The following points highlight the top eight fields of medical biochemistry. The fields are: 1. Chemistry of Tissues and Foods 2. Chemistry of Digestion and Absorption 3. Chemistry of Respiration 4. Chemistry of Blood 5. Chemistry of Cell Membrane and Physical Chemistry 6. Chemistry of Tissue Metabolism 7. Chemistry of Glands of Internal Secretion 8. Chemistry of Excretion.
Fields of Medical Biochemistry:
- Chemistry of Tissues and Foods
- Chemistry of Digestion and Absorption
- Chemistry of Respiration
- Chemistry of Blood
- Chemistry of Cell Membrane and Physical Chemistry
- Chemistry of Tissue Metabolism
- Chemistry of Glands of Internal Secretion
- Chemistry of Excretion
Medical Biochemistry: Field # 1. Chemistry of Tissues and Foods:
Since the foods are largely derived from animals or plant tissue, the study of the chemistry of one is identical with the other. The components of tissues and foods are carbohydrates, fats, proteins, and nucleic acids. Carbohydrates provide a greater part of the energy-needs for the body.
Improper utilization of glucose leads to the development of diseases like diabetes mellitus. Lipids provide a part of the energy-needs of the body.
Essential fatty acids are required for maintaining normal health. These essential fatty acids are also the precursors of prostaglandins. Complex lipids occur as integral parts of nervous tissue. Proteins are necessary for growth and maintenance of positive nitrogen balance.
Nucleic acids (DNA & RNA) of nucleus and cytoplasm respectively, are involved in the regulation of gene.
Medical Biochemistry: Field # 2. Chemistry of Digestion and Absorption:
The food is chiefly composed of large molecules of starch, proteins, and fats. These large molecules are digested into smaller molecules like glucose, amino acids, and fatty acids, for absorption by the organic catalysts (the enzymes) present in the digestive juice.
Along with their absorption, the entry of water, minerals, vitamins, and other diffusible molecules of the food also takes place. The absence of one of the digestive enzymes leads to serious disorders.
Medical Biochemistry: Field # 3. Chemistry of Respiration:
During respiration, in man, oxygen is taken into the lungs and it diffuses into the blood across the membranes.
It combines with the haemoglobin of red cells and, in this form, it is carried to the tissues where it is released for the oxidation of food to liberate energy.
The carbon dioxide—formed equal in volume to that of oxygen—passes from the tissues to the blood stream and is exhaled from the lungs, being reacted by chemical combination.
Medical Biochemistry: Field # 4. Chemistry of Blood:
The blood carries foods to the tissues and waste products from them to the excretory organ. The hormones produced by various glands pass into the blood and through its circulation these hormones reach the specific tissues.
The blood distributes heat from one part of the body to another and exerts cooling effect. The blood also distributes water and salts properly and maintains acid-base balance of the body. It contains substances that combat infection by microorganisms.
The composition of blood is normally constant but it is dynamic. Even one of the substances present in it, increased or decreased, causes pathological condition.
Medical Biochemistry: Field # 5. Chemistry of Cell Membrane and Physical Chemistry:
Hormones, foods, waste products, and other necessary substances required for cells pass through the cell membrane. Some substances easily pass through the membranes but some other substances pass by other mechanisms.
Normal permeability of cell membranes maintains normal physiological processes and abnormal permeability is associated with pathological conditions. The colloidal substances which do not diffuse through membranes exhibit Donnan membrane equilibrium resulting in secretion and excretion of substances.
The buffering system is most essential for maintaining pH of blood slightly alkaline for normal functioning of the body. The electrical potentials across cell membranes is of much significance. The ion exchange across the cell membrane maintains the cellular integrity.
The pH of blood, if altered from the normal value, leads to complicated disorders.
Medical Biochemistry: Field # 6. Chemistry of Tissue Metabolism:
The oxidation of foodstuff in tissues occurs by chemical processes with the liberation of energy and water. This is a very complicated process in biochemistry. Several diseases occur in the disorder of the metabolism of these foodstuffs.
Medical Biochemistry: Field # 7. Chemistry of Glands of Internal Secretion:
The control through glands of internal secretion is barely dependent on the activities of hormones and nervous system. The hormone of one gland regulates the activity of another gland. Biological achievement is recorded by the biochemistry of the glands of internal secretion. Overproduction of hormones also leads to serious disorders.
Medical Biochemistry: Field # 8. Chemistry of Excretion:
The excretory organs—kidneys, lungs, intestine, and skin—remove decomposition products of tissues and foods in order to make the composition of the body fluids constant. The most important decomposition products are urea, uric acid, and creatinine formed from proteins; carbon dioxide and water formed from carbohydrates, fats, and proteins.
The particular level of these decomposition products is compatible with health but, on excess, may lead to dysfunction and illness. The kidneys and the lungs chiefly perform the excretory functions of the body. The medical students must be quite aware of the concentration of the excretory products which may indicate certain diseases.
In severe diabetes mellitus, sugar is excreted to the urine as a result of high blood sugar level and along with this sugar the kidney is to excrete more water also. Consequently, there develops both hunger and thirst. These symptoms give a hint to the disease.