Physiology of blood cells and haematological terminology

Question 1

Where do blood cells originate from?

Answer 1

Multipotent haemopoietic stem cells => give rise to lymphoid/myeloid stem cells => RBC, granulocytes, monocytes and platelets

Question 2

Describe the stem cell hierarchy

Answer 2

Question 3

Essential characteristics of stem cells

Answer 3

> Ability to self-renew and produce mature progeny

(Divide into 2 cells, a stem cell and one capable of differentiating to mature progeny)

Question 4

What does a myeloid stem cell give rise to?

Answer 4

Proerythroblast which gives rise to erythroblasts and then erythrocytes/RBC

Question 5

What stage is this cell in regards to normal erythroid maturation?

Answer 5

Proerythroblast

Question 6

What stage is this cell in regards to normal erythroid maturation?

Answer 6

Early Erythroblast

Question 7

What stage is this cell in regards to normal erythroid maturation?

Answer 7

Intermediate erythroblast

Question 8

What stage is this cell in regards to normal erythroid maturation?

Answer 8

Late erythroblast

Question 9

A requirement for erythropoiesis?

Answer 9

Presence of erythropoietin

(synthesis of erythropoietin is mainly conducted in the kidneys in response to hypoxia)

Question 10

Outline the synthesis of erythropoietin

Answer 10

90% from Juxtatubular interstitial cells in the KIDNEY

10% from hepatocyte and interstitial cells in the LIVER

Both diffuse into the capillaries

Question 11

Function, survival and destruction of RBCs

Answer 11

Red blood cells survive about 120 days in the blood system

Involved in O₂ and CO₂ transport

Destroyed by phagocytic cells in the spleen

Question 12

What do myeloblast cells give rise to? and what is needed?

Answer 12

Granulocytes and monocytes

(Cytokines, G-CSF, M-CSF, GM-CSF and GM-CSF and other interleukins)

Question 13

What are the stages of normal granulocyte maturation?

Answer 13

Myeloblast => Promyelocyte => Myelocyte => Band form => Neutrophil

Question 14

Function and survival of neutrophil granulocytes

Answer 14

Defence against infection through phagocytosis of micro-organisms

Survives for 7-10hrs in circulation before moving into tissues

Question 15

Outline the movement of neutrophils into tissue

Answer 15

1. Adhesion and margination
2. Rolling
3. Diapedesis (move through capillaries, normally accompanied with inflammation)
4. Migration
5. Phagocytosis

Question 16

Function and development of the eosinophil granulocytes

Answer 16

Defence against parasitic infection

Develops from myeloblast stem cells

(stays in circulation for less time than neutrophils)

Question 17

Function and development of the basophil granulocytes

Answer 17

Involved in allergic responses

Develops from myeloblast stem cells

Question 18

Function and development of the monocyte

Answer 18

Arises from the myeloid stem cell through monocyte precursors

Develop into macrophages in tissue and other specialised cells with scavenging and phagocytic properties

Store Iron and remain in circulation for days

Question 19

Survival, function and development of platelets

Answer 19

Survive 10 days in circulation

Involved in primary haemostasis, contribute phospholipids which promotes blood coagulation

Haemopoietic stem cells => megakaryocytes => platelets

Question 20

Lymphocytes and their circulation

Answer 20

T/B/NK cells derive from lymphoid stem cells

The recirculate to lymph node/tissues before entering the bloodstream

Question 21

Anisocytosis

Answer 21

RBC show abnormal variations in size

Question 22

Poikilocytosis and types (6)

Answer 22

RBC show abnormal variations in shape

Spherocytes, Irregularly contracted cells, Sickle cell, Target cells, Elliptoctyes, Fragments

Question 23

Microcytosis

Answer 23

RBC are smaller than normal

Question 24

Macrocytosis and types

Answer 24

RBC are large than normal

can be round, oval or polychromatic

Question 25

Hypochromia

Answer 25

Normal RBC with a 1/3 of the diameter and is pale A larger area of central pallor Often seen with microcytosis *A result of low haemoglobin levels in the centre of the disk*

Question 26

Hyperchromia and types

Answer 26

RBC lack central pallor due to their abnormal shape or being thicker than normal Spherocytes and Irregularly contracted cells

Question 27

Hyperchromia - Spherocyte

Answer 27

Spherical in shape = round, regular outline and lack central pallor Loss of cell membrane whilst cytoplasm remains to cause the cells to round up

Question 28

Hyperchromia - Irregularly contracted cells

Answer 28

Smaller than normal cells and lost their cental pallor A result from oxidant damage to the cell membrane and haemoglobin

Question 29

Polychromasia

Answer 29

Increased blue tinge within the cytoplasm of an RBC This indicates that the RBC is young

Question 30

What test is used to detect young cells?

Answer 30

Reticulocyte stain ## Footnote *Exposes living RBC to new methylene blue = precipitate as a network/reticulum*