1. Hematopoietic System

Hematocrit

% of blood volume consisting of erythrocytes (red blood cells) Male average 47; female average 42

Eosinophil function

4-5 hours in circulation; 8-12 days ↑ in parasitic infections (toxic proteins) or allergies (receptors binding to IgE) Antigen presenting cells Participate in phagocytosis of antigen-antibody complexes, allergens & inflammatory chemicals Release enzymes to destroy parasites such as worms

Types of WBCs

5 types: Top left: PMNs (neutrophils) - left one more like nad which is earlier than poly -discs are RBCs -little blue dots are platelets Top right: monocyte (same size as poly basically) -function is to eat things (macrophage in tissue, monocyte in blood) Bottom left: eosinophil Bottom middle: basophil Bottom right: lymphocytes (same size as RBC) -nucleus to one size of cell

Neutrophil function

6 hours in circulation, 6 days in tissues ↑ in bacterial infections Phagocytosis of bacteria Releases antimicrobial chemicals: -proteolytic enzymes, cathepsin G, lysozyme, myeloperoxidase,

structure of the lymph node

An inner area called the medulla which contains plasma cells An outer area called the cortex which contains follicles with B lymphocytes surrounded by T lymphocytes and macrophages

Thymus structure

An outer area called the cortex which is densely packed with small lymphocytes and macrophages An inner area called the medulla which is less cellular with a few lymphocytes, macrophages, and epithelial cells.

Lymph node histology

B&T on outside (follicle) Plasma cells in center (medulla)

Lymph node structure

B&T on outside (follicle) Plasma cells in center (medulla)

Monopoiesis

Big cell becoming smaller

Abnormal Red Blood Cells: RBCs (shapes)

Can be compact RBCs, dark, dense, small = called spherocytes Can be crescent shape and pointed = called sickle cells (depranocytes) Can appear mouth-like = called stomatocytes Can appear like ovals or elongated = called ovalocytes or elliptocytes Can appear target shaped or bull's eye = called target cells (Codocytes)

Abnormal Red Blood Cells: RBCs (shapes cont)

Can be spiny = called acanthocytes Fragmented cells is a broad category and includes many different types of cells. Schistocytes (Keratocytes) and Helmet cells are examples of fragmented cells. Nucleated RBCS: usually found only in the bone marrow. -Can be seen in the peripheral blood in severe anemia and in newborns. ___ Fragmented- TTP (thrmbotic thrombocyto purpura- EMERGENCY)

Composition of blood

Cellular elements -RBCs, leucocytes, platelets Plasma -91-92% water -8-9% solids --Proteins: enzymes, clotting factors, immunoglobulins, hormones --Electrolytes --Glucose --Oxygen, carbon dioxide --Cholesterol Blood that is allowed to stand clots -Clot is a tangle of clotting factors and "formed elements" -Serum = clear fluid which is plasma without the clotting factors ___ If you allow blood to clot, what is left is called serum (plasma without clotting factors)

Leukopoiesis timeline

Circulating WBCs do not stay in bloodstream Granulocytes leave in 8 hours & live 5 days longer Monocytes leave in 20 hours, transform into macrophages and live for several years WBCs providing long-term immunity (lymphocytes) last decades

Leukopoiesis

Committed cell types - B and T progenitor lymphocytes and granulocyte-macrophage colony-forming units Possess receptors for colony-stimulating factors released by mature hematopoietic and stromal cells Red bone marrow stores and releases granulocytes and monocytes Some lymphocytes leave bone marrow unfinished and complete their development in the thymus (T cells)

Heinz bodies

Common Red Blood Cell Inclusion Denatured hemoglobin Large 1-3 micrometers in diameter. Located near the periphery of the RBC. Special staining with a supravital stain is needed to visualize Heinz bodies. Found in patients with G6PD deficiency and with some hemoglobinopathies. ____ denatured hemoglobin

Basophillic stippling

Common Red Blood Cell Inclusion Remains of RNA and mitochondia. Diffuse granules found throughout the cytoplasm. Found in patients that have fast RBC growth. Found in patients with lead poisoning. ___ lead poisoning

Erythrocyte Indices

Describe the size and hemoglobin content of red blood cells Help in the differential diagnosis of anemia Required parameters for calculation: -RBC = red blood cell volume in 106/µl -Hct = hematocrit in % -Hgb = hemoglobin in g/dl

Granulopoiesis

Earliest form of myeloblast looking like erythroblast Promyelocyte has granules & white area Myelocyte Metamyelocute Bands Neutrophils Myeloblast, Promyelocyte & Myelocyte all divide - so expand population

neutrophil differentiation

Earliest form of myeloblast looking like erythroblast Promyelocyte has granules & white area Myelocyte Metamyelocute Bands Neutrophils Myeloblast, Promyelocyte & Myelocyte all divide - so expand population 6-10 days (IMPORTANT) -neutropenia 7-10 days after chemo

Types of cellular elements in the blood

Erythrocytes (RBCs) 45% -Contain hemoglobin -Transport of O2 and CO2 Leukocytes (WBCs) and thrombocytes (platelets) ~1% -Leukocytes are involved in the body's defense against invasion of foreign antigens --5 different types of WBCs (leukocytes) -Platelets are involves in hemostasis which forms a barrier to limit blood loss at a site of injury

Erythropoiesis

Erythropoiesis produces 2.5 million RBCs/second from stem cells (hemocytoblasts) in bone marrow Pronormoblast has receptors for erythropoietin (EPO) from kidneys; EPO stimulates development of erythroblast Erythroblasts multiply & synthesize hemoglobin (late normoblast and reticulocyte). ____ 2.5 million PER SECOND! We give erythropoietin to people on dialysis

Hematopoiesis

Hematopoiesis in the bone marrow is called medullary hematopoiesis Hematopoiesis in areas other then the bone marrow is called extramedullary hematopoiesis -Extramedullary hematopoiesis may occur in fetal hematopoietic tissue (liver and spleen) or in an adult when the bone marrow cannot meet the physiologic needs of the tissues. This can lead to hepatomegaly and/or splenomegaly (increase in size of the liver and/or spleen) Hematopoietic tissues include tissues involved in the proliferation, maturation, and destruction of blood cells ____ 2 forms: -normally is medullary (made in bone marrow) -sometimes when marrow not working so well or excess requirement (extramedullary) - liver and spleen recruited (always pathologic conditions)

Blood cell production (Hematopoiesis)

Hematopoiesis is a term describing the formation and development of blood cells. In humans, occurs in bone marrow exclusively All cellular elements derived from pluripotent stem cell (PPSC) PPSC retains ability to both replicate itself and differentiate Types of differentiation determined by the influence of various cytokines Under normal conditions only mature cells are released into the peripheral blood. ___ Before birth have hematopoesis in variety of tissues -first in yolk sac, then liver, spleen then later on bone marrow picks up (pelvis and vertebral column) Should not see myelocyte, blasts, promyelocytes, nucleated red cells (immature) in periphery - only see in pathological state

Thrombopoiesis

Hemocytoblasts that develop receptors for thrombopoietin become megakaryoblasts Megakaryoblasts repeatedly replicate DNA without dividing forming gigantic cells in bone marrow called megakaryocyte (100 μm in diameter) Infoldings of megakaryocyte cytoplasm splits off cell fragments that enter the bloodstream as platelets (live for 10 days) Some stored in spleen and released as needed

Common Red Blood Cell Inclusions

Howell-Jolly bodies -From left over DNA found in the RBC. -Appear as round, deep purple circles around 2 micrometers in diameter. -Found in patients after their spleen has been removed or when RBC production is rushed, pernicious anemia and hemolytic anemia. Pappenheimer bodies -Small, light purple, beads, made from iron. -Located near the periphery of the RBC. -Need to be stained with Prussian blue to determine if they are true Pappenheimer bodies. -Seen in iron loading anemias and hereditary hemochromatosis. ___ HJ- patients with splenectomy or damaged spleen - pernicious. Hemolytic anemia Need special stain for pappenheimer (iron stain) - iron overload state

Spleen histology

If cut the spleen see these noduels (white pulp) and red pulp (RBCs)

Bone marrow aspirate

If they don't jump, you don't have it Pulling spicules out of bone Biopsy: tells you architecture and cellularity Aspirate: tells you MORPHOLOGY (not how arranged) Here we see many white cell precursors, no megakeryocytes, some red cells (central nucleus surrounded by cytoplasm), lymphocytes -want to see range of cells in both red and white cell series

Erythropoiesis- As red cell is maturing

Late normoblasts discard their nucleus to form a reticulocyte (named for fine network of endoplasmic reticulum) Reticulocyte enters bloodstream as 0.5 to 1.5% of circulating RBCs Development takes 3-5 days This mechanism will involve reduction in cell size, increase in cell number, synthesis of hemoglobin & loss of nucleus Blood loss speeds up the process increasing reticulocyte count ___ As red cell is maturing Can see nucleated RBC in hemolytic anemia, something in bone marrow (cancer) taking up space, hemolysis, chemotherapy with damaged marrow Reticulocyte is only other cell other than mature RBC in blood (have to use different stain to see) Process: reducing size, increasing number, making hemoglobin, losing nucleus

Liver with extramedullary hematopoiesis

Looks like bone marrow but in the liver Some pathological condition causing extramedullary hematopoiesis

Derivation of blood cells- renewal

Mature blood cells have a limited life span and with the exception of lymphocytes, are incapable of self-renewal. Replacement of peripheral hematopoietic cells is a function of the pluripotent (totipotent) stem cells found in the bone marrow -Pluripotential stem cells can differentiate into all of the distinct cell lines with specific functions and they are able to regenerate themselves. -The pluripotential stem cells provide the cellular reserve for stem cells that are committed to a specific cell line. -Differentiation into specific cell lines is stimulated by different cytokines: --Erythropoietin - RBC --Thrombopoietin - platelets --Colony stimulating factors - WBC ___ Understand pluripotent stem cell them cytokine -> myeloid and lymphoid

MCH

Mean corpuscular hemoglobin (MCH) -A measurement of the hemoglobin content in red blood cells MCH = Hgb / RBC x 10 -Normal/ normochromic: 26-32 pg -Hypochromic: less than 26 pg -Hyperchromic: above 32 pg

MCHC

Mean corpuscular hemoglobin concentration (MCHC) -A measure of the concentration of hemoglobin in the average red blood cell MCHC = Hgb / Hct x 100 -Normal: 32-36%

MCV

Mean corpuscular volume (MCV) -Indicates average size of red blood cells MCV = Hct / RBC x 10 -Normal/normocytic: 80-100 fl -Microcytic: less than 80 fl -Macrocytic: above 100 fl ___ Have 1000 red cells for one white cell

Abnormal White Blood Cells

Neutrophils (AKA: PMNs, Polys, Segs) Abnormalities in the neutrophil include..... 1. Greater than 5% bands 2. Hypersegmented nuclei (greater than 5 lobes) 3. Toxic granulation 4. Toxic vacuolization 5. Dohle bodies (rough ER) 6.Younger stages than the band When do you see them in high numbers? -Bacterial infections -Inflammation Toxic granulation, vacuolization, & Dohle bodies are seen during bacterial infections, burns, cancer, and toxic or inflammatory states. ___ 1- Bandemia- younger cells (infection) 2- Hypersegmented- b12/ folate deficiency 3- sepsis 4- sepsis 5- infection

Derivation of blood cells

Never see a megakeryocyte in blood (megakerocyte leukemia- really bad) Myeloid gives rise to all but lymphocyte (important in oncology for bone marrow recovery after chemo)

Normal WBC count

Normal count: 4-11 x 109/L Differential: -Granulocytes --neutrophils - 60-70% --eosinophils - 2-4% --basophils - <1% -Agranulocytes --lymphocytes (B/T cells) - 25-33% --monocytes - 3-8% _____ See basophilia with CML T cells > B cells

Erythrocytes

Normal erythrocyte is a round highly flexible biconcave disc-like cell; it is non-nucleated, containing hemoglobin. It measures about 7.2-7.8 µm, 80-100 fl in volume Flexibility essential for passage through capillaries Life span: the average is 80-120 days. Function: RBC carry oxygen from the lung to the body cells and carry carbon dioxide from the body cells to the lung. ___ NO NUCLEUS -extruded before gets to periphery (unless under stress- earlier forms) about same size a lymphocyte Normocytic 80-100 (micro less, macro more) Structure: like sickle cell - don't move easily and clog/ infarct 120 days life span -autoimmune might shorten, or unstable hemoglobin

Erythropoiesis: cell histology

Nucleus becoming more picnotic/ pink getting smaller, non nucleated and more hemoglobin

Lymphopoiesis

Plasma cell looks like fried egg (robins egg blue cytoplasm) - NEVER see in blood (just marrow) -clock face nucleus

Polychromasia

RBCs cells looking more blue than pink (earlier forms of RBCs) Nucleus from blue to pink

Abnormal Red Blood Cells: RBCs

Red Blood Cells (AKA: Erythrocytes or RBCs) Can be normal sized (oval or round) 6-8 micrometers in diameter= called normocytic Can be smaller than normal <6 micrometers = called microcytic Can be larger than normal >8 micrometers= called macrocytic Anisocytosis is when the RBCs vary drastically in size Poikilocytosis is when the RBCs vary drastically in shape If the RBC color is normal = called normochromic If the RBC color is increased = called hyperchromic If the RBC color is decreased = called hypochromic (larger central pallor)

Spleen - functions

Sequestering 1/3 of the platelet mass - in massive splenomegaly this can lead to peripheral thrombocytopenia (decrease in platelets in the peripheral blood) After a splenectomy (removal of the spleen), RBC inclusions (Howell-Jolly bodies) and abnormal RBC shapes are seen. Culling is taken over by the liver which is less effective in performing all of the splenic functions Hypersplenism (splenomegaly) - in a number of conditions the spleen may become enlarged and through an exaggeration of its normal functions of filtering, and destruction and sequestering, it may cause anemia (may be caused by decreased RBCs), leukopenia (decreased WBCs), or thrombocytopenia or combinations of these cytopenias. When all three cell types are decreased this is called pancytopenia. _____ Another function is sequestering platelets -if remove spleen will have more platelets (thrombocytosis) -and some cells circulating that spleen not there to remove OR big spleen (cirrhotic liver disease) spleen will pull out more (thrombocytpenia) Howell-Jolly bodies- little blue dots In some pts we take it out to increase platelet count (like in ITP- idiopathic thrombocyto purpura)

Platelets

Small fragments of megakaryocyte cytoplasm (2-4 μm diameter containing granules) 150,000-450,000/mm3; lifespan 8-9 days Pseudopods provide amoeboid movement & phagocytosis Alpha granules secrete FV,VIII, fibrinogen, VWF, PDGF; Delta granules contain ADP, calcium, serotonin, Produce vasoconstrictors (thromboxane A2) in endothelial injury Form temporary platelet plugs "Primary hemostasis" Dissolve old blood clots (lambda granules) Attract WBCs to sites of inflammation

What is blood?

Specialized connective tissue Blood cells (formed elements) suspended in plasma Blood volume: 5-6 liters (~ 1.5 gal) in males and 4-5 liters in females Centrifuged (spun) to separate

Basophils function

Survive hours to few days ↑ in chicken pox, sinusitis, diabetes Secrete histamine (vasodilator in inflammatory conditions), heparin (anticoagulant), prostaglandins,

Bone marrow biopsy

Take piece of bone Posterior iliac crest Drill into bone and use needle Bone with cells in middle Biopsy tells you architecture Different kinds of cell Hyperplastic: more cells than fat Hypoplasia: aplastic anemia Can see volume of bone marrow and relation to each other (architecture)

Derivation of blood cells: lymphoid and myeloid cells

The committed lymphoid stem cells will be involved in lymphopoiesis to produce lymphocytes The committed myeloid stem cell can differentiate into any of the other hematopoietic cells including erythrocytes, neutrophils, eosinophils, basophils, monocytes, macrophages, and platelets. Hematopoietic cells can be divided into three cellular compartments based on maturity: -Pluripotent stem cell capable of self-renewal and differentiation into all blood cell lines. -Committed progenitor stem cells destined to develop into distinct cell lines -Mature cells with specialized functions

Hematopoiesis: hypoplasia

The hematopoietic tissue may also become inactive or hypoplastic. This may be due to: -Chemicals -Radiation therapy -Genetic defects -Myeloproliferative disease that replaces hematopoietic tissue with fibrous tissue ___ 1- benzene 2- pancytopenia 3- aplastic anemia 4- spleen and liver take over hematopoesis

Reticular endothelial system (RES)- LIVER

The liver contains phagocytic cells known as Kupffer cells that act as a filter for damaged or aged cells in a manner similar to, but less efficient than the phagocytic cells in the spleen. If the bone marrow cannot keep up with the physiologic demand for blood cells, the liver may resume the production of blood cells that it began during fetal life

reticular endothelial system or RES

The mononuclear phagocytic system involved in cellular destruction and it includes: -Circulating blood monocytes -Fixed macrophages in the bone marrow, liver, spleen, and lymph nodes -Free macrophages These cells are involved in: -Engulfing particulate matter -Processing of antigens for lymphocyte presentation -Removal of damaged or senescent (aged) cells ____ Gets rid of old or damage cells Liver, spleen, lymph nodes macrophage with iron (hemosiderin)

Reticular endothelial system (RES)- Spleen

The spleen contains the largest collection of lymphocytes and mononuclear phagocytes in the body. Functions of the spleen include: -Filtering and destruction of senescent (aged) or damaged RBCS - also called culling -Removal of particles from RBC membranes - also called pitting - this causes a decrease in the surface to volume ratio of the RBC resulting in the formation of spherocytes -Enforcing close contact of blood borne antigens with lymphocytes and phagocytic cells - this is important in protection of the body from infections due to enveloped organisms _____ Getting rid of all cells (culling) - red cells that are old Gets rid of damaged cells (hemoglobin disorders, ox stress) -chews cells so become spherocytes (spherocytosis indicative of hemolytic process_ --smaller red cell Also where blodo elements can contact certain pathogens (capsulated ones)

Hypersplenism

There are two types of hypersplenism: -Primary - no underlying disease has been identified -Secondary - caused by an underlying disorder such as: --Inflammatory diseases --Infectious diseases --Blood disorders that cause compensatory or workload hypertrophy of the organ such as: ----abnormal blood cells ----antibody coated blood cells ----hereditary spherocytosis ___ Inflam: felty syndrome in RA

Thrombopoiesis- Images

Thrombopoetin influence 1/3 in spleen Multiply how many platelets you see by 10,000 and that's probably how many you have

Sites of hematopoiesis

Where our blood comes from Before blood - first in yolk sac Then liver, and lesser extent spleen Then after birth only bone marrow (vertebrae and pelvis, sternum, ribs- no long bones in adult)

Spleen structure

White pulp are factories of immune function -artery, arteriole, nodule -in center have T cells in periphery have B cells (follicular)

Structure of bone marrow

White stuff is bony spicules Biggest cells are megakeryocytes (huge, multinucleated, bluish pink cytoplasm) Cells of varying type (not monotonous) - of not, problem with maturation

Reticulocyte

Young red blood cell; still have small amounts of RNA present in their cytoplasm Tend to stain somewhat bluer than mature RBCs on Wright stain (polychromatophilic) Slightly larger than mature RBC Undergo removal of RNA on passing through spleen, in 1st day of life Can be detected using supra vital stain ____ Young red cell Bluer Larger than mature cell Macrocytic anemia

Kupffer cells

in liver -Phagocytic elements

Buffy coat

lies between RBCs and plasma -leukocytes (white blood cells) and -platelets

Bone marrow

located inside spongy bone In a normal adult, ½ of the bone marrow is hematopoietically active (red marrow) and ½ is inactive, fatty marrow (yellow marrow). The marrow contains erythroid (RBC), leukocyte (WBC) precursors and platelet precursors. Early in life most of the marrow is red marrow and it gradually decreases with age to the adult level of 50%. In certain (pathologic) states the bone marrow can increase its activity to 5-10x its normal rate. -When this happens, the bone marrow is said to be hyperplastic because it replaces the yellow marrow with red marrow. ____ Between bony spicules Pelvis, vertebrae, ribs, skull In adult: half bone marrow is real marrow and half is fat (yellow marrow) 100 minus age pf person is about the cellularity of bone marrow When do we need more cells- infection, pregnancy, bleeding !!! -Overactive bone marrow- yellow replaced by red (hyperplasia)

When would we see big buffy coat?

lots of wbcs: infection, leukemia

Hematopoiesis: Hyperplasia

occurs in conditions where there is increased or ineffective hematopoiesis. The degree to which the bone marrow becomes hyperplastic is related to the severity and duration of the pathologic state. Pathologic states that cause hyperplasia include: -Acute blood loss in which there is a temporary replacement of the yellow marrow -Severe chronic hemolytic anemia - erythropoiesis (RBC production) may increase to the extent that the marrow starts to erode the bone itself. -Malignant disease - both normal red marrow and fatty marrow may be replaced by proliferating abnormal cells. ___ Hyperplasia from increased hematopoesis (bleeding) Or ineffective (thallasemia- cells are pulled out of circulation) Severe chronic hemolytic anemia - erosion of bone (see with thallasemia major)

Lymph nodes

the lymphatic system is composed of lymph nodes and lymphatic vessels that drain into the left and right lymphatic duct. Lymph is formed from blood fluid that escapes into the connective tissue. -Lymph nodes are composed of lymphocytes, macrophages, and a reticular network. -They act as filters to remove foreign particles by phagocytic cells -As antigens pass through the lymph nodes, they come into contact with and stimulate immunocompetent lymphocytes to proliferate and differentiate into effector cells.

Thymus

this organ is well developed at birth and increases in size until puberty at which time it starts to decrease in size. -It serves as a compartment for the maturation of T lymphocytes into immunocompetent T cells. The hormone thymosin plays a role in this process. -The structure of the thymus consists of: --An outer area called the cortex which is densely packed with small lymphocytes and macrophages --An inner area called the medulla which is less cellular with a few lymphocytes, macrophages, and epithelial cells.

Lymphocytes function

↑ in diverse infections & immune responses, survival in weeks T cells -destroy cancer & foreign cells & virally infected cells -Present" antigens to activate other immune cells -Coordinate actions of other immune cells B cells -Secrete antibodies & provide immune memory (survive years) Natural Killer (NK) cells ___ Some of these lymphocytes are with us forever (immune memory) Splenectomy (capsulated organisms like pneumococcus)

Monocytes function

↑ in viral infections & inflammation; hours to days Differentiate into macrophages Phagocytize pathogens and debris "Present" antigens to activate other immune cells (APC)