BloodBlood Fluid that circulates through the

heart, arteries, capillaries, and veins;

chief means of transport within the body

the average human has 5 litres of blood

it is a transporting fluid

it carries vital substances to all parts of the body

BloodBlood

COMPONENTS OF BLOOD

Blood Is Composed Of Two Parts 1.Plasma 2.Cellular Components -RBC -WBC -Platelets

plasmaplasma

The blood consists of a suspension of special cells in a liquid called plasma. In an adult man, the blood is about 1/12th of the body weight and this corresponds to 5-6 litres. Blood consists of 55 % plasma, and 45 % by cells called formed elements.

Cells in Blood

•Erythrocytes (Red blood cells)

•Leukocytes (White blood cells)

•Thrombocytes (Platelets)

Erythrocytes

• 7.5 micron diameter

• No nucleus or organelles;

lots of hemoglobin

• Biconcave disc

• large surface to volume

ratio: efficient gas

exchange

• The erythrocytes are the most numerous blood cells i.e. about 4-6 millions/mm3.

• They are also called red cells. In man and in all mammals, erythrocytes are devoid of a nucleus and have the shape of a biconcave lens. In the other vertebrates (e.g. fishes, amphibians, reptilians and birds), they have a nucleus.

• The red cells are rich in hemoglobin, a protein able to bind in a faint manner to oxygen. Hence, these cells are responsible for providing oxygen to tissues.

the bodies “defence” part of the immune

system much larger than RBCs have a nucleus 4000-13000 per mm3

White blood cellsLeukocytes

• Granulocytes

Neutrophils

Eosinophils

Basophils

•Agranulocytes

Lymphocytes

Monocytes

GranulocytesGranulocytes neutrophils neutrophils

260 - 70% of circulating leukocytes

• Nucleus: 2-5 lobes ,dia –12-15 micro meter

•Have horshoe shoe shaped or band shaped nucleus called as band cells

• cytoplasm is transparent and its granules are pink coloured

Eosinophills

• 2-4% of circulating leukocytes

• Bilobed nucleus

•defense against parasites; modulation of inflammatory processes

• eosinophilic specific granules containing:

• major basic protein (toxic to parasitic larvae),

• lysosomal enzymes, peroxidase, histaminase

BasophillsBasophills

• < 1 % of circulating leukocytes

• Nucleus irregular lobes

•Dia-9-10 micro meter

Agranulocytes

Lymphocytes

• ~30 % of circulating leukocytes

• Round, densely stained nucleus; little cytoplasm

•Dia-8-10 micro meter

monocytes

• 5 % of circulating leukocytes

• indented folded nucleus

Fig. 12-18

•Opaque, slightly basophilic cytoplasm;

•fine azurophilic granules

•Dia-8-10 micro meter

Thrombocytes(platelets)

• They are small sized diskettes about 3 micro meter in diameter

• Cell Fragments produced of megakaryocytes

• no nucleus• Numerous cytoplasmic organelles• promote blood clotting, help

repair gaps in blood vessel walls