1. Blood Chapter 14, Section 1 of 2. ivyanatomy.com Functions of Blood:
Transports gasses, (O2 and CO2)
Transport nutrients, wastes, electrolytes, and hormones
Distributes heat throughout the body
Contains buffers
Immunity

2. Introduction Characteristics of Blood: Blood is a connective tissue
Cells are called= formed elements
Red Blood Cells
White Blood Cells
Platelets
Liquid Matrix = plasma
Centrifuged Blood:
Plasma, 55%
Buffy Coat, <1%
Proteins and WBCs
Red Blood Cells, 45%
Hematocrit = packed RBCs

3. Hematopoiesis Hematopoiesis is the formation of new blood cells.
Occurs within red bone marrow
Blood stem cells are called, hemocytoblasts ( or hematopoietic stem cells)
Hemocytoblasts can give rise to additional blood stem cells
Can differentiate into any of the blood cells
The fate of hemocytoblast depends on hematopoietic growth factors
Example:
Erythropoietin (EPO = growth factor)
Hemocytoblast erythroblast reticulocyte erythrocyte (RBC)

4. Erythrocytes: red blood cells (corpuscles)
Characteristics of erythrocytes
Biconcave cells
anucleated (nucleus dislodged during formation)
Average diameter = 7.5µm
1/3 volume is hemoglobin
Oxyhemoglobin – bright red
Deoxyhemoglobin – dark brick red
Red Blood Cell Counts
RBC counts is the number of RBCs in a cubic millimeter or microliter of blood
Male million cells per µL
Female million cells per µL
Child million cells per µL

5. Erythropoiesis: RBC production
Sites of Erythropoiesis
Adult – Erythropoiesis occurs primarily in red bone marrow, which is found within
flat bones (sternum, pelvis, ribs, skull)
Proximal end of long bones (femur, humerus)
Child
Erythropoiesis occurs within the yolk sac, liver, and spleen
Example of erythropoiesi:
Erythropoietin (EPO)
In red bone marrow
circulation

6. Erythrocytes: feedback loop
Erythopoiesis is stimulated by low blood oxygen.
Decreased blood O2 may cause the
kidneys and the liver (to a lesser extent)
to release erythropoietin (EPO)
EPO stimulates RBC production
This is a negative feedback
mechanism
Within a few days many new blood
cells appear in the circulating blood
Dietary Factors of Erythropoiesis
Iron – required for hemoglobin production
Vitamin B12 & Folic Acid – required for DNA synthesis (and thus, cell production)

7. Lifespan of Red Blood Cells
Red blood cells survive about 120 days in circulation.
With age, RBCs become fragile and easily rupture.
Old RBCs are removed by the liver and spleen
Hemoglobin is liberated and recycled in new RBCs

8. Hemoglobin breakdown Hemoglobin Heme Globin Biliverdin Iron (Fe2+)
Reused by liver in synthesis of new hemoglobin
Bilirubin
Excreted as bile pigment
Amino acids
recycled by body + +
Jaundice: yellowish staining of skin caused by the accumulation of bile pigments.
Jaundice may indicate increased RBC destruction, destruction of liver tissue, or blockage of the biliary tract.

9. Red Blood Cell Disorders
Erythrocytosis (polycythemia) is an excess number of RBCs in the blood.
Causes include
Genetic mutations
Poor blood oxygen levels or delivery
tumor
Polycythemia. The surplus of RBCs causes the blood to be more viscous and it slows its flow through the body. This increases the likelihood of clot formation.
Anemia
Low oxygen capacity of blood, several types
Iron deficiency – body cannot form hemoglobin
Hemolytic – excess RBC destruction
Sickle cell – sickle-shaped RBCs
Aplastic – inability to produce RBCs
Sickle cell anemia. RBCs take on a thin sickle shape when deoxygenated. The sickle cells sludge in capillaries, further reducing blood flow and oxygen levels

10. Leukocytes (White Blood Cells)
Functions of WBCs
Protect against infection
Remove worn out cells & debris
immunity
Colony Stimulating Factors and Interleukins are growth factors that promote the development of white blood cells.
There are five types of white blood cells within 2 categories
Granulocytes
Visible lysosomes “granules” in cytoplasm
Neutrophil
Eosinophil
Basophil
Agranulocytes
No visible granules in cytoplasm
Monocyte
Lymphocyte

11. Neutrophils Overview: Neutrophils stain in acid-base stains
Constitutes 54-62% of WBCs
Also called polymorphonuclear leukocytes “polymorphs”
Contain 2-5 nuclei + fine purple granules
12 hour lifespan
Functions
Phagocytosis
Kill bacteria, protozoa, fungi, parasites
Remove dead cells, debris, and foreign particulate
First to arrive at the site of infection
Fast moving cells
neutrophil, 1000x

12. Eosinophils Overview: Constitute 1-3% of all WBCs Bi-lobed nucleus
Granules stain bright red in acid stain
Functions
Defend against parasitic worms (tapeworm, hookworm, fluke worm, ect)
mediates allergic reaction and asthma attacks
eosinophil, 1000x

13. Basophils Overview: Constitutes <1% of WBCs
Deep blue granules stain in basic dye
Bilobed nucleus is usually obscured by the darkened granules
Functions
Secretes histamines
Histamines promote inflammation
Secretes heparin
Heparin is an anticoagulant “prevents clotting”
basophil, 1000x

14. Monocytes Overview: Constitutes 3-9% of WBC Largest of all WBCs
Large kidney-shaped nucleus
May live for several weeks up to a month
Functions
Leave the blood to become macrophages
Phagocytize bacteria, dead cells and other debris
platelet
monocyte, 1000x

15. Lymphocytes Overview: Constitutes 23-33% of all WBCs
Formed in red bone marrow and in lymphatic tissues
Large spherical nucleus with a thin sliver of cytoplasm
May live for many months to several years
Includes T-cells & B-cells
Functions
Lymphocytes provide immunity
T-cells directly attack microorganisms and tumor cells
B-cells produce antibodies
lymphocyte, 1000x

16. Functions of white blood cells
1. Leukocytes (primarily neutrophils & monocytes) are motile
Exhibit amoeboid movement
Neutrophils & Monocytes are the most mobile of WBCs
2. Leukocytes are capable of diapedesis.
They can squeeze between the cells of a capillary wall and enter the tissue space
outside the blood vessel.
3. Leukocytes exhibit chemotaxis.
They are attracted to chemicals released by damaged tissues.
4. Leukocytes contribute to the formation of pus.
Pus is the accumulation of bacteria, damaged tissue, and dead white blood cells.
Figure illustrates diapedesis of a WBC from a capillary into the surrounding connective tissue.

17. Activation of WBCs
Figure When bacteria invade the tissues, leukocytes migrate into the region and destroy the microbes by phagocytosis.

18. White Blood Cell Counts
A typical white blood count contains 4,500-10,000 WBCs per µL (mm3)
Leukopenia is a low WBC count (below 4,500 cells/µL)
Often associated with viral infections (influenza, chicken pox, measles, AIDS)
Leukocytosis is a high WBC count (above 10,000 cells/µL)
Acute infection, exercise, emotional distress
DIFF (differential WBC count)
Measures the percentages specific types of WBC
Table 14.4 illnesses associated with various DIFF counts

19. Thrombocytes (platelets)
TPO
Overview
Platelets are cell fragments released from Megakaryocytes within red bone marrow
Approximately 150, ,000 platelets per µL (mm3) of blood.
Thrombopoietin (TPO) = growth factor that promotes formation of platelets.
Functions include blood coagulation and blood vessel repair
Figure Development of platelets from hemocytoblasts. Exposure to TPO promotes the formation of megakaryocytes, which release thrombocytes from their plasma membrane.

20. Overview of Blood Cells
End of Section 1 of 2.

21. Plasma Chapter 14, Section 2 of 2. Overview
Plasma is the liquid portion of blood
Makes up 55% of blood volume
Straw colored
Components include Plasma proteins, Dissolved gasses, Wastes, Electrolytes, Nutrients, Hormones
Chapter 14, Section 2 of 2.

22. Plasma proteins Albumin 60% of plasma proteins Synthesized in liver
Creates an osmotic that helps maintain blood pressure
Globulins
36% of plasma proteins
Alpha & Beta globulins
Are produced by liver
Transports lipids
Gamma globulins
Are produced by lymphatic tissues
function as antibodies
Fibrinogen
4% of plasma proteins
Primary role in blood coagulation

23. Plasma proteins

24. Plasma Gasses & Nutrients
Blood Gasses:
Oxygen
Most is bound to hemoglobin. Less than 2% of oxygen is dissolved in plasma
Carbon dioxide
Most CO2 is transported as bicarbonate (HCO3-)
About 7% is dissolved in plasma
Nutrients:
Amino acids
Simple sugars
Nucleotides
Lipids
Hydrophobic lipids are bound to plasma proteins
within the plasma

25. Nonprotein Nitrogenous Substances
These are molecules containing nitrogen but are not proteins
In plasma they include:
Urea – product of protein catabolism; about 50% of nonprotein
nitrogenous substances
Uric acid – product of nucleic acid catabolism
Amino acids – product of protein catabolism
Creatine – biproduct of creatine phosphate metabolism
Creatinine – product of creatine metabolism
Common tests that evaluate kidney functions:
Creatinine test – measures creatinine
BUN – blood urea nitrogen; indicates health of kidney

26. Plasma Electrolytes
Plasma contains a variety of these ions called electrolytes
They are absorbed from the intestine or released as by-products of cellular metabolism
They include:
Sodium (most abundant with chloride)
Potassium
Calcium
Magnesium
Chloride (most abundant with sodium)
Bicarbonate
Phosphate
Sulfate

27. Hemostasis Hemostasis refers to the stoppage of bleeding
Actions that limit or prevent blood loss include:
Blood vessel spasm (vasospasm)
Platelet plug formation
Blood coagulation

28. hemostasis, step 1: vasospasm
Blood vessel spasm (vasospasm)
Cutting or breaking a vessel wall stimulates the smooth muscles in its walls to contract.
Vasospasm reduces blood loss almost immediately, and may close small blood vessels completely.

29. hemostasis, step 2: platelet plug formation
Platelet adhesion – platelets adhere to collagen fibers that become exposed due to the damage in a vascular walls
Platelets undergo a shape change, producing several processes to which additional platelets bind.
In addition, platelets secrete thromboxanes, which attract additional platelets to the site of injury.
A platelet plug may control blood loss from a small break.

30. hemostasis, step 3: coagulation
Blood coagulation
Is triggered by cellular damage and blood contact with foreign surfaces
Coagulation is a cascade reaction involving several biochemicals (clotting factors)
The major event is formation of a blood clot when fibrin (a thread-like protein)
forms a mesh surrounding the damaged vessel.
The cascade is divided into three events
Extrinsic mechanism
Intrinsic mechanism
Common pathway

31. Coagulation Extrinsic clotting mechanism
A chemical released from tissue outside the blood vessels trigger the extrinsic pathway
Damaged tissues releases thromboplastin
(also called factor III)
Factor III initiates a cascade reaction that, in the presence of Calcium, activates factor X.
Activation of factor X initiates the common pathway

32. Coagulation Intrinsic clotting mechanism
An inactive clotting factor within the blood (Hageman, or factor XII) is activated when foreign tissue, such as collagen enters the bloodstream.
Factor XII proceeds through a cascade of reactions in the presence of Calcium to activate factor X.
Activation of factor X initiates the common pathway.

33. Coagulation Common Pathway
Is the point at which intrinsic & extrinsic pathways converge
Activated factor X (with help of Calcium & factor V) leads to the release of prothrombin activator from platelets.
Prothrombin activator converts prothrombin into thrombin.
Thrombin, in turn converts fibrinogen into long threads of fibrin.
Fibrin forms an insoluble clot at the site of injury.

34. Coagulation
Figure 14.19c. Schematic of the common pathway in the blood clotting mechanism
Figure A scanning electron micrograph of fibrin threads. The insoluble fibers trap blood cells and platelets, which contribute to the blood clot formation.

35. hemostasis: review

36. Blood Clot Dissolution
After a blood clot forms it retracts and pulls the edges of a broken blood vessel together while squeezing the fluid serum from the clot
Platelet-derived growth factor stimulates smooth muscle cells and fibroblasts to repair damaged blood vessel walls
Plasmin digests the blood clots

37. Blood Clot Disorders A thrombus is an abnormal blood clot
Deep vein thrombosis – prolonged immobility causes blood to pool, especially in the deep veins of the legs or pelvis.
An embolus is a blood clot moving through the blood vessels
Pulmonary embolism – may occur when part of a thrombus breaks away from the clot and lodges in a pulmonary artery. Rapidly fatal.
Atherosclerosis – accumulation of fatty deposits along arterial lining
May cause inappropriate clotting
Most common cause of thrombosis in medium-sized arteries
Arteriosclerosis – hardening of an artery.
Stenosis – abnormal narrowing of a passage in a body
Atherosclerosis of an artery narrows the passage through which blood flows in an artery, and increases the likelihood of an embolism at that site.

38. Blood Clot Disorders Figure 14.20 Artery cross sections.
(a) light micrograph of a normal artery.
(b) The inner wall of an artery changed as a result of atheroclerosis.
Ultrasound image of stenosis within the internal carotid artery.

39. Blood Typing Terms to become familiar with:
Blood typing is the process of identifying an individual’s blood group.
(eg. Type A, B, AB or O)
Terms to become familiar with:
Antigen – a chemical (or membrane protein) that stimulates cells to produce antibodies
Foreign antigens in the body stimulate the immune response.
Antibodies – a plasma protein that reacts against a specific antigen
Agglutination – clumping of red blood cells in response to a reaction between an antibody and an antigen

40. ABO Blood Group
This blood group is based on the presence (or absence) of two antigens on red blood cell membranes: Antigen A & Antigen B
antigens
Type A blood contains A-antigens on the surface of its RBCs.
Type B blood contains B-antigens on the surface of its RBCs. and anti-A antibodies in its plasma.
Type AB blood contains A-antigens and B-antigens on the surface of its RBCs. and has neither antibody
Type O blood contains neither A or B antigen on the surface of its RBCs

41. Blood Typing antibodies
Type A blood plasma contains anti-B antibodies.
Type B blood plasma contains anti-A antibodies.
Type AB blood plasma contains neither antibody
Type O blood plasma contains both anti-A and anti-B antibodies.

42. ABO Blood Group

43. Rh Blood Group The Rh blood group was named for the rhesus monkey
Rh positive (Rh+) indicates the presence of D-antigen (or other Rh antigen) on the red blood cell membranes
Rh negative (Rh-) lacks the D-antigen
When Rh- blood is exposed to the D antigen, it becomes sensitized and develops anti-D antibodies
Anti-D antibodies are formed only after a person is exposed to D-antigen (Rh sensitization).

44. erythroblastosis fetalis
The seriousness of the Rh blood group is evident in a fetus that develops the condition erythroblastosis fetalis or hemolytic disease of the newborn.
If the mother is Rh- and has been sensitized to the D-antigen, her own antibodies may attack the red blood cells of a fetus that is Rh+.

45. erythroblastosis fetalis
Erythroblastosis fetalis can be prevented for women at high risk by administering a serum that contains anti-D antibodies into the mother during the pregnancy and after birth (before she becomes sensitized to D-antigen).
The injected antibodies quickly agglutinate any fetal red blood cells, thereby preventing her from becoming sensitized to the D-antigen.
End of Section 2 of 2.