Blood components

1. CHAPTER 16 (BLOOD)
OVERVIEW
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2. Blood Composition
• Blood: a fluid, connective tissue
1. Plasma (~55%)
2. Cells (formed elements) (~45%)
• Erythrocytes (red blood cells)
• Leukocytes (white blood cells)
• Platelets
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3. Blood Composition
Formed
elements
Plasma
Buffy coat
1 Withdraw
2 Centrifuge the
.
Erythrocytes
blood sample.
• Hematocrit a measure of % RBCs in blood
• 47% for males
• 42% for females
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Figure 16.1

4. Functions of Blood
1. Distribution
2. Regulation
•
O2
•
Body temperature
•
Nutrients
•
Buffer pH
•
Wastes
•
Blood pressure
•
Hormones
3. Protection
Blood loss – clot formation
•
•
platelets
Fight infection
•
•
•
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WBCs
Antibodies

5. Formed Elements
• Originate from red bone marrow
1.WBCs – involved in immunity
2.RBCs – transport oxygen
3.Platelets – form clots
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6. Erythrocytes (RBCs)
• Biconcave disc
• Large surface area : volume ratio
• No nucleus
• No organelles
• 120 day life span
• Filled with hemoglobin (Hb)
• transports O2
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7. Hematopoiesis
• Hematopoiesis: blood cell formation
• In epiphysis of long bones
• red bone marrow
• hematopoietic stem cells
• gives rise to all blood cells
• Erythropoiesis – specifically red blood cell
production
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8. Erythropoises
• Erythropoietin (EPO) is a hormone
• stimulates erythropoiesis
• produced by kidneys
Stem cell
Hemocytoblast
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Committed
cell
Developmental pathway
Proerythroblast
Early
Late
erythroblast erythroblast
Phase 1
Ribosome
synthesis
Phase 2
Hemoglobin
accumulation
Phase 3
Ejection of
nucleus
Normoblast
Reticulo- Erythrocyte
cyte
Figure 16.5

9. Erythropoiesis
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10. RBC Disorders
Anemia:
• blood has low O2-carrying capacity
• Low iron content
• Can be cause by diet, injury or genetic
• Symptoms:
• Fatigue / paleness / short breath / chills
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11. Causes of Anemia
Hemorrhagic anemia
•
•
loss of blood
Hemolytic anemia
•
•
RBCs rupture
Aplastic anemia
•
•
destruction of bone marrow
•
Usually associated with cancer
Pernicious anemia
•
•
Low B12
•
Low iron
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Genetic
• Thalassemia
• RBCs are weak
• Sickle-cell anemia
• abnormal Hb

12. Sickle Cell Anemia
Normal RBC
Normal biconcave shape
Normal a. a. sequence
1
2
3
4
5
6
7
146
1
2
3
4
5
6
7
146
Abnormal RBC
“sickle” shape
Mutated a. a. sequence
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Figure 16.8