Transcript PowerPoint to accompany Hole’s Human Anatomy and

Chapter 14
Lecture
PowerPoint
1
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14.1: Introduction
Blood:
• Is connective tissue
• Transports vital
substances
• 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
• Blood is about 8% of body weight
• Adult blood volume is about 5 liters
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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
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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%)
Electrolytes
(0.1%)
Water
(92%)
Proteins
(7%)
Wastes
Nutrients
Gases
Vitamins
Hormones
Neutrophils
Eosinophils
Basophils
(54–62%)
(1–3%)
(<1%)
Monocytes Lymphocytes
(3–9%)
Albumins
Globulins
Fibrinogen
N2
O2
(25–33%)
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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
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The Origin of Blood Cells
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Hematopoietic stem cell
Myeloid stem cell
Lymphoid stem cell
Lymphoblast
B cell
precursor
Proerythroblast
In red bone marrow
Myeloblast
Monoblast
Megakaryoblast
Lymphoblast
T cell
precursor
Progranulocyte
Erythroblast
Neutrophilic
myelocyte
Basophilic Eosinophilic
myelocyte myelocyte Promonocyte Prolymphocyte
Prolymphocyte
Normoblast
Megakaryocyte
Activated in tissues
In circulating blood
(some cells)
Reticulocyte
Neutrophilic
band cell
Basophilic Eosinophilic
band cell
band cell
Erythrocyte Thrombocytes
(platelets) NeutrophilBasophilEosinophil Monocyte
Granulocytes
T lymphocyte B lymphocyte
Agranulocytes
Macrophage
(a)
(b)
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
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
• 4,200,000 – 5,400,000 in adult females
• 4,500,000 – 5,100,000 in children
• RBC counts reflects 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
• 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
+
Red bone marrow
Increased
oxygencarrying
capacity
Increased
number of
red blood
cells
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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
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Red bone
marrow
Bone
3 Red blood
cells produced
2 Blood transports
absorbed nutrients
1 Absorption
Nutrients
from food
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
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Iron + Biliverdin
Bile
Liver
Bilirubin
Small
intestine
8
12
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(a)
(b)
a: © The McGraw-Hill Companies, Inc./Al Telser, photographer :b © Ed Reschke
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Destruction of Red Blood Cells
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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
stain
• Lobed nucleus
• Other names
• Segs
• Polymorphonuclear leukocyte
• Bands (young neutrophils)
• First to arrive at infections
• Phagocytic
• 54% - 62% of leukocytes
• Elevated in bacterial infections
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© Ed Reschke
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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
infestations and allergic
reactions
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© Ed Reschke
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Basophils
• Deep blue granules in basic
stain
• Release histamine
• Release heparin
• Less than 1% of leukocytes
• Similar to eosinophils in
size and shape of nuclei
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© Ed Reschke
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Monocytes
• Largest of all blood cells
• Spherical, kidney-shaped,
oval or lobed nuclei
• 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
• Both important in
immunity
• B cells produce antibodies
• 25% - 33% of leukocytes
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© Ed Reschke
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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
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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
• Leukocytosis:
• High WBC count (above 10,000)
• Acute infections, vigorous exercise, great loss of body
fluids
• Differential WBC count
• Lists percentages of types of leukocytes
• 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
• Includes transporting nutrients, gases, and vitamins
• Helps regulate fluid and electrolyte balance and
maintain pH
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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
• Uric acid – product of nucleic acid catabolism
• Amino acids – product of protein catabolism
• Creatine – stores phosphates
• Creatinine – product of creatine metabolism
• BUN – blood urea nitrogen; indicates health of kidney
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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
• They include:
• Sodium (most abundant with chloride)
• Potassium
• Calcium
• Magnesium
• Chloride (most abundant with sodium)
• Bicarbonate
• Phosphate
• Sulfate
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