophil primary granules contain?

Answer 26

Antimicrobial agents (MYELOPEROXIDASE, defensins, proteases, acid hydrolases)

Question 27

What do neutrophil secondary granules contain?

Answer 27

Antimicrobial agents (lysozyme, lactoferrin) Complement activators Collagenase NADPH OXIDASE

Question 28

What do neutrophil tertiary granules contain and what might they do?

Answer 28

Enzymes (like gelatinase) May insert adhesion proteins into membrane

Question 29

What do neutrophil secretory granules contain?

Answer 29

Membrane-associated receptors

Question 30

Why do neutrophils contain a lot of glycogen?

Answer 30

Rely on glycolysis (and hexose monophosphate pathway) for energy

Question 31

Describe the function of neutrophils

Answer 31

Highly phagocytic and motile Receptors for bacterial polysaccharides, complement factors and Fc portion of antibodies for tethering

Question 32

How do neutrophils carry out their function?

Answer 32

Engulf Primary and secondary granules fuse with phagosome Hydrolytic enzymes and reactive oxygen species generated by a “respiratory burst” involving NADPH oxidase and myeloperoxidase kills engulfed microorganism

Question 33

Lifespans of neutrophils?

Answer 33

In circulation - 5-90 hours In tissues - 1-2 days

Question 34

Size and nucleus of an eosinophil?

Answer 34

12-17 microns/micrometres Bilobed nucleus

Question 35

What do eosinophil primary granules contain?

Answer 35

Lysosomal enzymes

Question 36

What do eosinophil secondary granules contain? What do these look like?

Answer 36

Cytotoxic and highly basic proteins: major basic protein (MBP), eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN), eosinophil peroxidase (EPO) Histaminase (regulate allergic reactions) Arylsulphatase (breaks down leukotrienes) Collagenase, cathepsins Large, oval, striped

Question 37

Describe the role of eosinophils

Answer 37

Phagocytic and cytotoxic Destruction of parasites Initiate and maintain inflammatory responses Secondary granules contents (esp MBP, ECP) activate mast cells and basophils

Question 38

Lifespan of eosinophils?

Answer 38

In circulation - 8-12 hours In tissue (GI tract or inflammation sites) - several days

Question 39

Size and nucleus of a basophil?

Answer 39

14-16 microns/micrometres Bilobed nucleus

Question 40

What do basophil specific granules contain and what are the functions of these substances?

Answer 40

Heparin + chondroitin sulphate (anticoagulant) Histamine (vasodilation)

Question 41

What do basophils release when stimulated? (Not granules)

Answer 41

Lipid mediators (eg leukotrienes) Cytokines (ECF to attract eosinophils)

Question 42

What do mast cells and basophils have receptors for?

Answer 42

Immunoglobulin E (IgE)

Question 43

Size and nucleus of a monocyte?

Answer 43

Up to 20 microns/micrometres (largest WBC) Horseshoe/kidney-shaped nucleus

Question 44

Lifespan of a monocyte?

Answer 44

In circulation - 2 days In tissues (as macrophage) - months/years

Question 45

What are the functions of monocytes (macrophages in tissues)?

Answer 45

Defends against microorganisms Removes cell debris Antigen presentation to T cells Cytokine secretion

Question 46

Size and nucleus of a small lymphocyte?

Answer 46

6-9 microns/micrometres Condensed nucleus occupies 90% of cell

Question 47

What types of T-cells are there, what receptors do they have and what are their functions?

Answer 47

T helper - CD4 receptor; secrete cytokines to “help” other lymphocytes T cytotoxic - CD8; kill virus-infected cells

Question 48

Size of a large lymphocyte?

Answer 48

(Mostly activated B cells) 9-15 microns/micrometres

Question 49

Give an example of a type of large lymphocyte

Answer 49

Natural killer cells - kill virus-infected cells or tumour cells without specific antigens

Question 50

Define haematopoiesis

Answer 50

Process by which mature blood cells are generated from precursor cells

Question 51

Where does haematopoiesis begin? (2-2.5 weeks i.u.)

Answer 51

“Blood islands” in extraembryonic tissue

Question 52

What is different about early red blood cells?

Answer 52

Nucleated

Question 53

Where does haematopoiesis move to? (5 weeks i.u.)

Answer 53

Liver then spleen

Question 54

When do red blood cells gain adult form?

Answer 54

5 weeks i.u.

Question 55

When does haematopoiesis move to the bone marrow?

Answer 55

4-5 months i.u.

Question 56

What is the structure of a sinusoid and what does it drain into?

Answer 56

50-70 microns/micrometres Lined by endothelium Drain to central vein

Question 57

Where do haematopoietic compartments lie?

Answer 57

Outside endothelium lining sinusoids

Question 58

All blood cells originate from...

Answer 58

A common pluripotent stem cell (slow dividing)

Question 59

Give an example of a haematopoietic growth factor

Answer 59

Erythropoietin - stimulates RBC production; usually produced by kidneys

Question 60

What do the earliest progenitor cells depend on? What do the pluripotent stem cells also require?

Answer 60

Interleukin-3 (IL-3) Stem cell factor (steel factor) expressed on surface of stromal cells of bone marrow

Question 61

What is blood plasma?

Answer 61

Aqueous solution of salts, nutrients and plasma proteins

Question 62

What kind of pressure do plasma proteins exert?

Answer 62

Oncotic/colloid osmotic pressure

Question 63

What are the plasma proteins and what are their functions?

Answer 63

Albumins: (major fraction) bind and increase solubility if many otherwise poorly-soluble substances Globulins: include immunoglobulins Fibrinogen: precursor of fibrin (important for blood clotting)