Urine Biochemistry Lecture (Transes) PDF

BIOCHEMISTRY DAPHNE PANALIGAN LECTURE (TRANSES) NR-11 URINE URINE ✓ Produ...

BIOCHEMISTRY DAPHNE PANALIGAN LECTURE (TRANSES) NR-11 URINE URINE ✓ Produce ERYTHROPOIETIN – hormone that aids in formation of red blood cells Waste product of the kidneys, which filter blood to ✓ Release hormones to regulate blood pressure remove toxins, excess water, and other waste INNER PARTS: materials. A. NEPHRONS Contains 95% water and 5% nitrogenous wastes and Tiny filtering units inside the kidney salts. Removes the urea from the blood A person with an average diet excretes in the urine both organic and inorganic constituents, which can be B. GLOMERULUS a basis of an individual’s physiological and Ball-formed network of small blood pathological conditions. capillaries The kidney and urinary systems help the body to Crucial component of the nephron eliminate liquid waste called urea, and to keep Allows small molecules to pass chemicals, such as potassium and sodium, and water through its walls (e.g. waste products in balance. and excess fluids) Retains large molecules like proteins FUNCTIONS OF URINE and blood cells for reabsorption C. GLOMERULAR/BOWMAN’S CAPSULE 1. Remove waste products (such as urea), toxins, and Cup-like sack that encloses the excess water from the body network of glomerulus 2. Regulates water and electrolyte balance Located at the beginning of the 3. Regulates pH level tubular component of the nephron 4. Helps release important hormones Also known as: renal corpuscular capsule, capsular glomeruli UREA Performs the first step in the filtration of the blood derived from ammonia Bowman’s space – space or cavity in produced when foods containing protein, such as between the walls of the capsule. meat, poultry, and certain vegetables, are broken down D. RENAL TUBULE in the body. Collects the products that were carried in the bloodstream to the kidneys, where it filtered out from the blood (vital is removed along with water and other wastes in the water, electrolytes, amino acids, and form of urine. ions) When converted to uric acid, excess amounts in Reabsorbs useful substances and the bloodstream can cause gout secretes waste products FOUR PARTS: 1. PROXIMAL CONVOLUTED TUBULE URINARY TRACT (PCT) o first part of the renal tubule to 1. TWO (2) KIDNEYS leave the glomerulus Bean-shaped o collects the filtrate produced by Pair of purplish-brown organs located below the the glomerulus ribs toward the middle of the back o where maximum of reabsorption FUNCTION: of essential substances happen ✓ Remove liquid waste from the blood in the form of urine 2. LOOP OF HENLE ✓ Keep a stable balance of salts and other o reabsorption is limited in this substances in the blood. segment BIOCHEMISTRY DAPHNE PANALIGAN LECTURE (TRANSES) NR-11 URINE o descending limb is permeable to Muscles in the ureter walls continually tighten and water relax forcing urine downward, away from the o ascending limb is permeable to kidneys. electrolytes If urine backs up, or is allowed to stand still, a o the filtrate gets diluted as it moves to kidney infection can develop. the ascending limb in the Loop of About every 10 to 15 seconds, small amounts of Henle urine are emptied into the bladder from the ureters. 3. DISTAL CONVOLUTED TUBULE o last part of the nephron 3. URINARY BLADDER o connects and empties its contents to a triangle-shaped, hollow organ collecting duct located in the lower abdomen o conditionally reabsorbs Na (sodium) It is held in place by ligaments that are attached to ions and water, which maintains pH other organs and the pelvic bones. and sodium-potassium levels in the The bladder’s walls relax and expand to store blood cells urine, and contract and flatten to empty urine through the urethra. 4. COLLECTING DUCT The typical healthy adult bladder can store up to o long, straight tube two cups of urine for two to five hours. o where the maximum reabsorption of water takes place (to make the PARTS OF THE BLADDER: urine concentrated) or secretes A. TRIGONE excess water (makes urine diluted) o a triangle-shaped region near the o where H+ and K+ ions are secreted junction of the urethra and the bladder to maintain the electrolyte B. RIGHT & LEFT LATERAL WALLS balance in the blood o Walls on either side of the trigone C. POSTERIOR WALL o Back wall D. DOME o Roof of the bladder 4. TWO (2) SPHINCTER MUSCLES two circular muscles that help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder. 5. NERVES IN THE BLADDER alert a person when it is time to urinate, or empty the bladder. 6. URETHRA tube allows urine to pass outside the body The brain signals the bladder muscles to 2. TWO (2) URETERS tighten, which squeezes urine out of the bladder. narrow tubes carry urine from the kidneys to the At the same time, the brain signals the sphincter bladder muscles to relax to let urine exit the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs. BIOCHEMISTRY DAPHNE PANALIGAN LECTURE (TRANSES) NR-11 URINE Secretion usually removes substances from the blood that are too large to be filtered (ex: antibiotics, toxins) or those that are in excess in the blood (ex: H+, K+). These substances secreted into the tubule are destined to leave the body as components of urine. 5. CONCENTRATION & DILUTION As the tubular fluid flows through the collecting ducts, water is either reabsorbed or secreted to concentrate or dilute the urine, depending on the body’s needs. This is also regulated by ADH. 6. URINE FORMATION The resulting fluid is now called urine - a URINE FORMATION concentration of waste products, excess ions, and water. 1. BLOOD FILTRATION Blood enters the kidneys which filter wastes and 7. STORAGE & EXCRETION excess fluids from the blood. Inside contains tiny Urine flows from the kidneys through the ureters units called nephrons that each filters small and is stored in the bladder. amounts of blood. When the bladder is full, the muscle lining contracts and urine is excreted through the urethra 2. GLOMERULAR FILTRATION during urination. The filtered blood now passes through the glomerulus, a cluster of blood vessels, that act as a filter that allows small molecules like water, ions, and waste products to pass through while keeping large molecules like proteins and blood cells in the bloodstream. 3. TUBULAR FILTRATION The filtrate from the glomerulus enters a long, thin tube called renal tubule. During this process, the useful substances in the filtrate such as glucose, amino acids, and ions are being reabsorbed back into the bloodstream. The filtrate that is not reabsorbed becomes urine at the base of the collecting duct. This process is regulated by hormones like aldosterone and antidiuretic hormone (ADH). 4. TUBULAR SECRETION Tubular secretion occurs mostly in the proximal convoluted tubule (PCT) and distal convoluted tubule (DCT) where unfiltered substances are moved. BIOCHEMISTRY DAPHNE PANALIGAN LECTURE (TRANSES) NR-11 URINE PHYSICAL PROPERTIES OF URINE Excess/increase in turbidity is due to the 1. VOLUME presence of suspended particles in the urine Amount of urine output which can be determined by the result of Average adult can produce 1000 to 1500 mL of microscopic tests done on the urine sediments. urine output in 24 hours COMMON CAUSES OF EXCESS TURBIDITY: FACTORS AFFECTING THE VOLUME: ✓ Increase of cells ✓ Nature of the food and the amount of fluid ✓ Urinary Tract Infection (UTI) intake ✓ Obstructions ✓ Temperature and humidity 6. pH LEVEL ✓ Mental excitement normal range: pH 4.8 to pH 8 ✓ Diarrhea and excessive vomiting average pH is 6 ✓ Pathological condition: diabetes High protein diet = more acidic urine ✓ Certain medications Vegetarian diet = more alkaline urine 2. COLOR Normal: amber yellow color CHEMICAL COMPOSITION OF URINE Clear: overhydrated, low specific gravity Light yellow: well-hydrated, low specific 1. WATER 2. NITROGENOUS ORGANIC COMPOUNDS gravity ✓ Urea (9.3 g/L) Dark yellow: dehydrated, high glucose and ✓ Uric acid high specific gravity ✓ Creatine Colors other than yellow of any shade may be ✓ Creatinine (0.670 g/L) due to certain like food (eating large amounts ✓ Ammonia of pigment can dye the urine) and drugs. ✓ Hippuric acid UROCHROME – yellow pigment ✓ indican UROERYTHRIN – red pigment 3. NON-NITROGENOUS ORGANIC COMPOUNDS UROBILIN – responsible for orange-yellow 4. INORGANIC SALTS color formation ✓ Chlorides (1.87 g/L) 3. ODOR ✓ Phosphates Aromatic odor ✓ Na (Sodium) and K (potassium, 0.750 g/L) Fresh urine has a mild smell. ✓ Mg (Magnesium and Ca (Calcium) It is possible for fresh urine to also be odorless and that is only if the individual has not eaten PATHOLOGICAL CONSTITUENTS anything yet and is well-hydrated. Aged urine has a stronger odor that’s similar 1. PROTEINURIA to ammonia due to urea and similar Also known as albuminuria components. Excess presence of proteins in the urine 4. SPECIFIC GRAVITY normal urine does not have persistent protein Ranges from 1.015 to 1.025 in significant quantities FACTORS AFFECTING THE SPECIFIC GRAVITY: 2. GLUCOSURIA ✓ Amount of solid and fluid intake Excess glucose in the urine ✓ Time of the day seen most frequently in individuals suffering ✓ Pathological condition: Diabetes from diabetes mellitus 5. TRANSPARENCY/TURBIDITY 3. KETONURIA Normal urine is clear and transparent Presence of ketone bodies in the urine Turbidity of urine can range from clear to 4. HEMATURIA slightly cloudy, cloudy, and opaque. Presence of red blood cells in the urine BIOCHEMISTRY DAPHNE PANALIGAN LECTURE (TRANSES) NR-11 URINE 5. PYURIA Presence of white blood cells in the urine 6. BACTERIURIA Presence of bacteria in the urine counts of 5000 or more indicates urinary tract infection TESTS FOR KIDNEY EFFICIENCY 1. Water output test 2. Concentration test 3. Urea clearance test 4. Phenolsulfophthalein