Transcript Blood Physical properties

Blood Physical properties
• 8% of body weight
• Heavier than water
• 5x more viscous
• About 38o C
• pH 7.35 - 7.45
• Salty and sticky
Blood Functions
• Transportation
– O2 and CO2
– Nutrients
– Waste
• Regulation
– pH
– Body temperature
– Fluid volume and osmolarity
Blood Functions
• Protection
– Prevention of blood loss
– Prevention of infection
Blood Components
• Plasma
• Formed elements
Plasma
• Water - 90% of plasma volume
• Solutes - 8% of plasma volume
– Proteins
» Albumin
» Globulins - alpha , beta and gama
» Clotting proteins
» other
– Non protein nitrogenous waste
– Nutrients (organic)
– Electrolytes
– Respiratory gases
Formed Elements
• Erythrocytes
• Leukocytes
• Platelets
Unusual Features of Formed
Elements
• Erythrocytes and platelets are not “true cells”
• Most of formed elements survive in blood
stream only a few days
• Most blood cells do not divide
Formation of blood cells
Physical Characteristics of
RBCs
• Anucleated and lack most organelles
• Small in size and biconcave
• Flexible
• Mostly a “bag” to carry hemoglobin
Function of RBCs
• Transport of oxygen and carbon dioxide
Erythrocytes disorders
• Anemias
– Insufficient number of RBC
» Hemorrhagic
» Hemolytic
» Aplastic
– Decreases in hemoglobin content
» Iron deficiency
» B12 deficiency (pernicicous )
– Abnormal hemoglobin
» Thalassemias
» Sickle cell
• Polycythemia
General Characteristics of
Leukocytes
• Diapedesis - the ability of WBCs to exit the
circulatory system
• Ameboid motion - The characteristic motion
of leukocytes through tissue spaces
• Positive chemotaxis - The motion of WBCs
towards certain chemicals released by
damaged cells or other leukocytes
WBCs Classification
• Granulocytes
– Neutrophyls
– Eosinophils
– basophils
• Agranulocytes
– Lymphocytes
» T lymphocytes
» B lymphocytes
– Monocytes
Neutrophils
• Account for about half of all
leukocytes and are twice as big
as erythrocytes
• Take up both basic (blue) and
acidic (red) dyes resulting in
lilac color.
• Their nucleus has 3-6 lobes
resulting in polymorphonuclear
(PMNs) or Polys
• Phagocytic especially bacteria
and fungi
• Kill by respiratory burst and
defenses
Eosinophyls
• Account for 1- 4% of
all leukocytes
• Shaped as a old
fashion telephone
receiver
• Large coarse granules
stained in red brick
color
• Most important role
fight against invasion
of parasitic worms
– Reduce allergenic
reactions by
phagocytizing allergens
Basophyls
• Rarest of all leukocytes
about 0.5% of population
• Have large histamine
granules which stain
purplish black
• Main role in inflammatory
reaction by dilating blood
vessels and attacking
other leukocytes to the
site of inflammation
– Mast cells may be tissue
basophils
Lymphocytes
• Second most numerous
leukocytes
• Large round deep
purple nucleusclassified by size
• Found mainly in
lymphoid tissue
– T Lymphocytes- cell
mediated immunity
– B Lymphocytes - humoral
immunity
Monocytes
• Largest of all
leukocytes
• Abundant gray-blue
cytoplasm and dark
blue-purple kidney
shaped nucleus
• Wonder into tissues
and become
macrophages with
prodigal appetites
• Great increase in
chronic infections
Leukocyte Disorders
• Excessive production of leukocytes occur in
leukemias
– Cancer of white blood cells
» Usually single clone lines tend to remain
unspecialized mitotic and functionally inoperative
» their sheer number impairs bone marrow function
resulting in severe anemia, bleeding problems and
inability to mount a defense response against
infections
• Leukopenia - low white cell count
– usually drug induced, particularly glucocorticoids and
anti-cancer drugs
Platelets (thrombocytes)
• Cytoplasmic fragments megakaryocytes
• Essential for clotting process
– Contain, serotonin, Ca+2 , a variety of enzymes, ADP,
PDGF.
• Formation controlled by thrombopoietin
Hemostasis
• Vascular spasms
• Platelet plug formation
• Coagulation
Vascular Spasms
• Damage of smooth muscle in
blood vessels causes a
reflexive contraction
• Release of chemicals from
injured endothelial cells and
platelets release vasoactive
chemical which cause
vasoconstriction
These mechanisms result in
reduction in blood loss
• Thought question : Would you
rather be injured by blunt or
sharp object
Platelet Plug Formation
• Platelets adhesion- Sharp edges, release of
sticky chemical such as ADP and exposure of
collagen which is under injured epithelia
• Platelets release- Release of chemicals which
will attract more platelets and will make them
stick
• Platelet aggregation- by sending extensions
• Plug formation- fibrogen gets converted to
fibrin forms a mesh which traps formed
elements and make a plug
Coagulation
• Phase 1 - A complex
substance called
prothrombin activator is
formed
– Two pathways extrinsic and
intrisic
» Once factor X is
activated it complexes
with tissue
thromboplastin PF3 ,
factor V and calcium ions
to form prothrombin
activator
• Phase 2 - conversion of
prothrombin to thrombin by the action of
prothombin
– common pathway
• Phase 3 - conversion of
fibronogen to fibrin by the
action of thrombin
– common pathway
Human Blood Groups
• ABO blood groups
• Rh blood groups