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Access Biology.Access Biology.

Circulatory System.Circulatory System.

Leucocytes.Leucocytes.

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Blood: Introduction.Blood: Introduction. The human circulatory system contains The human circulatory system contains

blood.blood. Blood is a liquid connective tissue.Blood is a liquid connective tissue. Blood is a viscous (sticky) liquid that has Blood is a viscous (sticky) liquid that has

many cellular components suspended in it.many cellular components suspended in it. The temperature of the blood is usually 36-The temperature of the blood is usually 36-

37 degrees Centegrade.37 degrees Centegrade. The body contains around 5 litres of blood.The body contains around 5 litres of blood. Blood constitutes approximately 8% of body Blood constitutes approximately 8% of body

weight. weight. Blood is slightly alkaline (has pH 7.4).Blood is slightly alkaline (has pH 7.4). Blood is 55% plasma and 45% blood cells.Blood is 55% plasma and 45% blood cells.

Blood Hound.

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Functions of the Blood.Functions of the Blood.

There are three main functions of There are three main functions of the blood.the blood.

Defence (protection).Defence (protection). Regulation (control).Regulation (control). Transportation.Transportation.

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Composition of the Composition of the Blood.Blood.

Blood is composed of plasma and Blood is composed of plasma and blood cells.blood cells.

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Plasma.Plasma.

Plasma makes up 55% of the blood.Plasma makes up 55% of the blood. Plasma is a straw coloured slightly Plasma is a straw coloured slightly

alkaline fluid.alkaline fluid. Plasma is; water, (90%), plasma Plasma is; water, (90%), plasma

proteins, (8%), and enzymes, proteins, (8%), and enzymes, hormones, inorganic ions hormones, inorganic ions (electrolytes) nutrients and waste (electrolytes) nutrients and waste (2%).(2%).

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Plasma Proteins.Plasma Proteins.

Blood contains many plasma Blood contains many plasma proteins. proteins.

The most abundant plasma proteins The most abundant plasma proteins are:are:

Albumins.Albumins. Globulins.Globulins. Fibrinogens.Fibrinogens.

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Albumins.Albumins.

Albumins = 54% of plasma protein.Albumins = 54% of plasma protein. Albumins help to maintain the Albumins help to maintain the

pressure required for the process of pressure required for the process of osmosis.osmosis.

Albumins make the plasma sticky for Albumins make the plasma sticky for the viscosity of blood.the viscosity of blood.

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Globulins.Globulins.

Globulins = 38% of plasma protein.Globulins = 38% of plasma protein. Globulins include antibodies for the Globulins include antibodies for the

immune response against bacteria immune response against bacteria and viruses.and viruses.

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Fibrinogens.Fibrinogens.

Fibrinogens = 7% of plasma Fibrinogens = 7% of plasma proteins.proteins.

Fibrinogen is the key protein Fibrinogen is the key protein required for coagulation of the required for coagulation of the blood.blood.

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Blood Cells.Blood Cells.

Blood cells are manufactured in the Blood cells are manufactured in the red bone marrow.red bone marrow.

There are three types of blood cell.There are three types of blood cell.

Erythrocytes (red blood cells).Erythrocytes (red blood cells). Leucocytes (white blood cells).Leucocytes (white blood cells). Platelets (thrombocytes).Platelets (thrombocytes).

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Blood Cells.Blood Cells.

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Erythrocytes.Erythrocytes. Erythrocytes are bi-Erythrocytes are bi-

concave in shape.concave in shape. Why?Why? To provide a much To provide a much

larger surface area.larger surface area. Why?Why? To enable them to To enable them to

carry more oxygen carry more oxygen for transport around for transport around the body.the body.

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Leucocytes.Leucocytes.

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Platelets.Platelets.