Transcript BCBio12_Chapter10_Section10.2

UNIT B: Human Body Systems
Chapter 8: Human Organization
Chapter 9: Digestive System
Chapter 10: Circulatory System and
Lymphatic System: Section 10.2
Chapter 11: Respiratory System
Chapter 12: Nervous System
Chapter 13: Urinary System
Chapter 14: Reproductive System
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Chapter 10: Circulatory System and Lymphatic System
Chapter 10: Circulatory System and Lymphatic System
In this chapter, you will learn
about the structure and
function of the circulatory
system and lymphatic
system.
In 2013, Lance Armstrong confessed to long-term blood
doping and the use of banned substances. Blood doping
involves artificially boosting the blood’s ability to bring
more oxygen to muscles. Aerobic capacity and
endurance improve where there are additional red blood
cells available to carry oxygen.
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What is the composition of
blood, including blood cells?
What organs and structures
control the flow of blood
throughout the body?
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
10.2 Blood
Blood is a liquid connective tissue that has many different
functions.
• Transports nutrients, wastes, and hormones
• Regulates body temperature by dispersing body heat
• Regulates blood pressure (plasma proteins contribute to
osmotic pressure of blood)
• Protects the body against invasion by disease-causing
pathogens
• Clotting mechanisms protect the body against loss of blood
.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Composition of Blood
Blood separates into three
layers when centrifuged.
• Upper layer: plasma (liquid
portion of blood)
• Lower layers: formed
elements (white blood cells,
platelets, red blood cells)
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Figure 10.3 Composition of blood. When blood is collected into a test tube
containing an anticoagulant to prevent clotting and then centrifuged, it consists
of three layers. The transparent straw-coloured or yellow top layer is the
plasma, the liquid portion of the blood. The thin, middle buffy coat layer consists
of leukocytes and platelets. The bottom layer contains the erythrocytes.
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Chapter 10: Circulatory System and Lymphatic System
Plasma
Plasma contains a variety of
inorganic and organic
substances dissolved or
suspended in water.
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Section 10.2
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Chapter 10: Circulatory System and Lymphatic System
Plasma also contains plasma proteins,
which have many functions:
• Transport: albumin transports bilirubin;
lipoproteins transport cholesterol
• Blood clotting: fibrinogen
• Fighting infection: antibodies
• Maintaining blood volume: plasma
proteins are too large to leave the
capillaries
− Blood in capillaries has a higher
solute concentrate than tissue fluid,
causing water to diffuse in
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Section 10.2
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
The Red Blood Cells
Red blood cells (erythrocytes) are manufactured in the red
bone marrow of the skull, ribs, vertebrae, and ends of the long
bones. They transport oxygen and carbon dioxide in the blood.
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Chapter 10: Circulatory System and Lymphatic System
Mature red blood cells have no nuclei
and are biconcave.
• Only live about 120 days (possibly
due to lack of nuclei) and are
destroyed in the liver and spleen
• Biconcave shape increases
flexibility (for moving through
capillary beds) and surface area (for
diffusion of gases)
• Contain hemoglobin, a respiratory
pigment that carries oxygen
o Iron in hemoglobin acquires
oxygen in the lungs and gives it
up in the tissues
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Section 10.2
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Figure 10.4 Physiology of red blood cells. a. Red blood cells move in single file through the capillaries.
b. Each red blood cell is a biconcave disk containing many molecules of hemoglobin, the respiratory
pigment. c. Hemoglobin contains four polypeptide chains (purple). There is an iron-containing heme group
in the centre of each chain. Oxygen combines loosely with iron when hemoglobin is oxygenated.
Oxyhemoglobin is bright red, and deoxyhemoglobin is a dark maroon colour.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Anemia is a common blood disorder that results in a tired,
rundown feeling. Anemia has three basic causes:
• Decreased production of red blood cells
• Loss of red blood cells from the body
• Destruction of red blood cells within the body
Most common type of anemia: iron-deficiency anemia
• Caused by decreased production of red blood cells due to a
diet that lacks adequate iron
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Chapter 10: Circulatory System and Lymphatic System
The White Blood Cells
White blood cells (leukocytes)
are usually larger than red blood
cells, have a nucleus, lack
hemoglobin, and appear
translucent without staining.
They fight infection and play a
role in developing immunity.
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Section 10.2
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Figure 10.5 Micrograph of the Formed Elements. The formed elements include red blood
cells, different types of white blood cells, and platelets.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
White blood cells can be divided on the basis of structure into
granular leukocytes and agranular leukocytes:
Granular leukocytes
• Neutrophils
• Eosinophils
• Basophils
Agranular leukocytes
• Monocytes
• Lymphocytes
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Chapter 10: Circulatory System and Lymphatic System
Granular leukocytes
Granular leukocytes are filled with
spheres that contain enzymes and
proteins that help white blood cells
defend against microbes.
• Neutrophils: phagocytize pathogens
• Eosinophils: phagocytize antigenantibody complexes and allergens
• Basophils: release histamine to
promote blood flow to injured
tissues
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Section 10.2
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Chapter 10: Circulatory System and Lymphatic System
Agranular leukocytes
Agranular leukocytes include cells that can
phagocytize pathogens and cells that are
involved in specific immunity.
• Monocytes: largest white blood cells;
differentiate into phagocytic dendritic
cells and macrophages
• Lymphocytes:
o B lymphocytes (B cells): produce
antibodies
o T lymphocytes (T cells): helper T
cells regulate the responses of other
cells; cytotoxic T cells kill other cells
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Section 10.2
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
White Blood Cells and Disease
The number of white blood cells increases or decreases
beyond normal if disease is present.
• Neutrophils: increase in response to bacterial infections
• B cells: increase in response to infectious mononucleosis
• T cells: a low number of T cells indicates if an HIVinfected person has AIDS
• A large number of abnormal white blood cells is a
characteristic of leukemia, a form of cancer
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Figure 10.6 Macrophage (red) engulfing bacteria. Monocyte-derived macrophages
are the body’s scavengers. They engulf microbes and debris in the body’s fluids and
tissues, as illustrated in this colourized scanning electron micrograph.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
The Platelets and Blood Clotting
Platelets (also called thrombocytes) result from fragmentation
of large cells called megakaryocytes in the red bone marrow.
Platelets are involved in blood clotting (coagulation).
• There are at least 12 clotting factors in the blood that help
platelets in the formation of a blood clot (examples:
prothrombin, fibrinogen).
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Blood Clotting
• The process of clotting begins when a blood vessel is
damaged.
• Platelets clump at the site of damage and form a plug to
partially seal the leak.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Blood Clotting
• Platelets and damaged tissue release prothombin activator,
which converts prothrombin (a clotting factor) to thrombin
in the presence of calcium ions.
• Thrombin acts as an enzyme on fibrinogen (a clotting factor)
to form fibrin threads.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Blood Clotting
• Fibrin threads wind around the platelet plug and trap red
blood cells to form the framework of the clot.
• When blood vessel repair is initiated, plasmin (an enzyme)
destroys the fibrin framework and restores the fluidity of the
plasma.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Blood Clotting
• If blood is allowed to clot in a test tube, a yellowish material,
called serum, develops above the clotted material
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Chapter 10: Circulatory System and Lymphatic System
Figure 10.7 Blood clotting.
a. A scanning electron micrograph of a
blood clot shows red blood cells
caught in the fibrin threads.
b. Platelets and damaged tissue cells
release prothrombin activator, which
acts on prothrombin in the presence of
Ca2+ (calcium ions) to produce
thrombin. Thrombin acts on fibrinogen
in the presence of Ca2+ to form fibrin
threads.
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Section 10.2
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Hemophilia: A Blood Clotting Disorder
Hemophilia is a group of inherited clotting disorders caused by a
deficiency in a clotting factor.
Hemophilia A: 90% of all hemophilia cases
• Occurs frequently in males since the faulty gene is on the X
chromosome
• Individuals with hemophilia are more prone to bleeding
• Bleeding in the muscles can lead to nerve damage
• Bleeding into the brain can lead to neurological damage or death
• Individuals require frequent blood transfusions or injections of the
deficient clotting factor
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Chapter 10: Circulatory System and Lymphatic System
Bone Marrow Stem Cells
A stem cell is a cell that is ever capable of dividing and
producing new cells that go on to differentiate into
particular types of cells.
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Section 10.2
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Figure 10.8 Blood cell formation in red bone marrow. Multipotent stem cells give rise to two specialized types of
stem cells. The myeloid stem cells give rise to still other cells, which become red blood cells, platelets, and all the white
blood cells except lymphocytes. The lymphoid stem cells give rise to lymphoblasts, which become lymphocytes.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Multipotent stem cells in red bone marrow have the potential to
give rise to other stem cells for the various formed elements.
• Can also differentiate into other cells (liver, bone, fat,
cartilage, heart, neurons)
• A patient’s own bone marrow stem cells (adult stem cells)
could be used to treat diabetes, heart disease, liver disease,
or brain disorders
• Some researchers prefer using embryonic stem cells since
they may be more likely to become any type of cell
o Can be collected from unused embryos in fertility
clinics, or umbilical cord blood
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Capillary Exchange
Fluid in the blood is called plasma. When blood reaches a
capillary, the movement of fluid in the blood through the
capillary wall is controlled by:
• Osmotic pressure (causes water to move from the
tissue fluid to the blood)
• Blood pressure (causes water to move from blood to
tissue fluid)
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Figure 10.9 Capillary exchange in the systemic circuit. At the arterial end of a capillary (left) the
blood pressure is higher than the osmotic pressure; therefore, water tends to leave the bloodstream. In
the midsection, molecules, including oxygen and carbon dioxide, follow their concentration gradients.
At the venous end of a capillary (right), the osmotic pressure is higher than the blood pressure;
therefore, water tends to enter the bloodstream. Notice that the red blood cells and the plasma proteins
are too large to exit a capillary.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Arterial End of Capillary
• Blood pressure is higher than osmotic pressure of blood
• Water exits capillary
Midway Along the Capillary
• Blood pressure and osmotic pressure cancel each other out
• No net movement of water
• Solutes diffuse according to concentration gradient
o Nutrients and oxygen diffuse out of the capillary; wastes
and carbon dioxide diffuse into the capillaries
• Small substances leaving capillaries contribute to tissue fluid
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Venous End of Capillary
• Osmotic pressure is greater than blood pressure
• Water moves into capillary
• Excess tissue fluid is collected by lymphatic capillaries, where
it becomes lymph
Figure 10.10 Lymphatic
capillaries. A lymphatic
capillary bed (shown here
in green) lies near a blood
capillary bed. When
lymphatic capillaries take
up excess tissue fluid, it
becomes lymph.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
Check Your Progress
1. List the major components of blood, along with their
functions.
2. Describe the cellular and molecular events that lead to
blood clotting.
3. Identify some diseases that may be treatable with stem
cell therapy.
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2
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Chapter 10: Circulatory System and Lymphatic System
Section 10.2