blood Flashcards
coposition of blood
55% plasma, 45% cells
hematopoiesis
the formation of blood cellular components- stem from pluripoten matopoietic stem cell- split to lymphoid stem cells and trillineage stem cells
what is Hematopoietic System
Erythrocytes (RBCs) are ideally suited for
their primary function: transport of oxygen
from the lungs into the peripheral tissues.
• Hemoglobin is a complex molecule that
consists of four globin subunits each
containing a heme group that can carry an
oxygen molecule (or carbon monoxide)
synthesis require
Hemoglobin synthesis requires iron, vitamin
B12, vitamin B6
, and folic acid.
• Red blood cells survive in the circulation on
average for 120 days.
spleen
Spleen: contains phagocytic cells that digest
main components of RBC’s and release them
for reuse or excretion
anemia
Anemia is a reduction of hemoglobin in the blood to
below-normal levels.
• Normal levels are >130 g/L in males and >115 g/L in
females. Textbook is American so its units are
lower i.e. in g/dL
• This may be associated with the following:
– Appearance of abnormal hemoglobin
– Reduced number of red blood cells
– Structural abnormalities of red blood cells
Hypoxia-lack of oxygen to the tissues
what do cell counters do and what values do they give you
Complete blood count gives you a count of all
the cells present in the sample
• This instrument is also able to give you the
characteristics of the cells that are present
• The instrument will also give a value for the
total hemoglobin present and the hematocrit
(amount of RBCs by volume) i.e. a hematocrit
(Hct) of 40%
what mesurement are made
Objective measurements of red blood cell
parameters are done with instruments that
estimate the size of red blood cells and their
hemoglobin content.
– Mean corpuscular volume (MCV)-Mean corpuscular volume (MCV) =
• <80 fL: Microcytic Anemia fL= femtoliter =10 -15 one quadrillionth of a liter
• >100 fL: Macrocytic Anemia
– Mean corpuscular hemoglobin (MCH)-• Mean corpuscular hemoglobin (MCH) =
Normal Range 28-32 pg/cell. < 28: Hypochromic
– Mean corpuscular hemoglobin concentration
(MCHC) -Normal Range 320-360 g/L
• Low values: Hypochromic Anemia !!!!!!!!!!!!!!!!!!! be able to diferentiate
anemia occurs when
Anemia may be a consequence of:
– Decreased hematopoiesis ( production) (nutrient deficiency
– Abnormal hematopoiesis (sickle cell)
– Increased loss or destruction of red blood cells
know some deseases and what they are classified under
slide 23
Decreased Hematopoiesis
Bone marrow failure
– Aplastic anemia
– pancytopenia:: lack of all blood cells in peripheral blood
– Myelophthisic anemia: bone marrow cells may be damaged or
replaced by infiltrates of metastatic tumor cells
• Deficiencies of nutrients
– Deficiency of vitamin B12 and folic acid (megaloblastic anemia)
– Protein deficiency
– Iron deficiency: most common deficiency
Abnormal Hematopoiesis
Usually consequence of genetic
abnormalities
• Sickle cell anemia: substitution of a valine
for glutamic acid at position 6 of the Beta
chain of hemoglobin
Increased Loss and Destruction
of Red Blood Cells
• Bleeding: Dilutional Anemia • Intrasplenic sequestration: hypersplenism • Immune hemolysis • Infections (malaria): parasite Plasmodium
• Normocytic, normochromic anemia: Dilutional Anemia”
Usually following massive blood loss (or surgery because they give them more fluid): because of the loss of blood
fluid shifts from interstitial to ECF fluid compartment. Within a few
weeks blood cells are replenished by bone marrow
so looks the same just diluted
• Microcytic, hypochromic anemia
– Small & pale, Iron deficiency or thalassemia (affecting synthesis of
Hb)
• Macrocytic, normochromic anemia (normal in color, but large)
Deficiency of vitamin B12 and/or folic acid also in liver disease
• Anemia’s characterized by abnormal red blood
shapes
– Elliptocytosis, spherocytosis, sickle cell anemia
hypersplenism
increase destruction of RBC and loss
aplastic anemia
A pancytopenia or generalized bone marrow failure
Two Types
1. Idiopathic (cause unknown)
2. Secondary: bone marrow suppression. Due to cytotoxic
drugs, radiation therapy or viral infection.
• . Reversible with elimination of causative agent
• depleted of hematopoietic cells and consists only of
fibroblasts, fat cells, and scattered lymphocytes
• Anemia, leukopenia, and thrombocytopenia
• Symptoms - Uncontrollable infections, bleeding tendency,
chronic fatigue, sleepiness, and weakness
iron deficiency anemia
Most common form of anemia!!!!!!!!!
• Hypochromic microcytic anemia
• Bone marrow shows normal hematopoiesis
• Etiology
– Increased loss of iron (chronic bleeding)
– Inadequate iron intake or absorption
– Increased iron requirements (childhood growth and
pregnancy)
– Iron supplements usually solves problem
megaloblastic anemia
• Caused by a deficiency of vitamin B12 or folic acid
• Deficiency of either of the two cause a delay in hematopoiesis
• Normoblasts do not mature but are transformed to megaloblasts
– Vitamin B12 deficiency
• Pernicious Anemia: Lack of the gastric intrinsic factor due to
atrophic gastritis
– Folic acid deficiency
• Inadequate intake in the diet or because of malabsorption caused by
intestinal disease
megaloblastic anemia pathology
Bone marrow – Hypercellular, numerous megaloblasts • Peripheral blood – Decreased RBC that are macrocytic • Hypersegmentation of neutrophils
Pathologic Conditions Contributing to
Megaloblastic Anemia
Vitamin Deficiency or Malabsorption •Pernicious anemia •Resection of stomach •Celiac Disease •Crohn’s disease •Parasites
pernicious anemia
subheading of megoloblastic : Lack of the gastric intrinsic factor due to
atrophic gastritis- know how to diferentiate mega and iron deficient
Megaloblastic Anemia
Clinical Features
• Fatigue, shortness of breath, weakness
• Destruction of posterior and lateral columns in
the spinal cord—results in a loss of the senses
of vibration and proprioception, as well as loss
of the deep tendon reflexes
• Treatment Vitamin B12 injections or folic acid
supplementation.
Hemolytic Anemia
• Increased red blood cell Destruction (hemolysis)
• Intracorpuscular defects
– Structural abnormalities
Sickle cell anemia, thalassemia, or hereditary spherocytosis
• Extracorpuscular defects
– Antibodies, infectious agents, or mechanical factors
– Autoimmune hemolytic anemia, hemolytic disease of the
newborn, transfusion reactions, malaria, hemolytic anemia
caused by cardiac valve prosthesis, disseminated
intravascular coagulation
sickle cell anemia
Pathogenesis
Substitution of glutamic acid by valine in chain
• Synthesis of an abnormal beta chain of globin
• HbA gets mutated to HbS
• Low O2
tension causes deformities (sickling)
• Hemolytic crisis (avoidance of strenuous exercise)
• Aggregates cause tissue ischemia
sickle cell anemia does what
Multiple infarcts in various organs Neurologic defects; sharp pain in the bones, spleen (autosplenectomy), and extremities; retinal infarcts Hyperbilirubinemia and jaundice (bile stones). No definitive therapy, high mortality. Avoid conditions that cause sickling and combat infections
clinical features of sicke cell anemia
• Retarded intellectual development and neurologic deficits (TIAs, small infarcts, stroke) • Cardiopulmonary insufficiency (HF, MI, Pulmonary edema and PE) • Recurrent infections • HbS< 40% asymptomatic • HbS 40-80% mild to moderate disease • HbS>80% typical symptoms of disease • High mortality
