Body Fluids PDF

Body Fluids Assistant Lecturer: Ahmed Makki Body Fluids ⚫ Total amount of fluid in the human body is approximately 70% of body weight ⚫ Body fluid has been divided into two compartments – – Intracellular fluid (ICF) ⚫ Inside the cells ⚫ 55% of total bo...

Body Fluids Assistant Lecturer: Ahmed Makki Body Fluids ⚫ Total amount of fluid in the human body is approximately 70% of body weight ⚫ Body fluid has been divided into two compartments – – Intracellular fluid (ICF) ⚫ Inside the cells ⚫ 55% of total body water – Extracellular fluid ⚫ Outside the cells ⚫ 45% of total body water Body Fluid Compartments Extracellular fluid includes ⚫ Interstitial fluid ⚫ Present between the cells ⚫ Approximately 80% of ECF ⚫ Plasma ⚫ Present in blood ⚫ Approximately 20% of ECF ⚫ Also includes ⚫ Lymph ⚫ vitreous body, ⚫ endolymph, ⚫ synovial fluid ⚫ perilymph, ⚫ aqueous humor ⚫ pleural, pericardial ⚫ cerebrospinal fluid and peritoneal fluids Barriers separate ICF, interstitial fluid and plasma ⚫ Plasma membrane ⚫ Separates ICF from surrounding interstitial fluid ⚫ Blood vessel wall ⚫ Separate interstitial fluid from plasma Composition of body fluids ⚫ Organic substances ⚫ Inorganic substances ⚫ Glucose ⚫ Sodium ⚫ Amino acids ⚫ Potassium ⚫ Fatty acids ⚫ Calcium ⚫ Hormones ⚫ Magnesium ⚫ Enzymes ⚫ Chloride ⚫ Phophate ⚫ Sulphate Difference ⚫ ECF ⚫ ICF ⚫ Most abundant cation - Na+, ⚫ Most abundant cation - K+ – muscle contraction – Resting membrane potential – Impulse transmission – Action potentials – fluid and electrolyte balance – Maintains intracellular volume – Regulation of pH ⚫ Most abundant anion - Cl- – Regulates osmotic pressure ⚫ Anion are proteins and – Forms HCl in gastric acid phosphates (HPO42-) ⚫Na+ /K+ pumps play major role in keeping K+ high inside cells and Na+ high outside cell Distribution of Water and Solutes in the Body The composition of body fluid is composed of water and dissolved substances such as electrolytes (sodium, potassium, and chloride), gases (oxygen and carbon dioxide), nutrients, enzymes, and hormones. Water is essential for the body as it: 1-It is the major component of the body’s transport systems. The blood transports nutrients, oxygen, glucose, and fats to various tissues and cells. Also, the waste products of cellular metabolism 2-It is needed for the regulation of body temperature at 37 ° C. When body temperature rises, blood vessels near the skin's surface dilate to release some of the heat; the reverse happens when body temperature drops. Also, when body temperature rises, sweat glands secrete sweat, which is 99% water. As the sweat evaporates, heat is removed from the body. 3-Provides an optimum medium for the cells to function. 4-There are chemical reactions in the body that require water. 5-Breaks down food particles in the digestive system. 6-Provides lubrication for the joints as it is a component of synovial fluid to provide lubrication **Living cells use energy to maintain a state of chemical and electrical disequilibrium across the cell membrane. Cell membranes and capillary endothelial cells act as selective barriers establishing a solute disequilibrium. What this means is that there are very different concentrations of certain ions and substances in the different fluid compartments, Transport systems 1-Osmosis: Osmosis is the net movement of water across a semipermeable membrane from a higher water concentration to a lower water concentration. Hypotheses Isotonic solution: This is when the cell’s intracellular fluid has the same osmolarity as the fluid surrounding it in the beaker hypertonic solution: Salt will move into the cell from the cup and water will move out of the cell into the cup because of a difference in concentration. hypotonic solution: Water will move from the cup into the cell because water outside the cell will be in higher concentration than water inside the cell. 2- Simple diffusion: The process of the net movement of solutes from a region of high concentration to a region of low concentration is known as diffusion. The differences in concentration between the two regions are termed as concentration gradient and the diffusion continues until the gradient has vanished. 3- Facilitated diffusion: The process of the movement of molecules across the cell membrane via special transport proteins that are embedded within the cellular membrane is known as facilitated diffusion or called carrier- mediated diffusion. Many large molecules, such as glucose, are insoluble in lipids and too large to fit into the porins, therefore, they will bind with their specific carrier proteins, and the complex will then be bonded to a receptor site and moved through the cellular membrane 4- Filtration: Filtration is the process of the movement of water and solute molecules across the cell membrane due to hydrostatic pressure generated by the system. Depending on the size of the membrane pores, only solutes of a certain size may pass through it. The membrane pores of the Bowman's capsule in the kidneys are very small, and only albumins (the smallest of the proteins) can filter through. On the other hand, the membrane pores of liver cells are extremely large, to allow a variety of solutes to pass through and be metabolized. Active transport An example of active transport in the human body is The sodium- potassium pump. Transport by Vesicles Cells also have the ability to move large particles or numerous molecules at once through the plasma membrane. In this process, which also requires energy, the cell membrane creates a vesicle to transport the matter either into the cell or out of the cell A-Endocytosis Endocytosis is the process by which cells take in molecules such as proteins from outside the cell by engulfing them with their cell membrane. It is used by all cells of the body because most substances important to them are polar and consist of big molecules, and thus cannot pass through the hydrophobic plasma membrane. 1 Pinocytosis In pinocytosis, the molecule engulfed is relatively small molecules with amount of fluid, occurs in all cells. 2 phagocytosis results in the ingestion of particulate matter (e.g. bacteria) from the extracellular fluid, the endosome is so large that it is called a phagosome or vacuole and occurs only in certain specialized cells (e.g. neutrophils, macrophages) 3 Receptor-mediated endocytosis involves specific receptors that bind to large molecules in the extracellular fluid ,the substance bound to the receptor is called a ligand. B-Exocytosis Exocytosis is a process for moving items from the cytoplasm of the cell to the outside. The intracellular vesicle with its ingested substances fuses with the cell membrane to discharge of the unwanted substance from the cell. Specialized Fluids of the Body ⚫ Lymph ⚫ Milk ⚫ Cerebrospinal fluid ⚫ Amniotic fluid ⚫ Aqueous humor ⚫ Sweat ⚫ Tears Lymph ⚫ Clear and colorless fluid ⚫ 96% water and 4% solids ⚫ Solids – – Proteins ⚫ 2-6% of solids ⚫ albumin, globulin, fibrinogen, prothrombin, clotting factors, antibodies, enzymes – Lipids ⚫ 5-15% ⚫ Chylomicrons and Lipoproteins – Carbohydrates ⚫ Glucose mainly – Non-protein nitrogen compounds NPN ⚫ Urea and creatinine – Electrolytes ⚫ Sodium, calcium, potassium, chloride, bicarbonates Functions of Lymph ⚫ Return protein from tissue spaces into blood ⚫ Redistribution of fluid ⚫ Removal of bacteria, toxins and other foreign bodies from tissues ⚫ Maintain structural and functional integrity of tissue ⚫ Route for intestinal fat absorption ⚫ Transport lymphocytes  Milk ⚫ Secreted by mammary glands ⚫ Complete natural food ⚫ 83-87% water and 13-17% solids ⚫ Solids – Carbohydrates ⚫ Lactose – Lipids ⚫ Triacylglycerols ⚫ Palmitic acid, myristic acid, stearic acid, lauric acid, butyric acid, oleic acid – Proteins ⚫Caesin (80%), Lactalbumin ⚫ Enzymes (proteases, xanthine oxidase, lysozyme), immunoglobulins – Minerals:- Ca, Mg, P, Na, K, Cl – Vitamins:- Fat and water-soluble vitamins except Vit - C Cerebrospinal fluid (CSF) ⚫ Clear, colorless liquid formed within the cavities of brain and around spinal cord ⚫ 500ml CSF is formed every day ⚫ CSF is completely replaced about three times a day. Functions of CSF ⚫ Hydraulic shock absorber ⚫ Regulation of intracranial pressure ⚫ Influences the hunger sensation and eating behaviors Amniotic Fluid ⚫ Liquid produced by membranes and fetus ⚫ Volume of fluid increases with gestational age ⚫ Clear with some desquamated fetal cell and a little lipid. Functions of AF ⚫ Physical protection to the fetus ⚫ Medium for exchange of various chemical Aqueous Humor ⚫ Fluid that fills the interior chamber of eye ⚫ Secreted by ciliary body, enters anterior chamber Sweat ⚫ Secretion of sweat gland ⚫ Regulates body temperature by cooling and evaporation Sweat ⚫ Electrolyte in sweat varies – Na+ K+ Cl- Tears ⚫ Produced by lachrymal glands ⚫ Isotonic but becomes hypertonic due to evaporation as fluid passes over the cornea Functions of Tears ⚫ Lysozyme protects eye from infectious agents ⚫ Lubricate the surface of the cornea ⚫ Protects eyes from injury THANK YOU