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47 Cards in this Set
- Front
- Back
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Function of Urinary System |
- excretion of metabolic waste -maintenance of water-salt balance -maintenance of acid-base balance -secretion of hormones |
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Nitrogenous wastes |
-Urea -Creatinine -Uric Acid |
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Urea |
- by product of amino acid metabolism -ammonia from the liver combines with CO2 to form urea |
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Creatinine |
- by product of creatine phosphate breakdown |
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Uric Acid |
-by product of breakdown of nucleotides -build up causes gout |
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Maintenance of Water-Salt Balance |
- blood volume is associated with salt balance - salt causes osmosis into the blood, more water= higher blood pressure - kidneys regulate blood pressure through water and salt regulation -regulates potassium, bicarbonate and calcium ions |
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Maintenance of Acid-Base Balance |
- kidneys maintain acid base balance of the blood by keeping the urine pH level normal (6) - does this by excretion of hydrogen ions and reabsorption of bicarbonate -urine pH is around 6 due to high acid diet |
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Secreted Hormones |
-Renin -Erythropoietin |
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Renin |
-released by kidney, which leads to the secretion of aldosterone from the adrenal cortex -aldosterone promotes the reabsorption of sodium ions |
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Erythropoietin |
- secreted by the kidneys when oxygen level is low -stimulates red blood product which activates vitamin D for calcium absorption |
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Kidneys |
- located in lumbar regions - behind peritoneum - covered by a tough capsule - concave side of the kidney is called the hilum, where the renal artery and vein are located |
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Ureters |
- conduct urine from kidney to bladder - 3 layered wall; mucosa, smooth muscle, outer connective tissue - conveys urine by peristalsis |
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Bladder |
-stores urine -expandable due to the structure: middle layer of circular muscle, 2 layers of longitudinal muscle -lined with transitional epithelium |
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Internal Sphincter |
-one of two sphincters in the bladder - smooth muscle - around the opening of the urethra - involuntary control |
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External Sphinctor |
-one of two sphincters in the bladder - composed of skeletal muscle -voluntary control |
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Urethra |
- conducts urine out of the body - short in females, more likely for urinary tract infections - in males, associated with the prostate gland, connected with the reproductive system |
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Urination |
- when bladder fills up to 250mL, the receptors in the wall stretch - stretching sends impulses to the spinal cord -motor nerve impulses from the spinal cord causes the bladder to contract, then micturition occurs |
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Micturition |
-emptying of the bladder |
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Overriding urination |
- in older children and adults, brain controls the micturition reflex, which can delay urination till appropriate |
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Nephron |
- functional unit of the kidney - approx 1 million nephrons - composed of a system of tubules, which provides them their own blood supply -regulates the concentration of water and solutions of waste materials by filtering the blood |
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Glomerular Capsule |
- cuplike structure - surrounds glamorous at beginning of nephron - inner layer is lined with special cells called podocytes that cling to the glomerular capillaries and form pores for passage of small molecules |
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Glomerulus |
-capillary network within glomerular capsule of a nephron -location of glomerular filtration -afferent arterioles leads into the glomerulus - blood leaves by efferent arteriole |
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Proximal Convoluted Tubules |
-region of nephron near the glomerular capsule --lined with cuboidal epithelial cells packed with microvilli which increase the surface area for reabsorption |
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Loop of Henle |
-U shaped tube -lined with simple squamous epithelium -conducts urine within each nephron -reabsorbs water and important nutrients in the filtrate -extends to the medulla |
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Distal Convoluted Tubules |
-lined with cuboidal epithelial cells but no microvilli, so does not reabsorb -helps molecules from the blood into the tubule -DCT of several nephrons enter one collecting duct |
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Collecting Ducts |
-carry urine to the renal pelvis |
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Renal Vein |
- branch off the inferior vena cava - carry deoxygenated blood from the kidneys to the heart |
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Renal Artery |
- branch off from the aorta into the kidneys - carries blood from the heart to the kidneys |
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Capillary Network |
-recieves blood from the efferent arteriole -surrounds the nephron - then blood goes into the venule that joins the renal vein |
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Cortex |
-Outer region of the kidney -contains 1 million blood filtering nephrons |
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Renal Pelvis |
- collects urine from the nephrons, carried by the collecting ducts -narrows into the upper end of the ureters |
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Glomerular Filtration |
-blood enters glomerulus from afferent arteriole - high blood pressure causes water and small molecules to be filtered in to the glomerular capsule - large molecules will not be able to pass through the capillary wall -Filtered: water, nitrogenous wastes, salt -Not Filtered: blood cells, plasma |
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Glomerular Filtrate |
- composed of the same substance as blood plasma, minus the cells and large plasma proteins -remaining processes must reabsorb desirable substance and allow wastes to pass |
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What is reabsorbed into the blood stream? |
-Reabsorbed: most water, nutrients, required salts -not reabsorbed: some water, nitrogenous waste, excess salts |
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What are the 3 steps of water being reabsorbed? |
1. Reabsorption of salt 2. Establishment of solute gradient 3. Reabsorption of Water |
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Reabsorption of Salt |
-99% of sodium filtered is reabsorbed -67% reabsorbed by PCT, 25% by ascending limb of loop of Henle, rest by collecting duct and DCT |
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Established of a Solute Gradient |
-salt diffuses out of lower part of ascending limb of loop of Henle - upper part of ascending limb transports more salt out -creates high osmotic pressure in the medullary tissue, contributed by urea which leaks from the the lower collecting ducts -end result- concentration gradient favouring reabsorption of water |
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Reabsorption of Water |
- water leaves the DCT because of gradient -water also leaves the descending limb of loop of Henle - filtrate enters collecting ducts, this fluid is isontic to the cells in the renal cortex - filtrate passes down collecting duct encountering high osmotic gradient again - water diffuses out of collecting duct, and urine in the duct becomes hypertonic to blood plasma |
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Diuretic |
-chemicals that increase urine flow
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Diuretic Examples |
Alchol- shuts off ADH (hormone that increases water absorption, so less urine), dehydration causes hangover Caffeine- Increases glomerular filtrate rate, decreases tubular reabsorption of sodium Diuretic Drugs- inhibit active transport of sodium at loop of Henle or DCT |
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Hemodiaylsis |
artificial kidney machine or continous ambulatory peritoneal dialysis |
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How successful are kidney transplants? |
97% success rate when received from a related, 90% from non relative |
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Diabetes, hypertension, inherited condition |
-caused by progressive renal disease |
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Kidney Stones |
-caused by UTI, enlarged prostate, pH imbalance, indigestion of too much calcium |
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Cystitis |
inflammation of bladder |
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Pyelonephritis |
infection of kidneys |
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Urethritis |
inflammation of urethra |
