Flashcards in Urinary System Deck (68):
what are the 3 steps involved in performing a urinalysis?
- a gross examination of the physical properties of the sample
- a chemical analysis of substances dissolved in the urine
- a microscopic examination of the solid components in the urine
what are the 6 structures that make up the urinary system?
2 kidneys, 2 ureters, 1 urinary bladder, and 1 urethra
what are the nitrogenous waste materials from protein breakdown eliminated from the body as?
what is the hormone whose release is regulated by the kidney?
antidiuretic hormone ADH
what is the hormone that directly affects kidney function?
what is the hormone that is produced by the kidney?
what is the difference between the hilus of the kidney and the renal pelvis?
the hilus is the area on the medial side of each kidney where blood and lymph vessels, nerves, and the ureter enter and leave the kidney; the renal pelvis is inside the hilus and is a urine collection chamber at the beginning of the ureter
what is it meant by the term retroperitoneal?
outside of the abdominal cavity, between the parietal peritoneum and the dorsal abdominal muscles
what is the difference between glomerular filtrate and tubular filtrate?
glomerular filtrate contains waste products, as it enters the proximal convoluted tubule and is termed tubular filtrate, which travels through the tubular part of the nephron where some products are then reabsorbed from the tubular filtrate back into the body along with some urea
what is the function of the brush border on the epithelial cells of the PCT?
it increases the cellular surface area exposed to the fluid in the tubule by a factor of about 20, which is especially important to the PCT’s reabsorption and secretion functions
how does the blood in the efferent glomerular arteriole differ from the blood in the afferent glomerular arteriole?
blood in the afferent glomerular arteriole of the kidney gives up all of the small molecules that can fit easily through fenestrations in the glomerulus which include electrolytes, bicarbonate, glucose and water; the blood in the efferent glomerular arterioles is composed of large molecules such as proteins and blood cells including platelets
what is the difference between tubular reabsorption and tubular secretion?
tubular reabsorption involves removing these substances that the body actually needs from the tubular filtrate, the useful substances are reabsorbed from the tubules into the peritubular capillaries
how does ADH deficiency affect urine volume?
insufficient ADH will increase urine volume because ADH acts on the DCT to promote water reabsorption into the body; if ADH is absent, water will not be reabsorbed and will be lost in urine
why does proteinuria occur with renal failure?
in a normal kidney, large molecules such as protein are too big to fit through glomerular fenestrations and are retained in blood, during some types of kidney disease, the glomerulus is damaged, resulting in enlarged fenestrations and protein passing through them into urine
why are clinical signs of renal failure not observed until the disease process is advanced?
there are often no clinical signs of chronic renal failure until 65% to 75% of the nephrons in both kidneys are nonfunctional, therefore long-term kidney disease is often not detected until very late in the disease
diabetes insipidus gets its name from what physical characteristic of urine produced by patients with this disease?
the word insipid means tasteless; diabetes insipidus was given its name because clinically it looked similar to diabetes mellitus, but the urine was “tasteless” rather than sweet because it didn’t contain glucose
how do kidneys respond to a decrease in blood pressure?
when blood pressure falls, the juxtaglomerular cells within the renal cortex release renin which causes the formation of angiotensin I from angiotensin. Angiotensin I is subsequently converted to angiotensin II by another enzyme, angiotensin converting enzyme (ACE); angiotensin II causes the arteries in the body to constrict
why is it important that the ureters have an inner lining of transitional epithelium?
it allows the ureters to stretch as urine is passed through them on its way to the urinary bladder
what prevents urine from backing up into the ureters when the bladder wall contracts to expel urine?
the ureters enter the urinary bladder at such an oblique angle that when the bladder is full it collapses the opening of the ureter, preventing urine from backing up into the ureter
the ureter is continuous with what structure in the kidney, except in cattle?
the renal pelvis
how does the bladder know when to empty itself?
the pressure of the filling bladder reaches a certain “trigger” point that activates stretch receptors in the bladder wall, when that is reached, a spinal reflex is activated that returns a motor impulse to the bladder muscles; the muscles of the bladder wall contract
what part of the urinary bladder is under voluntary control and allows an animal to be housebroken?
the muscular sphincter around the neck of the bladder
does urine production stope when the urinary bladder is full?
no, the kidneys continue to produce urine regardless of the volume of urine present in the bladder
besides its urinary function, what other function does the urethra play in a male animal?
a reproductive function; the vas deferens and accessory reproductive glands enter the urethra as it passes through the pelvic canal
how much kidney function must be destroyed before clinical signs of renal dysfunction become evident?
two thirds of the total nephrons in both kidneys must be nonfunctional before clinical signs of renal dysfunction start to become evident
what is a urolith?
a stone anywhere in the urinary system (kidneys, ureters, urinary bladder, or urethra)
how do uroliths in cats differ from uroliths in other species?
they are much larger and resemble sand instead of stone
what is the chemical component of a struvite crystal?
magnesium, ammonium, and phosphate
condition which no urine is being passed from the body
passing small amounts of urine
what is the most important waste product of protein?
where is nitrogen waste produced?
in the liver and then it is sent to the kidney
the presence of myoglobin in the urine, usually associated with muscle destruction
why is it important to monitor kidney function during anesthesia?
because they are susceptible to hypertension (high blood pressure)
blood in the urine
excess sugar in the urine
what is the primary site for ADH and aldosterone action?
the distal convoluted tubule of the nephron, it also regulates K and acid-base balance
what nervous system has the most influence on water absorption?
the sympathetic nervous system
what does the glomerular filtration rate depend on?
the rate of blood flow to the kidney
what is the pH of a carnivore?
meat based diet will have a lower pH in their urine
what is the pH of an herbivore?
plant based diet will have a higher pH in their urine
means vitamin c present in urine on a u/a stick; may be seen with an animal that has a plant based diet
what is used to stain a urine slide?
hemoglobin present in urine from lysed RBC's
what color us equine urine?
normally cloudy due to presence of calcium carbonate crystals
what color is rabbit urine?
it is densely turbid as the result of mucus and calcium carbonate crystals
what is a specific gravity test used to determine?
it is used as an indicator of the concentrating ability of the kidney
specific gravity of a healthy kidney
1.008 or lower
the excretion of abnormally large amounts of ketone bodies in the urine, characteristic of diabetes mellitus, starvation, or other medical conditions
results from the metabolism of hemoglobin and is normally excreted in bile
what is the main function of the proximal convoluted tubule (PCT)?
absorption, it is where 65% if absorption takes place in the kidney
what is absorbed by the PCT?
- nutrients including glucose, amino acids, vitamins and proteins
- HCO3, H2O, urea (glomerular filtrate)
- Na, K, Mg
what influences calcium absorption in the PCT?
vitamin d, parathyroid hormone, and calcitonin
what hormone increases magnesium absorption in the PCT?
where does 100% of glucose and animo acids get absorbed?
the proximal convoluted tubule
where does 80% of water and bicarbonate get absorbed?
the proximal convoluted tubule
what is absorbed in the descending loop of henle?
what is absorbed in the ascending loop of henle?
Na and Cl
what is absorbed in the distal convoluted tubule (DCT)?
- Cl, Na, K, Ca, Mg
- ADH and aldosterone
what does the collecting duct absorb?
H2O, urea and Mg
what is the main function of the DCT?
secretion, it is the major site of tubular secretion
what is secreted in the PCT?
H, organic acids and bases, and ammonium
what is secreted by the descending loop of henle?
ammonium and urea
what is secreted by the ascending loop of henle?
what is secreted by the DCT?
K (if the body needs it), H, urea in the form of ammonium