physiology of blood cells and haematological terminology

Question 1

summarise the physiology of all blood cells *

Answer 1

origenate in bone marrow

derived form multipotent haemopoetic stem cells

they give rise to lymphoid and myeloid stem cells

myeloid goive rise to - granulocyte (monocyte), erythroid, megakaryocyte

lymphpoid - T B and NK cell

Question 2

what are the essential characteristics of stem cells

Answer 2

abiliuty to self renew

ability to make new mature progeny

Question 3

describe the origen of RBC *

Answer 3

myeloid stem cell give rise to 2 proerythroblasts (earliest RBC)

gives rise to 2 erythroblasts (has nucleus)

gives rise to early, intermediate and late erythroblasts

give rise to 2 erythrocytes (lost nucleus) - the cytoplasm is squezed through the endothelium to the sinusoid, leaving nucleus to be ingested by macrophage

this process is erythropoesis

Question 4

what is needed for erythropoesis and what stimulates it *

Answer 4

erythorpoeitin

stimulated by hypoxia

90% synthesised in the kidney by juxtatubular interstitial cell, 10% synthesised by hepatocytes and interstitial cells in liver - all pass into capillaries and enter marrow through blood

increased erythropoetin = increased bone marrow activity = increased red cell production

Question 5

what is the intravascular life span of erythrocytes *

Answer 5

120 days

ultimately destroyed by the phagocytic cells (macrophages) of the spleen and liver and reticuloendothelial system

Question 6

what is the function of RBC *

Answer 6

main - O2 transport

some CO2 transport (mainly in plasma though)

nitric oxide transport

Hb acts as buffer

Question 7

describe the origen of WBC *

Answer 7

myeloblast -> granulocyte and monocytes

chromatin gets more condensed and nucleus gets indented

cytokines influence the pathwya of stem cells

granulocyte colonly stim factor, macrophage - CSF, granulocyte macrophage CSF and inbterleukins stim the granulocyte and monocyte pathway

Question 8

describe polychromatic erythrocytes *

Answer 8

they are in circulation

larger and have ribosomes in cytoplasm that control Hb synth

Question 9

how can you see if there are young red cells

Answer 9

reticulocyte stain - reticulocytes take up methylene blue and it pptes into reticulum/network

or stain normal film see if there are any blue/larger cells

detecting reticulocytes is more reliable

Question 10

what is the lifespan of a neutrophil *

Answer 10

7-10 hrs in circulation before entering tissues

Question 11

function of neutrophil*

Answer 11

defence against infection - phagocytosis

2 pools:

circulating - flows down blood stream

marginating - adherent to endothelium, start to enter tissues - enter by diapedesis then chemotaxis in tissue under influence of chemokines

Question 12

what is the origen of eosinophils *

Answer 12

myeloblast

Question 13

what is the life span of an eosinophil *

Answer 13

less than neutrophil

Question 14

function of eosinophil *

Answer 14

fight paracytic infection by releasing granule contents

Question 15

describ ethe origin of basophils *

Answer 15

myeloblasts

Question 16

describe the function of basophils *

Answer 16

allergic responses - infective and inflammatory aspects

Question 17

describe the lifespan of monocytes *

Answer 17

several days in the circulation then migrate into tissues - become monlyctes

Question 18

function of macrophages *

Answer 18

phagocytic and scavenging

they take up erythrocytes that die, break down ferritin store as haemosiderin - provides a store of iron in the bone marrow when needed

Question 19

what is the lifespan for a platelet *

Answer 19

10 days in circulation

Question 20

describe the origin of platelets *

Answer 20

fragmentation of the cytoplasm of megakaryocytes

leave the nucleus in marrow to be destroyed

they are under the influence of thrombopoietin

Question 21

what is the function of platelets *

Answer 21

primary haemostasis

contribute phospholipid which promotes blood coagulation

Question 22

what is the life span for lymphocytes *

Answer 22

variable

they recirculate between the blood, lymph nodes and other tissues so provide host defence across whole body

Question 23

define anisocytosis *

Answer 23

RBC show more variation in size than is normal

Question 24

define poikilocytosis *

Answer 24

RBC show more variation in shape than is normal

Question 25

define microcytosis \*

Answer 25

RBC smaller than normal

Question 26

define macrocytosis \*

Answer 26

red cells are larger than normal

Question 27

how do you identify the size of red cells

Answer 27

compare diamter with nucleus of leukocytes - should be similar or use automated size counters

Question 28

what is a microcyte \*

Answer 28

a red cell that is smaller than normal

Question 29

what is a macrocyte \*

Answer 29

a red cell that is larger than normal

Question 30

describe the different types of macrocytes \*

Answer 30

depend on shape and staining characteristics - round macrocytes - oval macrocytes - indicative of B12 or folic acid deficiency - polychromatic macrocytes - young cell, present in response to heamorrage or administration of a vitamin that was lacking

Question 31

define microcytic \*

Answer 31

desribes red cells that are smaller than normal, or an anaemia with small red cells

Question 32

define normocytic \*

Answer 32

describes red cells that are of normal size or an anaemia with normal sized red cells

Question 33

describe macrocytic \*

Answer 33

describes red cells that are larger than normal, or an anaemia with larger than normal red cells

Question 34

desribe hypochromia in comparison to normal red cells \*

Answer 34

normal red cells have 1/3 diameter pale - because of disk shape centre has less Hb than edge therefore paler - this is central pallor in hypochromia - larger than normal central pallor - because of low Hb content, conc and a flatter cell - red cells are hypochromic hypochromia and microcytosis go together (same underlying condition eg Fe deficiency or thalassaemia)

Question 35

describe hyperchromia \*

Answer 35

cells lack central pallor because they are thicker (macrocytes) or because shape is abnormal cells are called hyperchromatic/hyperchromic

Question 36

2 main causes of hyperchromia \*

Answer 36

spherocytes (round outline) and irregularly contracted cells (Hb all in 1 place)

Question 37

cause of spherocytes \*

Answer 37

hereditory spherocytosis - membrane not tethered to the cytoskeleton so lose membrane loss of membrane w/o loss of equivalent amount of cytoplasm - so cell is forced to round up to enclose cytoplasm in remaining membrane

Question 38

describe irregularly contracted cells \*

Answer 38

irregular outline smaller than normal lost central pallor because of oxidant damage to the membrane and Hb because of foreign chemical or food eg broad beans - if dont have normal enzymes this causes haemolytic anaemia

Question 39

describe polychromasia \*

Answer 39

blue tinge to red cell cytoplasm - mean cell is young

Question 40

descirbe the different shapes of poikilocytes \*

Answer 40

spherocytes irregularly contracted cells sickle cells target cells - blob of Hb in central pallor elliptocytes fragments- angular

Question 41

the causes of target cells \*

Answer 41

obstructive jaundice liver disease haemoglobinopathies hyposplenism

Question 42

causes of elliptocytes \*

Answer 42

hereditory elliptocytosis iron deficiency

Question 43

cause of sickle cells \*

Answer 43

HbS polymerisation when present in high conc

Question 44

describe boat cells \*

Answer 44

some polymerisation of HbS - not enough to form sickle

Question 45

describe fragments \*

Answer 45

also called schistocytes small pieces of red cells indicate that a cell has fragmented

Question 46

describe rouleaux \*

Answer 46

stacks of red cells resemble a pile of coins result from alterations in plasma proteins eg increase in Ig (M - big molecular weight) mean neutralising force is negated = stack normally red cells repel each other

Question 47

describe agglutins \*

Answer 47

irregular clumps of red cells because of Ab on surface of red cells cause them to stick together

Question 48

what is a Howell-Jolly body and what is the cause \*

Answer 48

a nuclear remnant in a red cell commonest cause - lack of splenic func eg atrophy

Question 49

define leucocytosis \*

Answer 49

too many white cells

Question 50

define leucopinea \*

Answer 50

too few white cells

Question 51

define neutrophilia \*

Answer 51

too many neutrophils

Question 52

define neutropenia \*

Answer 52

too few neutrophils

Question 53

define lymphocytosis \*

Answer 53

too many lymphocytes

Question 54

describe eosinophilia \*

Answer 54

too many eosinophils

Question 55

define thrombocytosis \*

Answer 55

too many platelets

Question 56

define thrombocytopenia \*

Answer 56

too few platelets

Question 57

define erythrocytosis \*

Answer 57

too many RBC

Question 58

define reticulocytosis \*

Answer 58

too many reticulocyts

Question 59

define lymphopenia \*

Answer 59

too few lymphocytes

Question 60

what is an atypical lymphocyte \*

Answer 60

describes the abnormal cells present in infectious mononucleosis - glandular fever atypicalk mononuclear cell is anotehr term

Question 61

summarise left shift \*

Answer 61

there is an increase in non-segmented neutrophils or that there are neutrophil precursers in the blood sign of infection/inflammatiom

Question 62

summarise R shift \*

Answer 62

increase in segments or lobules in nucleus of neutrophils

Question 63

describe toxic granulation \*

Answer 63

heavy granulation of neutrophils from infection, inflammation and tissue necrosis normal feature of preg

Question 64

describe hypersegmented nuclei \*

Answer 64

there is increases in average number of neutrophil lobes or segments because of lack of B12 or folic acid

Question 65

How can you tell there is anaemia from a blood film \*

Answer 65

anaemia reduces the viscocity of the blood so cells are more spread out on the film

Question 66

how can sickle cell lead to Howell-Jolly bodies

Answer 66

polymerisation causes recurrant infarction of spleen = howell-jolly bodies

Question 67

what does a tetraploid neutrophil look like

Answer 67

--

Question 68

what is the function of lymphocytes \*

Answer 68

humoral and cellular immunity

Question 69

list the physiological factors that influence the rate of red cell production \*

Answer 69

anaemia hypoxia increased androgens

Question 70

what fascilitates oxygen delivery

Answer 70

teh sigmoid oxygen dissociation curve a lower pH reduces oxygen affinity to Hb = more offloading in met actiuve tissues