Physiology of blood cells

Question 1

what do pluripotent haematopoietic stem cells give ruse to?

Answer 1

• lymphoid stem cells

- myeloid stem cells

Question 2

what does the multipotent myeloid stem cell give rise to?

Answer 2

• granulocyte: monocyte
• erythroid
• megakaryocyte

Question 3

what do lymphoid stem cells give rise to?

Answer 3

• T cell
• B cell
• NK cells

Question 4

what ability do stem cells have?

Answer 4

• ability to self renew whilst also producing mature progeny

- divides into itself and a mature cell

Question 5

describe the steps to erythroid maturation

Answer 5

• multipotent myeloid stem cell
• proerythroblast
• erythroblast
• erythrocytes

Question 6

where is erythropoiesis synthesized? what is it released in response to?

Answer 6

90% from juxta tubular interstitial cells of kidneys
10% from hepactocytes and interstitial cells of liver
released in response to hypoxia

Question 7

how are erythrocytes destroyed?

Answer 7

• survive 120 days in blood stream

- destroyed by phagocytes in spleen

Question 8

describe the maturation of white cells. what is required?

Answer 8

multipotent myeloid stem cell –> myelobalst –> granulocytes/ monocytes
cytokines/ILs needed

Question 9

what is the life span and function of neutrophils

Answer 9

survive 7-10hrs in circulation
then migrate to tissues
defence against infection

Question 10

what is the fucnction of eosinophils? how long in circulation?

Answer 10

• less time in circulation than neutrophils

- defence against parasitic infection

Question 11

what are basophils involved in?

Answer 11

allergic response

Question 12

what are the functions of monocytes?

Answer 12

• spend several days in circulation
• phagocytose bacteria, fungi, dead tissue
• migrate to tissue –> become macrophages
• store and release iron

Question 13

describe how platelets are formed

Answer 13

multipotent haematopoietic stem cell –> megakaryocyte –> platelet

Question 14

what do platelets do and how long do they spend in circulation?

Answer 14

• survive 10 days in circulation
• role in primary haemostasis
• contribute phospholipid to promote blood coagulation

Question 15

what do lymphocytes do?

Answer 15

• recirculate to lymph nodes and other tissues and then back to blood stream
• variable life spans

Question 16

define anisocytosis

Answer 16

variation in size

Question 17

define poikilocytosis

Answer 17

variation in shape

Question 18

what does microcytosis mean?

Answer 18

smaller than normal

Question 19

define macrocytosis

Answer 19

• larger than normal

- round/ oval/ polychromatic macrocytes

Question 20

what are the 3 broad categories for anaemia?

Answer 20

• microcytic: red cells that are smaller than normal
• normocytic: red cells of normal size
• macrocytic: red cells that are larger than normal

Question 21

what is hypochromia?

Answer 21

• RBCs that have large central pallor
• less Hb in cell –> flatter cell
• also often microcytic

Question 22

what is the normal paleness of RBCs?

Answer 22

normal RBCs have 1/3 diameter than is pale

Question 23

what is hyperchromia?

Answer 23

• cells lack central pallor
• cells are thicker than normal
• have abnormal shape

Question 24

what are 2 important types of hyperchromic cells?

Answer 24

• spherocytes

- irregularly contracted cells

Question 25

describe spherocytes. what does it result from?

Answer 25

- spherical in shape --> lack central pallor - results from loss of cell membrane without equivalent loss of cytoplasm - cell is forced to round up - e.g. hereditary spherocytes

Question 26

describe irregularly contracted cells. what causes it?

Answer 26

- irregular in outline - smaller than normal cells - have lost central pallor - result of oxidant damage to cell membrane and Hb

Question 27

what is polychromasia?

Answer 27

- inc. blue tinge to cytoplasm of a red cell | - indicated cell is younger and much larger

Question 28

name all the different types of poikilocytes

Answer 28

- spherocytes - irregularly contracted cells - sickle cells - target cells - elliptocytes - fragments/shistocytes

Question 29

what are target cells?

Answer 29

cells with accumulation of Hb in centre of area of central pallor occurs in obstructive jaundice, liver disease, hyposplenism

Question 30

what are elliptocytes?

Answer 30

- elliptical in shape | - hereditary elliptocytosis and iron def

Question 31

what are sickle cells?

Answer 31

- results from polymerisation of Hb S chains when present at high enough conc

Question 32

what are fragments/shistocytes?

Answer 32

- small pieces of red cells indicating a cell has fragmened - can be due to abnormal stress on red cell - or if cell is intrinsically abnormal

Question 33

what is a rouleaux?

Answer 33

- stack of red cells | - result from alteration in plasma proteins

Question 34

what are agglutinated?

Answer 34

- irregular clumps of RBC | - result of antibodies on surface of cells

Question 35

what is a Howell- jolly body?

Answer 35

- nuclear remnant in red cell | - cause = lack of splenic fucntion

Question 36

define leucocytosis

Answer 36

too many white cells

Question 37

define leucopenia

Answer 37

too few white cells

Question 38

define neutrophilia

Answer 38

too many neutrophils

Question 39

define neutropenia

Answer 39

too few neutrophils

Question 40

define lymphocytosis

Answer 40

too many lymphocytes

Question 41

define eosinophilia

Answer 41

too many eosinophils

Question 42

what is left shift?

Answer 42

- inc. in non-segmented neutrophils - neutrophil precursors in blood - left --> right is normal - right --> left is left shift

Question 43

what is toxic granulation?

Answer 43

- heavy granulation of neutrophils - due to infection, inflammation, tissue necrosis - normal in pregnancy

Question 44

what are hypersegmented neutrophils?

Answer 44

- inc. in average number of neutrophil lobes/segments | - due to lack of Vit B12/folic acid