Unit 4

Question 1

Hematopoiesis

Answer 1

Production of blood cells and platelets

Question 2

Leukocytes

Answer 2

White blood cells

Question 3

Leukopoiesis

Answer 3

Production of white blood cells

Question 4

Erythrocytes

Answer 4

Red blood cells

Question 5

Erythropoiesis

Answer 5

Production of red blood cells

Question 6

Thrombocytes

Answer 6

Platelets

Question 7

Thrombopoiesis

Answer 7

Production of platelets

Question 8

What are granulocytes vs agranulocytes

Answer 8

White blood cell classifications

Granulocytes: characterized by segmented nuclei (neutrophils, eosinophils, basophils) and the presence of granules

Agranulocytes: (lymphocytes and monocytes) occasional have granules but they are in low numbers and hard to seen

Question 9

Hematopoesis begins during

Answer 9

Early embryonic life

Question 10

In the prenatal animal, hematopoiesis occurs in the

Answer 10

Liver
Spleen
Thymus
Red bone marrow

Question 11

In neonates and juvenile animals hematopoiesis is primarily made in

Answer 11

Red bone marrow (almost every bone in fetus/young animal)

Question 12

In adult animals, hematopoiesis occurs in the

Answer 12

Red bone marrow (fewer areas)

Question 13

The spleen and liver can help with hematopoiesis in times of

Answer 13

Stress

Question 14

What are pluripotent stem cells

Answer 14

All blood cells arise from the same pluripotent hematopoietic stem cells

These cells can develop into various types of cells, they are capable of regeneration and will stay at constant low numbers in the bone marrow

Question 15

Hematopoietic stem cells differentiate into two progenitors, how is this determined

Answer 15

Common myeloid progenitor

Common lymphoid progenitor

Pathways is determined by interactions with various chemical messengers known as cytokines

Question 16

What is erythropoietin

Answer 16

The primary cytokine responsible for RBC production

Primarily produced in the kidney (small amounts in the liver) (drop with kidney disease)

Normally present in the plasma to replace aging/dying RBCs

This cytokine travels in the blood to the bone marrow to bind to erythroid precursor cells to stimulate erythropoiesis

Stimulated by hypoxia

Question 17

How are aging/dying cells in peripheral circulation removed

Answer 17

Bone marrow is constantly replacing cells

Dying cells are usually removed by phagocytic cells in the spleen (splenectomised animals have bizarrely shaped RBCs)

Question 18

How does hypoxia impact erythropoiesis

Answer 18

Prolonged hypoxia: increases bone marrow RBC production 4-5x

Question 19

If the kidney is the main source of erythropoietin in dogs, what may you see in dogs with severe renal disease

Answer 19

Anemia (this is a significant problem in cats as well)

Question 20

What are the stages of erythropoiesis

Answer 20

1) Rubriblast (nucleoli present, large, small amount of dark blue cytoplasm, perinuclear clear zone)

2) prorubricyte (smaller than rubriblast, no nucleoli, prominent perinuclear clear zone, dark blue cytoplasm)

3) rubricyte (significantly smaller, nucleus’s is alternating dark/light pattern due to chromatin, dark purple nucleus, cytoplasm will gradually lighten and turn pink as hemoglobin matures)

4) metarubricyte (dark blue nucleus, deep red cytoplasm and skewed off to one side, slightly larger than mature cell, no longer capable of cell division now, hemoglobin formation is complete)

5) reticulocyte (polychromasia: a nuclear, contained ribosomal material which can give blue-purple look when stained, macrocytic)

6) erythrocyte (mature cell, anuclear, no ribosomal remnants, cytoplasm is pink due to hemoglobin)

Question 21

What is Thrombopoietin

Answer 21

Main cytokine that triggers thrombopoiesis

Primarily made in the liver (small amounts in the kidneys and bone marrow)

Question 22

What are the stages of thrombopoiesis

Answer 22

1) Megakaryoblast (larger than other blast cells, single nucleus, very basophilic, scant cytoplasm)

2) promegakaryocyte (contains 2-4 nuclei -nuclei continues to replicate, nuclear lines remain connected, cytoplasm doesn’t divide and consists of a rim around the nuclear mass)

3) megakaryocytes (extremely large at maturity, numerous nuclear lobes, abundant cytoplasm is pale
Blue and contains reddish granules, cytoplasm extends to finger like projections to be sheared off into platelets)

4) platelets (stage when platelets leave the bone marrow, not true cells -fragments- great deal of variation in size/shape, no nucleus, gets finger like projections when disrupted to try and clump)

Question 23

What species have platelets that are true cells (true thrombocytes)

Answer 23

Reptiles
Amphibians
Birds

Question 24

What is granulopoiesis

Answer 24

Production of granulocytes (neutrophils, eosinophils, basophils)

Triggered by hormone leukopoietin and other cytokines

Question 25

What are the two groups of the cells developing stages in granulocytes

Answer 25

Proliferation pool (cells capable of mitosis) (myeloblasts, promyeloblasts and myelocytes) Maturation pool (cells can no longer divide) (metamyelocytes, band cells)

Question 26

What is the difference between the stages of neutrophils, eosinophils and basophils development

Answer 26

They all follow the same path but only vary in the color of granules

Question 27

Where does neutrophil production take place

Answer 27

Exclusively in bone marrow in adult animals, some production in the spleen of young animals With chronic inflammation production of neutrophils will occur in the spleen, liver and lymph nodes of adults

Question 28

What are the stages of granulopoiesis

Answer 28

1) myeloblast (large, round-oval nucleus, one or more nucleoli, few reddish granules, pale to grey blue cytoplasm (larger and lighter color than rubriblast) 2) promyelocute (slightly smaller and lighter, azurophilic granules, may have nucleoli, more cytoplasm) 3) myelocyte (slightly smaller and lighter, nucleus is round and eccentrically placed, no nuclei, granules are visible as neutrophilic/eosinophilic/basophilic) 4) metamyelocyte (similar to myelocyte but nucleus is indented, lighter cytoplasm, can no longer undergo mitosis) 5) band neutrophil (same color as mature neutrophil, nucleus is indented -U shape- with parallel sides and clubbed ends) 6) segmented neutrophil (purple nucleus, segmented, granules may or may not be distinct)

Question 29

What are hypersegmented neutrophils

Answer 29

As cells age the number of loves in the nucleus increases If it is >5 then it is classified as hypersegmented

Question 30

How can you differentiate a band cell vs a segmented neutrophil

Answer 30

The narrowest part of the nucleus but be 2/3 or less the width of the widest part of the nucleus

Question 31

True or false If you see an early stage of cell development in the blood, you will see all of the other stages as well

Answer 31

True

Question 32

If you are unsure if a cell is a mature or immature cell, what should you classify it as

Answer 32

The mature cell type

Question 33

When is the only time you count disintegrating cells

Answer 33

When they total more than 10% of the WBCs counted

Question 34

What is transit time for neutrophils

Answer 34

The amount of time needed for the myeloblast to mature into a segmented neutrophil (7-2 days)

Question 35

What is Circulation time for neutrophils

Answer 35

The amount of time between the release of the cell into the blood and it’s arrival to the tissues (6-10 hours, pool is renewed 2-3 times a day)

Question 36

What is monopoiesis

Answer 36

Monocytic development The same pluripotent stem cell as granulocytes cells Isn’t responsive to an infection like neutrophils, only overcome by neoplasia, won’t be seen unless you examine bone marrow

Question 37

What are the stages of monopoiesis

Answer 37

1) mononlast (similar to myeloblasts but have irregularly shaped nucleus) 2) promonocyte (similar to myelocytes and metamyelocytes) 3) monocyte (can develop to macrophages if exposed to right cytokine) 4) macrophage (first 3 stages in bone marrow) (Monocytes seen in peripheral blood, macrophages In tissues)

Question 38

Lymphopoiesis

Answer 38

Triggered by cytokines and antibodies Starts with the lymphoid precursor stem cell in bone marrow, differentiate into T lymphocytes/NBK precursors or B lymphocyte precursors

Question 39

What are the stages of lymphopoiesis

Answer 39

1) lymphoblast (high nuclear to cytoplasmic ratio, oval to indented eccentrically placed nucleus, dark blue cytoplasm) 2) pro-lymphocyte (decreased nuclear to cytoplasm ratio, large nucleoli, lighter staining cytoplasm) 3) lymphocyte (round to slightly indented nuclei, dense and smooth chromatin, small amount Of basophilic cytoplasm, smallest WBC)

Question 40

Juvenile B lymphocytes mature in the

Answer 40

Bone marrow or ileal peyer’s patches in dogs/pigs/ruminants Or bursa of fabricus in birds

Question 41

T lymphocytes mature in the

Answer 41

Thymus

Question 42

Naturally killer cells mature in the

Answer 42

Bone marrow (can also mature in the thymus and lymphoid tissue)

Question 43

Immature stages of lymphocytes may be seen due to

Answer 43

Lymphocytic neoplastic diseases (common in cats) Neoplasia is normally seen in lymphocytes (abnormal size, color, may have nucleoli or mitotic figures) l