This chapter discusses the composition and functions of blood. Blood transports gases, nutrients, waste products, and regulatory molecules. It is composed of plasma and formed elements, including erythrocytes, leukocytes, and thrombocytes. Erythrocytes contain hemoglobin and transport oxygen, while leukocytes help fight infection. Platelets help form blood clots to prevent blood loss from damaged vessels. Blood grouping involves antigens and antibodies that determine blood type.

1. Seeley’s
ESSENTIALS OF
Anatomy &
Physiology
Tenth Edition
Cinnamon Vanputte
Jennifer Regan
Andrew Russo

2. 2
Chapter 11
Blood
Lecture Outline

3. 3
Functions of Blood
1. Transport of gases, nutrients and waste products
2. Transport of processed molecules
3. Transport of regulatory molecules
4. Regulation of pH and osmosis
5. Maintenance of body temperature
6. Protection against foreign substances
7. Clot formation

4. 4
Composition of Blood1
Plasma:
• 55% of total blood
• pale, yellow liquid that surrounds cells
• 91% water, 7% proteins, and 2% other
Formed Elements:
• 45% of total blood
• cells and cell fragments
• erythrocytes, leukocytes, thrombocytes

5. 5
Plasma Proteins
Albumin:
• 58% of plasma proteins
• helps maintain water balance
Globulins:
• 38% of plasma proteins
• helps immune system
Fibrinogen:
• 4% of plasma proteins
• aids in clot formation

6. 6
Composition of Blood2
Figure 11.1

7. 7
Hematopoiesis1
Hematopoiesis is the process that produces formed elements.
In the fetus, hematopoiesis occurs in several tissues, including
the liver, thymus, spleen, lymph nodes, and red bone marrow.
After birth, hematopoiesis is confined primarily to red bone
marrow, but some white blood cells are produced in lymphatic
tissues.

8. 8
Hematopoiesis2
All the formed elements of blood are derived from a single
population of cells called stem cells, or hemocytoblasts.
These stem cells differentiate to give rise to different cell lines,
each of which ends with the formation of a particular type of
formed element.

9. 9
Hematopoiesis3
Figure 11.2

10. 10
Erythrocytes
Red blood cells (RBC)
Disk-shaped with thick
edges
Nucleus is lost during
development
Live for 120 days
Function:
transport O2 to tissues
Figure 11.3

11. 11
Hemoglobin1
Main component of erythrocytes
• Transports O2
• Each globin protein is attached to a heme molecule
• Each heme contains one iron atom
• O2 binds to iron
Oxyhemoglobin:
• hemoglobin with an O2 attached

12. 12
Hemoglobin2
Figure 11.4

13. 13
Production of Erythrocytes
1. Decreased blood O2 levels cause kidneys to increase
production of erythropoietin.
2. Erythropoietin stimulates red bone marrow to produce more
erythrocytes.
3. Increased erythrocytes cause an increase in blood O2 levels.

14. 14
Red Blood Cell Production
Figure 11.5

15. 15
Fate of Old Erythrocytes and Hemoglobin
• Old red blood cells are removed from blood by macrophages
in spleen and liver
• Hemoglobin is broken down
• Globin is broken down into amino acids
• Hemoglobin’s iron is recycled
• Heme is converted to bilirubin
• Bilirubin is taken up by liver and released into small intestine
as part of bile

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Hemoglobin Breakdown
Figure 11.6

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Leukocytes
• White blood cells (WBC)
• Lack hemoglobin
• Larger than erythrocytes
• Contain a nucleus
Functions:
• fight infections
• remove dead cells and debris by phagocytosis

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Types of Leukocytes1
Granulocytes: contain specific granules and
include neutrophils, eosinophils, and basophils
1. Neutrophils:
• most common
• remain in blood for 10 to 12 hours then move to
tissues
• phagocytes

19. 19
Types of Leukocytes2
2. Eosinophils:
• reduce inflammation
• destroy parasites
3. Basophils:
• least common
• release histamine and heparin

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Types of Leukocytes3
Agranulocytes: no specific granules
1. Monocytes:
• largest sized white blood cells
• produce macrophages
2. Lymphocytes:
• immune response
• several different types (T cells and B cells)
• lead to production of antibodies

21. 21
Types of White Blood Cells
Figure 11.8

22. 22
Platelets
• Platelets are minute fragments of cells, each consisting of a small
amount of cytoplasm surrounded by a cell membrane.
• They are produced in the red bone marrow from large cells called
megakaryocytes.
• Small fragments break off from the megakaryocytes and enter the
blood as platelets.
• Platelets play an important role in preventing blood loss.

23. 23
Blood Loss
When blood vessels are damaged, blood can leak into other
tissues and disrupt normal function.
Blood that is lost must be replaced by production of new blood
or by a transfusion.

24. 24
Preventing Blood Loss
1. Vascular spasm:
• temporary constriction of blood vessel
2. Platelet plugs:
• can seal up small breaks in blood vessels
3. Blood clotting (coagulation)

25. 25
Vascular Spasm
• Vascular spasm is an immediate but temporary constriction of a
blood vessel that results when smooth muscle within the wall of
the vessel contracts.
• This constriction can close small vessels completely and stop the
flow of blood through them.
• Vascular spasm is stimulated by chemicals released by cells of the
damaged blood vessel wall and by platelets.

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Platelet Plug Formation1
• A platelet plug is very important in maintaining the integrity of the
damaged blood vessels.
• The formation of a platelet plug can be described as a series of
steps, but in actuality many of these steps occur at the same time.
• Platelet adhesion occurs first, when platelets stick to the exposed
collagen in the damaged blood vessel wall.
• After platelets adhere to collagen, they become activated, change
shape, and release chemicals.

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Platelet Plug Formation2
• In platelet aggregation, fibrinogen forms bridges between the
fibrinogen receptors of numerous platelets, resulting in a
platelet plug.

28. 28
Platelet Plug Formation3
Figure 11.9

29. 29
Blood Clotting
Blood can be transformed from a liquid to a gel
Clot:
• network of thread-like proteins called fibrin that trap blood cells and fluid
• depends on clotting factors
Clotting factors:
• proteins in plasma
• only activated following injury
• made in liver
• require vitamin K

30. 30
Steps in Clot Formation
1. Injury to a blood vessel causes inactive clotting factors to become
activated due to exposed conn. tissue or release of thromboplastin
2. Prothrombinase (clotting factor) is formed and acts upon prothrombin
3. Prothrombin is switched to its active form thrombin
4. Thrombin activates fibrinogen into its active form fibrin
5. Fibrin forms a network that traps blood (clots)

31. 31
Clot Formation
Figure 11.10

32. 32
Clot Formation Control
Clots need to be controlled so they don’t spread throughout the
body
Anticoagulants:
• prevent clots from forming
• Example - heparin and antithrombin
Injury causes enough clotting factors to be activated that
anticoagulants can’t work in that particular area of the body

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Clot Retraction and Fibrinolysis
Clot retraction:
• condensing of clot
• serum in plasma is squeezed out of clot
• helps enhance healing
Fibrinolysis:
• process of dissolving clot
• plasminogen (plasma protein) breaks down clot (fibrin)

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Fibrinolysis
Figure 11.11

35. 35
Blood Grouping
Injury or surgery can lead to a blood transfusion
Transfusion reactions/Aggulination:
• clumping of blood cells (bad)
Antigens:
• molecules on surface of erythrocytes
Antibodies:
• proteins in plasma
Blood groups:
• named according to antigen (ABO)

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ABO Blood Groups1
• In the ABO blood group system, there are two types of antigens
that may appear on the surface of the red blood cells, type A
antigen and type B antigen.
• Type A blood has type A antigens, type B blood has type B
antigens, and type AB blood has both types of antigens.
• Type O blood has neither A nor B antigens.
• The types of antigens found on the surface of the red blood cells
are genetically determined.

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ABO Blood Groups2
• Antibodies against the antigens are usually present in the
plasma of blood.
• Plasma from type A blood contains anti-B antibodies, which
act against type B antigens; plasma from type B blood
contains anti-A antibodies, which act against type A antigens.
• Type AB blood plasma has neither type of antibody, and type
O blood plasma has both anti-A and anti-B antibodies.

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ABO Blood Groups3
• In Caucasians in the United States, the distribution is type O,
47%; type A, 41%; type B, 9%; and type AB, 3%.
• Among African-Americans, the distribution is type O, 46%;
type A, 27%; type B, 20%; and type AB, 7%.

39. 39
ABO Blood Groups
Figure 11.12

40. 40
Agglutination Reaction
Figure 11.13

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Blood Donor and Recipient
According to ABO Blood Types
• O are universal donors because they have no antigens
• Type A can receive A and O blood
• Type B can receive B and O blood
• Type AB can receive A, B, AB blood
• Type O can only receive O blood

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Rh Blood Group
• Rh positive means you have Rh antigens
• 95 to 85% of the population is Rh+
• Antibodies only develop if an Rh- person is exposed to Rh+
blood by transfusion or from mother to fetus

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Rh Incompatibility in Pregnancy
• If mother is Rh- and fetus is Rh+ the mother can be exposed to
Rh+ blood if fetal blood leaks through placenta and mixes with
mother’s blood.
• First time this occurs mother’s blood produces antibodies
against antigens.
• Any repeated mixing of blood causes a reaction.

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Hemolytic Disease of Newborn1
This condition
• occurs when mother produces anti-Rh antibodies that cross placenta
and agglutination and hemolysis of fetal erythrocytes occurs
• can be fatal to fetus
• prevented if mother is treated with RhoGAM which contains
antibodies against Rh antigens

45. 45
Hemolytic Disease of Newborn2
Figure 11.14

46. 46
Diagnostic Blood Tests
Complete blood count:
• provides information such as RBC count, hemoglobin, hematocrit, and
WBC count
Hematocrit:
• % of total blood volume composed of RBC
Hemoglobin:
• determines amount of hemoglobin
• indicate anemia

47. 47
Hematocrit
Figure 11.15

48. 48
Diagnostic Blood Tests2
Prothrombin time:
• time it takes for blood to begin clotting (9 to 12 sec.)
White blood cell count:
• total number of white blood cells

49. 49
Diagnostic Blood Tests3
White blood cell differential count:
• Determines the % of each 5 kinds of leukocytes
• neutrophils: 60 to 70%
• lymphocytes: 20 to 25%
• monocytes: 3 to 8%
• eosinophils: 2 to 4%
• basophils: 0.5 to 1%

50. 50
White Blood Cell Disorders
Leukopenia:
• low white blood cell count
• caused by radiation, chemotherapy drugs, tumors, viral infections
Leukocytosis:
• high white blood cell count
• caused by infections and leukemia