Transcript Blood Cells

Hole’s Human Anatomy
and Physiology
Twelfth Edition
Shier w Butler w Lewis
Chapter
14
Blood
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1
14.1: Introduction
Blood:
• Is connective tissue
• Transports vital
substances (Like what?)
• Maintains stability of
interstitial fluid
• Distributes heat
Blood cells:
• Form mostly in red bone
marrow and are:
• Red blood cells (RBCs)
• White blood cells (WBCs)
• Platelets (cell fragments)
• The amount of blood varies with body size, changes in
fluid concentration, changes in electrolyte concentration,
and amount of adipose tissue (Why these changes?)
• Blood is about 8% of body weight
• Adult blood volume is about 5 liters
2
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Centrifuged Blood Sample
Liquid (plasma)
“Buffy coat” (white blood cells and platelets)
Red blood cells
Peripheral Blood Smear
White blood
cells
Red blood cells
Platelets
3
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Capillary tube
Plasma = 55%
Buffy coat
Red cells = 45%
(hematocrit)
Plug
4
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Blood
45%
55%
Plasma
Formed elements
Platelets
Red blood cells
White blood cells
(4.8%)
(95.1%)
(0.1%)
Electrolytes
Water
(92%)
Proteins
Wastes
Nutrients
(7%)
Gases
Vitamins
Hormones
Neutrophils
Eosinophils
Basophils
Monocytes
Lymphocytes
(54–62%)
(1–3%)
(<1%)
(3–9%)
(25–33%)
Albumins
Globulins
Fibrinogen
N2
O2
5
CO2
14.2: Blood Cells
• Blood cells originate in red marrow from hemocytoblasts or
hematopoietic stem cells
• Stem cells can then:
• Give rise to more stem cells
• Specialize or differentiate
6
The Origin of Blood Cells
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Hematopoietic stem cell
Myeloid stem cell
Myeloblast
Monoblast
Megakaryoblast
In red bone marrow
Proerythroblast
Lymphoid stem cell
Lymphoblast
T cell
precursor
Lymphoblast
B cell
precursor
Progranulocyte
Erythroblast
Neutrophilic Basophilic Eosinophilic
myelocyte myelocyte myelocyte
Promonocyte
Prolymphocyte Prolymphocyte
Normoblast
Megakaryocyte
Reticulocyte
Activated in tissues
In circulating blood
(some cells)
Neutrophilic Basophilic Eosinophilic
band cell band cell
band cell
Erythrocyte
Thrombocytes
(platelets)
T lymphocyte
Neutrophil
Basophil
Eosinophil
Agranulocytes
Granulocytes
Macrophage
(a)
(b)
B lymphocyte
Monocyte
Plasma cell
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Characteristics of Red Blood Cells
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Red blood cells are:
• Erythrocytes
• Biconcave discs
• One-third hemoglobin or:
• Oxyhemoglobin
• Deoxyhemoglobin
• Able to readily squeeze through
capillaries
• Lack nuclei and mitochondria –
(Can they reproduce or metabolize?)
Top view
7.5 micrometers
2.0 micrometers
Sectional view
(a)
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(b)
b: © Bill Longcore/Photo Researchers, Inc.
Red Blood Cell Counts
• RBC counts is the number of RBCs in a cubic millimeter
or microliter of blood
• It may vary depending on age and health
• Typical ranges include:
• 4,600,000 – 6,200,000 in males (Why so high?)
• 4,200,000 – 5,400,000 in adult females (Why so low?)
• 4,500,000 – 5,100,000 in children (Why more than
women?)
• RBC counts reflect blood’s oxygen carrying capacity
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Red Blood Cell Production
and Its Control
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• Low blood oxygen causes
the kidneys and the liver to
release erythropoietin
(EPO) which stimulates
RBC production
• This is a negative
feedback mechanism
(What does this mean?)
• Within a few days many
new blood cells appear in
the circulating blood
Low blood oxygen
Liver
Kidney
Release into
bloodstream
Stimulation
Inhibition
–
Erythropoietin
Bloodstream
+
Increased
oxygencarrying
capacity
Increased
number of
red blood
cells
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Red bone marrow
Dietary Factors Affecting Red
Blood Cell Production
• Vitamin B12 and folic acid are necessary
• They are required for DNA synthesis, making them
necessary for the growth and division of all cells
• Iron is also necessary
• It is required for hemoglobin synthesis
11
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Red bone
marrow
Bone
3 Red blood
cells produced
Nutrients
from food
2 Blood transports
absorbed nutrients
1 Absorption
Vitamin B12
Folic acid
Iron
4 Red blood cells
circulate in
bloodstream for
about 120 days
5
Macrophage
Old red
blood cells
6 Hemoglobin
Blood
Globin + Heme
7
Iron + Biliverdin
Bile
Liver
Bilirubin
Small
intestine
8
12
Destruction of Red Blood Cells
13
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(a)
(b)
a: © The McGraw-Hill Companies, Inc./Al Telser, photographer :b © Ed Reschke
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Types of White Blood Cells
• White blood cells:
• Are leukocytes
• Protect against disease
• WBC hormones are interleukins and colony-stimulating
factors which stimulate development
• There are five types of WBCs in two categories:
• Granulocytes
• Neutrophils
• Eosinophils
• Basophils
• Agranulocytes
• Lymphocytes
• Monocytes
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Neutrophils
• Light purple granules in acid-base
(neutral) stain
• Lobed nucleus
• Other names
• Segs
• Polymorphonuclear leukocyte
• Bands (young neutrophils)
• First to arrive at infections
• Phagocytic (What is this?)
• 54% - 62% of leukocytes
• Elevated in bacterial infections
(Why?)
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© Ed Reschke
16
Eosinophils
• Deep red granules in acid
stain
• Bi-lobed nucleus
• Moderate allergic reactions
• Defend against parasitic
worm infestations
• 1% - 3% of leukocytes
• Elevated in parasitic worm
infections and allergic
reactions
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© Ed Reschke
17
Basophils
• Deep blue granules in basic
stain
• Release histamine (What
does this do?)
• Release heparin (What
does this do?)
• Less than 1% of leukocytes
• Similar to eosinophils in
size and shape of nuclei
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© Ed Reschke
18
Monocytes
• Largest of all blood cells
• Spherical, kidney-shaped,
oval or lobed nuclei
• May leave bloodstream to
become macrophages
• 3% - 9% of leukocytes
• Phagocytize bacteria, dead
cells, and other debris
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© R. Kessel/Visuals Unlimited
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Lymphocytes
• Slightly larger than RBC
• Large spherical nucleus
surrounded by thin rim of
cytoplasm
• T cells and B cells (Why are
they named this?)
• Both important in
immunity
• B cells produce antibodies
• 25% - 33% of leukocytes
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© Ed Reschke
20
Functions of White Blood Cells
• WBCs protect against infection
• These leukocytes can squeeze between the cells of
a capillary wall and enter the tissue space outside the
blood vessel (called diapedesis)
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Connective
tissue
Blood capillary
Leukocyte
21
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1 Splinter
punctures
epidermis
2 Bacteria are introduced
into the dermis
3 Bacteria
multiply
4 Injured cells
release histamine,
causing blood
vessels to dilate
Epidermis
Dermis
Blood vessels
5
Neutrophils move through
blood vessel walls and
migrate toward bacteria
6 Neutrophils destroy
bacteria by phagocytosis
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White Blood Cell Counts
• A procedure used to count number of WBCs per cubic
millimeter of blood
• Typically 5,000 – 10,000 per cubic millimeter of blood
• Leukopenia:
• Low WBC count (below 5,000)
• Typhoid fever, flu, measles, mumps, chicken pox, AIDS
(Why?)
• Leukocytosis:
• High WBC count (above 10,000)
• Acute infections, vigorous exercise, great loss of body
fluids (Why?)
• Differential WBC count
• Lists percentages of types of leukocytes
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• May change in particular diseases
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Blood Platelets
• Platelets are also known as thrombocytes
• They are cell fragments of megakaryocytes
• They lack a nucleus and are roughly half the size of a RBC
• There are approximately 130,000 – 360,000 per cubic
millimeter of blood
• They help repair damaged blood vessels by sticking to
broken surfaces
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14.3: Blood Plasma
• Blood plasma is:
• Straw colored
• The liquid portion of blood
• 55% of blood volume
• 92% water
• Function includes transporting nutrients, gases, and
vitamins
• Helps regulate fluid and electrolyte balance and
maintain pH (How?)
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Plasma Proteins
• These are the most abundant dissolved substances
(solutes) in plasma
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Gases and Nutrients
• The most important blood gases:
• Oxygen
• Carbon dioxide
• Plasma nutrients include:
• Amino acids
• Simple sugars
• Nucleotides
• Lipids
• Fats (triglycerides)
• Phospholipids
• Cholesterol
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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 (What’s catabolism?)
• Uric acid – product of nucleic acid catabolism (When
would this happen?)
• Amino acids – product of protein catabolism
• Creatine – stores phosphates (For what purposes?)
• Creatinine – product of creatine metabolism
• BUN – blood urea nitrogen; indicates health of kidney
(Why is this an indicator of kidney health?)
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Plasma Electrolytes
• Plasma contains a variety of these ions called electrolytes
• They are absorbed from the intestine or released as byproducts of cellular metabolism (What are they used for?)
• They include:
• Sodium (most abundant with chloride)
• Potassium
• Calcium
• Magnesium
• Chloride (most abundant with sodium)
• Bicarbonate
• Phosphate
• Sulfate
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14.4: Hemostasis
• Hemostasis refers to the stoppage of bleeding
• Actions that limit or prevent blood loss include:
• Blood vessel spasm
• Platelet plug formation
• Blood coagulation
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Blood Vessel Spasm
• Blood vessel spasm
• Triggered by pain receptors, platelet release, or
serotonin
• Smooth muscle in blood vessel contracts (What does
this do?)
33
Platelet Plug Formation
• Platelet plug formation
• Triggered by exposure of platelets to collagen
• Platelets adhere to rough surface to form a plug
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Endothelial lining
Collagen fiber
1 Break in
vessel wall
Platelet
Red blood cell
2 Blood escaping
through break
3 Platelets adhere
to each othe ,
to end of broken
vessel, and to
exposed collagen
4 Platelet plug
helps control
blood loss
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Blood Coagulation
• Blood coagulation
• Triggered by cellular damage and blood contact with
foreign surfaces
• A blood clot forms
• This is a:
• Hemostatic mechanism
• Causes the formation of a blood clot via a series of
reactions which activates the next in a cascade
• Occurs extrinsically or intrinsically
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Extrinsic Clotting Mechanism
• Extrinsic clotting mechanism
• Chemical outside of blood vessel triggers blood
coagulation
• Triggered by tissue thromboplastin (factor III) (not
found in blood)
• A number of events occur that includes factor VII,
factor X, factor V, factor IV, and factor II (prothrombin)
• Triggered when blood contacts damaged blood vessel
walls or tissues
• This is an example of a positive feedback mechanism
(Why? How does this differ from a negative feedback
mechanism?)
37
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© SPL/Photo Researchers, Inc.
38
Intrinsic Clotting Mechanism
• Intrinsic clotting mechanism
• Chemical inside blood triggers blood coagulation
• Triggered by Hageman factor XII (found inside blood)
• Factor XII activates factor XI which activates IX which
joins with factor VIII to activate factor X
• Triggered when blood contacts a foreign surface (Can
you think of an example?)
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40
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Extrinsic Clotting
Mechanism
Intrinsic Clotting
Mechanism
Tissue damage
Blood contacts
foreign surface
Releases
Activates
Tissue thromboplastin
(Factor lll)
Activates
Hageman Factor Xll
(Ca+2)
Activates
Factor Vll
Activates
Factor Xl
(Ca+2)
Activates
Factor X
Factor lX
Activates
Factor V
(Ca+2)
Activates
Factor Vlll
platelet phospholipids
Factor X
(Ca+2)
Activates
Factor V
(Ca+2)
Prothrombin
activator
Converts
Thrombin
(Factor lla)
Prothrombin
(Factor ll)
Converts
Fibrinogen
(Factor l)
Fibrin
Factor Xlll
Stabilizes
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Fibrin
clot
Fate of Blood Clots
• 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
• A thrombus is an abnormal blood clot
• An embolus is a blood clot moving through the blood vessels
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Prevention of Coagulation
• The smooth lining of blood vessels discourages the
accumulation of platelets and clotting factors
• As a clot forms fibrin absorbs thrombin and prevents the
clotting reaction from spreading
• Anti-thrombin inactivates additional thrombin by binding to
it and blocking its action on fibrinogen
• Some cells such as basophils and mast cells secrete heparin
(an anticoagulant)
43
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Lumen
(a)
Artery wall
Lumen
Plaque
Artery wall
(b)
© The McGraw-Hill Companies, Inc./Al Telser, photographer
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14.5: Blood Groups
and Transfusions
• In 1910, identification of the ABO blood antigen gene
explained the observed blood type incompatibilities
• Today there are 31 different genes known to contribute to the
surface features of RBCs determining compatibility between
blood types
46
Antigens and Antibodies
• Terms to become familiar with:
• Agglutination – clumping of red blood cells in response
to a reaction between an antibody and an antigen
• Antigens – a chemical that stimulates cells to produce
antibodies
• Antibodies – a protein that reacts against a specific
antigen
47
ABO Blood Group
• Based on the presence or absence of two major antigens on
red blood cell membranes
• Antigen A
• Antigen B
48
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Red blood cell
Red blood cell
Anti-B antibody
Anti-A antibody
Antigen A
Antigen B
Type B blood
Type A blood
Red blood cell
Anti-A antibody
Anti-B antibody
Antigen A
Antigen B
Red blood cell
Type AB blood
Type O blood
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Red blood cell
Agglutinated red
blood cells
Antigen A
Anti-B antibody
(a)
(c)
Anti-A antibody
(b)
(d)
c: © G.W. Willis/Visuals Unlimited; figure d: © George W. Wilder/Visuals Unlimited
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Rh Blood Group
• The Rh blood group was named for the rhesus monkey
• The group includes several Rh antigens or factors
• Rh positive – presence of antigen D or other Rh antigens on
the red blood cell membranes
• Rh negative – lack of these antigens
• The seriousness of the Rh blood group is evident in a fetus
that develops the condition erythroblastosis fetalis or
hemolytic disease of the newborn (How does this happen?)
52
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– –
–
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+ + +
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+
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Rh-negative
woman with
Rh-positive
fetus
– –
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Cells from
Rh-positive
fetus enter
woman’s
bloodstream
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Woman
becomes
sensitized—
antibodies ( + )
form to fight
Rh-positive
blood cells
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In the next
Rh-positive
pregnancy,
maternal
antibodies
attack fetal red
blood cells
53
Important Points in Chapter 14:
Outcomes to be Assessed
14.1: Introduction
 Describe the general characteristics of blood and discuss its major
functions.
 Distinguish among the formed elements of blood and the liquid
portion of blood.
14.2: Blood Cells
 Describe the origin of blood cells.
 Explain the significance of red blood cells counts and how they are
used to diagnose disease.
 Discuss the life cycle of a red blood cell.
 Summarize the control of red blood cell production.
54
Important Points in Chapter 14:
Outcomes to be Assessed
 Distinguish among the five types of white blood cells and give the
function(s) of each type.
 Describe a blood platelet and explain its functions.
14.3: Blood Plasma
 Describe the functions of each of the major components of plasma.
14.4: Hemostasis
 Define hemostasis and explain the mechanisms that help to achieve it.
 Review the major steps in coagulation.
 Explain how to prevent coagulation.
55
Important Points in Chapter 14:
Outcomes to be Assessed
14.5: Blood Groups and Transfusions
 Explain blood typing and how it is used to avoid adverse reactions
following blood transfusions.
 Describe how blood reactions may occur between fetal and maternal
tissues.
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