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48 Cards in this Set
- Front
- Back
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FUNCTIONS OF THE URINARY SYSTEM |
- regulate aspects of homeostasis - electrolytes, water balance, acid-base balance, blood pressure, RBC production, activation of vitamin D, elimination of waste products, nitrogenous wastes, toxins, drugs |
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ORGANS OF THE URINARY SYSTEM |
- Kidneys - Ureters - Urinary Bladder - Urethra |
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LOCATION OF KIDNEYS |
- against dorsal body wall - retroperintoneal - at level of T12 to L3 vertebrae - right is slightly lower than left d/t liver |
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RENAL HILUM |
- medial indentation where several structures such as ureters, renal blood vessels, and nerves enter or exit the kidney - hilum = "eye of the bean" |
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FIBROUS CAPSULE |
- contains and protects renal cortex and renal medulla; surrounds kidney |
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PERIRENAL FAT CAPSULE |
- surrounds the kidney, cushions against blows |
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RENAL FASCIA |
outermost capsule, helps hold the kidney in place against the muscles of the trunk wall |
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RENAL ARTERY |
brings waste products to be filtered |
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CALYX (PLURAL CALYCES) |
- cup shaped structures that funnel urine towards renal pelvis |
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FLOW OF BLOOD THROUGH KIDNEYS |
aorta--renal artery--segmental artery--interlobar artery--arcuate artery--cortical radiate artery--afferent arteriole --GLOMERULUS--efferent arteriole--peritubular capillaries--cortical radiate vein--arcuate vein--interlobar vein--renal vein--inferior vena cava |
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NEPHRON |
- basic structural and functional units of the kidney - responsible for forming urine - main structures: glomerulus, renal tubule - 1 million in each kidney |
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GLOMERULUS |
- knot of capillaries - covered with podocytes from the renal tubule - sits within Bowman's capsule (first part of renal tubule) - |
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PODOCYTES |
- cells which wrap around the capillaries of the glomerulus - have filtration slits and foot processes that stick out of glomerulus
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GLOMERULAR (BOWMAN'S CAPSULE)
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- holds glomulus - fed and drained by arterioles - specialized for filtration - high pressure forces fluid and solutes out of blood and into glomerular capsule |
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PROXIMAL CONVOLUTED TUBULE (PCT) |
- portion of the duct system which leads from the Bowman's capsule to the loop of Henle - regulates pH of filtrate - malfunctioning can lead to proteinuria |
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LOOP OF HENLE |
- leads from proximal convoluted tubule to distal convoluted tubule |
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DISTAL CONVOLUTED TUBULE (DCT) |
- portion of the duct system which leads from the loop of Henle to the collecting duct system |
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CORTICAL NEPHRONS |
- located entirely in the cortex - includes most nephrons |
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JUXTAMEDULLARY NEPHRONS |
- found at the boundary of the cortex and the medulla |
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COLLECTING DUCT |
- receives urine from many nephrons - run through the medullary pyramids - deliver urine into the calyces and renal pelvis - associated with 2 capillary beds: glomerulus, peritubular capillary bed |
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PERITUBULAR CAPILLARY BED |
- arise from efferent arteriole of the glomerulus - normal, low pressure capillaries - adapted for absorption instead of filtration - cling close to the renal tubule to reabsorb some substances from collecting tubes |
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AFFERENT ARTERIOLE |
- arises from a cortical radiate artery and feeds the glomerulus |
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EFFERENT ARTERIOLE |
- receives blood that has passed through the glomerulus |
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THREE MAJOR RENAL PROCESSES |
- Glomerular Filtration: water, solutes smaller than proteins are forced through capillary walls and pores of the glomerular capsule into the renal tubule - Tubular Reabsorption: water, glucose, amino acids and needed ions are transported out of the filtrate into tubule cells and then enter the capillary blood - Tubular Secretion: H+, K+, creatine, drugs are removed from the peritubular blood and secreted by the tubule cells into the filtrate
ALL TOGETHER=FORMS URINE |
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PROTEINURIA |
- protein in urine - caused by physical exertion, pregnancy, glomerulonephritis, hyeprtension |
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GLOMERULAR FILTRATION |
- nonselective, passive process - water and solutes < proteins forced through capillary walls - filtrate collected in bowman's capsule, leaves via renal tube - no fluids pass from blood to bowman's capsule - filtrate is plasma w/o proteins - adequate blood pressure is ESSENTIAL |
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TUBULAR REABSORPTION |
- peritubular capillaries reabsorb: water, glucose, amino acids, ions - some reabsorption is passive, most is active - most occures in PCT - taken to the blood - NOT REABSORBED: urea, uric acid, creatinine |
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TUBULAR SECRETION |
- some materials move from blood of peritubular capillaries into renal tubules - taken FROM the blood - gets rid of substances not already in the filtrate - materials left move towards ureter
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CHARACTERISTICS OF URINE |
- in 24 hrs, about 1-1.8L urine produced - differs from filtrate: is what remains after filtrate has lost most of its water, nutrients, and necessary ions through reabsorption - yellow do to urochrome - sterile - slightly aromatic - normal pH of around 6 |
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GLUCOSURIA |
- glucose in urine - possibly caused by excess sugar intake or diabetes |
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PYURIA |
- presence of pus (WBC and bacteria) in urine - caused by UTI |
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HEMATURIA |
- presence of blood in urine - caused by bleeding in the urinary tract |
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HEMOGLOBEINURIA |
- hemoglobin in urine - caused by varied things including transfusion reaction, hemolytic anemia |
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BILIRUBINURIA |
- bile pigments in blood - caused by liver disease (hepatitis) |
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URETERS |
- slender tubes attaching kidney to bladder - runs behind peritoneum - peristalsis aids gravity in transporting urine |
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URINARY BLADDER |
- smooth collapsible muscular sac - temporarily stores urine - trigone: triangular region of the bladder base with openings from 2 ureters, one urethra |
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URINARY BLADDER WALL |
- 3 layers of smooth muscle (destrusor) - transitional epithelium - walls are thick and folded when empty - can expand significantly - capacity: 500mL of urine signals gotta go, can hold up to twice that |
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URETHRA |
- thin walled tube that carries urine from bladder to outside body - 2 sphincters: - Internal urethral sphincter at connection with bladder, involuntary - External urethral sphincter farther down, is voluntary - 20cm in males, 3-4cm in females |
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MICTURITION (VOIDING) |
- both sphincter muscles must open - pelvic splanchnic nerves initiate bladder contractions (reflexive) - forced past internal sphincter, person then feels urge to void - external sphincter must be voluntarily relaxed then to void |
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BODY WATER |
- in total: 60% body weight - 40% of which is intracellular fluid (ICF) - 20% of which is extracellular fluid (ECF) - interstitial is 80% of ECF - plasma is 20% of ECF
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OSMORECEPTORS |
- sensitive cells in hypothalamus - react to small changes in solute blood composition by becoming more active - when activated, thirst center notified - dry mouth also promotes thirst |
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ADH (antidiuretic hormone) |
- prevents excessive water loss in urine - causes kidney's collecting ducts to reabsorb more water |
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DIABETES INSIPIDUS |
- occurs when ADH not released - leads to huge outputs of dilute urine |
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ALDOSTERONE |
- regulates sodium ion content of ECF - sodium = most responsible for osmotic water flows - promotes reabsorption of sodium ions - water follows salt |
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RENIN-ANGIOTENSIN MECHANISM |
- when JG apparatus stimulated by low blood pressure, release enzyme renin - renin produces angiotensin - which then causes vasoconstriction and release of aldosterone - result is increase blood volume, increase blood pressure
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THREE WAYS TO MAINTAIN ACID-BASE BALANCE IN BLOOD |
1) blood buffers (work in seconds) 2) respiration 3) kidneys |
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BLOOD BUFFERS |
ACIDS are proton (H+) donors - strong acids dissociate completely, liberate all H+ locked in water - weak acids dissociate only partially
BASES are proton (H+) acceptors - strong bases easily tie up H+ in water - weak bases are slower to accept
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BIOCARBONATE BUFFER SYSTEM |
- mixture of carbonic acid and sodium bicarbonate - carbonic acid is weak, does not dissociate much in neutral/acid solutions - bicarbonate ions react with strong acids, change them to weak acids - carbonic acid dissociates in strong base to form weak base and water |
