renal system Flashcards
1
Q
what makes up the urinary system
A
2 kidneys
2 ureters
1 urinary bladder
1 urtherra
2
Q
functions of the urinary system
A
urine fomation
excretion of waste products
maintaining water balance and acid/base
3
Q
how much urine is made in one day
A
1.5 litres
4
Q
where are the kidneys
A
below the diaphram
high up
back wall
5
Q
why is one kidney higher than the other
A
liver being in the way
6
Q
position of the bladder
A
behind the pubic bone
changes shape and lifts when it fills
7
Q
how does the kidney mature in babies
A
changes a ot and they change kidneys as they mature
different kidney at each stage of maturation
most filtering done by placenta so only need primiteve ones
8
Q
what is the hilum
A
medial side of kidney
concave boarder where everything enters ad exits
9
Q
what is the renal pelvis
A
a collection of everything
10
Q
3 layers of the kidney
A
capsule
cortex
medulla
11
Q
what is the capsule of the kidney
A
outer layer
shiny
fibrous cap surronding
12
Q
what is the cortex of the kidney
A
peachy
smooth
13
Q
what is the medulla of the kidney
A
innermost layer
nephrons make it striped
renal pyramid structures here
14
Q
what are nephrons
A
functional units of the kidney
filtration occurs in them
15
Q
what do the nephrons do?
A
collect urine in ducts to go to the bladder
after filtering the blood
16
Q
describe the path of urine drainage
A
paillary duct in renal pyramids minor calyx major calyx renal pelvis ureter urinary bladder
17
Q
what is the glomerular/bowmans capsule
A
capillary netowk contaiiing the glomerulus
18
Q
what is the glomerulus
A
capillary bed within the glomerulus capsule
19
Q
name the sections of the nephron
A
proximal convoluted tubule
loop of helse
distal convoluted tubule
20
Q
describe the glomerular capsule
A
endothelial lining of the capillaries which are fenestrated s thus very permeable
lined by podocytes
21
Q
are there types of nephrons?
A
yes:
cortical
meduallr, juxamedullar
22
Q
what is the msot common type of nephron
A
cortical ones
23
Q
can nephrones be replaced?
A
no
they only grown in terms on size not number
24
Q
how does the kidney get its blood suply?
A
branches off the arterioles
renal artery enters hilium and divides into smaller arteris
afferent artiole enters glomerulus
efferent aferty eaves golmerulus
25
what artery enters the glomerulus
afferent
26
what artery leaves the glomerulus?
efferent
27
why is the afferent arteriole wider?
increases the capillary pressure keeping fluid in the nephron
28
what is the secondary capillary netrowk
peritubular network
| wraps around the ubules further exchange of materials in and out
29
what control the resistance to flow of fluids
diameter of the tube
length of the tube
viscosity of the fluid
30
is urine hypo or hyper tonic
urine is more concentrated than plasma
| hypertonic
31
organic compounds found in urine
```
urea
urobilin
uric acid
creatine
amino acids
metabolites of hormones
```
32
what is the pH of urine
acidic
33
what things are not found in urine
glucose
protein
bicarbonate
34
3 processes involved in urine formation
filtration
selective reabsorption
tubular secretion
35
what happens in the filtratio step
blood filtered by the nephron
| ultrafiltration takes place through the semipermeable membrane walls of the glomerulus capsule
36
what can pass through the glomerulus capsule?
```
water and small molecules
mineral salts
amino acids
ketoacids
glucose
creatine
urea
uric acid
soluble hormones, small drugs
```
37
what things cannot pass through the glomerulus capsule and stay in the capillaries/
```
RBC
WBC
platelets
plasma proteins like albumin
large drugs
```
38
describe the process of filtration
between podocytes are filtration slits
| small things can fit though
39
what drives filtration
pressure difference force
40
what affect does osmtic pressure have on filtration
pulls stuff back into capillaries
| but overall liquid leaves the blood entering the nephron
41
what effect does glomerular hydrostatic pressure ave on filtration
higher due to the narrowing of the efferent arteriole
| pushing forec
42
define GFR
glomerular filtration rate
| volume of filtrate formed by both kidney each minute
43
in a healthy adult what is the GFR
135mlper minutes
| 180L per day
44
what does a too low or high GFR cause
low: insufficient wast removal
high: loss of useful substances
45
how does blood pressure impact the kidneys
it drives the systme but doesnt stay constant all the time
| it varies but the GFR must stay constant
46
what keeps the GFR constant
autoregulation is the mechanism of maintaing a constant renal blood pressure
through casoconstrictio and dilation of the afferent arteriole
47
what happens in autregulation if the B\P goes up
afferent arteriole constricts
48
what happens in autoregulation if the BP drops
afferent arterioles dilates
49
what is selective resorption
deciding what the body wants to keep and some things are put back into the blood to be kept
50
what substanes can be resorbed
water
electrolytes
organic nutrients such as glucose and animo acids
51
where does most of the selective resorption occur?
proximal tubules
| the rest of the tubules are then used for fine tuning of this
52
how are solutes resorbed
actve and passive transport, channels and pumps
53
how are glucos and amino acids resporbed?
completely resorbed unless blood levels are excessice
| these thigns shoudnt be in urine in health
54
what is obligatory resorption
water followssolutes by osmosis
55
what is facultative resorption
ADH regulates water resorption n the collecting duct
56
what is the renal threshold
max capacity for resorbtionof certain substances
57
above waht does glucose appear in the urine
above 9mmol/l
58
what is tubular secretion
substances are secreted into the tubues out of the bood
transfere of substances not cleared by filtration earlier
actively get rid of them
59
what are the fina adjustments in tubular secretion?
ADH hormome helps
| collecting ducts aso make final adjustments
60
difference between selective resprtion and tubular secretion
selective resorption moves thigns from the lumen back into the blood
tubular secretion other way round, things move from blood to the tubules
61
what varies the balance of things on each side?
leakiness of junction between tubular epithelial cells
tight junctions make it less mearmeable moving from proximal to distal
carrier, channels and pups
62
what allows K to be resorbed?
leaky tight junctions allow water and K to be reabsorbed between cells
63
how is al the glucose kept in the body?
carried with sodium pumps
| 100% is resorbed by coupled facilitated diffusion into ISF
64
where has the most absorption?
proximal tubule and descending loop
65
key features of the proxima tubule and descending loop?
highly permeable to water and solutes
| most of the ions and water and resorbed here
66
which part of the nephron is very permeable to Na
ascending loop of henlee
67
what happens to ions in the ascending loop
Na/K ATPase sets up sodium gradient to resord it
Na/K co-transported with Cl
K leaks back in driving he movment of Ca and Mg
fitrate more dilute here
68
what happens to the filtrate in the ascending loop
more dilute
| the ISF becomes more concentrated, hypertonic
69
does the ascending loop let in water?
no
| tight junctions are no longer leaky
70
which direction does Na go?
out into blood
| while K is then pumped into the filtrate with it
71
what moves out into blood in the ascending loop?
Naa
K
Cl
Ca and mg
72
what moves back into the filtrate in the ascending loop?
K
73
what regulates the distal tubule
new hormones
regulates collecting ducts also
rennin-angiotensin-aldosterone system
74
what is rennin
and enzyme
75
what does rennin do?
activated angiotensin which in turn activat aldosterone
76
what does aldosterone do?
acts on P/principle cells to secrete K and resorb Na
water then follows with this
amount of K lost in urine is dependent on aldosterone
77
what regulates the collectng duct
ADH
78
what is ADH
pituitary hormone
receptor for the kidney
anti-diuretic hormone/vasopersin
79
what does ADh trigger
aquaproin channels to go into the membrane
80
what do aqua porins in the collecting ducts do?
allow water to move back to the blood from the filtrate
| concentrates the urine
81
what happens to ADH at night
release to stop urine
82
in respnse to what causes ADH to be released
increased plasma osmolarity
83
problems with kidney function may lead to
loss of nutrientes
failure t remove toxins
affect drug treatmentes
affect blood pressure
84
common measures for kidney function
clearance raate
GFR: glomerular filtration rate
PFR: plasma flow rate
85
what is the assumed clearance rate
V= 1ml/min
86
whats the glucose clearance rate for glucose
zero
| as 100% is resorbed and there shouldnt be any in the urine in a healthy state
87
what can clearance rates indicate?
disease
| be used to estimate GFR
88
what are clearance rates compared to to see if theya re healthy?
inulin
89
what does a clearance rate less than inulin mean?
glucose
| all resorbedand not kept
90
what does a clearance rate higher than inulin mean
the body is getting rid of that substance from the blood into the tubule
91
define clearance rates
the volume of plasma completey cleared of the substance in one minutes
the rate at which a substance is excreted in the urine
92
whats the equation for clearance rates
urine concentration X rate of urine production from 24hr colection
93
what does clearance measure compared to GFR
filtration, resorption and secretion combined
| while GFR is only filtration
94
but why is clearance rate useful for GFR estimations
because if the substance is being cleared fro the blood therefore...
- its freely filtred from blood
- neither resorbed or secreted from tubules and
- nas no ne effect of renal metabolism
so therfore clearance = gfr
95
what is inulin and whhys it used?
freely filtrered
not resorbed or secreed
inulin clearance equal to GFR
96
if the clearance of a substance is equal to that of inulin what does it mean
substance is only filtered
no resorption or secretion
its processed in the same way as inulin
97
if the clerance of a substance is smaller than inulin what does it mean
substance must undergo tubular resorbtion
98
if the clearance of a substance is larger than inulin what does it mean
the substance must undergo tubular secretion
99
whats the clearance rate of sodium
0.9
100
a eGFR of what indicates kidney disease
<60ml/min
101
what is RPF
renal plasma flow
| indicates blod flow to the kidney
102
how can RPF be found?
```
if a substance:
- freey filtred from blood
- secreted but not resorbed
-no net effect of mtabolism
PAH meets these criteria
```
103
what does eRPF equal
clearnce of PAH
104
what is the filtration fraction
the fraction of plasma through the kidney that is fltered
105
what is a nromal filtration fraction
GFR/renal plasma flow 20%
