Blood Flashcards
1
Q
Properties of Blood
A
- bright to dark red color
- viscous
- slightly alkaine (pH - 7.4)
- average total blood volume is 5 L/ 5.5kg
2
Q
Content of Blood
A
Blood is a specialized type of connective tissue composed of
- formed elements, or blood cells
- plasma
Blood cells:
1) erythrocytes (red blood cells’ RBCs)
2) leukocytes (white blood cells; WBCs)
3) platelets
3
Q
Plasma
A
Fluid component of blood comprising of about 55% of total blood volume
Pale yellow aqueous (90%) solution
- proteins (7-8%) - electrolytes and ions (0.9- 1%) - organic molecules
4
Q
Plasma Proteins
A
Albumin - most abundant (>50% of total plasma protein coming from the liver
- maintains colloid osmotic pressure of plasma
- carrier protein of insoluble metabolites, hormones, etc.
Globulins ( alpha, beta, and gamma)
- gamma immunoglobulins
> antibodies secreted by plasma cells (B cells) and lymphocytes)
> function in Immunity
Alpha and Beta non-immune globulins:
Source: liver
Transport substances in the body and maintain osmotic pressure
Fibrinogen
Source: liver
Function: formation of blood clots
5
Q
Other Plasma Components
A
Electrolytes (Ca2+, Fe2+ Na+ K+ Cl- Mg2+ HCO3- PO43- SO42-)
- Regulate osmotic balance and maintain pH - imbalance of electrolytes - serious medical condition
Nutrients: Amino Acids, glucose, lipids,
- building blocks of macromolecules and production of energy
Enzyme: alkaline phosphatase (ALP), creatinine kinase (CK) < asparatate transmaminase (AST) lactate dehydrogenase (LDH)
Hormones
Blood gases: (O2 diffuses OUT and Co2 diffuses IN)
Waste products: urea, uric acid, creatinine, ammonium salts
> transported to kidneys for removal from the body
6
Q
Serum
A
clear yellow liquid that separates from the coagulum (clot) when centrifuged
Basically, serum is plasma without clotting factors in it because all of the clotting factors went to forming a CLOT (blood cells)
7
Q
Layers of a centrifuge tube
A
3 layers:
Bottom - red blood cells
Upper - plasma
Middle - “buffy coat” white blood cells and platelets
**when the tube is coated with anti-coagulant, there is no no clotting; Anti-coagulants include heparin, EDTA, and citrate
8
Q
Blood Cell Types
A
Erythrocytes or mature red blood cells (RBCs)
Platelets (thrombocytes)
Leukocytes or white blood cells (WBCs) Neutrophils Eosinophils Basophils Monocytes Lymphocytes
9
Q
Erythrocytes or mature red blood cells (RBCs)
A
- Most numerous
- red color because of hemoglobin
- survival in circulation = 120 days
- transport Oxygen from lungs to tissues and Carbon Dioxide away from tissues
10
Q
Leukocytes or white blood cells (WBCs)
A
- Least numerous
- Neutrophils: most numerous in 8-10 hrs of circulation
> defense against bacterial and fungal infection
-Eosinophils: 4-5hrs in circulation
> defense against parasitic infestation and dampen allergic response
Basophils (<1% of WBCs)
> mediate anaphylactic and inflammatory rxns
- Neutrophils: most numerous in 8-10 hrs of circulation
11
Q
Leukocytes or white blood cells (WBCs)
A
- Least numerous
Neutrophils: most numerous in 8-10 hrs of circulation
> defense against bacterial and fungal infection
Eosinophils: 4-5hrs in circulation
> defense against parasitic infestation and dampen allergic response
Basophils (<1% of WBCs)
> mediate anaphylactic and inflammatory rxns
Monocytes (5% of WBCs)
- 10hrs in circulation - mature into macrophages - responsible for removal of unwanted aged cells and other debris - produce cytokines required for inflammatory and immune response
Lymphocytes (33% of WBCs)
- variable lifespan
- T-lymphocytes: 40-80% of lymphocytes; CELL MEDIATED IMMUNITY
- B-lymphocytes: 10-30% lymphocytes; HUMORAL IMMUNITY
12
Q
Function of Blood
A
1) Transport of Nutrients and Waste Products
- nutrients from gut to cells
- waste products of metabolism away from cells for excretion
2) Respiratory gas transport
- Oxygen to cells and Carbon dioxide away from cells through hemoglobin
3) Thermoregulation
- absorbing large amounts of heat energy for a small temperature rise
- control of blood flow via vasoconstriction - vasodialation
4) Maintenance of homeostatsis
- maintenance of acid-base balance and osmotic pressure of body fluids
5) Hemostasis
- clot formation after injury to prevent blood loss
6) Immunity
- contains and transports cells of the immune system to protect the body
13
Q
Standard Blood Test (Hematology)
A
CBC = Complete Blood Count
• RBC count: x 1012 / L (millions / mL)
• Hematocrit (Hct) or packed cell volume (PCV) - %
o Amount of space (volume) RBCs take up in blood
• Hemoglobin (Hb) – g / dL or g / L
o Amount of Hb in blood
• RBC Indices: based on other meas. in a CBC
o Mean corpuscular (cell) volume (MCV)
o Mean corpuscular (cell) hemoglobin (MCH)
o Mean corpuscular (cell) hemoglobin concentration (MCHC)
o Red cell distribution width (RDW)
• Mean corpuscular (cell) volume (MCV) – fL (10-15)
o Average volume of RBCs
o Measure of RBC size
o (Hct / RBC #) x 10
• Mean corpuscular (cell) hemoglobin (MCH) – pg
o Average weight of Hb in an RBC
o Measure of RBC weight
o (Hb / RBC #) x 10
• Mean corpuscular (cell) hemoglobin concentration (MCHC) – g / dL
o Average concentration (relative to cell size) of Hb in an RBC
o Measure of how many RBCs in a certain amount of fluid
o (Hb / Hct) x 10
• Red cell distribution width (RDW) - %
o Measure of size variation of RBCs
• WBC count - x 109 / L (thousands / mL)
• WBC Differential count: o Neutrophils o Lymphocytes o Monocytes o Eosinophils o Basophils
• Platelet count - x 109 / L (thousands / mL)
• Mean Platelet Volume (MPV) – fL
o Measure of the average amount (volume) of platelets
14
Q
Blood Smears
A
Thin layer of blood spread on a glass slide to form a blood film
Blood cells are preserved by fixation (methanol fixation usually)
Fixed film is stained so that individual cells can be recognized under the microscope
15
Q
Criteria for Leukocyte Identification
A
Cell size/shape
Nuclear size (nucleus to cytoplasm ratio)
Nuclear shape
Cytoplasmic staining
Cell inclusions (granules)
16
Q
Blood Stains
A
Romanowsky stains (all of which contain two dyes of Tolene blue and Eosin)
- Wright's stain - simpler method - Giemsa stain - more complex stain; for delicate staining characteristics and detection of blood parasites - May- Grunwald stain - good for routine work
17
Q
Appearance of Blood Cells on Blood Films
A
- RBCs: reddish-pink
- Platelets: purple
• Neutrophils: dark purple nuclei, reddish
granular cytoplasm
• Lymphocytes: dark purple nuclei, varying
shades of blue cytoplasm
• Monocytes: lighter purple nucleus, gray-
blue cytoplasm
- Eosinophils: bright red/orange granules
- Basophils: dark purple nuclei and granules
18
Q
Red Blood Cells (RBCs) - Erythrocytes
A
• Erythropoiesis: the process of RBC formation
• RBCs: made in bone marrow under the influence of erythropoietin (Epo)
produced by the kidneys
• Characteristics:
o Smallest and most numerous (5 x 1012 / L)
o Plasma membrane but no nucleus (anucleate) or organelles
o Immature RBCs have nucleus but lose it as they mature
o No DNA/RNA, thus no cell division
o Packed with Hb – gives them red color
o Major role – carry O2 to & CO2 away from tissues
19
Q
Immature RBCs –
Reticulocytes
A
- Still have small amounts of ribosomal RNA
- Slightly larger than mature RBCs, no nucleus
- Tend to stain slightly bluer than mature RBC’s on Wright’s stain
- Circulate for 1 day and undergo removal of RNA
• Can be detected using supravital staining – identifies RNA filaments
NOTE Supravital staining can stain living cells!!
• The reticulocyte count is an important marker of RBC production – BM activity
20
Q
Characteristics of Red Blood Cells (Erythrocytes)
A
o Shape: highly flexible biconcave discs
o 80-100 femtoliters in volume, 140mm2 area
o Flexibility essential for:
§ Maximizing surface area:volume ratio for gas exchange
§ Passage through smallest capillaries
o Produced in BM, approx. 7 days for maturation
o Lifespan: 120 days – 300 miles around the body
o 1 circulation cycle: 20 secs
o Spleen: RBCs graveyard
21
Q
High reticulocyte count (Reticulocytosis): more made in Bone Marrow
A
o Premature destruction of RBCs (i.e. hemolysis)
o Anemia due to premature destruction of RBCs
o Bleeding
o High altitude
22
Q
Low reticulocyte count: poor production in Bone Marrow
A
o Anemia due to decreased production of RBCs
o Vitamin / mineral deficiency
o BM malignancy
o Radiation (chemotherapy)
o Chronic infection
o Drugs
23
Q
Hemoglobin (Hb)
A
large protein composed of 4 amino acid chains, globin chains, each bound to an iron containing heme group
- The heme group consists of an iron (Fe) ion, which is the site of O2 binding
- Hb also carries CO2 that binds to N-terminal groups of the globin chains
• Synthesis:
o Heme in mitochondria and cytoplasm of immature RBCs
o Globin protein in cytoplasm by ribosomes
• Normal Hb: 6 globin chains; a-cluster: a, and z; b-cluster: b, g, d, and e
o 3 -10 wks gestation: z and e
o Fetus: Hb F - a2g2
o Adult : Hb A - HbA1: a2b2 (97%); HbA2: a2d2 (2-3%); HbF (1%)
o Oxyhemoglobin: Hb carrying O2
oCarbaminohemoglobin: Hb carrying CO2
• Abnormal Hb:
o Carboxyhemoglobin: binds to CO instead of O2
o Methemoglobin: Fe2+ to Fe3+; cannot bind O2
24
Q
RBC Assessment
A
Number
Size
Color
Shape
Distribution in blood smear
Red cell inclusions
25
RBC Assessment with Numbers
measured by automated counters; also in blood smear
o Increased number: erythrocytosis (POLYCYTHEMIA)
o Decreased number: anemia, erythropenia (ERYTHROCYTOPENIA)
26
RBC Assessment with Size
MCV by automated counters; also in blood smears
o Same or variable size:
ANISOCYTOSIS
o Normal: NORMOCYTIC
o Small: MICROCYTIC
o Large: MACROCYTIC/ MEGALOCYTIC
27
RBC Assessment with Color
blood smear; [Hb]
o Normal: NORMOCHROMIC
o Pale: HYPOCHROMIC
o Darker: HYPERCHROMIC
28
RBC Assessment with Shape
POIKILOCYTOSIS
o Normal biconcave vs. different and oddly shaped cells
29
RBC Assessment by Distribution in Blood Smear
o Rouleaux: like stacks of coins; due to increase in high MW plasma proteins
o Red Cell Agglutination: due to antibody on surface of RBCs
30
RBC Assessment by Red Cell Inclusions
o Pappenheimer Bodies: small basophilic inclusions in cell periphery
o Basophilic Stippling: small basophilic inclusions throughout cell
o Howell-Jolly Bodies: large round densely stained inclusions on
edge of cell; nuclear remnant
31
Polycythemia (erythrocytosis)
increased # of RBCs, Hb, Hct and can be absolute or relative
o ABSOLUTE: Primary or Secondary
> Primary: overproduction of RBCs (Polycythemia (rubra) Vera (PV)
```
>Secondary: caused by increased erythropoietin (Epo)
secretion due to hypoxia
• High altitude
• Cigarette smoking
• COPD
• Renal and heart
disease
```
o RELATIVE: due to dehydration and fluid loss
> Diuretics, diarrhea, vomiting, burns
32
Polycythemia (Rubra) Vera (PV)
o PRIMARY POLYCYTHEMIA
o Myeloproliferative disease; rare
o Due to increased RBC proliferation in bone
marrow (BM)
o Cause not known; mutation in JAK-2 gene (diagnostic test?)
```
o Clinical features:
Red complexion
Viscous blood
Splenomegaly
Gums bleeding
```
o Treatment
Therapeutic phlebotomy
Blood thinners (e.g. aspirin)
33
Anemia
decreased # of RBCs in blood due to
1. Blood loss – acute or chronic
2. Decreased production of RBCs
- Iron deficiency anemia
- Megaloblastic/macrocytic anemia – B12/Folic acid
- Sideroblastic anemia
- Anemia of chronic disease
- Thalassemia (a, b)
o Increased destruction of RBCs
- Hemolytic anemia
- Hereditary spherocytosis
- G6PD deficiency
- Sickle cell disease
o Almost 1/3 of the world’s population is anemic!
34
Causes of Anemia
Rate of RBC production ≠ rate of RBC destruction > CAUSES:
o Blood loss (bleeding): acute (trauma) or chronic (ulcers,
menstruation)
```
o Insufficient RBC production by BM: microcytic (low MCV)
or macrocytic (high MCV)
```
o Insufficient HB concentration in RBCs
o Accelerated RBC destruction: hemolysis (hemolytic)
o Cause is distinguished by reticulocyte count
> Decreased in state of decreased production
> Increased in RBC destruction
35
IRON DEFICIENCY ANEMIA
o Decreased RBC Production: Microcytic Anemia (most common)
o Insufficient iron stores due to
• Poor diet
• Poor iron absorption / utilization
o Body iron stores are depleted by prolonged bleeding
o Common in menstruating and pregnant women
o CBC: low reticulocytes, MCV, MCH, iron, ferritin (iron-storing
protein)
o Blood smear: hypochromic microcytes
36
SIDEROBLASTIC ANEMIA
o Decreased RBC Production: Microcytic Anemia
o Abnormal incorporation of iron into the heme group of Hb
o Toxic accumulation of iron in mitochondria = ringed sideroblasts
o Classified as:
§ Hereditary – deficiency of enzyme involved in heme
synthesis
§ Secondary - drug-induced or alcohol-induced, lead poisoning
§ Idiopathic – cause not known; primarily in elderly
o Blood smear: sideroblasts, basophilic stippling
37
ANEMIA OF CHRONIC DISEASE
o Decreased RBC Production: Microcytic Anemia (second most common)
o Cause:
§ Chronic infection
§ Chronic inflammatory diseases (rheumatoid arthritis)
o Mechanism: blocked iron transport from storage sites to
developing RBC in BM
o Associated with renal failure and decreased erythropoietin production
o Blood smear: marked rouleaux formation due to increased plasma
protein concentration
38
THALASSEMIAS
o Decreased RBC Production: Microcytic Anemia
o Inherited genetic disorders
o Reduced or absent production of normal Hb A
o Thalassa - sea, haima - blood; most common in Mediterranean Sea
area
o 2 types:
1. a thalassemia – caused by deletion of 1, 2, 3, or 4 alpha
globin genes
2. b thalassemia – caused by mutations in the beta globin
gene cluster
39
Alpha Thalassemia
• Deficiency or no synthesis of a-globin chains
• Severity of disease depends on number of a-globin chains deleted
o 1 a-globin gene: “silent” carriers who are asymptomatic; only identified by pedigree and DNA
analyses
o 2 a-globin genes: a-thalassemia trait:mild hypochromic microcytosis
o Identified by pedigree and DNA analyses
o 3 a-globin genes: hemoglobin H disease
o 4 a-globin genes: hemoglobin Barts hydrops fetalis
40
a Thalassemia – Hemoglobin H disease
o Hemoglobin H disease: production of Hb H (b4)
o moderately severe hypochromic microcytic anemia (due to
reduced Hb synthesis and hemolysis)
o Blood smear: hypochromic microcytosis, target cells, tear-drop
cells, inclusions (precipitated Hb H; cause of hemolysis)
41
a Thalassemia Major – Hemoglobin Barts Hydrops Fetalis
o Most severe form of a-thalassemia
o Complete absence of a-globin chains; hemoglobin Barts (g4)
o Incompatible with life: stillbirth by 3rd trimester or shortly after delivery
- Hydrops fetalis: fluid buildup in multiple organs, cardiac failure
- Toxemia in mother carrying fetus with Barts hydrops fetalis
42
b Thalassemia minor (trait)
o Mildest form; one b-globin gene is defective
o Moderately reduced Hb A1; increased Hb A2 (4-8%) and Hb F (2-
5%)
o Asymptomatic
o High RBCs (distinct from iron iron deficiency)
o Blood smear: hypochromic microcytic, target cells, basophilic
stippling
o Genetic counseling; 2 parents with b-thalassemia trait
= 1 in 4 chances to have a child with b-thalassemia major
= 1 in 2 with b-thalassemia trait
= 1 in 4 healthy
43
b Thalassemia major (Cooley’s anemia)
o Most severe form; both b-globin genes are defective
o Reduced or absent Hb A1; increased Hb A2 and Hb F (up to 98%)
o Blood smear: hypochromic microcytosis, target cells, nucleated
red cells, tear drop cells, fragmented cells
o Signs and Symptoms: after 6 months of age
o Prognosis: average life 17 years, die by 30 years due to
cardiotoxicity
44
Macrocytic Anemias
* Elevated MCV
* Impaired DNA synthesis but normal RNA synthesis
• Usually due to B12 and folic acid deficiency due to
o Inadequate dietary intake (in vegans), poor diet (no fresh fruits/vegetables) or overcooked food
o Intestinal malabsorption due to lack of intrinsic factor
(gastrectomy, pernicious anemia), alcoholism, drugs
(anticonvulsive)
o Increased requirements during pregnancy
* B12: years to develop deficiency because of sufficient body stores
* Folic acid deficiency develops fast; body stores only for 3 months
• B12 and folic acid deficiency
o Folic acid deficiency: neural tube defects (e.g. spina bifida)
• Blood smear: macrocytosis, oval cells, tear-drop cells, red cell
fragments; hypersegmented neutrophils, circulating nucleated red
cells (severe cases)
45
Increased RBC Destruction– Hemolytic Disorders
• Reduction in RBC lifespan and compensatory increase in rate of
erythropoiesis
* Causes: incompatible blood transfusion, cancer, drugs, etc.
* Intravascular or extravascular hemolysis:
• Extravascular: most common form of hemolytic anemia
o Premature destruction of RBCs by macrophages in spleen, liver,
BM
• Intravascular: abnormal breakdown of RBCs within blood vessels
• Inherited or acquired hemolytic disorders:
o Inherited: usually caused by intrinsic defect
o Acquired: caused by extrinsic defect
• Intrinsic defect: structural or functional defect within the red cell
o Red cell membrane (e.g. hereditary spherocytosis)
o Red cell metabolism (e.g. G6PD deficiency)
o Hb (e.g. sickle cell disease and thalassemias)
• Extrinsic defect: abnormality in red cell environment
o Immunologic abnormalities
o Mechanical injury
o Infectious organisms that invade and destruct RBCs or produce toxins
46
Hereditary Spherocytosis
• Most common inherited red cell membrane abnormality
• Transmitted in autosomal dominant manner but autosomal recessive
form also exists
* Defective gene encodes for the red cell cytoskeletal protein spectrin
* Major site of hemolysis: SPLEEN
47
G6PD Deficiency
• Glucose-6-phosphate dehydrogenase - red cell enzyme
• Role: protects red cell proteins from endogenous or exogenous oxidant
stress
* Mechanism: converts glucose to ribose-5-phosphate - NADPH production
* NADPH prevents building up of free radicals within cells
* G6PD deficiency – hereditary enzyme deficiency; malaria immunity
* Increased susceptibility of RBCs to oxidative stress - hemolysis
* Most common enzyme deficiency – 400 million people
* X-linked recessive disorder affecting more males than females
• Triggers of hemolysis:
o Ingestion of drugs (antimalarial, aspirin) - induce oxidant stress on RBCs
o Ingestion of fava beans – divicine
o Viral infections: lung infection, hepatitis - activated neutrophils
* Reason: production and release of free radicals
* Blood smear: keratocytes (bite cells), Heinz bodies (red cell inclusions composed of denatured Hb), red cells with Hb retracted into half of the red cell membrane
48
Leukocytes - White Blood Cells
Least numerous blood cells
Function: defend the body against foreign substances
Unlike RBCs, retain their nucleus; nucleus + cytoplasm
cytoplasm - protein synthesis
Unlike RBCs, WBCs do not function WITHIN the bloodstream; travel from one region of the body to another
Diapedesis: WBCs moving through intact vessel walls into surrounding body tissues
Function: defend the body against foreign substances
49
Types of White Blood Cells (WBCs)
2 groups:
-granulocytes – presence of specific granules in
cytoplasm
-agranulocytes – absence of specific granules in
cytoplasm
Granulocytes:
> Neutrophils – normal value : 2000-7500/ml; 60-70%
WBCs
> Eosinophils - normal value : < 450 / ml; <4% of WBCs
> Basophils - normal value : < 200 / ml; <1% of WBCs
Agranulocytes:
> Lymphocytes – normal value : 1000-4000/ml; 20-35%
WBCs
> Monocytes – normal value : < 900 / ml; 5% of WBCs
Both granulocytes and agranulocytes possess lysosomes
50
for Leukocyte Identification
Cell size and shape
Nuclear size (nucleus to cytoplasm ratio)
Nuclear shape
Cytoplasmic staining
Cell inclusions (granules)
51
Neutrophils
produced in bone marrow
8-10 hrs in bloodstream
10-12mm diameter in blood smear
multi-lobed nucleus (2-5 segments) joined by chromatin strands; polymorphonuclear leukocytes
lobes increase with age of cell
in females, Barr body: drumstick appendage of nucleus
cytoplasm contains granules; pale pink
52
3 Types of Neutrophils
1) Azurophilic (primary) – lysosomes; largest and fewest; bactericidal
2) Specific (secondary) - smallest and most numerous; bactericidal
3) Tertiary – facilitate diapedesis
Function: defense against acute bacterial and fungal infection and move to site of infection by CHEMOTAXIS
> Engulf invading microbes – phagocytosis
> Kill by releasing toxic substances stored in their
granules
HIGH neutrophil numbers – neutrophilia; response to infection
LOW neutrophil numbers – neutropenia; increased risk for infection and bacterial sepsis
53
Abnormal Neutrophils
Hypersegmented neutrophils: 6 or more lobes; Vitamin B12 or folic acid deficiency; interferes with DNA synthesis
Hyposegmented neutrophils: defect in chromatin synthesis e.g. myelodysplasia
Increased granulation or cytoplasmic vacuolation: infection / inflammation; toxic granulation; also during pregnancy
54
Eosinophils
respond to chemotactic stimuli, phagosytose and kill
Function: defense against parasitic infestation, dampen allergic reaction
Produced in BM; 4-5 hours in bloodstream
Bilobed nucleus; large ORANGE-RED cytoplasmic granules
Acidophilic granules – contain enzymes/lysosomes with cytotoxic effect to destroy parasites; neutralization of histamine
Increased eosinophil numbers: eosinophilia allergic reactions (asthma) parasitic infections
55
Basophils
least numerous
lobed S-shape nucleus with large dark purple-staining cytoplasmic granules
Specific granules – histamine, slow-reacting substance-A (SRS-A); vasodilation
Azurophilic granules – lysosomes
produced in BM, circulate in blood, migrate to tissues
Function: initiators of inflammatory processes, involved in anaphylactic, hypersensitivity, and inflammatory reactions
> antigen triggers release of IgE
> IgE binds to basophil surface receptors
> cell degranulates and releases inflammatory
mediators (histamine, SRS-A) to surrounding tissues
Increased basophil numbers:
- allergic diseases
- chronic inflammatory disorders
56
Lymphocytes
Type of Agranulocytes
2nd most numerous
Irregular outline, roundish dark blue nucleus off center almost fills the cell, scant pale blue clear cytoplasm
Function: body’s immune response
```
3 functional types:
1) T cells – differentiate in thymus; (75-80%); cell-
mediated immunity (needs to come in contact with infected cells)
```
2) B cells - differentiate in BM; (15%); plasma cells;
humoral immunity
Natural killer cells (NK) - programmed to kill foreign, virally altered cells, some types of tumor cells; (5-10%); cell-mediated immunity
larger than B and T cells
contain large cytoplasmic granules – large granular lymphocytes
3 types depending on
- size
- amount of cytoplasm
- presence or absence of cytoplasmic granules
Small - most numerous, dense homogeneous nucleus; N/C >90%
Medium - less dense, somewhat heterogeneous nucleus; N/C 80%
Large - (granular or agranular) lymphocytes; N/C 40-60%
produced in BM and thymus
circulate in bloodstream and enter lymphoid tissues (lymph nodes, spleen, tonsils)
Elevated or decreased levels of lymphocytes can be caused by infection – bacterial or viral
Increased levels - lymphocytosis chronic lymphoid leukemia (CLL)
Decreased levels – lymphopenia acute stressful illness (MI, pneumonia) lymphoma
57
Monocytes
largest normal blood cells (16-22mm in diameter)
Function: body’s defense against bacterial and fungal infections; also ingest and break down dead and dying body cells during inflammation
large lobed kidney-shaped or distinctly cleft nucleus off center
Voluminous grayish-blue cytoplasm, may be vacuolated or contain a scattering of delicate azurophilic granules
in blood stream for short time, then migrate to tissues where they mature into actively phagocytic macrophages
Monocyte leaves blood vessels at site of inflammation,
transforms into a tissue macrophage, and
phagocytoses bacteria, other cells and tissue debris
Macrophages secrete cytokines that activate inflammatory response, proliferation and maturation of other cells
Increased monocyte # - monocytosis
58
Neutropenia
Most common type of leukopenia - (decrease in # of neutrophils)
```
Many causes:
-Decreased / defective production
- Accelerated removal or destruction
> aggressive and chronic infections (TB, Hepatitis,
HIV)
- Drug-induced
> antibiotics (penicillin), analgesics, anti-
inflammatory etc.
```
Susceptibility to bacterial & fungal infections – lack of innate immune defense and reduced phagocytosis
- Death from overwhelming infections
59
Leukocytosis - Neutrophilia
Increased number of neutrophils
Results from:
- Increased BM output
- Increased mobilization from BM to bloodstream
- Decreased egress to the tissues
Causes:
- Acute bacterial/fungal infections (abscesses,
tonsillitis, appendicitis, meningitis)
- Non-infectious: inflammatory conditions (rheumatic
fever, gout)
> cancer, drugs (steroids), strenuous exercise
Blood smears: toxic granulation and cytoplasmic vacuoles
60
Leukocytosis - Eosinophilia
Increased eosinophil number
Causes:
- parasitic infections
- allergic reactions (asthma)
- certain skin diseases (rash)
- cancer (leukemia, adenocarcinoma)
- certain drugs
- vascular disease
Management: Corticosteroids
61
Leukocytosis - Monocytosis
Elevation in monocyte count
Causes:
- inflammatory disorders (granulomatous disease)
- infections (TB, malaria, syphilis)
- autoimmune disorders (lupus, rheumatoid arthritis)
- connective tissue disorders (ulcerative colitis,
collagen vascular disease)
- cancer (leukemia, Hodgkin’s Disease)
62
Leukocytosis - Lymphocytosis
increase in lymphocyte count above normal
Results from:
- Increased mobilization from tissues to blood
- Increased production
Causes:
- viral infections (infectious mononucleosis, rubella,
chicken pox, hepatitis)
- cancer (chronic or acute lymphoid leukemia,
lymphoma)
- bacterial infections (TB, whooping cough)
allergic drug reaction
- reaction to physical stress following trauma, MI,
cardiac arrest, sickle crisis
63
Infectious Mononucleosis (IM)
cause of benign Lymphocytosis
Increase in lymphocyte # and changes in lymphocytes
also known as “mono”, “glandular fever” or “the kissing disease;" spread primarily by saliva; sneezing and coughing
virus-induced – Epstein-Barr virus (EBV); type of herpes virus; EBV infects epithelial cells and B cells
95% of population exposed to EBV by 40 – most no symptoms
virus lingers in inactive form in WBCs until gets reactivated - IM
very large
primitive nuclei with diffuse chromatin pattern and nucleoli
lobed nuclei
voluminous basophilic cytoplasm = Atypical lymphocytes
```
Diagnosis:
CBC - high WBC and lymphocyte count
blood smear – atypical lymphocytes
Monospot screening test – detects specific antibody formed after infection
EBV antibody detection test
```
64
Neoplastic WBC disorders
Leukemias:
- Acute leukemias:
> Acute lymphocytic / lymphoblastic leukemia(ALL)
> Acute myeloid / myelogenous leukemia (AML)
- Chronic:
> Chronic lymphocytic leukemia (CLL)
> Chronic myeloid / myelogenous leukemia (CML)
Lymphomas:
- Non-Hodgkin’s Lymphoma
- Hodgkin’s Disease
Plasma Cell Disorders:
- Multiple myeloma
Treatment: local radiation, chemotherapy to reduce disease progression, BM transplantation to replace patient’s cells with healthy donor cells
65
Leukemias
malignant disorders of blood characterized by uncontrolled proliferation of hematopoietic cells in BM
Acute: uncontrolled proliferation of immature blood cells
– "blasts" cells
- impaired BM function
- rapid, usually fatal, survival less than 6 months
Chronic: uncontrolled proliferation of well-differentiated mature blood cells
- long-term disease, often long survival
- incidental findings during routine exam
Cause: unknown; genetic, exposure to radiation, cytotoxic drugs
Lab findings:
Blood smear: immature lymphoid or myeloid cells (blasts), or mature
Clinical features:
flu-like symptoms: fatigue, fever, weight loss,
lymphadenopathy, hepatosplenomegaly
bone and joint pain due to marrow expansion
bruising, hemorrhage, (brain, posterior palate), gingival bleeding
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Acute Lymphocytic/Lymphoblastic Leukemia (ALL)
Proliferating cell – primitive lymphoid cell
Most common leukemia in children <15 years (60-70%)
Principal cause of cancer deaths in children; peak incidence age 4
TREATABLE and potentially curable – half the children (age 2-10) are cured
Poor prognosis for adults
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Acute Myeloid / Myelogenous Leukemia (AML)
Proliferating cell – primitive myeloid cell
Most common acute leukemia in adults, but occurs at all ages (from neonatal to adult)
In blood smear cytoplasm contains inclusions, Auer rods, diagnostic
Auer rods = FUSED LYOSOMES; CHARACTERISTIC
FOR THIS TYPE OF LEUKEMIA
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Chronic Lymphocytic Leukemia (CLL)
Proliferating cells – mature but incompetent lymphocytes, don’t make antibodies in response to antigens; 95% B lymphocytes
Accounts for 2/3 of chronic leukemias ; most common over 60 yrs
Male : female ratio 2:1
Early stages ASYMPTOMATIC; later stages fatigue, weight loss, lymphadenopathy, hepatosplenomegaly
Lab findings:
> Blood smear: increased small lymphocytes anemia,
thrombocytopenia
- CBC: leukocytosis 5-10x higher WBC count,
> low Hb and platelets
> Survival with treatment 4-6 yrs
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Chronic myeloid / myelogenous Leukemia (CML)
Due to Philadelphia chromosome mutation; translocation between chromosomes 9 and 22
Abnormal proliferation of myeloid cells results in myeloid marrow hyperplasia
Accounts for 1/3 of chronic leukemias; young adults (10-20 yrs) and middle age (50-60 yrs)
2 phases:
1. Chronic: 3-5 yrs; asymptomatic
2. Acute: 2-4 months; increased blasts (>30%) in blood and BM
- No response to treatment – blast crisis
- BM transplantation during chronic phase
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Lymphomas
Solid tumors that arise in lymphoid tissue but then spread to other solid tissues, blood and BM
3rd most common malignancy in children
2 types:
Hodgkin’s Lymphoma / Disease
Non-Hodgkin’s Lymphoma
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Hodgkin’s Lymphoma / Disease
2 types: classic and nodular
95% have classic form
presence of rare malignant Hodgkin’s Reed-Sternberg cells
Reed-Sternberg cells = ABNORMAL TYPE OF B CELL (A LOT LARGER AND HAS 2 NUCLEI)
Unknown cause; genetic and environmental e.g. EBV
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Non-Hodgkin’s Lymphoma
Associated with chronic inflammatory diseases e.g. rheumatoid arthritis
Often develops after organ transplantation in immunosuppressed patients
90% of NHL B-cell lymphomas; 10% T-cell lymphomas
Causes: unknown
- Genetic – chromosomal translocations
- Viral - HIV, EBV
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Multiple Myeloma
3rd most common hematologic malignancy after leukemia and lymphoma
Males > females; patients 50-60 years old
Originates in bone marrow; presence of large numbers of malignant plasma cells
(mature b-cells = plasma cells)
Plasma cells produce abnormal proteins (eg. Bence-Jones)
Bence-Jones proteins, excreted in urine; diagnostic
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Platelets
Also known as thrombocytes – thrombos (Greek) = clot
Smallest blood cell (2-4mm diameter)
Life span: 10-12 days
Derived from cytoplasm fragmentation of megakaryocytes (giant multinucleated cells) residing in BM
Promote blood clotting and help repair gaps in the walls of blood vessels, preventing blood loss
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Platelets
Small, disk-shaped, non-nucleated cell fragment
Peripheral light blue-stained transparent zone, the HYALOMERE and central darker zone with purple granules, the GRANULOMERE
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Platelet structure
Platelet membrane with glycoproteins – platelet adhesion
Hyalomere:
> Microtubules – allow platelets to maintain their
discoid shape
> Actin / myosin – contraction – platelet movement &
aggregation
> Surface-opening system – take up and release
molecules
> Dense-tubular system – calcium storage, prevent
platelet stickiness
```
Granulomere:
> Mitochondria
> Glycogen deposits
> Enzymes – catabolize glycogen, consume O2, and generate ATP
Granules – 3 types: a, d, l
```
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Platelet structure
alpha-granules – largest, most numerous
> contain fibrinogen, clotting factors, platelet specific
> proteins
vessel repair, blood coagulation, and platelet aggregation
delta-granules (dense bodies) – smaller, less numerous, denser
- contain Ca, ADP, ATP, histamine, serotonin
- facilitate platelet adhesion and vasoconstriction
lamda - granules (lysosomes) – smallest vesicles
contain lysosomal enzymes
clot resorption
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Hemostasis
Clotting mechanism of blood; Sequence of events
leading to cessation of bleeding by formation of a stable plug (clot)
Stages of hemostasis:
1. Vascular wall injury and exposure of sub-endothelial collagen
2. Vasoconstriction
3. Formation of platelet plug
4. Coagulation cascade
5. Formation of fibrin clot (plug)
6. Healing and fibrinolysis
Platelet functions in hemostasis:
- Adhesion to the injured surface
- Shape change
- Release of granule contents
- Aggregation
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Mechanism of Hemostasis
1. blood vessel wall injured, collagen fibers exposed at damaged site
2. release of endothelin (vasoconstrictor) and von Willebrand factor (vWF) which binds exposed collagen fibers
3. Platelets adhere to exposed collagen by binding to vWF and they get activated (platelet activation)
> Platelet shape transformation
FROM NORMAL DISC SHAPE TO IRREGULAR SHAPE SO THAT THEY CAN BIND TO EACH OTHER
> Platelet degranulation (a/d granules)
> Platelet aggregation
BECOME STICKY SO THEY CAN "STICK" TOGETHER
- Primary hemostatic plug (loose)
4. Conversion of fibrinogen to fibrin
> Platelet cross-linking by fibrin
- Secondary hemostatic plug (solid)
- Blood coagulation
5. Clot shrinks
- Clot Retraction
6. Vessel wall repaired
- Clot dissolves after fibrin degradation by proteolytic
enzyme plasmin
- Clot Removal - Fibrinolysis
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Coagulation Pathways
Calcium-dependent process
Vitamin K-dependent factors (II, VII, IX, X)
2 pathways
- Extrinsic
- Intrinsic
Converging to a common pathway
to convert
fibrinogen to fibrin
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Intrinsic Pathway
Begins with activation of F XII by surface contact
F XII interacts with F XI
F XI activates F IX → (F IXa) - calcium required
F IXa forms complex with F VIII
F VIII converts F X → F Xa
- Calcium and
phospholipid required
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Extrinsic Pathway
Predominant pathway
Depends on release of tissue factor (TF) - thromboplastin (F III)
TF released from endothelial cells at damaged site
TF binds F VII
- calcium required
TF:F VII complex converts F X → F Xa
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Common Pathway
Activation of F X → F Xa
F Xa in presence of calcium, phospholipid and F V converts prothrombin (F II) → thrombin (F IIa)
Thrombin converts fibrinogen (soluble) → fibrin (insoluble) (Fibrinogen – F I)
Fibrin polymerizes to a gel
Thrombin converts F XIII → F XIIIa
F XIIIa cross-links fibrin
- solid clot
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Thrombocytosis (secondary / reactive)
benign - increased platelet count
```
Causes:
infection / inflammation
iron deficiency
malignancy / chemotherapy reaction
Splenectomy
```
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Essential Thrombocythemia (primary)
Malignant disorder – increased platelet count
Causes:
- primary myeloproliferative disorder
- genetic (JAK2 mutation)
Thromboembolic: 2 degrees to high platelet count
Hemorrhagic: 2 degrees to platelet dysfunction
Lab findings:
- Blood smear: platelet clumps, variation in size, shape,
granulation
- Bone marrow: hypercellularity, megakaryocytic
hyperplasia
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Thrombosis
Thrombus: clot that develops & persists in an unbroken blood vessel
- May block circulation, leading to tissue death
- Blockage of coronary artery – Myocardial Infarction
Embolus: thrombus that becomes dislodged or fragmented freely circulating in the blood stream; thromboembolism
Most common thromboembolytic conditions:
deep vein thrombosis (DVT) of lower limbs
cerebral ischemia – cerebral emboli can cause stroke
pulmonary embolism – impaired ability of the body to obtain O2
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Bleeding Disorders
Classified as:
acquired – vitamin K
deficiency, liver disease, DIC
hereditary - hemophilia
low blood platelets – thrombocytopenia
Vitamin K required by the liver as a cofactor in the synthesis of clotting factors VII, IX, and X and prothrombin
Absence of or reduced levels of these factors result in partial or complete dysfunction of the clotting process
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Disseminated Intravascular Coagulation (DIC)
triggered by potent stimuli that activate both F XII and tissue factor
formation of microthrombi and emboli throughout the microvasculature
Thrombosis (leading to ischemic damage) and hemorrhage
consumption of coagulation factors and platelets, generation of FDPs that have antihemostatic effects
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Hemophilia
sex-linked recessive inherited genetic disorder
caused by deficiency or defect in a clotting factor
severe bleeding even after mild injuries e.g. skin cut, and may bleed to death after more severe injuries
spontaneous hemorrhages in body cavities, e.g. major joints, intracranial, urinary tract
Hemophilia A – defect in factor VIII
Hemophilia B - defect in factor IX (Christmas Factor)
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Hemophilia A
deficiency or defect in factor VIII (involved in fibrin generation)
only males are affected by hemophilia A (transmitted from their mothers)
females have one defective X chromosome
females develop hemophilia only when they have the abnormal gene in both X chromosomes - rare
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von Willebrand’s disease (vWD)
defects in concentration, structure, or function of vWF
defective platelet plug formation
autosomal dominant trait with varying penetrance
most common blood clotting disorder – 1:8,000-10,000 persons
females and males are equally affected in a heterozygous state
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Thrombocytopenia
Decreased Platelet count
Caused by
Decreased platelet production (drugs, viral infections, cancer)
Increased platelet destruction (most common)
Immune (antibodies against platelets)
Non-immune (abnormal platelet activation and consumption)
Bleeding (epistaxis, gum, small vessels, skin, GI tract)
Purpura and petechiae – purple spots and patches on skin
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Idiopathic or Immune Thrombocytopenic Purpura (ITP)
caused by accelerated antibody-mediated platelet consumption – failure of blood to clot
Spleen makes antibodies against platelet antigens (e.g. GpIb)
platelets are destroyed in spleen by macrophages
acute (postviral; 2 to 6 weeks) in children
chronic form in adults; 1o or 2o to another disorder e.g. SLE, HIV
cause of death: Intracerebral hemorrhage
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Prenatal Hematopoiesis
2 – 10 weeks gestation: yolk sac
> 2 weeks post-conception: “blood islands”; erythroid precursors
> 6 weeks gestation: granulocytes and megakaryocytes
> 7+ weeks gestation: lymphocytes in lymph
sacs
THE PRIMARY HEMATOPOIETIC ORGA N IS THE FETAL LIVER
FETAL SPLEEN IS SECONDARY
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Postnatal Hematopoiesis
At birth and after: PRIMARY HEMATOPOIETIC ORGAN IS THE BONE MARROW!!
SECONDARY are lymphatic organs
children: bone marrow of long bones – femur and tibia
adults: bone marrow of pelvis, cranium, vertebrae, sternum liver, spleen and thymus become active in postnatal hematopoiesis, IF NEEDED– extramedullary hematopoiesis
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Hematopoietic Stem Cells (HSCs)
have the ability to give rise to all different mature blood cell types-
pluripotential
capable of self-renewal: some remain as HSCs after proliferation
HSCs give rise to 2 types of multipotential cells
1. Common myeloid progenitors (CMP; CFU-GEMM)
2. Common lymphoid progenitors (CLP; CFU-L)
morphologically identical to HSCs but limited capacity for self-renewal
CFU-GEMM give rise to myeloid cells (granulocytes, erythrocytes, monocytes, megakaryocytes (platelets)) - myelopoiesis
CFU-L give rise to lymphoid cells (B, T, NK cells) – lymphopoiesis
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Hematopoietic Cell Differentiation
precursors arise from progenitor cells (CFU-GEMM or CFU-Ly)
Incapable of self renewal
First cells of a particular cell line – lineage-
committed
Undergo cell division & differentiation, give rise to mature cells
As they mature they become smaller, lose their nucleoli, chromatin becomes denser
suffix – blast
Mature hematopoietic cells do not undergo cell division
Abundant in peripheral blood
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Hematopoietic Growth Factors
Growth factors or colony-stimulating factors (CSFs) affect blood cell proliferation and differentiation
stimulate proliferation of immature (progenitor and precursor) cells
support the differentiation of maturing cells
enhance the functions of mature cells
CSFs also stimulate cell division and differentiation of progenitor cells of the granulocytic and monocytic series
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Two Hematopoietic Growth Factors We Need to Know
erythropoietin - activation of erythroid cells
thrombopoietin – stimulation of platelet production
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Erythropoiesis
process of red blood cell formation – 7 days
Maturation: synthesis of hemoglobin and formation of enucleated, biconcave, small erythrocyte
RBC production under control of erythropoietin (Epo)
Epo: kidney-secreted hormone produced in response to hypoxia
- stimulates production of globin, the protein component of Hb
iron, B12 and folic acid also essential for RBC production
HSCs →CFU-GEMM → Burst Forming Unit – Erythrocyte (BFU-E) →Colony Forming Unit- Erythrocyte (CFU-E)
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Proerythroblast
Cytoplasm –pale grayish-blue
nucleus – large round; rich, burgundy red with visible nucleoli
102
Basophilic erythroblast
Cytoplasm –pale blue grayish-pink background
nucleus - round, smaller and coarser than Pro-E; burgundy
103
Polychromatic erythroblast
Cytoplasm –gray or lilac
nucleus – small round and coarse; dark reddish black
104
Orthochromatic erythroblast: normoblast
not capable of division
Cytoplasm –pinkish with a hint of blue
nucleus – small compact densely stained about to be extruded
105
Reticulocytes
not capable of division
Cytoplasm – blue (methylene blue); residual rRNA
Nucleus – not present
106
Mature RBCs
not capable of division
Cytoplasm – round biconcave shape
nucleus – not present
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Granulopoiesis
process of granulocyte formation – neutrophils, eosinophils, basophils
under the influence of G-CSF and GM-CSF, IL-3, IL-5
Granulocytes originate from CFU-GEMM progenitor which differentiates into
CFU-GM →neutrophils
CFU-Eo →eosinophils
CFU-Ba → basophils
first 2 stages of granulocytic series: myeloblast and promyelocyte, possess no specific granules
Granules appear in myelocyte stage; distinguish neutrophilic, eosinophilic, basophilic
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Stages in Granulocyte Maturation
Myeloblast :
Cytoplasm –light blue, no granules
nucleus – large round; reddish with visible nucleoli
Promyelocyte:
Cytoplasm –bluish with many dark purple azurophilic granules
nucleus – reddish round, coarser
Neutrophilic Myelocyte :
Cytoplasm –pale blue with azurophilic and specific granules
nucleus –round acentric, coarse ,reddish
Neutrophilic Metamyelocyte : no cell division
Cytoplasm –similar to myelocyte but paler
nucleus – kidney-shape, acentric, dense
Neutrophilic Band (Sta
b) cell : no cell division
Cytoplasm – bluer than neutrophil with azurophilic and specific granules
nucleus – elongated, horseshoe-shape
Segmented Neutrophil : no cell division
Cytoplasm – reddish and granular
nucleus – 2-5 lobes; Barr body
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Stages in megakaryocyte maturation
Platelets produced in BM by CFU-GEMM, same as erythroid and myeloid cells
CFU-GEMM → CFU–Meg under the influence of GM-CSF and IL-3
CFU-Meg → Megakaryoblast
Megakaryoblasts: large cells, large nonlobed nucleus, numerous nucleoli; homogeneous cytoplasm
Megakaryoblast → Promegakaryocyte → Megakaryocyte under hormonal stimulation by thrombopoietin
Megakaryocytes: giant cells
Multilobed nucleus
No visible nucleoli
Scattered azurophilic granules
Mitochondria, Golgi, ER in cytoplasm
Upon maturation, invaginations of cytoplasm – demarcation membranes
demarcation membranes shed platelets, extruding them into the circulation
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Lymphopoiesis
HSCs give rise to CFU-Ly progenitor cells in the lymphoid series
CFU-Ly forms CFU-LyB and CFU-LyT progenitor cells
CFU-LyB cells differentiate and mature in the BM
CFU-LyT cells travel to thymus, where they proliferate and mature
CFU-LyB / CFU-LyT → lymphoblasts
Lymphoblasts: large cells capable of cell division
Lymphoblasts differentiate to prolymphocytes - smaller cells
Both B and T lymphocytes proceed to lymphoid organs (spleen and lymph nodes), where they continuously proliferate
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Monocytopoiesis
Monocytes originate in BM from CFU-GEMM
CFU-GEMM → CFU-GM (mature into neutrophils or monocytes)
The differentiation of CFU-GM into monocytes is stimulated by GM-CSF, IL-3 and M-CSF
monocyte precursors: monoblasts and promonocytes
Monoblasts identical to myeloblasts
Promonocytes: large cells, basophilic cytoplasm, large, slightly indented nucleus; nucleoli
Promonocytes → monocytes containing granules primarily lysosomes
Mature monocytes enter the bloodstream, circulate for about 8 h, then enter tissues, where they mature into macrophages
