3. 19-3
19.1 Functions of Blood
1. Transport of gases, nutrients and waste products;
e.g. oxygen
2. Transport of processed molecules; e.g., precursor of
vitamin D from skin to liver then kidneys
3. Transport of regulatory molecules; e.g., hormones
4. Regulation of pH and osmosis (normal pH of most
body tissues between 7.35 and 7.45)
5. Maintenance of body temperature; e.g., warm blood
shunted to the interior of the body
6. Protection against foreign substances; e.g.,
antibodies
7. Clot formation
8. 19-8
19.4 Formed Elements
• Red blood cells (erythrocytes). Biconcave discs,
anucleate, contain hemoglobin; transports oxygen
and carbon dioxide.
• White blood cells (leukocytes)
– Granulocytes: cytoplasm contains large
granules; have multi-lobed nuclei. Three
distinctive types: neutrophils, eosinophils,
basophils
– Agranulocytes: cytoplasm contains small
granules and nuclei that are not lobed. Two
distinctive types: lymphocytes and monocytes
• Platelets (thrombocytes). Cell fragment. Form
platelet plugs, release chemicals necessary for
blood clotting.
9. 19-9
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,
neutrophils, eosinophils
– Lymphoblasts: Develop into lymphocytes
– Monoblasts: Develop into monocytes
– Megakaryoblasts: Develop into platelets
12. 19-12
Red Blood Cells
• Found in higher
concentration in
male than in female
plasma
• Components
– 1/3 Hemoglobin
– 2/3 Lipids, ATP,
carbonic anhydrase
13. 19-13
RBC Function: Transport
• Oxygen from lungs to tissues: 98.5%
attached to hemoglobin; 1.5% dissolved in
plasma
• Carbon dioxide from tissues to lungs.
– 7% dissolved in plasma
– 23% in combination with hemoglobin
– 70% transported as bicarbonate ions
produced as a result of combination of
H2O and CO2 because of enzyme
carbonic anhydrase found within RBCs
14. 19-14
Hemoglobin
• Types of hemoglobin
– Embryonic and fetal:
have greater attraction for
oxygen than adult. Fetal
production stops after
birth.
– Adult
• Oxyhemoglobin:
transporting oxygen
• Deoxyhemoglobin
• Carbaminohemoglobin:
transporting carbon dioxide
15. 19-15
Hemoglobin Composition
• Four globin molecules (polypeptide chains):
Transport carbon dioxide (carbonic anhydrase
involved), nitric oxide. NO brought from lungs to
tissues, induces smooth muscles to relax, lowering
BP.
• Four heme molecules, each containing one iron
atom: transport oxygen
• Iron required for oxygen transport. Iron absorbed
in upper small intestine; absorption increased by
stomach acid and vitamin C. Iron lost in urine,
feces, menstrual fluid.
16. 19-16
Please note that due to differing
operating systems, some animations
will not appear until the presentation is
viewed in Presentation Mode (Slide
Show view). You may see blank slides
in the “Normal” or “Slide Sorter” views.
All animations will appear after viewing
in Presentation Mode and playing each
animation. Most animations will require
the latest version of the Flash Player,
which is available at
http://get.adobe.com/flashplayer.
17. 19-17
Erythropoiesis
• RBCs last 120 days in circulation (enucleated)
• Production of red blood cells
– Stem cells → proerythroblasts → early erythroblasts →
intermediate erythroblasts → late erythroblasts → reticulocytes
• Erythropoietin: hormone stimulates RBC production;
produced by kidneys in response to low blood O2 levels.
20. 19-20
White Blood Cells
• Protect body against microorganisms and remove
dead cells and debris
• Movements
– Ameboid: pseudopods
– Diapedesis: cells become thin, elongate and move
either between or through endothelial cells of
capillaries
– Chemotaxis: attraction to and movement toward
foreign materials or damaged cells. Accumulation of
dead white cells and bacteria is pus.
22. 19-22
• Neutrophils: after leaving bone
marrow, stay in circulation 10-12
hours then move into other
tissues. Become motile,
phagocytize bacteria, antigen-
antibody complexes and other
foreign matter. Secrete lysozyme.
Last 1-2 days. Account for 60-
70% of the WBC.
• Eosinophils. Leave circulation
and enter tissues during
inflammatory response. Prevalent
in allergic reactions. Destroy
inflammatory chemicals like
histamine. Release chemicals that
help destroy tapeworms, flukes,
pinworms, and hookworms.
Account for 2-4% of the WBC.
23. 19-23
•Basophils: least common. Leave circulation and
migrate through tissues, play a role in both
inflammatory response and allergic reactions. Produce
histamine and heparin. Account for less than 1% of the
WBC.
•Lymphocytes: produced in red bone marrow but then
migrate to lymphatic tissues and proliferate.
Responsible for antibody production. Studied
extensively with the immune system. Account for 20-
25% of the WBC.
•Monocytes: remain in circulation for 3 days, leave
circulation and become macrophages. Phagocytic cells.
Can break down antigens and present them to
lymphocytes for recognition. Account for 3-8% of the
WBC.
24. 19-24
Platelets
• Cell fragments pinched off
from megakaryocytes in
red bone marrow
• Surface glycoproteins and
proteins allow adhesion to
other molecules; i.e.,
collagen
• Important in preventing
blood loss
– Platelet plugs
– Promoting formation and
contraction of clots
25. 19-25
19.5 Hemostasis
• Arrest of bleeding
• Events preventing excessive blood loss
– Vascular spasm: Vasoconstriction of damaged
blood vessels. Can occlude small vessels.
Caused by thromboxanes from platelets and
endothelin from damaged endothelial cells.
– Platelet plug formation
– Coagulation or blood clotting
26. 19-26
Platelet Plug Formation
* Also expression of coagulation factor V and phospholipid (platelet factor
III). Important for coagulation
27. 19-27
Coagulation
• Stages
– Activation of prothrombinase
– Conversion of prothrombin to
thrombin
– Conversion of fibrinogen to
fibrin
• Coagulation factors.
– Proteins found in plasma.
– Circulate in inactive state until
tissues are injured.
– Damaged tissues and platelets
produce chemicals that begin
activation of the factors.
• Pathways
– Extrinsic
– Intrinsic
• Result: blood clot. A network of
threadlike fibrin fibers, trapped
blood cells, platelets and fluid
30. 19-30
Extrinsic Clotting Pathway
• Begins with chemicals outside of blood
• Stage 1
– Damaged tissues release tissue factor (TF; factor III)
– When Ca2+
is present, forms complex with factor VII,
activating factor X
– Prothrombinase is formed
• Stage 2: prothrombinase converts prothrombin
into thrombin
• Stage 3
– Thrombin converts fibrinogen to fibrin
– Thrombin activates factor XIII, which stabilizes clot
31. 19-31
Intrinsic Clotting Pathway
• Begins with chemicals that are part of the blood
• Stage 1
– In damaged blood vessels, factor XII comes in contact
with exposed collagen, activating factor XII
– Stimulates factor XI, activates factor IX
– Activated factor IX joins with factor VIII, platelet
phospholipids and Ca2+
to activate factor X
– Prothrombinase is formed
• Stages 2 and 3 progress to clot formation
32. 19-32
Control of Clot Formation
• Anticoagulants: prevent coagulation factors from
initiating clot formation.
• Coagulation occurs when coagulation factor
concentration exceeds a given threshold. At site of
injury, threshold is exceeded.
• Anticoagulants
– Antithrombin: produced by liver, slowly inactivates
thrombin
– Heparin: produced by basophils and endothelial cells.
Increases effectiveness of antithrombin
– Prostacyclin: prostaglandin derivate from endothelial
cells. Causes vasodilation and inhibits release of
coagulating factors from platelets
34. 19-34
19.6 Blood Grouping
• Transfusion: transfer of blood or blood
components from one individual to another
• Infusion: introduction of fluid other than
blood
• Determined by antigens (agglutinogens) on
surface of RBCs
• Antibodies (agglutinins) can bind to RBC
antigens, resulting in agglutination
(clumping) or hemolysis (rupture) of RBCs
• Groups: ABO and Rh
37. 19-37
Transfusion
• Type A blood has anti-B antibodies; Type B blood
has anti-A antibodies
• Suggested that these antibodies are present
because of exposure to A and B antigens on
bacteria and food
• Donor: gives blood. Recipient: receives blood
• Type O as “universal donor”. Can actually cause
transfusion reactions because of antibodies in O
blood plasma
38. 19-38
Rh Blood Group
• First studied in rhesus monkeys
• Types
– Rh positive: Have these antigens present on surface of RBCs
– Rh negative: Do not have these antigens present
• Hemolytic disease of the newborn (HDN)
– Rh positive fetus, Rh negative mother.
– Late in pregnancy, Rh antigens of fetus cross placenta (through a
tear in placenta or during delivery); mother creates antiRh
antibodies (primary response)
– Second Rh positive pregnancy might initiate secondary response
and HDN (potentially fatal to fetus since antibodies to its RBCs
would cross the placenta from the mother to the fetus, destroying
fetal RBCs).
– Injection of RhoGAM. Contains antibodies against Rh antigens.
Antibodies attach to any fetal RBCs and they are destroyed.
40. 19-40
19.7 Diagnostic Blood Tests
• Type and Crossmatch: determination of ABO
and Rh blood types. Red cells tested against
antibodies
• Complete Blood Count
– Red Blood Count: number of RBCs/ microliter of
blood
– Hemoglobin Measurement: grams of hemoglobin/100
mL of blood. For a male, 14-18, female 12-16 g/100
mL
– Hematocrit Measurement: percent of blood that is
RBCs
– White Blood Cell Count: 5,000-10,000 /microliter of
blood
42. 19-42
• Differential White Blood Count: determines
percentage of each of the five types of WBC
– Neutrophils: 60-70%
– Lymphocytes: 20-30%
– Monocytes: 2-8%
– Eosinophils: 1-4%
– Basophils: 0.5-1%
• Clotting
– Platelet Count: 250,000- 400,000/microliter
– Prothrombin Time Measurement: measures how
long it takes for blood to start clotting. 9-12 seconds.
To test, thromboplastin is added to whole plasma
• Blood Chemistry: composition of materials
dissolved or suspended in the plasma. Used to
assess functioning of many body systems
