Blood
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The
Connective
Tissue of
the
Circulatory
System
Objectives
Describe three functions of blood
 Describe the composition of blood
 Describe the three types of blood cells
 Explain the formation of blood cells
 Explain the breakdown of RBC’s and the
formation of bilirubin
 Identify the steps of hemostasis
 Describe the four blood types
 Describe the Rh factor

Functions of Blood
 Transport
– Oxygen to cells, wastes from cells,
nutrients, ions, hormones
 Regulation
– Fluid and electrolyte balance, acid-base
balance, body temperature
 Protection
– From infection, coagulation prevents
excessive blood loss
Properties of Blood
Blood Volume and Composition
–
8% of body weight
–
Avg. adult has 5 liters
–
Blood is
1.
55% plasma
–
2.
water, amino acids, proteins, carbohydrates, lipids,
vitamins, hormones, electrolytes, wastes
45% cells formed elements
–
hematocrit or packed cell volume
–
99% of blood cells are RBC’s
–
remainder (< 1%) is white blood cells and blood platelets
Hematocrit Procedure
The hematocrit procedure is a test to
determine the percentage of RBC’s
found in whole blood.
Click here to view a demonstration of this
process.
Composition of Blood
Click here to visit Get Body
Smart for an introduction to
blood composition and
formed elements
Test your skills
Click here to visit Hole’s
Human Anatomy and
Physiology site and label
the components of blood
diagram.
Origin of Blood Cells
 Hematopoiesis
formation
is blood cell
– Two types

Red bone marrow
– Found in flat and irregular bones

Lymphatic tissue
– Found in spleen, lymph nodes, and thymus
gland
 All
cells begin as stem cells
– Changes in stem cells allow the formation
of erythrocytes, leukocytes, and
thrombocytes
The diagram below shows the formation of different
types of blood cells from a the stem cell
Click here to download
A diagram of blood
Cell formation
 Erythrocytes
Small, biconcave discs 7.5 um
 Mature cells lack nuclei, cannot divide or
synthesize proteins
 Red blood cells lack mitochondria and produce
ATP through glycolysis only
 1/3 hemoglobin 2/3 membrane water electrolytes
 Oxygenated blood is bright red
 Deoxygenated is darker, bluish red
 Someone who has oxygen deficiency may become
cyanotic-giving a bluish tint

Erythrocytes
 Concave
shapethinner in center,
allows for greater
Click here to
surface area for gases Participate in a
to permeate
demonstration
Of RBC’s
 Nucleus during early
stages..No nucleus
later to take up room.
Hemoglobin
Found in RBC’s
 Made of globin (protein) & heme (ironcontaining substance.
 Oxyhemoglobin transports oxygen
 Carbaminohemoglobin transports carbon
dioxide.
 Blood appears red when oxygenated and
blue-red when deprived of oxygen.

Erythrocyte Homeostasis
 Classic
negative feedback control
– drop in RBC count causes hypoxemia to
kidneys
– Erythropoietin (hormone) production increases
– stimulation of bone marrow
– RBC count increases in 3-4 days
 Stimulus
for erythropoiesis
– low levels of atmospheric O2
– increase in exercise
– hemorrhaging
Hemoglobin Structure
Hemoglobin consists of 4 protein chains
called globins (2 alpha & 2 beta)
 Each protein chain is connected with a heme
group which binds oxygen to ferrous ion
(Fe+2)
 Hemoglobin molecule can carry four O2

Click here to investigate hemoglobin
Removal & Breakdown of RBC’s
Average life span is 120 days
 Tissue macrophage system detects worn out
cells and phagocytose them
 Takes place in spleen, liver, and RBM
 Hemoglobin is broken down into

– Globin – returns to amino acids & reused
– Heme – iron portion returns to marrow and is
used to make new hemoglobin – bile pigments
(bilirubin) are excreted in bile or feces.
More on
Erythrocytes and Hemoglobin…

RBC count & hemoglobin concentration indicate
the amount of oxygen the blood can carry
– hematocrit is % of blood composed of cells

men 42-52% cells; women 37-48% cells
– hemoglobin concentration of whole blood

men 13-18g/dL; women 12-16g/dL
– RBC count

men 4.6-6.2 million/L; women 4-2-5.4 million/L
– Values are lower in women


androgens stimulate RBC production
women have periodic menstrual losses
Leukocytes or WBC’s
Large
 Contain nuclei
 Lack hemoglobin – appear white
 Less numerous than RBC’s
 Protect body from pathogens
 Can squeeze through blood vessels and
move to site of infection
 Remove dead tissue and cellular debris

FYI
An extraordinary and prolonged
proliferation of leukocytes is known
as leukemia. This overproduction
suppresses the production of
normal blood cells. Conversely, a
sharp decrease in the number of
leukocytes (leukopenia) strips the
blood of its defense against
infection and is an equally serious
condition. A dramatic fall in levels
of certain white blood cells occurs
in persons with AIDS.
Leukocytes (White Blood Cells)
Leukocytes as well as
erythrocytes are formed from
stem cells in the bone
marrow. They have nuclei and
are classified into two groups:
granulocytes and
agranulocytes.
WBC Differentiation
 Click
here to view how a white blood
cell differentiation test is performed.
 Click
here to participate in a WBC
differential test.
Granulocytes
The granulocytes form in the bone
marrow and account for about
70% of all white blood cells.
Granulocytes include three types
of cells: neutrophils, eosinophils,
and basophils. Neutrophils
constitute the vast majority of
granulocytes. They travel about
by ameboid movement and can
surround and destroy bacteria
and other foreign particles.
Granulocytes
The eosinophils, ordinarily about 2%
of the granulocyte count, increase
in number in the presence of
allergic disorders and parasitic
infestations. The basophils account
for about 1% of the granulocytes.
They release chemicals such as
histamine and play a role in the
inflammatory response to infection.
Agranulocytes

The agranulocytes include the
monocytes and the lymphocytes.
Monocytes are derived from the
phagocytic cells that line many
vascular and lymph channels, called
the tissue macrophage system.
Monocytes ordinarily number 4% to
8% of the white cells.
Agranulocytes

They move to areas of infection,
where they are transformed into
macrophages, large phagocytic cells
that trap and destroy organisms left
behind by the granulocytes and
lymphocytes. In certain diseases of
long duration (tuberculosis, malaria,
and typhoid) the monocytes act as
the main instrument of defense.

Lymphocytes, under normal conditions,
make up about 20 to 35% of all white
cells, but proliferate rapidly in the face of
infection. There are two basic types of
lymphocytes: the B lymphocytes and the T
lymphocytes. B lymphocytes tend to
migrate into the connective tissue, where
they develop into plasma cells that
produce highly specific antibodies against
foreign antigens.

Other B lymphocytes act as memory
cells, ready for subsequent infection by
the same organism. Some T
lymphocytes kill invading cells directly;
Others interact with other immune
system cells, regulating the immune
response.
Thrombocytes
Platelets (or thrombocytes) are very small
cellular components of blood that help the
clotting process by sticking to the lining of blood
vessels. Platelets are made in the bone marrow
and survive in the circulatory system for an
average of 9–10 days before being removed from
the body by the spleen. The platelet is vital to life,
because it helps prevent massive blood loss
resulting from trauma, as well as blood vessel
leakage that would otherwise occur in the course
of normal, day-to-day activity.
Thrombocytes
The arrows on this slide point to platelets or thrombocytes.
Click here to copy
And paste a
Picture of thrombocytes
ABO Blood Groups
Blood types are
determined by identifying
specific markers found on
red blood cells. Click here
to view the four blood
groups possible.
Rh Factor
In addition to the four blood
types, blood may be Rh+ or
Rh-. Click here for an
explanation of the Rh factor.
U.S. Blood Type Distribution

According to the American Association of Blood Banking, these are
the percentages of different blood types in the U.S. population:
A+ 34 percent

A-
6 percent

B+
9 percent

B-
2 percent

AB+ 3 percent

AB-
1 percent

O+
38 percent

O-
7 percent

Blood Typing Procedure
Blood types are determined by a simple
lab procedure. Click here to watch the
blood typing procedure.
Online Activities
Click here to participate in three
different online quizzes.
Click here to visit an excellent
source of Anatomy & Physiology I
Tutoring Links