Composition of Human Blood

Composition of Human Blood

Composition of Human Blood

1. 55% blood plasma

2. 45% erythrocytes

3. <1% leucocytes and platelets

Blood plasma components

1. Water

2. Plasma proteins

3. Solutes

4. Hormones and enzymes

Water in blood plasma

Blood plasma is 90% water. Water is a medium of transportation and a solvent for respiratory gases, ions, digestive products and excretory substances.

Plasma proteins

1. Fibrinogen - blood clotting

2. Albumin - maintain blood osmotic pressure

3. Globulin - a type of antibody

Solutes

1. Nutrients - energy, growth, maintenance of health

2. Excretory substances - toxic substances that need to be disposed

3. Oxygen - cellular respiration

Hormones and enzymes

1. Hormones control physiological activities in the body

2. Enzymes control metabolic processes of cells

State the characteristics of erythrocytes.

1. Has an elastic plasma membrane

2. Has a biconcave disc shape

3. Does not have a nucleus when matured

4. Has haemoglobin which is the red pigment of blood

Explain the functions of the characteristics of erythrocytes.

1. Elastic plasma membrane for a higher rate of diffusion of respiratory gases.

2. Biconcave disc shape enables a large TSA/V for efficient gaseous exchange.

3. Does not have a nucleus so more haemoglobin can be carried by the erythrocytes.

4. Has haemoglobin to combine with oxygen to form oxyhaemoglobin.

Where are erythrocytes produced?

Bone marrow of bones such as sternum and ribs

What is the lifespan of a erythrocyte?

120 days, until it is destroyed in the liver or lymph through phagocytosis.

Where are platelets produced?

Fragments or scraps of cell cytoplasm that originate from the bone marrows.

What is the lifespan of a platelet?

Less than one week

What is the function of a platelet?

Acts as one of the blood clotting factors

State the characteristics of leucocytes.

1. Irregular shape

2. Contains nucleus

3. Produced in the bone marrow

4. Does not contain haemoglobin

What is the function of leucocytes?

Diffuse out of the capillary pore and fight pathogens in tissue fluids.

What are the types of leucocytes?

1. Granulocytes [contain granules]

2. Agranulocytes [no granules]

Granulocytes

1. Neutrophil

2. Eosinophil

3. Basophil

Neutrophil

1. Nucleus is made up of two to five lobes.

2. Ingests bacterial cells and dead cells of tissues by phagocytosis

Eosinophil

1. Nucleus is made up of two lobes.

2. Releases enzymes that fight inflammation and allergy reaction.

Basophil

1. Contains heparin which prevents blood clotting to keep blood flowing smoothly

Agranulocytes

1. Lymphocyte

2. Monocyte

Lymphocyte

1. Contains a large nucleus with very little cytoplasm

2. Produces antibodies to destroy bacteria and viruses in the body

3. Produces antitoxins against toxins that are produced by bacteria and viruses

Monocytes

1. The biggest leucocyte

2. Spherical-shaped nucleus

3. Ingests bacterial cells and dead cells of tissues by phagocytosis

Number of leucocytes present in the body

Neutrophils > Lymphocytes > Monocytes > Eosinophils > Basophils