Topic: Bleeding 2015
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Department of General Surgery Medical Academy named after S.I. Georgievskiy, The Federal State Autonomous Educational Establishment of Higher Education “Crimean Federal University named after V.I. Vernadsky” Ministry of Education and Science of the Russian Federation For the 3rd year students The text of the lectures and the minimum amount of knowledge necessary for a understanding of the subject material. Topic: Bleeding Authors: prof.Mikhailychenko V.Yu, Starykh A.A. 2015 Bleeding Bleeding, technically known as hemorrhaging or hæmorrhaging (see American and British spelling differences), is blood escaping from the circulatory system. Etiology : trauma and some diseases (tuberculosis, cancer, peptic ulcer). What is blood? Functions of blood. Blood is basically a type of a connective tissue which is found in the human body in fluid state. It is made up of plasma which is a highly viscous liquid and 3 different types of blood cells that are floating around in it. Almost 92% of the plasma is water while the rest consists of enzymes, hormones, antibodies, nutrients, gases, salts, proteins and metabolites of various kinds. Besides plasma, the cellular constituents of blood are red and white blood cells and platelets. What are the functions of blood? What about the functions for each blood component? Functions of Blood Blood performs many important functions within the body including: Supply of oxygen to tissues (bound to hemoglobin, which is carried in red cells) Supply of nutrients such as glucose, amino acids, and fatty acids (dissolved in the blood or bound to plasma proteins (e.g., blood lipids)) Removal of waste such as carbon dioxide, urea, and lactic acid Immunological functions, including circulation of white blood cells, and detection of foreign material by antibodies Coagulation, the response to a broken blood vessel, the conversion of blood from a liquid to a semi-solid gel to stop bleeding. Messenger functions, including the transport of hormones and the signaling of tissue damage Regulation of body pH Regulation of core body temperature Hydraulic functions Blood Components and Their Functions 1. Plasma About 55% of blood is blood plasma, a fluid that is the blood's liquid medium, which by itself is straw-yellow in color. The blood plasma volume totals of 2.7–3.0 liters (2.8–3.2 quarts) in an average human. It is essentially an aqueous solution containing 92% water, 8% blood plasma proteins, and trace amounts of other materials. Plasma circulates dissolved nutrients, such as glucose, amino acids, and fatty acids (dissolved in the blood or bound to plasma proteins), and removes waste products, such as carbon dioxide, urea, and lactic acid. Other important components include: Serum albumin Blood-clotting factors (to facilitate coagulation) Immunoglobulins (antibodies) lipoprotein particles Various other proteins Various electrolytes (mainly sodium and chloride) The term serum refers to plasma from which the clotting proteins have been removed. Most of the proteins remaining are albumin and immunoglobulins. Plasma is the most abundant component of blood. It has a number of functions which includes carrying glucose which is the most important nutrient required by each cell for generating energy. The other nutrients that are also carried by plasma include vitamins, cholesterol, amino acids, triglycerides and fatty acids. All of these nutrients are carried by plasma to and from each and every cell present in the body. Plasma is also responsible for the transportation of Cortisol and thyroxin hormones, which attach themselves to the plasma proteins and are then taken to all parts of the body. Homeostasis and management of the functioning of cells is also among the duties performed by plasma with the help of the inorganic ions that it contains in large quantities. Healing of wounds and stopping spillage of blood through clotting is another function of plasma which is made possible due to the presence of clotting agents in it. Plasma even plays a part in helping the body fight against the germs and infections thanks to the antibodies named gammaglobulins that are present in it. 2. White Blood Cells The infections that threaten to damage the body are handled by the white blood cells found in blood. White blood cells contain bacterial agents trying to penetrate into the body. These cells which are also known by the name of leukocytes are formed in the stem cells of the bone morrow and start circulating in the body by means of blood as well as the lymph fluid. The whole immune system of a human body is dependent on these white blood cells to identify the pathogens, cells with cancerous material in them and matters which is foreign to the body. In addition to identifying them, leukocytes are also tasked with the duty of destroying and cleaning the body of these enemy cells. 3. Red Blood Cells 4.7 to 6.1 million (male), 4.2 to 5.4 million (female) erythrocytes: Red blood cells contain the blood's hemoglobin and distribute oxygen. Mature red blood cells lack a nucleus and organelles in mammals. The red blood cells (together with endothelial vessel cells and other cells) are also marked by glycoproteins that define the different blood types. The proportion of blood occupied by red blood cells is referred to as the hematocrit, and is normally about 45%. The combined surface area of all red blood cells of the human body would be roughly 2,000 times as great as the body's exterior surface. The main job assigned to the red blood cells present in the blood is to make sure that the oxygen is delivered to all the cells of the body when the pumping of the blood has been carried out by the heart. The red blood cells have a very quick speed at which they travel through both the veins and arteries. The veins have a relatively smaller wall around them as compared to the arteries since the pressure of the blood is not too intense when it passes through them in comparison to the arteries. 4. Platelets 200,000–500,000 thrombocytes:Also called platelets, they take part in blood clotting (coagulation). Fibrin from the coagulation cascade creates a mesh over the platelet plug. The platelets are the lightest and the smallest components of blood. Due to their small size they usually travel near the walls of the vessels carrying blood. The wall of the blood vessels which is made up of special cells named endothelium stop the platelets from sticking to them. However, in the case of an injury, this layer of endothelium cells gets damaged and the blood starts flowing out from the blood vessels. When this happens the platelets react immediately and get attracted by the tough fiber which surrounds the walls of the blood vessels. The platelets then stick to the fibers and begin changing their shape thereby making a type of seal which stops the blood from flowing out of the body. Classification of bleeding I) Bleeding may occur: 1. Inside the body when blood leaks from blood vessels or organs Intratissue Internal Bleeding into pleural cavity, cranial cavity, abdominal cavity. 2. Outside the body when blood flows through a natural opening (such as the vagina, mouth, or rectum) 3. Outside the body when blood moves through a break in the skin. II ) Three Main Types of Bleeding In preparing yourself to identify and treat different types of bleeding, you must first have a good understanding of the three distinct types of bleeding that a person can experience. 1. Capillary Bleeding Capillaries are the smallest blood vessels in your body; they are about as thin as the hairs on your head. When a minor scrape or cut opens some capillaries, the bleeding is almost always very slow and small in quantity. Your body's natural clotting mechanism is able to stop most cases of capillary bleeding within seconds to minutes. 2. Venous Bleeding Deep cuts have the potential to cut open veins. A cut vein typically results in a steady but relatively slow flow of dark red blood. The best way to stop most cases of venous bleeding is to put direct pressure on the wound. 3. Arterial Bleeding This is the least common and most dangerous type of bleeding. It involves bright red blood that comes out in large volume, and in spurts that correspond with each beat of your heart. In most cases of arterial bleeding, direct and extremely firm pressure on the wound is the best way of stopping it. If direct pressure is not applied, a severe arterial wound can cause you to bleed to death within a few minutes. 4. Parenchymal hemorrhage Intraparenchymal hemorrhage is bleeding into the tissue of the internal organs. III) occult bleeding- escape of blood in such small quantity that it can be detected only by chemical tests or by microscopic or spectroscopic examination. Occult gastrointestinal bleeding commonly manifests as iron deficiency anemia or fecal occult blood. Iron deficiency anemia results from chronic occult gastrointestinal bleeding. Evaluation of asymptomatic patients who have iron deficiency anemia or fecal occult blood usually should begin with investigation of the colon. Colonoscopy is preferred, but flexible sigmoidoscopy plus air contrast barium enema, or computed tomographic colonography may be acceptable in certain circumstances. If evaluation of the colon does not reveal a bleeding site, evaluation of the upper gastrointestinal tract is mandatory in patients who have iron deficiency anemia, and this should be considered in those who have fecal occult blood. In patients who have gastrointestinal symptoms, evaluation of the portion of the gastrointestinal tract from which the symptoms is derived should be pursued initially. The role of small intestinal investigation is controversial, and this probably should be reserved for patients who have iron deficiency anemia and persistent gastrointestinal symptoms or those who fail to respond to appropriate therapy.