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ob/gyn
| Question | Answer |
|---|---|
| the kidneys maintain . . . | the constancy of fluids in our internal environment |
| kidneys are a perfect example of what type of organs | homeostatic organs |
| the kidneys are what type of major organs | major excretory organs |
| how do the kidneys perform their excretory functions | they simultaneously regulate the volume & chemical makeup of the blood, maintaining the proper balance between water & salts & between acids & bases |
| name another important renal function | gluconeogenesis |
| when would it go through this process | only during prolonged fasting |
| the kidneys supply approximately how much glucose compared to that of the liver | one-fifth as much glucose as the liver |
| how do the kidney's act as endocrine glands | the produce the enzyme renin and the hormone erythropoietin |
| what does the enzyme renin do? | it helps regulate blood pressure and kidney function |
| what does the hormone erythropoietin do? | it stimulates red blood cell production in bone marrow |
| what do the kidneys metabolize to its active form | vitamin D |
| what is the purpose of the urinary bladder | provides a temporary reservoir for urine & three tubelike organs-- the paired ureters & the urethra (it is a temp. storage area for urine) |
| what does the urethra do | it furnishes transportation channels for urine |
| the bean0shaped kidneys lie in what type of position | a retroperitoneal position (between the dorsal body wall & the parietal peritoneum) in the superior lumbar region |
| what vertebra do the kidneys lie inbetween? | extend from the level of the 12 thoracic verebra to the 3rd lumbar vertebra |
| what is so special about the right kidney | it is crowded by the liver & lies slightly lower than the left |
| the lateral surface of the kidney is | convex |
| the medial surface of the kidney is | concave & has a vertical cleft called the renal hilus |
| what is the renal hilus? | it leads into a space within the kidney called the renal sinus |
| what is the renal sinus | allows several structures to enter or exit the kidney at the hilus & occupy the sinus |
| what are the 3 layers of supportive tissue that surround each kidney | the fibrous renal capsule; the fatty mass called the adipose capsule & the outermost layer the renal fascia |
| what is the purpos of the fibrous renal capsule | it adheres directly to the kidney surface, its a transparent capsule that provides a strong barrier that prevents infections in surrounding regions from spreading to the kidneys |
| what is the purpose of the adipose capsule | it helps attach the kidney to the posterior body wall & cushions it against blows |
| what is the purpose of the renal fascia | it is a dense fibrous connective tissue, that surrounds the kidney & its attendant membranes & also the adrenal gland & anchors these organs to surrounding structures |
| name the three distinct regions of the kidney | the cortex, the medulla, & the pelvis |
| what is the most superficial region of the kidney | the renal cortex |
| what exhibits cone-shaped tissue masses | the medullary or renal pyramids |
| what is the purpose of the calyces in the kidneys | they collect urein, which drains continuously fromteh papillae, & empty it into the renal pelvis |
| what type of muscle is in the walls of the calyces, pelvis & ureter | smooth muscle |
| how do they contract | rhythmically & propels urine along its course by peristalsis |
| each renal artery approaches a kidney and divides into | 5 segmental arteries that enter the hilus |
| name the arteries in order | segmental, lobar, interlobar, arcuate, & interlobular |
| name the veins; blood leaving the renal cortex | interlobular, arcuate, interlobar & renal veins |
| what is the renal plexus | a variable netwrok of autonomic nerve fibers & ganglia; it provides the nerve supply of the kidney & its ureter; it is largely supplied by sympathetic fibers from the least thoracic & first lumbar splanchnic nerves |
| what are the sympathetic fibers | they are vasomotor fibers that regulate renal blood flow by adjusting the diameter of renal arterioles & influence the urine-forming role of thenephrons |
| what do the nephrons do? | they carry out the processes that form urine |
| what is the purpose of the collecting ducts? | they collect urine from several nephrons & conveys it to the renal pelvis |
| what does each nephron consist of | a glomerulus, & a tuft of capillaries associated w. a renal tubule |
| what is the end of the renal tubule called | the glomerular (Bowman's ) capsule; it completely surrounds the glomerulus |
| collectively teh glomerular capsule & the enclosed glomerulus are called what? | the renal corpuscle |
| the glomerular's endothelium is | fenestrated (penetrated by many pores); which makes these capillaries exceptionally porous |
| what does this type of endothelium allow? | large amounts of solute-rich, virtually protein-free fluid to pas fromt eh blood into the glomerular capsule |
| what is the plasma-derived fluid/filtrate | it is the raw material that is processed by the renal tubules to form urine |
| the external parietal layer of the glomerular capsule is what type of epithelium | simple squamous epithelium |
| the visceral layer which clings to the glomerulus conssits of . . . | highly modified branching epithelial cells called podocytes |
| what is foot processes | the intertwine w. one another as they cling to the basement membraneof the glomerulus |
| what are the clefts or openings between the foot proceses called | filtration slits or slit pores |
| what do they allow | the filtrate to pas to the interior of the glomerular capsule, a region called the capsular space |
| name the 3 parts of the renal tubule | glomerular capsule; proximal convoluted tubule; loop of Henle; & the distal convoluted tubule |
| by the renal tuble increasing its length what does it enhance | its filtrate processing capabilities |
| the collecting ducts | receive urine frommany nephrons, by running through the medullary pyramids & give them their striped appearance |
| as the collecting ducts approach the rnal pelvis the fust to form the large | papillary ducts |
| what is the purpose of the papillary ducts? | to deliver urine into the minor calyces via papillae of the pyramids |
| the walls of the proximal convoluted tubule are formed by what type of cells | cuboidal epithelial cells |
| what do these cells do | they actively reabsorb substances from the filtrate & secrete substances into it; th cells have large mitochondria & their luminal surfaces bear dense microvilli that tremendously increase their surface area |
| what is a nickname for all of this? | "brush border" |
| why does it have this name | bc it dramatically increases their capacity for reabsorbing water & solutes from the filtrate |
| the descending limb of the U-shaped loop of Henle is called what | the thin segment |
| what type of epithelium is present in the this segment | simple squamous epithelium that is freely permeable to water |
| what is the thick segment | when the epithelium becomes cuboidal or even low columnar in the ascending part of the loop of Henle |
| epithelial cells of the distal convoluted tubule are | confined tot eh cortex & are cuboidal, but they are somewhat thinner & almost entirely lack microvilli |
| these tubule paly a greter role in what? | secreting solutes into the filtrate than in reabsorbing substances from it |
| the DCT is sometimes called what? | connecting tubule |
| the collecting ducts are what type of cells | intercalated cells, cuboidal cells w. abundant microvilli & more numerous principal cells which lack microvilli |
| what do the intercalated cells play a major role in | maintaining the acid-base balance of the blood; the prinipal cells help maintain the body's water & Na+ (salt) balance |
| the cortical nephrons represent | 85% of the nephrons in the kidneys |
| where are the cotical nephrons located | entirely int he cortex |
| the juxtamedullary nephrons play an important role in what? | the kidney's ability to produce concentrated urine |
| every nephron is closely associated w. two capillary beds, name them. | the glomerulus & the peritubular capillaries |
| the glomerulus is specialized for | filtration |
| how does te glomerulus differ from all other capillary beds in the body | it is both fed & drained by arterioles (afferent & efferent) |
| the afferent arterioles arise from the | interlobular arteries that run through the renal cortex |
| what is the difference in size between the afferent arterioles & the efferent | the afferent have a larger diameter tan the efferent |
| blood pressure in the glomerulus is | extrodinarily high for a capillary bed & easily forces fluid and solutes out of the blood intot he glomerular capsule along nearly its entire length |
| most of the filtrate (99%) is reabsorbed by what? it is returned where? | reabsorbed by the renal tubule cells & returned to the blood in the peritubular capillary beds |
| the peritubular capillaries arise from | the efferent arterioles draining the glomeruli |
| the peritubular capillaries are adapted for | absorption |
| describe the pressure in the peritubular capillaries | it is low-pressure, porous capillaries that redily absorb solutes & water from the tuble cells as these substances are reclaimed from the filtrate |
| all substances secreted by the nephrons are derived from | the blood of the peritubular capillaries |
| what is the vasa recta | bundles of long straight vessels that extend deep into the medulla paralleling the courses of the longest loops of Henle |
| renal blood pressure declines from aprox. __ mm Hg in the renal arteries to __ mm Hg or less in the renal veins | 95; 8 |
| juxtaglomerular (JG) cells are what type of muscle | smooth muscle cells w. prominent secretory granules containing renin |
| what do these type of cells ace as | mechanoreceptors that directly sense the blood presure in the afferent areriole |
| what is the macula densa | a group of tall, closely packed distal tubule cells that lies adjacent to the JG cells |
| the mascula densa cells are | chemoreceptors that respond to changes in teh solute content of the filtrate in the tubule lumen |
| what is the filtration membrane | the actual filter that lies between the blood & the interior of the glomerular capsule |
| what type of membrane does it have | a porous membranethat allows free passage of water & solutes smaller than plasma proteins |
| the 3 layers of the filtration membrane are: | (1) the fenestrated endothelium fo the glomerular capillaries (2) the visceral membrane of the glomerular capsule mad eof podocytes (#) the intervening basment membrane composed of the fused basal laminas of the other layers |
| the capillary pores (fenestrations) prevent | passage of blood cels |
| what do capillar pores (fenestrations) allow to pass? | all plasma componets |
| teh basement membrane restricts passage of all but the | smallest proteins while permitting most other solutes to pass |
| the structural makeup of the gel-like basement membrane also seems to confer | elevtrical selectivity on teh filtration process |
| what are the three major processes of urine formation | glomerular filtration; tubular reabsorption; & secretion |
| explain what filtration is | a passive, nonselective process where fluids & solutes are forced through a membrane by hydrostatic pressure |
| glomerular blood pressure is__ compared to that of other capillary beds | higher |
| approx. what is the glomerular blood pressure | 55 (-70)mm Hg; as opposed to 18 mmHg |
| what is this pressure result in | much higher net filtration pressure |
| kidneys produce how many L of filtrate dily | 180L |
| how many L of urine are produced daily | 1-1.5L |
| glomerular hydrostatic pressure (HPg) is what | glomerular blood pressure, the chief forc pushing water & solutes out of the blood across the filration membrane |
| what is the pressure in teh colloid osmotic pressure in the intracapsular space of the glomerular capsule is essentially what? | zero; bc virtually no proteins enter the capsule |
| glomerular hydrostatic pressure is about what | 55-70 mm Hg |
| colloid osmotic (oncotic) pressure of glomerular blood (OPg) is what | 28 to 30 mm Hg |
| capsular hydrostatic pressure (HPc) exerted by fluids in the glomerular capsule is about how many mm Hg | 15 mm Hg |
| the net filtration pressure is responsible for forming what? | renal filtrate from plasma (10 mm Hg) |
| glomerular filtration rate is | the total amount of filtrate formed per minute by the kidneys |
| the normal GFR in both kidneys in adults is | 120-125 ml/min |
| the GFR is _____ proportional to the net filtration pressure | directly |
| dehydration causes what to glomerular osmotic pressure | increase; inhibits filtate formation |
| Flomerular filtration rate is held relatively constant by what 3 important mechanisms that regulate renal blood flow? | renal autoregulation (intrinsic system), neural controls & the reninangiotensin system (basically a hormonal mechanism) |
| what is the pressure in teh colloid osmotic pressure in the intracapsular space of the glomerular capsule is essentially what? | zero; bc virtually no proteins enter the capsule |
| glomerular hydrostatic pressure is about what | 55-70 mm Hg |
| colloid osmotic (oncotic) pressure of glomerular blood (OPg) is what | 28 to 30 mm Hg |
| capsular hydrostatic pressure (HPc) exerted by fluids in the glomerular capsule is about how many mm Hg | 15 mm Hg |
| the net filtration pressure is responsible for forming what? | renal filtrate from plasma (10 mm Hg) |
| glomerular filtration rate is | the total amount of filtrate formed per minute by the kidneys |
| the normal GFR in both kidneys in adults is | 120-125 ml/min |
| the GFR is _____ proportional to the net filtration pressure | directly |
| dehydration causes what to glomerular osmotic pressure | increase; inhibits filtate formation |
| Flomerular filtration rate is held relatively constant by what 3 important mechanisms that regulate renal blood flow? | renal autoregulation (intrinsic system), neural controls & the reninangiotensin system (basically a hormonal mechanism) |
| where are the tubuloglomerular feedback mechanisms located | in the walls of the distal tubules, respond to filtrate flow rate & osmotic signals by causing or not causingthe release of a chemical that produces intense vasoconstriction of the afferent arterioles |
| when the mascula densa cells are exposed to slowly flowing filtrate or filtratew. low osmolarity they promote | vasodilation of the fferent arterioles |
| what does this allow | more blood to flow into the glomerulus, thus increasing the NFR & GFR |
| filtrate is flowing rapidly &/or it has a high sodium & chloride content (or high osmolarity ingeneral) the macula densa cells prompt | generation of the vasoconstrictor chemical by the JG cells |
| what effect does this have on blood flow | it hinders blood flow into the glomerulus, which decreases the GFR & allows more time for filtrate processing |
| the mascula densa cells send messages to the JG cells of the juxtaglmerular apparatus that set the | renin-angiotensin mechanism into motion |
| why is this mechanism important | it balances filtration & tubular reabsoption |
| a relatively constant blood flow through the kidneys over an arterial pressure range from | 80 to 180mm Hg |
| once mean systemic blood pressure drops below 70 mm Hg autoregulation effectively | ceases |
| when the sympathetic nervous sytem is at rest, the renal blood vessels are | maximally dialated & renal autoregulation mechanisms prevail |
| the basic functional unit of the kidney is | the nephron |
| the ability to concentrate urine depends on the functions of | the loop of henle |
| what urine formation process results in acid elimination | secretion |
| one of the roles of the countercurrent mechanism in the nephron is to | produce a concentration gradient that will allow thenephron to concentrate filtrate |
| when the concentration of ADH increases | less urine is produced |
| in response to increased levels of aldosterone, the kidneys produce | urine with a lower concentration of sodium ions |
| the blood supply to the nephron is the | afferent arteriole |
| nephron cells that respond tot eh concentration of filtrate are | macula densa cells |
| the most important factor affecting the glomerular filtration rate is | blood hydrostatic pressure |
| what process results in incrased glomerular filtration in response to hormone release | renin-angiotensin mechanism |
| what substance would probably have the lowest rebsorption rate? | urea |
| facultative Na+ rabsorption occurs in teh | distal convoluted tubule |
| how is Na+ reabsorbed | by active transport using ATP |
| what substance would you not expect to find in urine | protein |
| what structure is the muscular tube that delivers urine to the bladder | ureter |
| what artery has the smallest diameter | interlobular artery |
| major calyces are | large brances of the renal pelvis |
| micturation is | a sacral reflex |
| the bowman's capsule & glomerulus make up the | renal corpuscle |
| creatinine | a protein metabolite found in skeletal muscle & excreted in urine |
| glucose in the urine | not normally found |
| Na+ in urine | is reabsoption occurs w. K+ efflux; this is a common electrolyte in extracellular fluids |
| urea in urine | a detoxified ammonia compund; produced from ammonia following deamination |
| uric acid in the urine | a nitrogen waste product from RNA metabolism; a metabolic waste product of nucleic acid metabolism |
| juxtaglomerular cells | specialized barorreceptors |
| juxtamedullary | long nephrons |
| macula densa cells | specialized chemoreceptors |
| renal capsule | outer covering; helps provide a barrier against microbe invasion |
| renal fascia | anchors kidneys; this tissue is made of dense irregular connective tissue |
| regulatory function of the kidney include the production of 2 hormoens for | erythropoiesis & calciu absorption |
| the renal cortex contains the | glomeruli |
| reabsorption occurs through the tubule wall & into the | peritubular capillaries |
| the juxtaglomerular apparatus contains both | osmoreceptors & barorreceptors |
| the myogenic control mechanism reflects the fact that vascular smooth muscle tends to | contract when stretched |
Created by:
Brina
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