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urinary

Terms in this set (60)

what consist in the urinary system
2 kidneys ("beans"), 2 ureters, 1 urinary bladder, 1 urethra
what are the functions of the kidney
regulation of blood (ionic composition, pH, volume, pressure, osmolality, glucose levels), production of hormones, excretion of wastes, red& bean shaped, retroperitoneal, 4" x 2", renal hilum, indented part is renal hilum on medial side
what are the 3 layers of the kidney
1) renal capsule dense irregular CT, most inner
2) adipose (capsule fatty tissue, surrounding & holds kidney in place)
3) renal fascia ( anchors kidney to posterior wall)
what is a nephron
filters the blood, not actual tubes bc they're made up of cells & things pass thru them to got thru capillaries that are around them, renal capsule, loop of Henele, distal convoluted tubule, collecting duct, surrounded by capillaries, 2 types
what is the renal capsule
made up of bowman's capsule and glomerulus, first area where blood gets filtered
what is the proximal convoluted tubule
1st part of tube system that receives the FILTRATE
what is the loop of henle
where the filtrate continues to move thru
what is the distal convoluted tubule
filtrate still moving thru, many of these merge and empty into a collecting duct
what is the collecting duct
taking on many DCT and eventually more CDs merge together forming papillary duct
what are the 2 types of nephrons
juxtamedullary and cortical
what is the juxtamedullary nephron
"G"is in deep cortex and has a long loop that extends into the pyramid
what is the cortical nephron
"G" is in outer cortex and has a short loop
what is the glomerulous "G"
mass of capillaries specialized for filtration, most permable, unique bc supplied and drained by arterioles (afferent and efferent), capillaries in here are covered by a visceral layer of podocytes (modified simple squamous cells)
afferent is the drainer or the supplier?
supplier
efferent is the drainer or supplier?
drainer
what is the bowman's capsule
structure that collects filtrate from "G" , 2 layers
what is the first layer of bowman's capsule
parietal layer- simple squamous, 1 layer of flat cells
what is the second layer of bowman's capsule
visceral layer- podocytes covering capillaries in "G"
what is the space between the 2 layers of bowman's capsule called
capsular space
Renal tubules:
PCT- what is it made out of ? what mostly happens here and what does that mean?
simple cuboidal with a brush border ( microvilli)
most reabsorption happens here meaning all 100% of nutrients are put back into bloodstream
Renal tubules:
Loop of henle- what are the 2 parts of it made of ?
descending and 1st part (thin part of loop) of ascending is simple squamous
2nd part- (thick ascending limb) is simple cuboidal
renal tubules:
DCT & CD- what do they both have? what do they alternate between?
both have simple cuboidal cells & alternates between 2 types -
primary cells: have receptors for ADH aldostenone (increase BP)
intercalated cells: helps with PH bc allows movement of H+ ions to enter/leave
several DCT's empty into a single CD
CD's then merge & form papillary ducts
urine production:
performed by the what
filter what
reabsorption of what (into what from what )
secretion of (into what from what)
nephrons
blood plasma ("G" filtration)
H2O, nutrients, and electrolytes (into blood from tubule)
wastes, drugs, and excess ions (into tubule from blood)
Glomerular Filtration-
what does it do
what kind of transport process is it?
what are forced across the EC membrane and what does this?
what does that produce
moves water and solutes from blood into nephron
non-selective passive transport process
solute and solvent and pressure does this
produces a filtrate
in glomerular filtration, it's efficient bc-
pressure in here si what bc why (outflow resistance is what)
millions of what are very what (increased what)
EC membrane is what and lots of what
high bc efferent arteriole is smaller in size that the afferent arteriole (outflow resistance is high)
capillaries are very long (increased surface area)
thin and lots of fenestration
1 of 3 pressures that affect filtration:
GBHP- what is it
glomerular blood hydrostatic pressure- actual BP in "G" (55 mmHg)
2 of 3 pressures that affect filtration:
BCOP- what is it
blood colloid osmotic pressure which is exerted by proteins in blood plasma (30 mmHg)
3 of 3 pressures that affect filtration:
CHP- what is it
capsules hydrostatic pressure (15 mmHg) which is pressure exerted by the filtrate that entered the renal tubule
net filtration pressure-
what is the formula ?
must be what despite what ?
NFP-GBHP - (BCOP+CHP)
must be maintained despite systemic changes
glomerular filtration rate-
what is it (where does this occur)
normal GFR is what ( that is normal in males and what is it in females)
how much of it is reabsorbed
how much of it becomes urine
is the total amount of filtration each min (in both kidneys)
180L/day or 125mL/min (in females its around 105mL/min)
178-179 are reabsorbed
1-2L become urine
I of 3 major mechanisms that control GFR:
renal autoregulation- what is it
negative feedback loop involving JGA
intrinsic system
helps maintain constant filtration pressure and rate in 2 ways
1 of 2 ways renal auto regulation helps maintain constant filtration pressure and rate:
myogenic mechanism- what is it
when systemic BP decreases, receptors in JGA respond & dilation of afferent arteriole & constriction of efferent, increasing blood flow to g
increase GFR
2 of 2 ways renal auto regulation helps maintain constant filtration pressure and rate:
tubuloglomenular feedback- what is it
when BP is increased filtered fluid flows more rapidly therefore less reabsorption of ions & H2O. when that happens, the macula densa cells inhibit the release of Nitricoxide, constricting the blood vessels therefore decrease blood flo to "g"
2 of 3 major mechanisms that control GFR:
Neural regulation- what is it
kidney's are innervated by sympathetic fibers (those fivers release NE)
at rest, stimulation is low; arterioles are dilated (no NE)
during exercise, stimulation is high: releasing NE causing vasoconstriction therefore GFR decreases, lowering urine production, increasing blood flow to needed parts of body during fight or flight
3 of 3 major mechanisms that control GFR:
Hormonal regulation- 1 of the 2 hormones that contribute to this is angiotensin II which does what
reduces GFR, potent vasoconstriction
hormonal regulation- 2 of the 2 hormones that contribute to this is atrial natriuretic peptide (ANP) which does what
increases GFR, ANP released from cardiac myofibers due to stretching during HIGH BP, it inhibits secretion of ADH (pulls h2O back into blood stream) & aldosterone
tubular regulation and tubular secretion-
what happens here (what to what) by what kind of transport processes
how much of water are reabsorbed
how much of nutrients reabsorbed
wastes are secreted from what into what
what type of transport mechanisms are needed for this to occur
cell lining the what have what kind of concentration of what due to what
what does TM mean
how much of h2O is reabsorbed occurring by what
substances can move in 2 ways: paracellular-what is it & trancellular-what is it
solutes are reabsorbed (tubule to blood) by active & passive processes
99% of water
100% of nutrients
blood into tubule system
simple diffusion, primary active transport, secondary active transport, facultative water reabsorption, obligatory water reabsorption
renal tubule, low concentration Na+ due to Na+/K+ pump
transport maximum can create body to release glucose in urine
90%, obligatory reabsorption
movement between cells (50% of specific ions & h2o)
movement thru cells
what is simple diffusion
small enough to pass thru membranes driven by the concentration gradient
what is primary active transport
Na+/K+ pump
what is secondary active transport
symporter/antiporter
what is the facultative water reabsorption
hormones build channel for H2O to get into blood
what is obligatory water reabsorption
H2O goes to party, think osmosis for obligatory
capillaries of nephron-
glomerular arterioles: what do afferent arterioles do? what do efferent arterioles do?
what are they both considered what
afferent- supplies "G" with blood
efferent- drains "G"
high pressure
capillaries of nephron-
peritubular arterioles: loops around what
what kind of pressure
drains what
specialized for what
the PCT, upper loop, DCT, and CD
low pressure
"G"
ion and solute exchange (reabsorption)
capillaries of nephron-
vasa recta: drops over what
what kind of pressure
reabsorption of what
low part of loop of henle
low pressure
ions, H2O, and solutes from loop of henle
Juxtaglomerular Apparatus:
what happens here
modified in 2 ways : 1) arteriole wall which is what? 2) macula densa cells- which is what?
both of them make up what?
where the last part of the ascending limb lies against the arterioles
1) contains modified smooth muscle cells called JG cells (glomerular cells)
2) tightly packed columnar cells of ascending limb (LoH)
both make up JGA= maintain a constant filtration rate despite system changes in BP
Nerve supply of kidneys:
what is it
the amount of stimulation changes what
at rest, stimulation is what
during exercise, stimulation is what
the renal plexus of the sympathetic nervous system innervates the kidneys
changes the effects on the kidney
low
high
Ureter:
how many ureters
how long
what kind of tissue
urine transport from renal pelvis to bladder occurs from what
2
10in
transitional epithelium tissue (cube cells/flat cells allows for expansion)
peristaltic waves
Bladder:
what is it
where is it located
where is it located in females
how much urine does it hold
how many layers does it have
what is the trigone
what are the external urethral sphincters
what kind of reflex
what happens if the bladder exceeds 200-400mL
causes what and is it voluntary or involuntary
hollow muscular organ that stores urine
it lies in the body posteriorly to the pubic synthesis
in females: anterior to vagina and inferior to uterus
holds 700-800mL of urine
3 layers
it is at the floor of bladder and contains ureteral openings
under voluntary control (being able to hold pee)
micturition reflex
stretch receptors stimulate this reflex
causes contraction of detrusor and relaxation of internal u.s. (involuntary)
Urethra:
what is it
what kind of tissue
Males: how long, what does it carry
Females: how long, what does it carry
opening to external body
non-keratinized stratified squamous
8-10" long, carries urine and semen
1-15" long, carries urine
3 layers to the bladder:
1) mucosa
2) detrusor muscle
3) serosa
1) innermost layer, transitional epithelium and the submucosa which supports the mucosa
2) contracts to expel urine and forms the internal urethral sphincter (smooth muscle), involuntary
3) visceral peritoneum (fibrous CT)
PCT- tubular reabsorption ( what to what )
what happens here ex: ?
wastes can be what
substances that can be reabsorbed are what
wastes that go back thru bloodstream are what
high #'s of what and what does it do
based on what and how does that occur
ex. of Na+/H+ antiporter
everything else in PCT is what which occurs by what
at end of PCT, how much water has been reabsorbed and there are no what present in filtrate
most reabsorption occurs here ex: albumin 3g/day filtered, 98% of that is reabsorbed
reabsorbed
H2O (65%), Cl-, K+, Na+, Mg+2, H30-, HPO4-2, SO4-2 ions
urea, small nutrients
aquaporins1, this lets H2O into blood
based on movement of Na+ ions and this occurs by symport and antiport mechanisms
moves Na+ into cell and H+ into lumen, so its the same as diagram above instead H+ is moving opposite way
passive reabsorption which occurs by H2O osmosis, other ions by electrochemical gradients
65% water reabsorbed and no nutrients present
PCT-tubular secretion-
substances that are secreted are
NH3 (what kind of waste) is what
H+ ions, NH+4, K+, creatinine, drugs
(poisonous waste) the body's really good at getting rid of it, moves into lumen easily
loop of henle:
what Is determined here
thick= what
thin= what
thin loop=
thick loop=
urine concentration
cuboidal cells
simple squamous
15% of H2O is reabsorbed
Na+, K+, 2Cl- are symported, impermeable to H2O, doesn't let in H2O, K+ also have many leakage channels is move back into lumen
DCT and CD: reabsorption in EARLY DCT-
how much water has been reabsorbed at this point
what do the Na+ and Cl- symporters do
PTH acts on cells to what
80%
move from lumen into cell
acts on cell to reabsorbed Ca+2 based on body needs
Reabsorption & secretion in LATE DCT & then CD:
how much water is reabsorbed to blood stream
what happens to K+ here
2 types of cells- 1) intercalated: what is it 2) principle: what is it
what are the leakage channels for
what does released hormones determine
10-15%
it gets secreted and reabsorbed
1) reabsorbed K+ and HCO-3 also secrete H+
2) reabsorbed Na+ and secrete K+
Na+ (lumen to cell)
determines reabsorption based on dietary changes
secretion in LATE DCT and then CD:
what happens to K+ here and what makes that happen
controlled in 3 ways...what are they
most of it is secreted into CD and will occur by principle cells
1) when K+ levels in plasma are excessive (heart problems)
2) aldosterone indirectly causes secretion of K+ (antiporter)
3) Na+ concentration in DCT indirectly controls K+ secretion (Na+ to cell, K+ to lumen)
Hormone regulation:
what does ADH stand for
where does ADH play a major part in the urinary system
what is ADH produced by and what releases it into the bloodstream
when is ADH released and should you think of
what happens when ADH binds to principle cells and what does it allow H2O to do
what happens to water if ADH isn't present
what happens to ADH if there is an excessive amount of water
what is diabetes insipidus
antidiuretic hormone
major factor in urine concentration
produced by hypothalamus and released into blood from posterior pituitary
when there's a drop in BP and think of dehydration
makes aquaporin2 channels and this allows water to move from lumen to blood
water is not reabsorbed
there'll be a decrease in ADH so it's not released
pathological absence of ADH, they excrete (urinate) 20L/day
RAS = what does that stand for
what is category is it under
what drops and what happens in result of that
renin clips off what and what is it called
what is angiotensin1 converted to and what allows that to happen
Renin (enzyme) angiotensin aldosterone system
hormone regulation
BP drops and decreases stretch on afferent arteriole, triggering release of renin from JG cells
10aa peptide called aniotensin1 from angiotensinogen
angiotensin2 (triggers release of aldosterone) by ACE (angiotensin converted enzyme)
RAS- Renin Angiotensin Aldosterone System cont'd:
in 3 ways angiotensin2 affects renal physiology-
1) decreases GFR by what
2) increases ion (Na+, Cl-) and H2O reabsorption by what
3) causes release of what
what does aldosterone stimulate to reabsorb what and what does it secrete and what does this cause an increase in
what is the end result
1) vasoconstriction of afferent arteriole
2) stimulating Na+/H+ antiporters in PCT
3) aldosterone from adrenal cortex
stimulates principle cells of CD to reabsorb Na+ to Cl- and secrete more K+
This causes an increase in obligatory H2O reabsorption
end result is increase in BP
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