1: Physiology of blood cells

Question 1

Describe how all blood cell types are formed

Answer 1

Multipotent haemopoietic stem cells

-> Lymphoid/myeloid stem cells

Question 2

What can lymphoid stem cells produce?

Answer 2

T cell
B cell
NK cell

Question 3

What can myeloid stem cells produce?

Answer 3

Erythroid
Megakaryocyte
Granulocyte
Monocyte

Question 4

What is the function of stem cells?

Answer 4

Produce mature progeny and also self-renewing

Question 5

What is the name of the process of erythrocyte production? Describe the steps

Answer 5

Erythropoiesis

Myeloid stem cell -> proerythroblast -> erythroblast -> erythrocyte

Question 6

What substance is required for erythropoiesis? Where is it produced

Answer 6

Erythropoietin
90% from Juxtatubular Interstitial cells (KIDNEY)
10% from Liver

Question 7

How long do RBCs last in the blood

Answer 7

120 days

Question 8

What is the function of red blood cells and how is it destroyed

Answer 8

Transport O2 and some CO2

Destroyed by phagocytic cells in SPLEEN

Question 9

What are myeloblasts and what can they produce?

Answer 9

Come from multipotent haemopoietic stem cells
Produce granulocytes and monocytes (neutrophils)
Cytokines needed for this

Question 10

How long do neutrophils stay in blood?

Answer 10

7-10 hours before migrating into tissues

Question 11

Describe the physiology of neutrophils

Answer 11

Derived from myeloblasts
Stays in blood 7-10 hours before migrating into tissues
Phagocytosis
Kills micro-organisms

Question 12

How do neutrophils get out of the capillary?

Answer 12

Adhesion + rolling

Question 13

Describe the physiology of eosinophils

Answer 13

Granulocytes derived from myeloblasts
Stays in blood shorter than neutrophils
Defense against parasitic infection

Question 14

Describe the physiology of basophils

Answer 14

Granulocytes derived from myeloblasts

Involved in allergic responses

Question 15

Describe the physiology of monocytes

Answer 15

Myeloid stem cell -> monocyte precursor -> monocyte
Stays several days in circulation
Migrate to tissues -> develop into macrophages and other cells with phagocytic function
Macrophages also store/release iron

Question 16

Describe the physiology of platelets

Answer 16

Derived from megakaryocytes
Stays 10 days in blood
Primary haemostasis
Contributes phospholipid, promotes blood coagulation

Question 17

Describe the physiology of lymphocytes

Answer 17

Derived from lymphoid stem cell
Recirculate to lymph nodes/other tissues then back to blood stream
Variable life span

Question 18

What is anisocytosis/poikilocytosis

Answer 18

anisocytosis = Red cells show more variation in SIZE than normal
poikilocytosis = Red cells show more variation in SHAPE than normal

Question 19

What is micro/macrocytosis

Answer 19

Microcytosis = red cells SMALLER than normal (microcytes)
Macrocytosis = red cells LARGER than normal (macrocytes)

Question 20

Why is the centre of normal red cell paler?

Answer 20

It has less haemoglobin

Question 21

What is hypochromia

Answer 21

Red cells have larger than normal central pallor
Due to lower haemoglobin content and flatter cell
Often goes together with microcytosis

Question 22

What is hyperchromia

Answer 22

Red cells lack central pallor

Due to being thicker/abnormal shape

Question 23

What are two important types of hyperchromia

Answer 23

Spherocytes = spherical, regular outline, lack central pallor, result of loss of cell membrane without loss of cytoplasm
Irregularly contracted cells = irregular outline, smaller than normal, lack central pallor, result of oxidant damage