Structure of Blood Plasma

Blood plasma is a pale, yellow-colored liquid in which various substances like food, waste products, hormones and gases remain in solution. It transports everything except fat droplets and, in vertebrates, oxygen.

Composition

• Plasma is the fluid part of blood. The exact composition of the plasma varies greatly. For instance, in the hepatic portal vein (which leads from the intestines to the liver), the plasma is much richer in dissolved foods such as sugars, vitamins and amino acids than plasma in a vein in another part of the body.

Protein

• Blood plasma contains a number of proteins, like albumin, antibodies and fibrinogen. Protein molecules play vital roles in processes such as osmotic balance, immunity and blood clotting.

Salts

• Blood plasma contains many inorganic salts, such as sodium, potassium chloride bicarbonate (hydrogencarbonate) and calcium. Plasma salts facilitate the conduction of nerve impulses across synapses, carrying carbon dioxide and playing a part in both buffering and blood clotting.

Hormones

• Blood plasma also contains some important hormones, such as insulin and testosterone.

Coloring Pigments

• Within the body of invertebrate animals, the coloring pigments remain in the plasma, i.e., hemocyanin in prawns and hemoglobin in earthworms.