anatomy and physiology of blood

1. The Cardiovascular System

2. BLOOD
• Learning Outcomes:
1. List and describe the components of blood.
2. Give the functions of red blood cells, the
different types of white blood cells, and
platelets.
3. List the substances normally found in plasma.
4. Explain the differences among blood types A, B,
AB, and O.
5. Explain the difference between Rh-positive
blood and Rh-negative blood.
6. Explain the process of blood clotting.

3. BLOOD
• Blood is a specialized type of connective tissue
in which living blood cells, the formed
elements, are suspended in a nonliving fluid
matrix called plasma . The collagen and elastic
fibers are absent from blood.
• It is formed in the redbone marrow by the
process called hematopoiesis and the blood
forming tissue is called the hematopoieic
tissue.

4. Stages of Differentiation of Blood
Cells
Figure 17.9

6. Composition of blood
• Forms about 8% of the total body weight in an
average person.
• Has a liquid part called plasma which forms
about 55% of the total whole blood volume
and also formed elements of about 45%
• Formed elements include ;
– RBC/erythrocytes
– WBC/leukocytes
– PLATELETS/thrombocytes

7. characteristics
• Blood is a sticky, opaque fluid with a
characteristic metallic taste
• the color of blood varies from scarlet (oxygen
rich) to dark red (oxygen poor).
• slightly alkaline, with a pH between 7.35 and
7.45, and its temperature (38°C
• average volume in healthy adult males is 5–6L,
healthy adult females (4–5 L)

8. Blood plasma
• It is the fluid portion of blood.it accounts for
55% of total blood volume.about 90% of plasma
is water,proteins make 8% while solutes make
2%. Plasma proteins include:
– Albumin 60%
– Globulin 36% antibodies, transport hormones
– Fibrinogen 4% for blood clotting
solutes include ions(Na, K) nutrients, waste
products(urea,creatinine, uric acid),gases(O2
CO2,N2), regulatory enzymes(hormones)

9. Formed Elements
• The formed elements of blood;
– erythrocytes
– leukocytes
– platelets

10. Erythrocytes
• Most numerous of the formed elements 45%
• Structural Characteristics
– lack a nucleus (are anucleate) and have essentially
no organelles.
– Shaped like biconcave discs—flattened discs with
depressed centers ;they appear lighter in color at
their thin centers than at their edges
– Have hemoglobin (Hb), the RBC protein that
functions in gas transport.
• Females: 4.3–5.2 million cells/mm³
• Males: 5.2–5.8 million cells/ mm³
• Live 100–120 days

11. An Erythrocyte
Figure 17.3

12. Function
• respiratory gas (oxygen and carbon dioxide)
transport.
Hemoglobin,
• the protein that makes red blood cells red, binds
easily and reversibly with oxygen, and most
oxygen carried in blood is bound to hemoglobin.
Normal values for hemoglobin are 14–20 g/dl in
infants, 13–18 g/dl in adult males, and 12–16
g/dl in adult females

13. cont’
• protein globin bound to the red heme
pigment. Globin consists of four polypeptide
chains—two alpha (α) and two beta (β)—each
bound to a ringlike heme group.
• Oxygen +haemoglobin=oxyhemoglobin
• CO2 + hemoglobin=carbaminohemoglobin

14. Production of Erythrocytes
• They are produced in the red bonemarrow
through the process of erythropoiesis which is
stimulated by the hormone erythropoietin
released by the kidney but is also released by
the liver in small amounts.
• Erythropoietin is released in response to
hypoxia.
• Rbcs are destroyed by the spleen and the liver
due to old age, abnormality or damage through
the process of hemolysis which produces heme
and globin.

15. • The globin is converted into amino acids while
the heme is further broken down to iron and
bilirubin which is taken to the liver for
excretion.

16. Leukocytes
• Leukocytes are crucial to our defense against
disease.They form a mobile army that helps
protect the body from damage by bacteria,
viruses, parasites, toxins, and tumor cells. As
such, they have some special functional
characteristics. they account for less than 1%
of the formed elements. On average, there
are 4800–10,800 WBCs/mm3 of blood.

17. • Leukocytes are grouped into two major
categories on the basis of structural and
chemical characteristics:
– Granulocytes contain obvious membrane-bound
cytoplasmic granules
– agranulocytes lack obvious granules

18. Granulocytes
which include:
• neutrophils
• basophils
• eosinophils

19. Neutrophils
• the most numerous of the white blood cells,
account for 50–70% of the WBC population.
They are also called polymorphonuclear
leukocytes.
• Their nuclear has 2-3 more lobes. They are
mobile,phagocytic and are capable of moving
out of blood capillaries in a process called
diapedesis and have an enzyme that digests
microbes

20. • They are attracted to areas of inflammation
and infection and are increased in cases of
infection , tissue damage,leukemia,heavy
smoking, use of oral pills.

21. Eosinophils
• account for 2–4% of all leukocytes.
• it has two lobes connected by a broad band of
nuclear material
• lead the counter attack against parasitic worms,
such as flatworms (tapeworms and flukes) and
roundworms (pinworms and hookworms) that
are too large to be phagocytized.
• lessen the severity of allergies by inactivating
certain inflammatory chemicals released during
allergic reactions.

22. Basophils
• rarest white blood cells, averaging only 0.5–
1% of the leukocyte population.
• Their cytoplasm contains large, coarse,
histamine-containing granules that acts as a
vasodilator (makes blood vessels dilate) and
attracts other white blood cells to the
inflamed site.

23. Agranulocytes
include
• lymphocytes
• monocytes

24. Lymphocytes
• accounting for 25% or more of the WBC
population, are the second most numerous
leukocytes in the blood.
• T lymphocytes (T cells) function in the immune
response by acting directly against virus-
infected cells and tumor cells.
• B lymphocytes (B cells) give rise to plasma
cells, which produce antibodies
(immunoglobulins) that are released to the
blood.

25. Function of a Cytotoxic T
Lymphocyte
Figure 17.6a

26. Function of a B Lymphocyte
Figure 17.6b

27. Monocytes
• which account for 3–8% of WBCs and are the
largest leukocytes.
• When circulating monocytes leave the
bloodstream and enter the tissues, they
differentiate into highly mobile macrophages .
Macrophages are actively phagocytic, and they
are crucial in the body’s defense against viruses,
bacteria.

28. Cont’
• The macrophages include:
– Histiocytes-connective tissue
– Synovial cells-joints
– Langerhans cells-skin
– Microglia-brain
– Kupffer cells-liver
– Sinus lining macrophages reticular cells in the
spleen,lymphnodes and thymus gland
– Mesangial cells-kidney
– Osteoclasts-bones
– Alveolar macrophages-lungs

29. Production of WBC
• Leukopoiesis- the production of white blood
cells
• Granulocytes and a few lymphoctes and
monocytes originate in the bone marrow.
• Monocytes and lymphoctes develop in the
lymphatic tissue.
• Their lifespan is 5-9days.

30. Platelets
• are essential for the clotting process that
occurs in plasma when blood vessels are
ruptured or their lining is injured. By sticking
to the damaged site, platelets form a
temporary plug that helps seal the break.
• They are about 150,000/mm³-400,000/mm³ .
• Their lifespan is about 7-10days.

31. Blood types/groups
• antigen /agglutinogens-proteins present on
the RBC membranes.
• The most important antigens include;A,B, Rh
• Agglutinins are antibodies dissolved in plasma
that react with specific blood group antigen.
The agglutinins act against RBCs carrying ABO
antigens that are not present on a person’s
own red blood cells.

32. THE ABO SYSTEM
• Blood type is named according to the antigen
present on the RBC membrane. That is antigen
A and B.
• Blood type O has no antigen
• Blood type AB has both antigen A and B
• Blood type A has antigen A
• Blood type B has antigen type B

33. CONT’
• Blood plasma may or may not contain preformed
antibodies that can react with the RBC antigens A or
B.
• Plasma will never contain antibodies against antigen
present on its RBC as they would react and destroy
it. equally plasma will contain antibodies against
antigen A or B if not present on the RBC
• Therefore, a type A person has anti-B antibodies in
the plasma; a type B person has anti-A antibodies; a
type AB person has neither anti-A nor anti-B
antibodies; and a type O person has both anti-A and
anti-B antibodies

35. For example,
let us say that a type A person needs a transfusion to
replace blood lost in hemorrhage. If this person were to
receive type B blood, what would happen? The type A
recipient has anti-B antibodies that would bind to the type
B antigens of the RBCs of the donated blood.
The type B RBCs would first clump (agglutination) then
rupture (hemolysis), thus defeating the purpose of the
transfusion. An even more serious consequence is that the
hemoglobin of the ruptured RBCs, now called free
hemoglobin, may clog the capillaries of the kidneys and
lead to renal damage or renal failure.
Blood grouping and cross matching is therefore important
before blood transfusion.

36. RHESUS SYSTEM
• This are agglutinogens on the RBC called rhesus
factor. Those with the antigen Rh are called
rhesus positive while those without are called
rhesus negative.
• Unlike the ABO system antibodies, anti-Rh
antibodies are not spontaneously formed in the
blood of Rh– (Rh negative) individuals. However,
if an Rh– person receives Rh+ blood, the immune
system becomes sensitized and begins producing
anti-Rh antibodies against the foreign antigen
soon after the transfusion

37. • Hemolysis does not occur after the first such
transfusion because it takes time for the body
to react and start making antibodies. But the
second time, and every time thereafter, a
typical transfusion reaction occurs in which
the recipient’s antibodies attack and rupture
the donor RBCs.

38. COAGULATION / BLOOD CLOTTING
• It is the process of forming a network of
impermeable plug across the injured part of the
body in order to stop bleeding and prevent loss of
vital body fluid. It involves a series of chemical
reactions that take place in a definite and rapid
sequence that results in a net of fibers that trap
the RBCs.
• Critical components for this process include;
– Prothrombin
– Thrombin
– Fibrinogen and fibrin.

39. Phases of blood clotting
It is a multistep process that leads to its critically
important last three phases:
1. A complex substance called prothrombin
activator is formed.
2. Prothrombin activator converts a plasma protein
called prothrombin into thrombin, an enzyme.
3. Thrombin catalyzes the joining of fibrinogen
molecules present in plasma to a fibrin mesh,
which traps blood cells and effectively seals the
hole until the blood vessel can be permanently
repaired.

40. Phase 1: Two Pathways to
Prothrombin Activator
• Clotting may be initiated by either the intrinsic
or the extrinsic pathway .Both lead to
formation of prothrombin activator required
in phase 2.
• In the extrinsic pathway damaged tissues
release chemicals(thromboplastin ,tissue
factor,factor iii) that trigger the events that
eventually result in prothrombin activator

41. • In intrinsic pathway all factors needed for
clotting are present in the blood.

42. Phase 2: Common Pathway to
Thrombin
• Prothrombin activator with Ca2+ catalyzes the
transformation of the plasma protein
prothrombin to the active enzyme thrombin

43. Phase 3: Common Pathway to the
Fibrin Mesh
• The thrombin formed in phase 2 catalyzes the
formation of fibrin from fibrinogen together
with Ca2+. The fibrin glues the platelets
together and make a web that forms the
structural basis of the clot.
• Clot formation is normally complete within 3
to 6 minutes after blood vessel damage

44. Fibrinolysis
• It’s the removal of unneeded clots when
healing has occurred. Blood normally contains
an inactive substance/plasma protein called
plasminogen.it is activated whenever a clot is
formed into plasmin ie a fibrin digestive
enzyme.
• Plasmin hydrolyzes fibrin and dissolve them.