Assoc. Prof. Dr. Karim Al-Jashamy
Formed Elements of Blood
• Erythrocytes (RBC)
• Leukocytes (WBC)
• Platelets (Thrombocytes)
• Blood smear, stain using Wright.
• Aspirate bone (sternum, iliac crest) for bone
Functions of Blood
• Transport of:
– Gases, nutrients, waste products
– Processed molecules
– Regulatory molecules
• Regulation of pH and osmosis
• Maintenance of body temperature
• Protection against foreign substances
• Clot formation
• Liquid part of blood
– Pale yellow made up of 91% water, 9% other
• Colloid: Liquid containing suspended
substances that don’t settle out
– Albumin: Important in regulation of water
movement between tissues and blood
– Globulins: Immune system or transport
– Fibrinogen: Responsible for formation of blood
• Red blood cells (erythrocytes)
• White blood cells (leukocytes)
• Platelets (thrombocytes)
Production of Formed Elements
• Hematopoiesis or hemopoiesis: Process of
blood cell production
• Stem cells: All formed elements derived
from single population
– Proerythroblasts: Develop into red blood cells
– Myeloblasts: Develop into basophils,
– Lymphoblasts: Develop into lymphocytes
– Monoblasts: Develop into monocytes
– Megakaryoblasts: Develop into platelets
– Biconcave, anucleate
– Lipids, ATP, carbonic
– Transport oxygen from
lungs to tissues and
carbon dioxide from
tissues to lungs
• Numerous (5 x 106) /
• Mature cell has no
• Transports O2 and
Biconcave shape increases surface area 20-30%.
Readily deform and pass through capillaries.
Cytoskeleton is unique. Spectrin is major protein.
Energy from anaerobic respiration of glucose. (No
Lifespan is 120 days. Removed by spleen and liver.
Reticulocyte with a RBC in capillary
Hemoglobin (haemoglobin and abbreviated Hb or Hgb) is the iron-
containing oxygen-tran also spelled sport metalloprotein in the
red blood cells of vertebrates.
In mammals, the protein makes up about 97% of the red blood cell's
dry content, and around 35% of the total content (including
Hemoglobin has an oxygen binding capacity of between 1.36 and
1.37 ml O2 per gram of hemoglobin, which increases the total
blood oxygen capacity seventyfold.
Hemoglobin is also found in outside red blood cells and
their progenitor lines.
Other cells that contain hemoglobin include
dopaminergic neurons in the substantia nigra,
macrophages, alveolar cells, and mesangial cells in the
In these tissues, hemoglobin has a non-oxygen carrying
function as an antioxidant and a regulator of iron
• Consists of:
– 4 globin molecules: Transport carbon dioxide
(carbonic anhydrase involved), nitric oxide
– 4 heme molecules: Transport oxygen
• Iron is required for oxygen transport
Hemoglobin is measured in grams per deciliter of blood. The normal
levels are 1.5-3 years - 12±.5
5 y - 12.7±1
Birth - 17±2 10 y - 13.2±1
1 day - 19±2 Men - 15.5±1
2-6 d - 19±2.5 Women - 13.7
14-23 d - 15.5±1 Pregnant women: 11 to 12
24-37 d - 14±2 g/dl
40-50 d - 13±2
Women: 12.1 to 15.1 g/dl
2-2.5 month- 11.5±1
Men: 13.8 to 17.2 g/dl
3-3.5 m - 11±1
Children: 11 to 16 g/dl
5-7 m - 11.5±1
Pregnant women: 11 to 12 g/dl
8-10 m - 11.7±.5
11-13.5 m - 12±.5
• Production of red blood cells
– Stem cells proerythroblasts early erythroblasts
intermediate late reticulocytes
• Erythropoietin: Hormone to stimulate RBC production
• Protect body against
remove dead cells and
– Passive Immunity
– Active Immunity
– Antigen – Antibody
Diapedesis: The movement or passage of blood cells, especially white blood cells,
through intact capillary walls into surrounding body tissue
• 60-70% of leukocytes
• diameter 10-12 µm
• nucleus 2-8 lobes
• chromatin in dense coarse lumps
• 'drumstick' on lobe in 3% of neutrophils in
females (Barr body)
Mature and younger
Movement by pseudopodia.
• Produced in bone marrow. Granulocyte.
• Highly motile, phagocytic.
• Acute inflammatory response to tissue
injury; ingest, destroy damaged tissue &
• Lifetime activity consists of one burst of
5 lobed nucleus.
Primary granules are lysosomes.
Secondary granules (secretory)
contain substances for
inflammatory processes (comple-
ment activation, leucocyte
bacterial cell wall lysis).
Few other organelles
Glycogen for glycolysis in O2-
• 20-25% of leukocytes
• Diameter 6-8 µm.
• Nucleus spheroid or ovoid.
• Chromatin in dense lumps.
• Cytoplasm scarce and stained pale blue
Functions of Lymphocyte
• Central role in immunological defense.
• Most in circulating blood are inactive.
• Large lymphocytes (9-15m) are active B
cells en route to tissues where they become
• T lymphocytes form in red marrow and
move to thymus.
Large (activated) and small (inactive) lymphocytes.
A few mitochondria and
other organelles are present.
• 3-8% of leukocytes.
• Largest leukocyte (20 µm).
• Nucleus indented and pale.
• Cytoplasm abundant and basophilic, non-
uniform (foamy) appearance.
• Cytoplasm may contain a few fine
Functions of Monocytes
• Migrate to tissues and become microphages.
• Respond to necrotic material, invading
microorganisms, and inflammation.
• Large content of hydrolytic enzymes.
• Great capacity for phagocytosis!
• Concept of a single functional unit, the monocyte-
macrophage system consisting of Kupffer cells of
liver, microglia of CNS, osteoclasts.
Mature cell has greater
Indentation of nucleus.
Granules are similar to
lysosomes (acid phosphatase,
• Less than 1% of leukocytes.
• Diameter 14 µm.
• Forms in red bone marrow.
• Nucleus large and bilobed.
• Chromatin is more finely textured so nucleus is
more pale staining.
• Cytoplasm filled with large dark-blue staining
granules (basophilic) which may obscure nucleus
Function: immunological response to
parasites. Contain many mediators of
inflammatory response. Closely related
to mast cells. Basophils and mast cells
bind to IgE produced in response to
allergens. Triggers rapid exocytosis of
granule contents (degranulation).
This is the cause of immediate hypersensitivity reaction
characteristic of allergic rhinitis, some forms of asthma, urticaria,
Granules (S) contain heparin, leukotrienes, histamine.
Mitochondria, ribosomes, glycogen in cytoplasm.
• Up to 5% of leukocytes.
• Diameter 12-15 µm.
• Nucleus usually bilobed.
• Chromatin clumped but not as dense as in
• Cytoplasm filled with numerous large
eosinophilic (acidophilic) granules which
Functions of Eosinophils
• Phagocytic for antigen-antibody complexes.
• Defense against parasites.
• Release granules against parasites which are
injured by enzymes.
• Undergo chemotaxis in response to bacteria
but preferentially respond to basophils and
Specific granules (S) stains
S granules contain many
Contains glycogen, some
• Cell fragments
pinched off from
megakaryocytes in red
• Important in
preventing blood loss
– Platelet plugs
– Promoting formation
and contraction of clots
• Arrest of bleeding
• Events preventing excessive blood loss
– Vascular spasm: Vasoconstriction of damaged
– Platelet plug formation
– Coagulation or blood clotting
Very complex with organelles but no nuclei.
Function: form plugs in damaged vessels, promote clot
formation, secrete substances that are involved in repair of
Platelet Plug Formation
– Activation of
– Conversion of
– Conversion of
fibrinogen to fibrin
• Clot dissolved by
activity of plasmin,
an enzyme which
• Determined by antigens (agglutinogens) on
surface of RBCs
• Antibodies (agglutinins) can bind to RBC
antigens, resulting in agglutination
(clumping) or hemolysis (rupture) of RBCs
– ABO and Rh
ABO Blood Groups
Rh Blood Group
• First studied in rhesus monkeys
– Rh positive: Have these antigens present on
surface of RBCs
– Rh negative: Do not have these antigens present
• Hemolytic disease of the newborn (HDN)
– Mother produces anti-Rh antibodies that cross
placenta and cause agglutination and hemolysis
of fetal RBCs
Diagnostic Blood Tests
• Type and crossmatch
• Complete blood count
– Red blood count
– Hemoglobin measurement
– Hematocrit measurement
• White blood count
• Differential white blood