Download Blood clot - Jordan High School

Chapter 11
The Cardiovascular
System: Blood
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11-1: Blood Characteristics
• Blood—connective tissue containing cells
suspended in fluid matrix
• Functions
– Transport gases, nutrients, hormones & waste
– Regulate pH & ions
– Restrict fluid loss at injury sites
– Defend against toxins & pathogens
– Stabilize body temp
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Composition of Blood
• Made of plasma & formed elements
• pH: 7.35 – 7.45; volume: males 5 – 6 L,
females 4 – 5 L
Blood Collection & Analysis
• Blood collected through venipuncture
• Blood can be used to prepare blood smear
to show different formed elements
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11-1 Checkpoint
1. List five major functions of blood.
2. What two components make up whole
blood?
3. Why is venipuncture a common technique
for obtaining a blood sample?
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11-2: Plasma
Composition of Plasma
• Blood is 55% plasma
– Composed of plasma proteins, solutes & water
Plasma Proteins
• Types of plasma proteins
– Albumins—majority of plasma; maintain
pressure
– Globulins—antibodies & transport proteins
– Fibrinogens—blood clotting
11-2 Checkpoint
1. List the three major types of plasma
proteins.
2. What would be the effects of a decrease in
the amount of plasma proteins?
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11-3: Red Blood Cells (RBCs)
Abundance of RBCs
• Blood is 45% RBCs (erythrocytes)
• Hematocrit—percentage of whole blood
volume occupied by formed elements
– 99.9% RBCs, <0.1% WBCs, <0.1% platelets
Structure of RBCs
• RBC is biconcave disc, lacks a nucleus
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Hemoglobin Structure & Function
• Hemoglobin in RBC transports O2 & CO2
– 4 heme subunits bind with iron
• Hemoglobin binding process
– Lungs: hemoglobin binds to O2, releases CO2
– Tissues: hemoglobin binds to CO2, releases O2
• Anemia—RBCs have reduced hemoglobin
content
– Iron-deficiency anemia more common in
women
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RBC Life Span & Circulation
• RBCs last about 120 days
• Hemoglobin recycling
– Hemolysis: RBC ruptures
– Phagocytosis: Macrophages in body engulf
RBCs, hemoglobin broken apart into heme &
recycled by body
• Heme converted to bilirubin (yellow
pigment)
– Excess bilirubin causes jaundice
RBC Formation
• Erythropoiesis—formation of RBCs
– Occurs in red bone marrow
• Erythropoiesis requires amino acids, iron &
vitamins
• Erythropoietin (EPO) released during
low O2 levels (hypoxia)
– Stimulates cell division in bone marrow
– Speeds RBC maturation
11-3 Checkpoint
1. Describe hemoglobin.
2. What effect does dehydration have on an
individual’s hematocrit?
3. What effect does a reduction in oxygen
supply to the kidneys have on levels of
EPO in the blood?
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11-4: ABO Blood Types
• Surface antigens trigger immune response
• Presence/absence of antigens determines
blood type
– Type A—antigen A only
– Type B—antigen B only
– Type AB—antigens A & B
– Type O—no antigens
– Rh positive—Rh antigen present
– Rh negative—Rh antigen absent
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Cross-Reactions in Transfusions
• Antibodies attack foreign antigens on RBCs
• Type A blood
– Antigen: Antigen A
– Antibody: Anti-B
– Can receive type A & O blood, not B or AB
• Type B blood
– Antigen: Antigen B
– Antibody: Anti-A
– Can receive type B & O blood, not A or AB
• Type AB blood
– Antigen: Antigens A & B
– Antibody: no antibodies
– Can receive all types of blood—universal
recipient
• Type O blood
– Antigen: no antigens
– Antibodies: Anti-A & Anti-B
– Can be given to people with any blood type—
universal donor
– Can only receive type O blood
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• Surface antigens + antibodies from
incorrect blood = cross-reaction
(transfusion reaction)
• Agglutination—clumping of antigens &
antibodies
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Rh Blood Group Interactions
• Rh- person receives Rh+ blood:
• Immune system produces anti-Rh antibodies
• No reaction until next transfusion
• Rh- mother delivers Rh+ baby
• Placenta causes blood to mix
• Anti-Rh antibodies formed
• Next Rh+ baby attacked by anti-Rh
antibodies—erythroblastosis fetalis
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11-4 Checkpoint
1. Which blood type(s) can be safely
transfused into a person with Type AB
blood?
2. Why can’t a person with Type A blood
safely receive blood from a person with
Type B blood?
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11-5: White Blood Cells (WBCs)
• WBCs (leukocytes) larger than RBCs, have
a nucleus
• Defend the body against pathogens;
remove toxins, wastes, abnormal or
damaged cells
• Compose <0.1% of hematocrit
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WBC Circulation & Movement
• Characteristics of WBC movement:
– Amoeboid movement—extend cytoplasm to
move
– Diapedesis—squeeze through capillary cells
to exit bloodstream
– Positive chemotaxis—attracted to chemical
stimuli
– Capable of phagocytosis—engulf pathogens or
other materials
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Types of WBCs
• Neutrophils
– Most numerous WBC
– Attack & digest bacteria
• Eosinophils
– Attack objects coated with antibodies
• Basophils
– Release heparin (blood clotting) & histamine
(inflammation
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• Monocytes
– Attack large objects, release chemicals to
attract other WBCs
• Lymphocytes
– Continuously migrate through body
– Attack foreign cells (crucial in immunity)
Differential Count of WBCs
• Differential count—indicates number of
each type of cell
– Determines presence of infections, disorders
• Leukopenia—reduced number of WBCs
• Leukocytosis—excessive numbers of
WBCs
– Extreme leukocytosis indicates leukemia
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11-5 Checkpoint
1. Identify the five types of WBCs.
2. Which type of cell would you find in
elevated numbers in a person producing
large amounts of circulating antibodies to
combat a virus?
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11-6: Platelets
• Platelets—cell fragments
– Compose <0.1% of hematocrit
• Megakaryocytes release platelets into
bloodstream
– Initiate clotting process
• Thrombocytopenia (low platelet number) &
thrombocytosis (high platelet number)
11-6 Checkpoint
1. Explain how platelets form.
2. List the primary functions of platelets.
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11-7: Hemostasis
• Hemostasis—process that halts bleeding
& prevents loss of blood
Phases of Hemostasis
• Vascular phase
– Cut blood vessel triggers vascular spasm
(contraction)
– Blood flow from small vessels slowed or
stopped
• Platelet phase
– Platelets attach to inner blood vessel & mesh
of collagen fibers
– Forms a platelet plug to close break
• Coagulation phase (blood clotting)
– Protein mesh grows, traps blood cells &
platelets
– Uses clotting factors to aid in clotting process
– Blood clot seals off damaged vessel
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Clot Retraction & Removal
• Clot retraction—platelets contract to pull
edges of wound closer together
• Fibrinolysis—dissolves clot
– Plasminogen & tissue plasminogen
activator (t-Pa) digest protein strands
• t-Pa used in treatment of strokes
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Abnormal Hemostasis
• Thrombus—large blood clot attached to
vessel wall
• Embolus—drifting blood clot in the
bloodstream
– Can result in an embolism—blockage of blood
vessel due to embolus
• Hemophilia—inadequate production of
clotting factors
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11-7 Checkpoint
1. If a sample of red bone marrow has fewer
than normal megakaryocytes, what body
process would you expect to be impaired
as a result?
2. What are the phases of hemostasis?
3. How is a thrombus different from an
embolus?
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