Urinary System Flashcards
(146 cards)
1
Q
what structures are involved with filtering blood?`
A
spleen, liver, kidneys
2
Q
how much blood passes through kidneys per day
A
180L
3
Q
components of urinary system
A
2 kidneys
2 ureters
urinary bladder
urethra
4
Q
kidneys are size of ____ and located in ______
A
fist; small of back
5
Q
ureters
A
drainage tube off kidney
as blood gets filtered by kidney, filtrate collects and moves through ureters to urinary bladder
6
Q
urethra
A
exit for urine to outside of body
includes 2 sets of sphincters (internal/external)
7
Q
how are female and male urethras different?
A
female- shorter, urine only
male- longer, urine and semen
8
Q
accessory organs of urinary system
A
there aren’t any!
9
Q
functions of urinary system
A
fluid filtration regulate blood volume maintains water/salt balance gluconeogenesis renin production erythropoietin production activates vitamin D
10
Q
how is urinary system involved with fluid filtration
A
plasma gets filtered
of 180 L of blood, we eliminate 1% as urine (waste)
reliant on pressure
11
Q
how is urinary system involved in regulation of blood volume
A
as we filter blood, most of it gets reclaimed by body
blood volume and blood pressure have positive correlation
12
Q
how is urinary system involved with maintaining water/salt balance
A
uses osmotic gradients to move ions and fluids back and forth
13
Q
how is urinary system involved in gluconeogenesis
A
conversion of noncarbs to carbs occurs in kidneys
14
Q
how is urinary system involved in renin production
A
part of renin-angiotensin mechanism
involved in bp regulation and kidney functioning
15
Q
how is urinary system involved in erythropoietin production
A
erythropoietin is signal that tells blood cells to produce more red blood cells
16
Q
why does the urinary system need to activate vitamin D
A
when in sunlight , skin produces inactive vitamin D
this must be activated to absorb dietary vitamin C
17
Q
components of kidney structure
A
capsule cortex medulla pelvis pyramids columns major calyx minor calyx
18
Q
renal pelvis
A
where ureter flattens out as it gets toward hilum of kidney
19
Q
renal sinus
A
space within renal pelvis
20
Q
renal pyramids
A
triangular structures in medulla
striped bc they are collections of collecting tubules that collect filtrate and move it to ureter
21
Q
renal columns
A
spaces between renal pyramids
made of inward extension of cortical tissue
22
Q
what are renal columns made of?
A
inward extensions of cortical (cortex) tissue
23
Q
major calyces
A
junction of 2+ minor calyces
connect to become renal pelvis
24
Q
minor calyces
A
collection chamber at end of each pyramid
collects filtrate and moves it to major calyx to ureter
25
supportive layers of kidney
renal capsule
adipose capsule
renal capsule
26
renal capsule
outer layer of kidney; identifies boundaries of edge of kidney
27
adipose capsule
surrounds kidney; protects from heat loss when blood gets close to shell of body when going to kidney
insulates and cushions
28
renal fascia
anchors kidney in place
| bc kidney is retroperitoneal, and mesentery doesn't keep it in place
29
nephron
structural and functional unit of kidney
over 1m nephrons in kidney
where filtrate is changed to urine
30
t/f arterioles supply nephron, venules drain nephron
false! arterioles both supply and drain capillary beds of nephron (glomerulus)
31
nephron components
glomerulus
renal tubule
collecting ducts
renal corpuscle
32
glomerulus
modified capillary bed in nephron
afferent arteriole supplies with blood, efferent arteriole drains
bp in this capillary is higher than any other in body --> more filtration
33
renal tubule
component of nephron that captures all stuff that was filtered in capillaries
where we turn filtrate to urine
composed of glomerular capsule, PCT, loop of hence, and DCT
34
collecting ducts
component of nephron that contains many renal tubules
| makes renal pyramids striped
35
renal corpuscle
glomerulus + glomerular capsule
36
glomerular (bowman's) capsule
surrounds glomerulus
| anything that moves out of capillary gets contained here
37
proximal convoluted tubule
continuation of bowman's capsule
| leads to loop then to DCT
38
types of nephrons
cortical nephrons
| juxtamedullary nephrons
39
cortical nephrons
mostly in cortex of kidney; only small part of loop of Henle goes into medulla
85% of nephrons in body
40
juxtamedullary nephrons
close to medulla; larger part of loop of henle goes into medulla
deeper the nephron goes into medulla --> the more concentrated the urine that's produced
15% of neurons in body
41
how does the body change concentration based on water needs
if we're dehydrated...
send more blood to juxtamedullary nephrons than if we weren't dehydrated
arterioles supplying cortical nephrons constrict; arterioles supplying juxtamedullary nephrons dilate
this is done in varying degrees to fine tune concentration of urine we eliminate
42
nephron vasculature components
```
afferent arteriole
efferent arteriole
glomerulus
peritubular capillaries
vasa recta
```
43
efferent arteriole
drains blood from glomerulus
| creates capillary bed that surrounds renal tubule
44
site of filtration
glomerulus
45
peritubular capillaries
capillary bed that surrounds renal tubule
| connect to venule; carries blood back to heart
46
vasa recta
modified peritubular capillaries in juxtamedullary nephron
surround loop of Henle
more efficient than peritubular capillaries
47
juxtamedullary apparatus
modification where distal convoluted tubule runs closely against afferent arteriole
modification of cells of tubule and cells of capillary
mostly affects rate of filtrate formation
48
afferent arteriole wall cell modification of juxtaglomerular apparatus
JG Cells
49
distal convoluted tubule cell modification of juxtaglomerular apparatus
macula densa cells
50
jg cells
```
smooth muscle cells become enlarged and gain ability to produce renin
function as mechanoreceptors (monitor pressure)
afferent arteriole supplies blood to glomerulus; as bp changes, filtration changes
```
51
macula densa cells
act as chemoreceptors- monitor concentration of filtrate that passes through DCT
these changes in concentration are detected --> changes activity of what happens in kidney
md cells can tell jg cells to secrete renin
52
components of filtration membrane
fenestrated epithelium
podocytes
basement membrane
53
fenestrated epithelium of filtration membrane
has little pores that allow everything in plasma to pass through
except does not let cells pass through
54
podocytes
part of filtration membrane that limits amount of filtration that can occur so we don't lose too much fluid
has cytoplasmic extensions that wrap around capillary
makes filtration slits where filtration can occur
55
filtration slits
spaces between podocytes where filtration can occur
56
basement membrane of filtration membrane
surrounds capillaries
| prevents proteins from being able to escape out of circulation
57
_____ allow proteins out; ____ prevents proteins from actually getting out
pores and capillaries; basement membrane
58
3 steps of urine formation
filtration
tubular reabsorption
tubular secretion
59
filtration stage of urine formation
```
only occurs at glomerulus
passive process (no energy)
mostly non-selective process
uses mostly hydrostatic pressure of fluid inside capillary to filter
```
60
hydrostatic pressure inside capillary is the same as
blood pressure
61
where do resorption/secretion occur?
along entire length of PCT, and sometimes in top part of collecting duct
starts immediately along PCT
62
tubular reabsorption (second stage of urine formation)
resorbing things from filtrate/tubule back into blood circulation to stay in body
organic nutrients completely reabsorbed (100%)
ions and water- amount of reabsorption varies based on hormonal control
can be passive or active
63
how are glucose and amino acids reabsorbed
completely! bc they are organic nutrients
64
how are ions and water reabsorbed?
amount of reabsorption varies based on hormonal control
65
tubular secretion (third stage of urine formation)
putting stuff back into filtrate/tubule bc we don't want it
clearing plasma of unwanted substances
end result is urine that contains both filtered and secreted substances
66
2 reasons for tubular secretion
never filtered bas stuff out
| accidentally reabsorbed bad stuff
67
major controlling force of filtration pressure
blood pressure
68
types of filtration pressure
glomerular hydrostatic pressure
colloid osmotic pressure of intracapsular space
colloid osmotic pressure of glomerular blood
capsular hydrostatic pressure
end result= net filtration pressure
69
glomerular hydrostatic pressure
pressure inside glomerular capsule
| same as bp
70
t/f glomerular hydrostatic pressure is same as bp
truw
71
colloid osmotic pressure of intracapsular space
proteins that have never been filtered out and accumulate in filtrate
this should be 0! bc proteins should not be in filtrate
solute dissolves in liquid
72
colloid osmotic pressure of glomerular blood
where we should have protein accumulation --> creates pressure of water wanting to come back in
putting some fluid back in
generally not v significant, but contributes to net filtration pressure
73
capsular hydrostatic pressure
as fluid moves out into bowman's capsule, this creates hydrostatic pressure
pressure inside blood vessels pushes on pressure outside of blood vessels
pressure inside blood vessels always higher
74
net filtration pressure
end result of all other filtration pressures
| always positive --> we want to filter whatever is in capillary
75
what would happen to filtration rate if liver starts producing extra albumin (protein)?
filtration would decrease because more proteins in blood means more H2O gets into blood
76
if theres a kink in renal tubule that prevents filtrate from moving through, what effect will that have on filtration?
pressure increases until pressures are equal, then filtration stops (renal failure)
77
rbf
renal blood flow
| amount of blood passing through glomerulus
78
gfr
glomerular filtration rate
| how much the blood that passes through glomerulus is filtered
79
constriction of afferent arteriole causes...
decreased rbf
| decreased gfr
80
dilation of afferent arteriole causes...
increased rbf
| increased gfr
81
constriction of efferent arteriole causes ______. Why?
decreased rbf, increased gfr
blood is still being sent to glomerulus but cannot pass through as quickly; blood pooling on back pressure causes increased filtration
82
dilation of efferent arteriole causes ___. Why?
increased rbf, decreased gfr
| blood passes through faster, but bc its passing through so quickly less filtration can occur
83
kidney can regulate amount of filtration by ________
changing diameter of afferent or efferent arteriole
84
t/f kidney tries to change its amount of filtration based on body needs
false
| kidney tries to maintain constant rate of filtration
85
intrinsic mechanisms of filtration regulation
myogenic mechanism of autoregulation
| tubuloglomerular mechanism of auto regulation
86
extrinsic mechanisms of filtration regulation
neural mechanism
| hormonal (renin-angiotensin) mechanism
87
filtration regulation mechanisms
```
myogenic mechanism of autoregulation
tubuloglomegular mechanism of autoregulation
neural mechanism
hormonal mechanism
prostaglandins
nitric oxide
adenosine
endothelin
```
88
myogenic mechanism of autoregulation
if we put stretch on wall of blood vessel --> renal vascular smooth muscle thats stretched responds by contracting
so, if bp is low, then less stretch, then blood vessel dilates and GFR increases
89
how to increase gfr by myogenic mechanism of autoregulation
if bp low --> reduction of stretch --> vasodilation of afferent arterioles --> increased GFR
90
tubuloglomerular mechanism of autoregulation
controlled by macula dense cells in JG apparatus
MD cells monitor concentration of filtrate passing through DCT
if low flow or low osmolality (dilute) --> causes vasodilation of afferent arteriole --> increased GFR
links to hormonal mechanism
91
neural mechanism of filtration regulation
changes diameter of vessels supplying kidney so blood goes to other places
baroreceptors in blood vessels of systemic circulation
sympathetic nervous system releases norepinephrine --> causes vasoconstriction --> increased GFR
can override everything else in time of emergency
92
hormonal mechanism of filtration regulation
- JG cells are in walls of arterioles monitoring bp
- if bp decreases, JG stimulates production/release of renin --> renin activates angiotensinogen
- renin distributed by circ. system, which causes systemic vasoconstriction, which slightly increases bp
- renin directly causes increases of Na reabsorption
- renin activates angiotensin, stimulates adrenal cortex to release aldosterone
- drop in blood pressure would cause drop in filtration in kidney
93
what happens because of renin directly causing increase of sodium reabsorption
sodium creates gradient --> movement of water
| water out of tubule causes bp to increase
94
what happens bc of renin activating angiotensin and stimulating adrenal cortex to release aldosterone
aldosterone is major hormonal regulator of Na reabsorption in kidney --> more water follows --> bp increases
95
how do prostaglandins regulate filtration?
prostaglandins are localized signaling molecules --> kidney secretes these to cause other things to happen
they cause vasodilation in afferent arterioles
96
how does nitric oxide regulate filtration?
vasodilator
| increases filtration rate
97
how does adenosine regulate filtration?
vasoconstrictor in kidneys --> causes decreased filtration rate
in all rest of body, adenosine is vasodilator
98
how does endothelin regulate filtration?
vasoconstriction
| endothelia is secretions from endothelial cells lining blood vessels in kidneys
99
where does most reabsorption occur
proximal convoluted tubule
100
2 mechanisms of reabsorption in renal tubule
transepithelial process
| paracellular process
101
there are some things we do not want to reabsorb, such as ________
products of protein metabolism
urea, creatine, uric acid
nitrogenous compounds from protein metabolism
102
biggest users of ATP
kidney
103
___% of glucose, lactic, acid, etc should be reclaimed
100%
104
__% of H2O comes back into bloodstream
99
105
__% of Na is reabsorbed into blood
99.5
106
most common mechanism of tubular reabsorption
transepithelial process
107
transepithelial process
filtrate goes out of tubule into walls of tubule --> interstitial space --> lumen
has to go through 3 layers of epithelial cells to get out
has to move things passively and actively
water will follow an osmotic gradient --> needs solutes then
cells that make up tubule have tight impermeable junctions (tightly anchored on lumen side, looser on other side)
108
paracellular process
channel proteins help
ions are out in interstitial space; create gradient for H2O movement
increase efficiency of transepithelial process by allowing ions to separate from H2O
creates osmotic gradient that causes fluid to move out of cells; ions/fluids move into capillaries
109
action in descending limb of loop of henle
freely permeable to water
force is osmosis (passive)
only water can pass out
110
action in ascending limb of loop of henle
impermeable to water
permeable to ions (these create gradient for osmosis in descending limb)
requires energy
111
how does ascending limb require energy
Na can move passively or actively
aldosterone impacts this ^ because increased aldosterone causes increased Na absorption --> creates gradient
can modify concentrations
ADH changes amount of water movement in DCT and CT
112
ADH changes amount of water movement in ________
distal convoluted tubule and collecting duct
113
increase in aldosterone causes _______ Na absorption
increased
114
is urine in loop of henle very concentrated or very dilute?
very concentrated
| less and less water as you move up ascending limb
115
action of proximal convoluted tubule
most active of all reabsorptive portions of renal tubule
100% of glucose, Amino Acids, Lactate reabsorbed
65% of water and Na reabsorbed here (rest is under hormonal control)
reabsorbs bicarbonate and Cl
tubular secretion and reabsorption occurring simultaneously
116
collecting duct action
under hormonal influences
| aquaporins are in walls of collecting duct; generally closed channel for water; opened by ADH!
117
action of distal convoluted tubule
continued reabsorption and secretion
major hormonal influences (absorption based on body needs)
change reabsorption of water and ions
normally impermeable to water, but hormones (like ADH) can change that
118
countercurrent mechanism
flow in one tubule is going opposite direction of flow in another tubule --> this increases efficiency of exchange because it causes a gradient
this is happening in loop of henle
almost 100% efficiency
119
renal gradient
as we move from cortex, the fluids in interstitial spaces get more and more concentrated --> this pulls more H2O
all glomerular capillaries are in cortex; loop of Henle is in medulla
120
countercurrents exchanger
by suppressing aldosterone and shutting off reabsorption of Na
keeps aquaporins closed --> dilute urine
vasa recta are freely permeable to H2O and salt
121
vasa recta are freely permeable to _____
water and salt
122
steps of micturition
1. urine accumulates in bladder
2. eventually stretch receptors activated
3. stretch receptors send signal to brain
123
are voiding reflexes conscious or unconscious?
conscious
124
voiding reflex
parasympathetic stimulation contracts bladder and relaxes internal/external sphincters
external sphincters are under conscious control so you can "hold it" and override voiding reflex
125
concentration of urine dependent on ______
ADH secretion and aldosterone
126
ADH is released by _____
posterior pituitary
127
ADH release if (Shut off/Turned on) when you drink alcohol, which is why you pee a lot
shut off
128
how does ADH affect reabsorption
ADH increases reabsorption to help form a more concentrated urine
129
how does ADH affect urine concentration
ADH production increases water reabsorption from collecting duct
low ADH --> dilute urine
more ADH --> more water absorbed --> more concentrated urine
130
flow is ___ from kidney to ureter to bladder
passive
131
are there any sphincters along ureter to regulate flow?
no
132
trigone
below ureter openings, creates triangle shape into urethra
made of 2 ureteric orifices and internal urethral orifice
sensitive to expansion --> once stretched enough, sends signal to brain to pee
133
rugae of urinary bladder
changes volume of bladder without stretching/distending bladder and causing us to pee
134
___ sends signal to brain to bee
stretch
135
lining of bladder is made of ______
transitional epithelium
136
internal sphincter of urethra is (involuntary/voluntary)
involuntary
137
external sphincter of urethra is (involuntary/voluntary)
voluntary
138
urinary bladder
muscular storage sack for urine
139
countercurrent multiplier
descending limb and ascending limb in different directions
greatest concentration of ions are at bottom of descending limb
loop of Henle surrounded by vasa recta (runs in diff direction, multiplies amt of absorption)
capillaries that run around this are also running in opposite directions
fluids in PCT osmotically equal to plasma (except proteins)
we increase efficiency of kidney by running things in opposite directions
140
loop of henle surrounded by _____
vasa recta
141
fluids in PCT osmotically = to ____
plasma
142
descending limb freely permeable to _______; impermeable to ________
water; solutes
| so filtrate gets more concentrated as it moves down
143
ascending limb selectively permeable to _______; impermeable to ________
solutes; water
144
collecting ducts permeable to ______
urea
145
how does urea permeability of collecting duct help with gradient
some urea can sneak out of collecting duct to increase gradient when we need more water
146
deeper into medulla, there is a _____ gradient; this causes ______ absorption
greater; greater
