Clinical Chemistry Fluids and Electrolytes PDF
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Al Maqal University College of Dentistry
2024
Dr/ Wael Sobhy Darwish
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Summary
These lecture notes cover the topic of fluids and electrolytes in clinical chemistry. The document details the functions of water, body fluid compartments, and electrolyte balance, including disorders like dehydration and edema. It is aimed at a first-year undergraduate medical or dentistry student
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Clinical Chemistry Almaaqal University Collage of Dentistry Fluids and Electrolytes Dr/ Wael Sobhy Darwish Lec-4 1ST stage&2024 ...
Clinical Chemistry Almaaqal University Collage of Dentistry Fluids and Electrolytes Dr/ Wael Sobhy Darwish Lec-4 1ST stage&2024 Body Fluids Fluids make up a large portion of the body, about 60% of adult human body is fluid mainly a water solution of ions and other substances. Body fluids are divided into two main compartments Intracellular fluid. Intracellular fluid functions as 1- A stabilizing agent for the parts of the cell 2- Helps maintain cell shape 3- Assists with transport of nutrients across the cell membrane, in and out of the cell. Extracellular fluid. Extracellular fluid mostly appears as interstitial tissue fluid and intravascular fluid. Two-thirds of the water is in the Intra Cellular Fluid (ICF), and one-third is in the Extra Cellular Fluid (ECF). Body Fluid Compartment Total body water (TBW) 60% of body weight Component of body fluids FUNCTIONS OF WATER 1. Act as a solvent: water is the most suitable solvent for cellular components 2. Catalytic action: Water accelerates a large number of chemical reactions in the body due to its ionizing power. 3. Lubricating actions prevent friction in joints, pleura, conjunctiva, and peritoneum. 4. Heat regulation: The loss of heat from the body is also regulated by the evaporation of water from skin and lungs and its removal in urine. Disturbances of Water Homeostasis. 1. Gain or loss of extracellular fluid volume. 2. Gain or loss of electrolyte (solute) Fluid and electrolyte balance is a dynamic process that is crucial for life and homeostasis. The homeostasis of body fluid is maintained by: 1- The endocrine system 2-Nervous system. Sources of water to the body a. Dietary liquids b. Solid foods c. Oxidation of foodstuffs Water output a. Urine b. Respiration c. Lactation d. Feces e. Eyes (Tears) f. Evaporation from skin and lungs Normal Intake and Output Daily intake. An adult human at rest takes appropriately 2,500 ml of fluid daily. Levels of intake. Approximate levels of intake include fluids 1, 200 ml, foods 1, 000 ml, and metabolic products 30 ml. Daily output. Daily output should be approximately equal in intake. Overhydration and Dehydration Overhydration: occurs when too much water is taken by drinking without solute, volume increases, but because solute is not present, plasma osmolarity decreases. Water intoxication This can occur when excessive amounts of water, low sodium or hypotonic solutions are taken or given by any route. When sodium is too low, extra water goes into your cells and makes them swell. This swelling can be dangerous, especially in the brain. Edema Edema is the excess accumulation of fluid in interstitial tissue spaces, also called third-space fluid. Cause of edema. Edema is caused by a disruption of the filtration and osmotic forces of the body’s circulating fluids. Dehydration: When water is lost and solute is not lost. Dehydration involves a loss of volume but, because solutes are not lost in the same proportion, plasma osmolarity increases. Treatment of dehydration. Supplemental fluids and electrolytes are often administered. Fluid Regulation Mechanisms 1. The thirst center. The thirst center in the hypothalamus stimulates or inhibits the desire for a person to drink. 2. Antidiuretic hormone. ADH acts to maintain blood pressure, blood volume and tissue water content by controlling the amount of water and hence the concentration of urine excreted by the kidney. 3. The Renin–angiotensin system (RAA). The RAA system controls fluid volume, in which when the blood volume decreases, blood flow to the renal juxtaglomerular apparatus is reduced, thereby activating the RAA system. 4. Atrial natriuretic peptide. The heart also plays a role in correcting overload imbalances, by releasing ANP from the right atrium. Electrolytes An electrolyte is a substance that will disassociate into ions when dissolved in water. Represent 7% of total body weight Function of electrolyte in the human body: 1- Maintenance of acid base balance 2- Maintenance of normal osmolality and valium of body fluid 3- They regulate nerve and muscle function 4- Help rebuild damaged tissue. Electrolytes are found in the form of inorganic salts, acids, and bases. Electrolyte concentrations are measured according to their chemical activity and expressed as milliequivalents. Electrolytes are divided into two main compartments Intracellular electrolytes. Such as: potassium, magnesium, sulfate, and phosphate, and the most dominant cation is potassium while the most dominant anion is phosphate. Extracellular electrolytes. Such as: sodium, chlorine, calcium, and bicarbonate, and the most essential cation is sodium while chlorine is the most important anion. Electrolyte imbalance An electrolyte imbalance occurs when you have too much or not enough of certain minerals in your body. Causes include: 1. Kidney damage caused by illness, such as diabetes or high blood pressure. 2. Severe vomiting, diarrhea, GI malabsorption. 3. Lifestyle, such as drinking too much water and eating poorly. 4. Inherited genetic conditions. Types of electrolyte disorders 1. Hyper means too high. 2. Hypo means too low.