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The Composition of Blood
● Blood is a fluid connective tissue (made up of cells, protein fibers, and an extracellular
matrix)
a
...
Protein fiber- dissolved within
c
...
Erythrocytes (red blood cells)
b
...
Platelets (thrombocytes)
● Heart creates a pressure gradient that helps move blood through the body
Functions of Blood
1
...
Defense
- White blood cells provide protection against infection
- Platelets protect from blood loss
3
...
Albumins
- most abundant plasma proteins

-

Made by liver
Major regulator of blood osmotic pressure
retain water inside the blood vessels

2
...
Fibrinogen
- least abundant plasma protein
- Involved in blood clotting
- Produced by liver
●

Other solutes
- Nutrients, gases, wastes, regulatory substances, electrolytes
- Includes ions, glucose, lipids, oxygen, carbon dioxide, and amino acids
Major Blood Components

I
...
2 billion O2 mol
- Binds oxygen in oxygen-rich environments
- Releases oxygen in oxygen-poor environments

Pulse Oximetry
● Saturation of hemoglobin with oxygen detected by pulse oximeter
● Oxygenated blood carries higher amounts of oxygen
- 95-100% saturated
● Deoxygenated blood carries less oxygen
- Usually 70-80% oxygenated
Erythropoiesis
● Production of red blood cells
● Begins in red bone marrow
● Stimulated by erythropoietin (EPO)
- A hormone secreted in response to hypoxemia
● Results in formation of new RBCs
- If all necessary components are available (Such as iron and vitamin B12)
The Life Cycle of Erythrocytes
● Produce in red bone marrow in irreg and flat bones (2M RBC/sec)
● Nutrients needed for rbc synthesis: glucose, lipids, and amino acids
● RBCs live up to 120 days
● Broken down and recycled in liver or spleen (store iron in the form of ferritin and
hemosiderin
...
Globin—recycled into amino acids

b
...
Non-iron portion of heme is toxic
- Converted to biliverdin (green) and then bilirubin (yellow)
> Bilirubin
- removed from blood by liver
uses it in the manufacture of bile (help emulsify dietary fats)
- Eliminated from body in urine and feces (brown color of poop)
> Biliverdin
- It turns green when the hemoglobin is recycled and converted
>> kidney is responsible for filtering waste from blood, therefore, it serves as a site to monitor
the function of blood
Low O2 saturation= kidney secrete erythropoietin (EPO) hormone that promote formation of
RBC in bone marrow
- Iron and Vitamin B12 is important in EPO synthesis

Hematocrit
● The percentage of RBCs in a whole sample of blood
- 36-50% is homeostatic range
- Can vary depending on muscle mass, gender, and fitness levels (more muscle=
high hematocrit)
● Anemias = conditions with insufficient RBC numbers or insufficient ability to carry oxygen
● Polycythemias = conditions that lead to overproduction of RBC
...
Sickle cell anemia – defective hemoglobin causes RBC shape change
b
...
Pernicious anemia – due to inadequate vitamin B12
d
...
Aplastic anemia – due to deficient numbers of RBC stem cells
● Menstruation in women and other chronic bleeding conditions can lead to anemia as well
Leukocytes and Platelets
● Leukocytes
- Help protect the body against infection and eliminate body cells with mutated
DNA
- Clean up debris

Characteristics of Leukocytes
● Produced by hematopoiesis in red bone \marrow
● Larger and Less numerous than RBCs
● All have a nucleus and organelles
● Can last hours to years
● Leave blood vessels via diapedesis
> diapedesis
- process where they leave the capillaries—the smallest blood
vessels
- they squeeze between the cells that make up the blood vessel
wall
> positive chemotaxis
- Attracted to areas where needed by chemotaxis
Classification of Leukocytes
●

Granules- Dots that contain chemicals used in the cell’s response to a
pathogen
1
...
Neutrophils—most common leukocyte (40–60%)
- Faint purple granules
- Nucleus has two to five lobes; e number increases as the
cell ages
rapid responders to the site of induction and quickly
phagocytize (Phagocytic cells)
● High counts= bacterial infection
...
Eosinophils (2-4% of leukocyte count)
- Eosin is acidic stain
- Bright pink to red granules
- Nucleus has two to three lobes
- contain molecules toxic to parasitic worms
● High count=allergies, parasitic worm infestations, and some
autoimmune diseases
...

c
...

Low counts= pregnancy, stress, and hyperthyroidism
...
Agranular leukocytes—have granules, but not easily seen
a
...

- Large nucleus with a thin rim of cytoplasm
Three groups:
I
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T lymphocytes
III
...

● low counts = of prolonged (chronic) illness or immunosuppression,
HIV infection and drug therapies involve steroids
...
Monocytes
- Large, with a horseshoe-shaped nucleus
- Phagocytes
- Mature into macrophages- Fixed versus wandering
macrophages
leave the blood and reside in the tissues they differentiate
into macrophages,
● high counts = fungal infections, tuberculosis, and leukemia and
other chronic diseases
...
Neutrophils—increase during bacterial infections
b
...
Monocytes—increase during viral or fungal infections
d
...
Basophils—increase during allergic reactions
●

Platelets
- not cells but rather fragments of cytoplasm surrounded by a plasma membrane
- Involved in blood clotting and vessel repair
- produced by megakaryocytes (f cell found in the bone marrow
...
Erythropoietin (EPO)—promotes erythrocyte production called erythropoiesis
b
...
Cytokines—chemical signals released from a variety of tissues
> Stimulate production of various leukocytes as necessary

Hemostasis
The Process of Hemostasis
● Process by which the body plugs a ruptured blood vessel to
minimize blood loss
- Platelets play a significant role
● Effective for smaller vessels, not larger ones
- Prevents loss of blood
- Allows for vessel to be repaired
Steps of Hemostasis
1
...
Formation of platelet plug
3
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Vascular Spasm
● Smooth muscle in the walls of the damaged vessel contracts
- Triggered by chemicals released from endothelium
● Continues for approximately 30 minutes
● Decreases blood flow and blood loss from damaged area
● Allows other steps of hemostasis to occur

2
...
Extrinsic pathway triggered by trauma that breaks blood vessel wall
- Activated by tissue trauma that breaks the wall of the blood vessel
- Response is faster in comparison to the intrinsic pathway
- Factor III enters vessel from tissues due to damage
- Factor III activates Factor VII that will combine with calcium to form an
enzyme complex
- This enzyme complex will activate factor X
- Enters common pathway after activation of factor X
b
...
Prothrombinase converts factor II (prothrombin) into thrombin
b

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