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what are the functions of the urinary system?
- excretion of wastes
- elimination to external environment
- regulation of blood plasma volume and solute concentration
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what are the homeostation functions?
- regulate blood volume and bp
- regulate plasma ions
- stablize pH
- conserve glucose and amino acids
- eliminate wastes (urea and uric acid)
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describe the location and shape of the kidney
- retroperitoneal; supported by connective tissue
- convex lateral surface
- concave medial surface
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what are the tissues that make up/ close to kidney?
- fibrous capsule: absorbs impact and fill in space, protect it from infection
- renal fascia: brown line holds kidney and fat capsule in place
- last thoracic vertebrate: protects kidney
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what would happen in a saggin kidney?
sagging kidney when there is no perirenal fat capsule; it blocks where ureters are; build up of urine in kidney
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why is the ureter lined with smooth muscle?
move urine down by parastalsis, ureters go to backside of bladder
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where does the ureters begin and end?
begins at renal pelvis and ends at posterior, inferior bladder wal
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what happens with the slit like ureteral openings as bladder pressure increases?
closes, to prevent backflow
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what are the three layers of the ureter wall from inside out?
- mucosa (transitional epithelium-can stretch)
- muscularis (contracts in response to stretch)
- adventitia (outer fibrous connective tissue)
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what happens in urinary reflex? what is most likely the cause?
- urine backflows through utreters to kidney
- short muscle through mucosa (reflux happens); normally, ureters enter urinary bladder obliquely
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what is the trigone?
outlined by openings for ureters and urethra in the bladder
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what are the layers of the bladder?
- mucosa, detrusor (layers of smooth muscle), adventitia (peritoneum on superior surface only)
- when bladder expands, smooth out mucosa layer, ridges disappear (ragae)
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what is the lining of the urethra?
epithelial lining is mostly pseudostratified columnar epithelium, true stratified at edge of uretha and mucuous cells (protect from outside)
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what is the difference between internal urethral sphincter and external urethral sphincter?
- internal (involuntary; smooth muscle at bladder urethra junction)
- external is voluntary (skeletal surrounded urethra
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what is the differnce between sympathetic control and parasympathetic control in micturition?
- sympathetic allows bladder to fill (NE relaxes smooth muscle-inhibits bladder contraction and excited internal urethral sphincter-keep closed)
- parasympathetic empties bladder: excites smooth muscle and relaxes internal urethral sphincter
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what are the brain centers involved in micturition?
- pontine storage center (inhibit)
- pontine micturition center
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what contracts the external sphincters?
increase in somatic motor nerve
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what are the different types of incontinence?
- overflow: urine dribbles, common in men with enlarged prostate which squeezes the sphincters
- stress incontinence: increased intraabdominal pressure forces urine through external sphincter (only signal bladder knows is stretch), also occurs in weak muscles, weakening of sphincters
- urge: UTI consistently receiving signal to contract
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what does it mean that the glomerulus has a fenetrated endothelim
highly porous; allows filtrate formation
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what are the epithelium layers of teh renal corpuscle?
- simple squamous epithelium (parietal layer) forms wall of corpuscle
- inner capsule layer (visceral layer) made of branching epithelial podocytes
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what are podocytes?
- epithelial cell extensions terminate in foot processes that cling to basement membrane and wrap around capillaries
- filtration slits between foot processes allow filtrate to pass into capsular space
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what is the hilum?
where artery, vein goes in and where teh renal pelvis is emtying, beginning of ureter
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what is the renal papilla?
urine filter at the top of each renal pyramid
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what is a renal lobe?
renal pyramid with coritcal tissue
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when does filtrate become urine?
once it leaves nephron
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where is PCT? what does it consists of?
in cortex, cuboidal cells with dense microvilli (increase SA-allow for reabsorption) and large mitochondria to supply transport mechanisms, which creates concentration gradient for water
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what kind of limbs does the nephron loop have?
thin descending loop (simple squamous) flows through the renal pelvis and thick ascending loop (cuboidal and oclumnar cells) flows toward the renal cortex
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where in the nephron loop is the concentration of solute the highest?
IF of renal medulla
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describe the DCT, where is it?
- confined to cortex, cuboidal cells with few microvilli
- secretion, selective reabsorption of sodium and water
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what is it called when several collecting ducts fuse together to deliver urine?
through papillae into minor calyces
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what is the function of the collecting duct?
- adjusts final filtrate composition
- determines final osmotic concentration
- determines final volume of urine
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how is the pressure of the glomerulus capillary bed kept high?
afferent arterioles are larger than efferent
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what is the characteristics of the peritubular capillaries?
- arise from efferent arterioles
- low pressure, adopted for absorption of water and solutes in cortical nephrons
- cling to adjacent renal rubles in cortex, empty into venules
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what is the vasa recta?
- arise from efferent arterioles
- long, thin walled parallel to nephron loops of juxtamedullary nephrons
- functions in formation of concentrated urine
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what is the juxtaglomerular complex?
- involves modified portions of DCT and ascending limb of nephron loop and afferent arteriole
- regulate rate of filtrate formation and blood pressure
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macula densa
chemoreceptors: sense NaCl content
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granular cells
- secretory granules contain renin
- mechanoreceptors; sense blood pressure in afferent arteriole
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extraglomerular mesangial cells
interconected with gap junctions for signals to travel quickly
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