Lecture 11:
Cardiovascular System (blood)
Functions:
 Transport of gases, nutrients, and
waste products.
 Transport of processed molecules.
 Transport of regulatory molecules.
 Regulation of pH and osmosis.
 Maintenance of body temperature.
 Protection against foreign
substances.
 Clot formation.
Composition of blood:
 Liquid matrix (plasma) – 55%
 Formed elements – 45%
o Cells
o Cell fragments
Total blood volume in adults:
 Male – 5 – 6 Liters
 Female – 4 – 5 Liters
Plasma
 It is the liquid matrix of blood.
 It is a pale-yellow fluid that consists
of about 91% water and 9% other
substances.
Composition of Plasma
 Water – acts as a solvent and
suspending medium for blood
components.
Plasma Proteins
 Albumin – partly responsible for
blood viscosity and osmotic
pressure.
 Globulins - They are antibodies
produced by plasma cells in response
to the presence of pathogens like
bacteria and viruses.
 Fibrinogen – Functions in blood
clotting.
Ions
 Sodium, Potassium, Calcium,
Magnesium, Chloride, Iron,
Phosphate, Hydrogen, Hydroxide,
Bicarbonate – involved in osmosis,
membrane potentials, and acid-base
balance.
Nutrients
 Glucose, Amino Acids,
Triglycerides, Cholesterol – source
of energy and basic “building
blocks” of more complex molecules.
 Vitamins – Promote enzyme
activity.
Waste Products
 Urea, uric acid, creatinine,
ammonia salts – Breakdown
products of protein metabolism;
excreted by the kidneys.
 Bilirubin – Breakdown product of
red blood cells; excreted as part of
the bile from the liver into the small
intestine.
 Lactate – End product of anaerobic
respiration; converted to glucose by
the liver.
Gases
 Oxygen – Necessary for aerobic
respiration; terminal electron
acceptor in electron-transport chain.
 Carbon dioxide – Waste product of
aerobic respiration; as bicarbonate,
helps buffer blood.
 Nitrogen – Inert
Regulatory Substances
 Enzymes catalyze chemical
reactions; hormones stimulate or
inhibit many body function.
Serum
 Plasma without clotting factors.
 No fibrogen
Formed Elements
 Consist of cells and cell fragments.
 The cells include red blood cells and
white blood cells.
 Cell fragments are more commonly
called platelets.
Production of Formed Elements
Hematopoiesis
 the process of blood cell production.
Hemocytoblasts
 Precursor cells capable of dividing
to produce daughter cells that can
differentiate into various types of
blood cells.
Myeloid stem cells
 Give rise to several intermediate cell
types.
Proerythroblasts
 Produce red blood cells
Myeloblasts
 Produce basophils, eosinophils, and
neutrophils.
Monoblasts
 Produce monocytes.
Megakaryoblasts
 Produce platelets.
Red Blood Cells (RBC)
 Also called erythrocytes.
 No nucleus
 Biconcave disc
 Normal life span is 120 days
 Oxygen transport
 Removal of metabolic waste
Hemoglobin
 Is a complex protein consisting of
four subunits.
 Each subunit is composed of one
polypeptide chain called globin that
is bound to one heme group.
Erythropoiesis
 The process by which new red blood
cells are produced.
White Blood Cells (WBC)
 Also called leukocytes.
 Have a nucleus.
 Grouped into two categories based
on their appearance in stained
preparations:
 Granulocytes (with granules)
o Neutrophils
o Eosinophils
o Basophils
 Agranulocytes (without granules)
o Lymphocyte
o Monocytes
Granulocytes
Neutrophils
 60 – 70% of white blood cells
 Small cytoplasmic granules
 Statin with both acidic and basic
dyes
 Normally remain in the circulation
for about 10-12 hours.
Eosinophils
 2 – 4% of white blood cells
 Stain bright red with eosin, an acidic
stain
 Two-lobed nucleus
 They attach to the worms and release
substances that kill the parasites.
Basophils
 0.5 – 1% of white blood cells
 Large granules – stain blue or purple
with basic dyes
 Increase in number in both allergic
and inflammatory reactions.
 Contains large amounts of histamine.
Vascular Spasm
 Immediate but temporary
constriction of a blood vessel.
 Allows platelets to adhere to exposed
tissue.
 ADP/ATP release – promotes platelet
aggregation.
Mast cell
 Similar to basophil
 Contains histamine and heparin.
 Matured in tissue site.
Platelet Plug Formation
 Accumulation of platelets – seal
small breaks in blood vessel
 Steps:
1. Platelet Adhesion
2. Platelet Activation
3. Platelet Aggregation
Agranulocytes
Monocytes
 3 – 8% of white blood cells
 Largest of the white blood cells
 Kidney bean shaped nucleus
 Increase in chronic infection.
Lymphocyte
 20 – 25% of WBC
 Smallest WBC
 B cells – produces antibodies
 T cells – protect against viruses and
other intracellular microorganism.
Platelets (Thrombocytes)
 Minute fragments of cells.
 Consist of a small amount of
cytoplasm surrounded by a plasma
membrane.
 Life expectancy of platelets is about
5 – 9 days.
Hemostasis
 Complex network of interactions
involving vessels, platelets, and
factors.
Hemostasis involves:
 Vascular spasm
 Platelet plug formation
 Coagulation
Coagulation
 Blood clotting – formation of clot
 Blood clot – network of threadlike
protein fibers (fibrin) that traps blood
cells, platelets and fluid
 Formation is dependent on the
clotting factors.
 Activated only after injury.
Extrinsic Pathway
 Begins with chemicals that are
outside of blood.
 Factor III, Factor VII
 Damaged tissue releases
THROMBOPLASTIN (tissue
factor/factor III)
 Thromboplastin forms a complex
with Factor VII (stable factor,
proconvertin)
 Presence of Ca – begins common
pathway
Intrinsic Pathway
 Factory XII, XI, IX, VII
 It begins with chemicals that are
inside the blood
 Damage BV expose collagen – active
Factor XII – Factor XI – Factor IX
and VII – common pathway
Common Pathway
 Involves fibrinogen (factor I),
factors II (prothrombin), V, X
 Thrombin converts soluble
fibrinogen to insoluble fibrin.
Control of Clot Formation
 Blood contains several
anticoagulants – to prevent unwanted
clotting.
Clot Retraction
 Consolidation or tightening of fibrin
clot.
 Clot retracts it pulls the edges of the
damaged vessel close together.
Fibrinolysis: Clot Dissolution
 Plasminogen/ Profibrinolysin –
trapped the clot; activated plasmin
(fibrinolysin)
 Plasmin – digests fibrin threads and
other clotting factors and removes
the clot.
Blood Grouping
 Transfusion – transfer of blood or
blood components from one
individual to another.
 Infusion – introduction of fluids
other than blood (saline or glucose
solution) into the blood.
 Antigen – present in the surfaces of
RBC (blood groups)
 Antibodies – proteins present in
plasma.
 Donor – person who gives blood.
 Recipient – person who receives it.
ABO Blood Group
 Used to categorize human blood
based on the presence or absence of
ABO antigens on the surface of red
blood cells.
 Type A – A antigens; anti-B
antibodies



Type B – B antigens; anti-A
antibodies
Type AB – A and B antigens;
neither type of antibody
Type O – A nor B antigens; anti A
and anti-B
Rh Blood Group
 First studied in rhesus monkeys
 Rh-positive – Rh antigen (the D
antigen) on the surface of their red
blood cells
 Rh-negative – Do not have Rh
antigen.
Diagnostic Blood Tests
Type and Crossmatch
 Blood typing - Determines the ABO
and Rh blood groups of the blood
sample.
 Crossmatch - Donor's blood cells
are mixed with the recipient's serum;
Donor's serum is mixed with the
recipient's cells.
Complete Blood Count
 Analysis of blood that provides
much useful information
Consists:
o RBC count
o Hemoglobin levels
o Hematocrit levels
o WBC count
o Differential WBC
RBC Count
 Number (expressed in millions) of
red blood cells per microliter of
blood.
Normal:
o Male 4.6-6.2 million/µL
o Female 4.2-5.4 million/µl
Hemoglobin levels
 Determines the amount of
hemoglobin in a given volume of
blood
 Expressed as grams of hemoglobin
per 100 mL of blood
Normal:
o Male - 14-18 g/100 mL
o Female - 12-16 g/100 mL
Hematocrit levels
 Percentage of the total blood volume
that is composed of red blood cells
 RBC account for 40-54% of the total
blood volume - males
 38-47% females
 Number and size of red blood cells
affect the hematocrit measurement.
o Normocytes – Normal-sized
red blood cells with a
diameter of 7.5 mm
o Microcytes – Smaller than
normal (6 µm or less
diameter)
o Macrocytes – Larger than
normal (9 µm or greater
diameter)
WBC Count
 Measures the total number of white
blood cells in the blood.
 5000-10,000 white blood cells are
present in each microliter of blood.
o Leukopenia – lower than
normal WBC resulting from
depression or destruction of
the red marrow.
o Leukocytosis – abnormally
high WBC
Differential WBC
• Determines the percentage of each of the
five kinds of white blood cells
• Neutrophils – 60-70%
• Lymphocytes – 20-30%
• Monocytes – 2-8%
• Eosinophils – 1-4%
• Basophils – 0.5-1%
Platelet Count
 Normal: 250,000-400,000 platelets
per microliter of blood
 Thrombocytopenia – platelet count
is greatly reduced chronic bleeding
through small vessels and capillaries.
Bleeding time
 Assessment of platelet function
 In vivo measure of primary
hemostasis
o Duke Method
o Ivy Method
Clotting
 Blood's ability to clot can be
assessed by the platelet count and the
prothrombin time measurement.
Prothrombin time measurement
 Expresses how long it takes for the
blood to start clotting.
 Normal: 9-12 seconds
Blood Chemistry
 Analyzed the composition of
materials dissolved or suspended in
the plasma.
 Function Assessment of many body's
systems
• Blood glucose
• Blood Urea Nitrogen
• Bilirubin
• Cholesterol