Transcript Blood

Blood
Composition of Blood
Blood is composed of two main elements
1. Plasma – liquid portion
• 55%
2. Formed elements – various blood
cells
• 45%
Blood Volume
About 8% of total body weight in averaged
sized adults
4-5 liters in a female and 5-6 liters in a
male
Direct measurement and indirect
measurement
Formed Elements of Blood
Red Blood Cells
(RBCs) = erythrocytes
White blood Cells
(WBCs) = leukocytes
Platelets =
thrombocytes
Hematocrit
Packed Cell Volume (PCV)
Volume % of red blood
cells in whole blood
Anemias – decreased red
blood cells
Physiological polycythemia
– increased red blood cells
Red Blood Cells
Erythrocytes
No nucleus
7.5 μm in diameter
Biconcave disk (increases
surface area)
Doesn’t contain ribosomes,
mitochondria or other
organelles
Hemoglobin
200 – 300 million
molecules per cell
Composed of four protein
chains and a red pigment
called a heme
Each heme has an iron
molecule that allows it to
bond to four oxygen
molecules
Formation of Red Blood Cells
In adults, erythrocytes begin maturation in the
red bone marrow from nucleated cells known as
hematopoietic stem cells
Divide by mitosis
Entire maturation process takes about 4 days
200 Billion RBCs per day
Erythropoiesis
Destruction of Red Blood Cells
Average life span of 105 – 120 days
Often break apart as they age and are
destroyed by macrophages—mostly in the
liver and spleen (phagocytosis)
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Iron returned to marrow
Bilirubin excreted as bile
Amino acids released a globin for new
proteins
Destruction of Red Blood Cells
White Blood Cells
5 Types of White Blood Cells
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Granulocytes
Neutrophils
Eosinophils
Basophils
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Agranulocytes
Lymphocytes
Monocytes
Neutrophils
Small cytoplasmic granules stain light purple and
give the cytoplasm a coarse appearance.
Polymorphonuclear leukocytes – nuclei have
multiple lobes
Highly mobile and phagocytic
Migrate out of blood vessels
Eosinophils
Large, numerous
cytoplasmic granules
that stain orange
Nuclei with two lobes
Involved in allergic
reactions
Weak phagocytes
Basophils
Large but sparse
cytoplasmic granules
Least numerous of
WBCs
Motile
Contain histamine
and heparin
Lymphocytes
Smallest WBCs
Large spherical nuclei
T Lymphocytes –
directly attack
infected or cancerous
cells
B Lymphocytes –
produce antibodies
Monocytes
Largest WBC
Dark, kidney bean
shaped nuclei
Motile and highly
phagocytic (engulf
bacteria and viral
infected cells)
Platelets
Small and nearly colorless
Irregular spindles or oval disks
Function in blood clotting