Clinical Chemistry PDF - 1st Lecture

CLINICAL CHEMISTRY 1ST LECTURE Clinical Chemistry This field is also called clinical biochemistry, clinical pathology, medical biochemistry, or blood chemistry, which is one of the branches of pathology and can also be defined as biochemical tests for vario...

CLINICAL CHEMISTRY 1ST LECTURE Clinical Chemistry This field is also called clinical biochemistry, clinical pathology, medical biochemistry, or blood chemistry, which is one of the branches of pathology and can also be defined as biochemical tests for various body fluids (blood, urine, feces, spinal cord fluid, saliva, stones, all kinds of tissues) to provide the researcher with information in the diagnosis of clinical diseases. Clinical chemical tests include more than a third of the amount of laboratory investigations conducted in hospitals, and the continuous demand for clinical chemical testing is due to several factors, including: 1-Early detection and diagnosis of diseases. 2- Determination of the treatment of the patient better after clinical examinations as well as understand the chemistry of the disease in the body and determine the best treatment for it. 3- Conducting periodic monthly examinations, especially for people of older ages to identify diseases early, which reduces the risk of diseases, especially age-related disease. Blood: Blood is considered a specialized connective tissue as it connects all systems of the body and transports oxygen, nutrients, and wastes. Blood is a fluid tissue of complex composition that flows throughout the human body through the blood vessels and the heart and its amount is between 5 – 6 liters in the human body where it is approximately 80 milliliters / kg of body weight and the blood Viscosity is 4.5 times the viscosity of water. This value changes according to the number of cells present, Temperature, and the amount of water in the body.  Blood functions: Blood functions are divided into three main sections: 1. Transport: which includes: a) Transport of nutrients from the gastrointestinal tract to the cells of different tissues. b) Transport of waste products resulting from metabolism and digestion processes from cells to excretory organs (kidneys, lungs, skin and gastrointestinal tract). c) Transfer of oxygen from the lungs to tissues. d) Transport of carbon dioxide from tissues to the lungs. e) Transport of endocrine secretions (hormones) to different parts of the body Protection 2. Protection: a) Protect the body against foreign bodies such as bacteria, viruses or some Helminths. b) Work to stop bleeding when a wound occurs in the body by forming what is known as blood coagulation or blood coagulation. 3. Regulation: a) Regulating body temperature as it participates with the skin in keeping the temperature constant through blood vessels that expand or narrow depending on body temperature. b) Maintaining the constant concentration of water and salts in cells. c) Regulates the concentration of hydrogen ions (pH) in the body. Blood Components: Blood Consist of Red Blood Cell (RBC) or Erythrocytes, White blood cell (WBC) or Leucocytes, Platelets or Thrombocytes and plasma. 2  Figure1: Blood components Red blood cell (RBC) or Erythrocytes: Red blood cells are immobile, free of nucleus, Golgi complex, mitochondria, ribonucleic acid, its shape is concave-sided, circular disc of 5.7micron size. Figure 2: Side and top view of red blood cell The diameter and thickness of red blood cells change depending on their nutritional status and the physiological state of the body. They have the ability to change shape when they pass through the capillary blood vessels. 3  Its primary function is to transport gases and transport glucose through its membrane to various tissues. It originates from the sponge marrow in large bones in adults. Its color is red because of the presence of hemoglobin because when saturated with oxygen it becomes bright red to form oxyhemoglobin and when the formation of carboxy hemoglobin as a result of the binding of CO2 with hemoglobin becomes blue. Figure 3: Combination of red blood cell with oxygen Factors influencing the concentration of erythrocytes: The number of RBCs changes between venous and arterial and there are other factors that affect not only the number but even the concentration of hemoglobin and the Packed cell volume (PCV). These factors are: 1. Age 2. Sex 3. Nutritional status 4. Pregnancy and psychological state 5. Blood volume and stages of the menstrual cycle 6. Rise and fall above sea level. 7. Environment temperature 4 RBC numbers: in males 5-6 million cells/mm3 and in females 4-5 million cells/mm3. The main components of blood cells are water, which constitutes 62-72% of red blood cells and dry substances 35%, hemoglobin constitutes 95% of dry matter, and the remaining 5% are proteins, fats, vitamins, enzymes, mineral salts and others. The formation of erythrocytes and their lifespan: Kidneys control the formation of erythrocytes by the hormone erythropoietin and the secretion of this hormone depends on the molecular pressure of oxygen in the blood as shown in the figure below: Figure 4: Formation of red blood cell The figure shows that the action of the hormone erythropoietin shows that the kidneys release erythropoietin when the blood is less able to carry oxygen, which stimulates the red bone marrow to produce red blood cells in larger quantities and that works to carry oxygen to supply various cells in the body, and then the kidneys inhibited to secrete this hormone when oxygen is sufficient. When the fetus grows during pregnancy, erythrocytes are built in different tissues, mainly in the yolk sac, liver, spleen and lymph nodes. starting from 5 the third month of fetal formation. After birth, erythrocytes arise completely in the red bone marrow because all bones contain red marrow after birth and the red marrow is replaced in the bones after adolescence with fatty marrow, in which case the construction of erythrocytes in the flat and membranous bones Such as ribs, sternum, vertebrae, pelvic bone and skull bones. Erythrocytes leave the bone marrow and enter the bloodstream, where they circulate between 110-126 days, as 1% of the cells is damaged daily, erythrocytes live for 3 months, and the lack of erythrocytes as a result of bleeding or increased breakdown for any reason will stimulate the bone marrow to form new cells. After the erythrocyte is damaged it is engulfed by a group of phagocytes located in the liver, spleen, bone marrow and lymph. These cells digest and damage the erythrocytes by the enzymes found in the organelles of the cell lysosomes as the hemoglobin molecules are broken down into heme and the globulin protein and ferric is released from heme by the enzyme Heme Oxygenase and then ferric is stored in the liver and spleen for later reuse in making new hemoglobin and the remaining part of the Heme to Biliverdin, which is reduced to Bilirubin by the enzyme Biliverdin reductase, bilirubin is a reddish yellow pigment excreted from the liver with bile, while globulin is included in the body's proteins for use in new hemoglobin or other proteins. 6