urine Flashcards
blood is filtered through the ______ in order to eliminate wastes
kidneys
____ L of blood passes through the kidneys per day
180 L
the good stuff in the blood goes where after being filtered through the kidneys? bad stuff?
into circulation
in urine
components of the urinary system (4)
- kidneys (2)
- ureters (2)
- urinary bladder
- urethra
component of the urinary system: filters blood
kidneys
component of the urinary system: drainage tubes of kidneys; drains FILTRATE
ureters
what do the ureters drain?
filtrate
component of the urinary system: muscular storage tank for urine
urinary bladder
component of the urinary system: exit point of body
urethra
which gender’s urthera is used for both the urinary and reproductive system?
males (urine + semen)
functions of urinary system (8):
1) fluid filtration
2) regulates blood volume
3) maintains salt/water balance
4) maintains acid/base balance
5) gluconeogenesis
6) renin production
7) erythropoietin production
8) activates vitmain D
function of urinary system: major job; filters plasma
fluid filtration
only about ___% of the 180 L is urine and the rest goes BACK TO THE BODY
1% (aka 1.8 Liters is urine)
function of urinary system: related to BLOOD PRESSURE; both kidneys are involed in this
regulate blood volume
function of urinary system: use osmatic gradients to regulate ions
maintains salt/water + acid/base balance (2 functions)
function of urinary system: involved in the conversion of non-carbohydrates to carbohydrates
gluconeogenesis
function of urinary system: cause angiotensin production which leads to aldosterone (movement of salt + water)
renin production
function of urinary system: signal to tell RBC to produce more; kidney does this
erythropoietin production
function of urinary system: kidney activates this vitamin; nonactive form —> active (produced on skin); important for absorption of calcium
activates vitamin D
important for calcium absorption
vitamin D
kidney structure parts (9)
- capsule
- cortex
- medulla
- pelvis
- pyramids
- columns
- major calyces
- minor calyces
- hilum
part of kidney structure: outter covering; outtermost
capsule
part of kidney structure: deep to capsule
cortex
part of kidney structure: deepest region; innermost
medulla
part of kidney structure: flattened part of ureter; renal sinus is here**
pelvis
part of kidney structure: triangles; always appear striped bc it is composed of collecting tubules
pyramids
part of kidney structure: spaces between renal pyamids; inward extension of cortical (cortex) tissue
colummns
part of kidney structure: connect and become renal pelvis; collection tubule
major calyces
part of kidney structure: collection tubules; connect and become major calyces
minor calyces
part of kidney structure: indention of kidney
hilum
the 2 MAJOR regions of the kidney
medulla + cortex
T/F: filtrate is the same as urine
FALSE
- filtrate eventually becomes urine along the path of the renal tubules
supportive layers of the kidney (3):
- renal capsule
- adipose capsule
- renal fascia
supportive layer of the kidney:outter layer; protects organ; acts as a boundary
renal capsule
supportive layer of the kidney: prevents heat loss as blood filters through; insulates + cushions
adipose capsule
supportive layer of the kidney: anchors kidney in place
renal fascia
kidneys are _________ because they are located behind the abdominal cavity
retroperitoneal
structural + functional unit of the kidney
nephron
filtration is a funciton of _______
pressure
how many nephrons are there in a kidney?
more than a million
parts of a nephron (8):
- renal corpuscle
- glomerulus
- renal tubule
- Bowman’s (glomerular) capsule
- proximal convoluted tubule
- Loop of Henle (descending + ascending)
- distal convuluted tubule
- collecting ducts
part of a nephron: consists of glomerulus + Bowman’s capsule
renal corpuscle
part of a nephron: modified capillary bed (special); supplied and drained by an arteriole and a venule
glomerulus
part of a nephron: captures filtered stuff from glomerulus + modifies it
renal tubule
part of a nephron: surrounds glomerulus; continues with proximal convuluted tubule
Bowman’s Capsule (glomerular capsule)
parts of Renal Tubule + order (5):
1) Bowman’s capsule
2) proximal convuluted tubule
3) Loop of Henle (descending + ascending)
4) distal convuluted tubule
5) collecting ducts (**kind of part of renal tubule; continous tho so technically)
why is the glomerulus “special”?
has the highest BP of all the capillaries in the body
all the parts of the renal tubule connect to many ______
glomeruluses
are all nephrons the same?
no (2 different types!)
types of nephrons (2):
- cortical
- juxtamedullary
type of nephron: mostly in the cortex; the MAJORITY of nephrons are this type
cortical nephrons
___% of all nephrons are cortical nephrons
85%
type of nephron: ascends much depper into the medulla; other 15%; deal with more concentrated urine
juxtamedullary nephron
the DEEPER you go into the medulla, the more ________ the urine
concentrated
(less water in the urine so more water goes back to the body)
if you’re dehydrated, your body sends more blood to ______ nephrons by dilating arteriole supply; concentrates your urine and supplies more water to your body
juxtamedullary
if you’re dehydrated, your body CONSTRICTS arteriole supply to _____ nephrons
cortical
nephron vasculature components (5):
- afferent arteriole
- efferent arteriole
- glomerulus
- peritubular capillaries
- vasa recta
component of nephron vasculature: supplies glomerulus
afferent arteriole (“A” for arrive)
component of nephron vasculature: drains glomerulus; becomes peritubular capillaries
efferent arteriole
component of nephron vasculature: capillaries surrounding renal tubule
peritubular cacpillaries
efferent arterioles become ____ ____
peritubular capillaries
component of nephron vasculature: modified pertubular capillaries in a juxtamedullary nephron (look like a ladder and more uniform)
vasa recta
modification where distal convoluted tubule runs against the afferent arteriole
juxtaglomerular apparatus
cells in wall of arteriole that enlarge and gain the ability to produce renin; mechanoreceptors that monitor pressure; modifies BP of afferent arteriole blood to glomerulus that can bring about change to apparatus
juxtaglomerular cells (JG cells)
JG cells =
juxtaglomerular cells
act as chemoreceptors; monitor concentration of filtrate passing through
macula densa cells (in distal convoluted tubule)
what two types of cells BOTH affect the rate of filtrate formation?
JG cells + macula densa cells
where are the JG cells found?
afferent arteriole (mostly) + efferent arteriole
where are macula densa cells found?
distal convoluted tubule (and ascending limb)
JG apparatus can change the function of the ______
kidney
filtration membrane (in glomerulus) components (3):
- fenestrated epithelium
- podocytes
- basement membrane
filtration membrane component: has pores; allows everything in in plasma but cells
fenestrated epithelium
filtration membrane component: cytoplasmic extensions that wrap around capillaries; no filtration except INBETWEEN them; “filtration slits”
podocytes
filtration membrane component: surround capillary; prevents proteins from escaping
basement membrane
site of filtration
glomerulus
3 parts of urine formation:
1) glomerular filtration
2) tubular reabsorption
3) tubular secretion
part of urine formation: the movement of substances from the blood within the glomerulus into the capsular space; PASSIVE process; nonselective process that uses hydrostatic pressure (mostly — aka BP) of the fluid inside the capillaries to filter
glomerular filtration
as BP increase, filtration ______
increases
part of urine formation: the movement of substances (IONS + WATER) form the tubular fluid back INTO the blood; based on hormonal control;
pulling things out of the tubule; can be passive OR active; organic nutrients (ex: glucose + amino acids) get absorbed back 100%
tubular reabsorption
part of urine formation: the movement of substances from the blood into the TUBULAR FLUID; clearing plasma of unwanted substances
tubular secretion
filtration only occurs where?
glomerulus
tubular reabsorption and tubular secretion start immediately in the _____ _____ and occurs ALL ALONG the tube
proximal tubule
urine contains both _____ and _____ substances
filtered + secreted
types of filtration pressure (4)
- glomerular hydrostatic pressure
- colloid osmotic pressure of intracapsular space
- colloid osmotic pressure of glomerular blood
- capsular hydrostatic pressure
type of filtration pressure: deal with BIG things (proteins that have been filtered and accumulated = BAD)
colloid osmotic pressure of intracapsular space
type of filtration pressure: where proteins SHOULD be (bc of basement membrane)
colloid osmotic pressure of glomerular blood
type of filtration pressure: pressure pushing on and out of the capillaries
capsular hydrostatic pressure
ALL of the filtration pressure combined =
net filtration pressure
the net filtration pressure should be _____
positive
kinks in renal tubules are associated with _____ _____
renal failure
amount of blood flow passing through glomerulus
renal blood flow (RBF)
RBF =
renal blood flow
GFR =
glomerular filtration rate
what happens to RBF and GFR when the afferent arteriole CONSTRICTS?
RBF: decreases
GFR: decreases
what happens to RBF and GFR when the afferent arteriole DILATES?
RBF: increases
GFR: increases
what happens to RBF and GFR when the efferent arteriole CONSTRICTS?
RBF: decreases
GFR: increases (blood hangs out for longer; more filtration)
what happens to RBF and GFR when the efferent arteriole DILATES?
RBF: increases
GFR: decreases (pass thru so quickly, less filtration)
kidney regulates filtration by regulated the ______ of the afferent and efferent tubules (direct relationship between this and the amount of blood that is filtered)
diameter
filtration regulation is both ______ and ______
intrinsic and extrinsic
intrinsic filtration regulation mechanisms (2):
- myogenic mechanism of auto regulation
- tubuloglomerular mechanism of autoregulation
extrinsic filtration regulation mechanisms (2):
- hormonal (renin-angiotensin) mechanism
- neural controls
all filtration regulation mechanisms (both intrinsics and extrinsic) are stimulated by what?
low BP in the renal blood vessels
all filtration regulation mechanisms (both intrinsics and extrinsic) are end with what?
increased GFR
myogenic mechanism of autoregulation steps (4):
1) low BP
2) renal vascular smooth muscle is INHIBITED
3) vasodilation of afferent arterioles
4) increased GFR
tubuloglomerular mechanism of autoregulation steps (6):
1) low BP in renal blood vessels
2) reduced filtrate flow or osmolality in distal tubules
3) macula densa cells of JG apparatus of kidney are INHIBITED
4) prompts release of vasoactive chemical
5) vasodilation of afferent arterioles
6) increased GFR
control tubuloglomerular mechanism of autoregulation; monitor the concentration of filtrate
macula densa cells in JG apparatus
LOW BP + osmolarity _____ macula densa cells, which leads to _______ of afferent arterioles and _____ GFR
activate
vasodilation
increased
HIGH BP + osmolarity _____ macula densa cells, which leads to _______ of afferent arterioles and _____ GFR
inhibits
vasoconstriction
decreased
2 controls of the tubuloglomerular mechanism of autoregulation:
- macula densa cells
- hormones
hormonal (renin-angiotensin) mechanism steps (5… but rlly 10)
1) low BP in renal blood vessels
2) JG cells (of JG apparatus of kidney) release renin (only if BP is low)
3) angiotensinogen is activated to angiotensin II
4) stimulates: adrenal cortex + systemic arterioles (2 dif pathways):
- adrenal cortex releases aldosterone in kidney tubules
- increase Na+ reabsorption; water follows
- increased blood volume and systemic BP
AND
- systemic arterioles cause vasoconstriction; increases peripheral resistance
- increased systemic BP
5) increased GFR
in the hormonal (renin-angiotensin) mechanism, the JG cells can also (2):
- STIMULATE the macula densa cells (in tubuloglomerular mechanism)
- stimulate sympathetic nervous system (in neural control) to stimulate the systemic arterioles
neural control steps (6)
1) low BP
2) baroreceptors in blood vessels of systemic circulation are STIMULATED
3) stimulates sympathetic nervous stystem (release norepinephrine)
- — now in hormonal mechanism
4) systemic articles are stimulated
5) vasoconstriction; increases peripheral resistance
6) increased systemic BP
7) increased GFR
which filtration regulation mechanism can override EVERYTHING?
neural control
kidneys try to maintain a _____ rate of filtration (homeostasis)
constant
_____ changes in the body change kidney activityd
systematic
BP decreases, filtration ______
decreases (but kidney doesn’t like it so it tries to fix it)
how does renin control BP (3):
- causes systemic vasoconstriction (BP increases a little)
- directly causes an increase in sodium reabsorption
- —> Na+ creates an osmotic gradient that moves water
- —> water follows Na+ (BP increases)
- activates angiotensin (stimulates cortex to produce aldosterone = major hormonal regulator of Na+ reabsorption in the kidney)
major hormonal regulator of Na+ reabsorption in the kidney
aldosterone
other factors that regulate filtration (4):
- prostaglandins
- nitric oxide
- adenosine
- endothelin
other factor that reg. filtration: eicosanoids; singular molecule; only have a LOCAL effect; result in VASODILATION of afferent arterioles; released by kidneys
prostaglandin
other factor that reg. filtration: cause vasoDILATION; increase filtration rate
nitric oxide
other factor that reg. filtration: vasodilator in the rest of the body, BUT vasoCONSTRICTOR in the kidney; decrease filtration rate
adenosine
other factor that reg. filtration: released by blood vessels; vasoCOSNTRICTOR
endothelin
2 forces of tubular reabasorption (of urine formation):
- transepithelium
- paracellular process
force of tubular reabasorption: MOST of reabsorption; crossed epithelium 3 times; moves things actively + passively; cells have TIGHT JUNCTIONS (tight on lumen side)
transepithelium
force of tubular reabasorption: have carrier molecules in between cells to move IONS; increase in efficiency of transepithelium movement
paracellular process
biggest user of ATP in the body
kidney
most of the absorption during tubular reabsorption occurs WHERE?
proximal convulsed tubule
but does occur along entire length of tube
during tubular reabsorption, we do we NOT want to reabsorb back into the blood vessels (3)?
- urea
- creatine
- uric acid (toxic)
during tubular reabsorption, we DO we want to reabsorb back into the blood vessels (3)?
- water (99%)
- sodium (99.5%)
- glucose (100%)
____% of filtered glucose goes back into the blood during tubular reabsorption
100%
T/F: secretion of unwanted things occurs at the same time as reabsorption (aka step 2 and 3 of urine formation)
true
the action of tubular reabsorption can be split into what 2 regions?
- descending loop of Henle
- ascending loop of Henle
region of tub. reabsorption action: PERMEABLE; water leaves (hypnotic –> hypertonic) passively in response to a gradient
descending loop of Henle
region of tub. reabsorption action: IMPERMEABLE to water, but NOT ions (they can move); cause a gradient that causes water to leave the descending loop; ACTIVE transport (mostly but Na+ movement can be passive or active); more hormones increase Na+ reabsorption here
ascending loop of Henle
most reabsorption occurs here; gets ride of unwanted stuff
proximal convoluted tubule
___% of water and odium get reabsorbed in the proximal convoluted tubule and the rest is controlled by _______
65%
hormones
changes water amount in collecting duct (and I think distal convoluted tubule)
ADH (Antidiuretic hormone)
ADH =
antidiuretic hormone
the amount of water moving out is HIGHER than ion movement (more water reabsorption than ion) b running in opposite direction; efficiency increases bc of the difference between the ascending and descending tubules
countercurrent mechanism
countercurrent multiplier: fluids in PCT osmotically equal to _____
plasma
countercurrent multiplier: _______ ______ freely permeable to water and IMPERMEABLE to solutes
descending limb
countercurrent multiplier: _____ _____ IMPERMEABLE to water but selectively permeable to solutes
ascending limb
countercurrent multiplier: _____ ____ permeable to urea (helps with gradient when we need more water)
collecting ducts
capillaries/blood around tubules are also running in ______ directions
opposite
all glomerular capillaries are in the _______
cortex (of kidney)
Loop of Henle extends to the ______ of the kidney
medulla
vasa recta are freely permeable to water and salt; picks EVERYTHING up
countercurrent exchanger
concentration of urine is depending on ______ secretion
ADH
low ADH produces _____ urine
dilute
high ADH produced ______ urine
concentrated
ADH production increases ______ reabsorption from the collecting duct
water
hormone regulators of urine (2):
1) aldosterone
2) ADH
what releases ADH?
posterior pituitary gland
increases reabsorption of water to help form a more CONCENTRATED urine; suppressed by alcohol; opens up aquaporins
ADH
a channel for water; opened by ADH
aquaporin
movement of urine from the ureter to the bladder is _____
passive
each ureter has an opening, known as an ______
orifice
bladder haws _____ that prevents stretch by changing size
rugae
what type of tissue is the bladder?
transitional epithelium
the act of emptying the bladder
micturition
micturition process (3):
1) urine accumulates in the bladder
2) stretch receptors are activated (send signal to brain)
3) voiding reflexes under conscious control
- - parasympathetic stimulation contracts bladder and relaxes internal (involuntary) and external (voluntary temp.) sphincters
under conscious control, we can override parasympathetic impulses to urinate immediately
voiding reflex
