BloodBlood

Composition of Blood Composition of Blood

Blood is composed of two main elementsBlood is composed of two main elements

1. Plasma – liquid portion 1. Plasma – liquid portion

• • 55% 55%

2. Formed elements – various blood 2. Formed elements – various blood cells cells

• • 45%45%

Blood Volume Blood Volume

About 8% of total body weight in averaged About 8% of total body weight in averaged sized adultssized adults

4-5 liters in a female and 5-6 liters in a 4-5 liters in a female and 5-6 liters in a malemale

Direct measurement and indirect Direct measurement and indirect measurementmeasurement

Formed Elements of BloodFormed Elements of Blood

Red Blood Cells Red Blood Cells (RBCs) = erythrocytes(RBCs) = erythrocytes

White blood Cells White blood Cells (WBCs) = leukocytes(WBCs) = leukocytes

Platelets = Platelets = thrombocytesthrombocytes

Hematocrit Hematocrit

Packed Cell Volume (PCV)Packed Cell Volume (PCV)

Volume % of red blood Volume % of red blood cells in whole bloodcells in whole blood

Anemias – decreased red Anemias – decreased red blood cells blood cells

Physiological polycythemia Physiological polycythemia – increased red blood cells– increased red blood cells

Red Blood Cells Red Blood Cells ErythrocytesErythrocytes

No nucleus No nucleus

7.5 7.5 μμm in diameterm in diameter

Biconcave disk (increases Biconcave disk (increases surface area)surface area)

Doesn’t contain ribosomes, Doesn’t contain ribosomes, mitochondria or other mitochondria or other organellesorganelles

HemoglobinHemoglobin

200 – 300 million 200 – 300 million molecules per cell molecules per cell

Composed of four protein Composed of four protein chains and a red pigment chains and a red pigment called a hemecalled a heme

Each heme has an iron Each heme has an iron molecule that allows it to molecule that allows it to bond to four oxygen bond to four oxygen moleculesmolecules

Formation of Red Blood Cells Formation of Red Blood Cells

In adults, erythrocytes begin maturation in the In adults, erythrocytes begin maturation in the red bone marrow from nucleated cells known as red bone marrow from nucleated cells known as hematopoietic stem cellshematopoietic stem cells

Divide by mitosisDivide by mitosis

Entire maturation process takes about 4 daysEntire maturation process takes about 4 days

200 Billion RBCs per day200 Billion RBCs per day

ErythropoiesisErythropoiesis

Destruction of Red Blood CellsDestruction of Red Blood Cells

Average life span of 105 – 120 days Average life span of 105 – 120 days

Often break apart as they age and are Often break apart as they age and are destroyed by macrophages—mostly in the destroyed by macrophages—mostly in the liver and spleen (phagocytosis)liver and spleen (phagocytosis) Iron returned to marrow Iron returned to marrow Bilirubin excreted as bileBilirubin excreted as bile Amino acids released a globin for new Amino acids released a globin for new

proteins proteins

Destruction of Red Blood CellsDestruction of Red Blood Cells

White Blood Cells White Blood Cells

5 Types of White Blood Cells 5 Types of White Blood Cells GranulocytesGranulocytes

Neutrophils Neutrophils

Eosinophils Eosinophils

BasophilsBasophils Agranulocytes Agranulocytes

Lymphocytes Lymphocytes

MonocytesMonocytes

Neutrophils Neutrophils

Small cytoplasmic granules stain light purple and Small cytoplasmic granules stain light purple and give the cytoplasm a coarse appearance.give the cytoplasm a coarse appearance.

Polymorphonuclear leukocytes – nuclei have Polymorphonuclear leukocytes – nuclei have multiple lobesmultiple lobes

Highly mobile and phagocyticHighly mobile and phagocytic

Migrate out of blood vesselsMigrate out of blood vessels

EosinophilsEosinophils

Large, numerous Large, numerous cytoplasmic granules cytoplasmic granules that stain orangethat stain orange

Nuclei with two lobesNuclei with two lobes

Involved in allergic Involved in allergic reactions reactions

Weak phagocytesWeak phagocytes

BasophilsBasophils

Large but sparse Large but sparse cytoplasmic granules cytoplasmic granules

Least numerous of Least numerous of WBCsWBCs

Motile Motile

Contain histamine Contain histamine and heparinand heparin

Lymphocytes Lymphocytes

Smallest WBCsSmallest WBCs

Large spherical nucleiLarge spherical nuclei

T Lymphocytes – T Lymphocytes – directly attack directly attack infected or cancerous infected or cancerous cells cells

B Lymphocytes – B Lymphocytes – produce antibodies produce antibodies

Monocytes Monocytes

Largest WBCLargest WBC

Dark, kidney bean Dark, kidney bean shaped nuclei shaped nuclei

Motile and highly Motile and highly phagocytic (engulf phagocytic (engulf bacteria and viral bacteria and viral infected cells)infected cells)

PlateletsPlatelets

Small and nearly colorlessSmall and nearly colorless

Irregular spindles or oval disksIrregular spindles or oval disks

Function in blood clottingFunction in blood clotting