urinary system part 2 Flashcards
what is a filtering device
renal corpuscle
what processes and carries away filtered fluid
renal tubule
what is the functional unit of the kidney
nephron
2 parts of the nephron are
renal corpuscle
renal tubule
what does the renal corpuscle contain (2)
glomerulus and bowmans capsule
what does the renal tubule contain (4)
proximal convulated tubule
loop of henle
distaI convoluated tubule
collecting duct
what are the three steps in urine formation
- filtration
- reabsorption
- secretion
out of the three steps in urine formation, which one is to remove unwanted substances from blood
filtration
what step moves H2O and nutrients back into the bloodstream
reabsorption
in filtration the initial formation of tubular fluid is by?
hydrostatic pressure
initial formation of tubular fluid by hydrostatic pressure is where
glomerular capillaries
what does the hydrostatic pressure in the glomerular capillaries force
ultrafiltrate through filtration membrane
what is the tubular process which returns water, electrolytes, and other substances from the tubular fluid to the blood
reabsorptioin
water reabsorption is active or passive
passive
reabsorption of other substances may be passive or active or either
either
what secreted from blood complete formation of urine
waste ions
what is the tubular process which moves substances from the blood to the tubular fluid
secretion
what is the result of secretion
elimination of substances in urine
the renal corpuscle is entirely in what
renal cortex
the renal tubule begins where and then what
begings in cortex then to medulla and back into cortex
what does the renal corpuscle: glomerulus and bowmans capsule do
filters blood
what does the PCT do
returns filtered substances to blood
what does the loop of henle do
conserves H2O and solutes
what does the DCT do
last ditch effort to rid blood of additional waste products
what does the collecting duct do
hormonal regulation of urine concentration
collects from multiple nephrons and sends urine to papillary duct into renal papilla-> minor major calyx-> renal pelvis-> ureter-> urinary bladder-> urethra
what is a twisted capillary network
glomerulus
what kind of layers does the glomerular capsule have
visceral and parietal
what layer has specialized cells called podocytes
visceral layer
what ET does the pariteal layer have
simple squamous
blood enters glomerular capillaries and filtered fluid=
filtrate
what are 3 unique characteristics to enhance glomerular filtration
porous capillaries
porous visceral layer
high pressure
porous capillaries are highly permeable or impearmeable
highly permeable (fenestrae)
large proteins/ blood cells=
too big
in the porous visceral layer, what is between the podocyte cell processes
filtration slits
what is high pressure due to in glomerular filtration
due to smaller diameter efferent vs afferent arteriole
what is in the filtration membrane
capillary endothelium, basement membrane and podocytes if bowmans
what is the 1st major step in urine production
filtration membrane filters blood and filtrate enters lumen
in addition to having high BP in the glomerular capillaries, this capillary bed is special in what way
fenestrated capillaries
what does it mean to have fenestrated capillaries
the cells of the capillaries have gaos or holes between the cells, so fluid can leak out of these capillaries much more easily than in other body tissues
specialized cells of the bowman capsule (podocytes) do what
wrap around the glomerular capillaries forming narrow openings called flitration slits through which the filtered fluid must pass
what combo makes up the filtration membrane of the renal corpuscle
capillary fenestrations and filtration slits
fluid escapes rapidly from blood plasma into the space formed by what?
bowmans capsule
filtered fluid then travels into what to start the conversion into urine
PCT
the fluid that entered the PCT cause the fluid to be what
ultrafiltrate
the small opening through which filtered blood plasma must pass does what
prevents big things from getting through
what does the ultrafiltrate contain
H2O
electrolytes
AA’s
Glc
urea
most toxic substances that might be ingested with food
what does ultafiltrate not usually contain
proteins
blood cells
other large molecules from the plasma
what reabsorbs almost all of the H2O intiallt filtered by the glomerulus
kidneys
what is the basic stratgey of the kidney
throw everything out and then reclaim what you need
what is the totla GFR from both kidneys
180 L/ day
what is the fluid loss rate
1-2 L/ day
glomerular ultrafiltrate must be reabsorbed in what?
renal tubule and collecting duct
how much ultrafiltrate is lost in the form of urine
1%
since H2O has no active transport mechanisms for its movement what occurs
All H2O reabsorption must be accomplished by actively transporting Na and causing H2O to follow salt
do kidneys require a lot of energy
yes
since the bulk of H2O and other needed molecules are reabsorbed in the renal tubule anything not reabsorbed does what
it is excreted at high concentration in the urine
what is the regulatory structure
juxtaglomerular apparatus
what does the juxtaglomerular apparatus consist of
afferent arteriole cells and specialized cells in DCT
what and where are the juxtaglomerlar cells
specialized smooth muscle cells
around entry
what are specialized cells of DCT
macula densa
where is macula densa found
between afferent and efferent arterioles
whay does the macula densa do
detects rate of fluid flow in DCT and gives feeback fultration system
decreased flow in DCT->
dilation of afferent arteriole-> increase GFR and tubular flow
what does juxtaglomerular apparatus secrete
renin
what does renin do
plays a role in regulating filtrate formation and BP
rest of nephron action is what
fluid modification to finalize urine formation
what does the renal tubule consist of
PCT
loop of henle
DCT and collecting duct
what is Simple Cuboidal ET with Microvilli extending into Lumen (Filtrate) to increase surface area
PCT
what has a descending and ascending limb
loop of henle
what is the thin inferior bend that narrows
descending limb
what kind of ET is the descending limb
simple cuboidal and simple squamous
ascending limb has what kind of ET
simple squamous to simple cuboidal
Ascending limb travels closer to what and becomes what
travels closer to renal corpuscle becoming DCT as near macula densa
what is shorter than PCT
DCT
what et is DCT
simple cubdoidal
what do the cells look like in DCT
smaller with less microvilli
several DCTs attach where
collecting duct
what ET is collecting duct
simple cuboidal
what has a large diameter, and forms bulk of medullary rays
collecting duct
where does the collecting duct span from
renal cortex and extend through medulla through renal pyramid tips
what are the two nephron types
cortical and juxtamedullary
renal corpuscles distributed throughout the cortex is what type
cortical
the nephron in cortical is shorter or longer deeper or superficial
shorter and more superficial
what capillaries are in the cortical type
peritubular capillaries
what type is next to medulla
juxtamedullary
where are the renal corpuscles
deep in cortex
is the nephronn is juxtamedullary short or long deep or superfiical
long and deep into medulla
the longer loops in juxtamedullary help with what
better adaption to conserve H2O
where is the vasa recta cortical or juxt
juxt
does the efferent arteriole have a high or low oxygen content
high
is the efferent arteriole thick or thin
thick so it cant distend like a vein
is the diameter for efferent artiole smaller or larger than afferent
smaller
what capillaries are wrapped around the tubes
peritubular
where do the peritubular capillaries branch from
efferent arterioles
peritubular caps are seen with what nephron
cortical nephron
what do the peritubular caps surround
PCT
DCT
loop of henle
what are straight tubues, string of pearls
vasa recta
vasa recta are specialized parts of what and extend where
specialized parts of peritubular caps and extend deep into the medulla
what does the vasa recta surround
loop of henle and collecting duct
both peritubular and vasa recta return to where
circulation via renal veins
the affernet arterioles have resistance which means
increases constriction
the increased constriction of afferent arterioles means
decrease renal blood flow
if you have a decrease downstram pressure what happens
decreases GFR and urine production
afferent arterioles protect glomeruli from what
fluctuation in systemic BP
if there is a significant drop in BP what happens to afferent arterioles
opposite effect with dilation to preseve blood flow to kidney
what is released in response to drop in BP
juxtaglomerular cells release renin in response to decreased stretch to preserve GFR
if there is resistance in efferent arterioles what happens
reinforces high glomerular pressure
reduces hydrostatic pressure in peritubular capillaries
