Renal Flashcards
(92 cards)
1
Q
three main functions of the kidney
A
- excretion
- regulation
- absorption
2
Q
six major functions of the kidney
A
- stabilizing electrolytes
- water balance/proper osmolarity
- excretion of nitrogenous waste
- acid/base regulation
- maintaining the blood concentration and ridding of hormones, drugs, pesticides, food additives, and nonnutritive materials
- production of 2 VIP hormones
3
Q
what two VIP hormones do kidneys produce?
A
erythropoietin and renin
4
Q
what is the smallest functional unit of the kidney?
A
nephron
5
Q
two types of nephrons
A
juxtamedullary and cortical
6
Q
cortical nephron
A
glomeruli in the outer cortex, smaller loops of Henle, ~80% of nephrons
7
Q
juxtamedullary nephron
A
glomeruli next to medulla, long loops of Henle penetrating into medulla, ~20% of nephrons
8
Q
five major regions
A
- Bowman’s capsule/glomerulus
- proximal convoluted tubule
- loop of Henle
- distal convoluted tubule
- juxtaglomerular apparatus
9
Q
region 1
A
glomerulus and Bowman’s capsule
10
Q
Bowman’s capsule and glomerulus primary function
A
filtration
11
Q
ultrafiltration
A
pressure inside the capillaries is greater than outside, driving fluids through pores
12
Q
fenestrae
A
pores in Bowman’s capsule
13
Q
what size substrates fit in the fenestrae
A
less than 6 nm or 68 kDa
14
Q
four types of filtrate entering the proximal convoluted tubule
A
- carbohydrates
- electrolytes
- H2O and small particles
- plasma and free cellular material
15
Q
to be filtered a substance must pass through…
A
- the pores between endothelial cells of the glomerular capillaries
- an acellular basement membrane
- the filtration slits between the foot processes of the podocyte
16
Q
podocyte
A
- contraction causes foot processes to flatten, decreasing pore diameter
- contraction under sympathetic stimulation, acts upon actin-like filaments
- can also decrease the number of slits, decreasing glomerular filtration rate
17
Q
glomerular filtration rate
A
how many pore of the glomerulus are available for permeation
(Kf)(NFP)
18
Q
Kf in glomerular filtration rate
A
filtration coefficient
19
Q
NFP in glomerular filtration rate
A
net filtration pressure based on 3 pressures
20
Q
what three pressures are NFP based on?
A
- glomerular-capillary bp
- plasma-colloid osmotic psi
- Bowman’s hydrostatic psi
21
Q
glomerular-capillary bp
A
systemic bp, favors filtration
22
Q
plasma-colloid osmotic psi
A
blood osmolarity, opposes filtration
23
Q
Bowman’s hydrostatic psi
A
the psi pushing against the glomerular capillaries, opposes filtration
24
Q
greatest factor in changing GFR is…
A
systemic bp
25
how does exercise affect systemic bp?
increases blood pressure
26
how does hemorrhage affect systemic bp?
decreases blood pressure
27
how does excess fluids affect systemic bp?
decreases blood pressure
28
what does diarrhea do?
increases/decreases plasma osmolarity
29
what do burns and trauma do?
decreases NFP
30
what do kidney stones do?
increase Bowman's hydrostatic psi
31
vasa recta
straight (vertical) vessels
32
peritubular capillaries
convoluted
33
region 2
proximal convoluted tubule
34
main function of the proximal convoluted tubule
glucose uptake
35
what particles does the PCT take up?
small mw amino acids and proteins, 100% of glucose, polypeptides, organics, salts, and water
36
hyperglycemia
high concentrations of glucose in the blood
37
glucosuria
glucose in urine
38
glucose has a _____ _____ because of limited supply of glucose transporters
renal threshold
39
renal threshold
the amount of glucose the renal system can filter at any given point, 300mg/100mL
40
tubular maximum
375mg/min
41
how is glucose reabsorbed via the PCT?
secondary active transport via Na+ support
42
how is sodium reabsorbed via the PCT? (4 steps)
1. luminal membrane
2. basal lateral membrane *
3. interstitial fluid
4. endothelial membrane
*requires Na/K pump, making the whole process active
43
what does alcohol block?
secondary active transport
44
uremia
renal failure
45
water moves through the tight junction attracted by the _____ _____ of sodium
osmotic force
46
water is osmotically attracted to _____ _____ in the blood
plasma proteins
47
plasma proteins can/cannot pass through podocytes?
cannot
48
region 3
loop of henle
49
counter-current multiplication
descending loop of Henle is very permeable, ascending loop is not permeable
50
as you enter the medulla, there will be...
a steep salt gradient
51
salts act as an attractant to _____
water
52
descending loop of Henle does what
releases lots of water, leaving salts behind
53
ascending loop of Henle does what
releases a lot of salt, so the water can be reabsorbed
54
region 4
distal convoluted tubule
55
distal convoluted tubule primary function
hormone regulation
56
hormones produced by the distal convoluted tubule
ADH and aldosterone
57
aldosterone
increases Na+ and K+ secretion
58
aldosterone is what type of hormone?
steroid hormone
59
how does aldosterone work?
turns on gene transcription in the nucleus to produce new Na/K pumps and Na channels
60
ADH - vasopressin
increases H2O absorption, lowers blood pressure and volume
61
what type of hormone is ADH?
protein hormone
62
how does ADH work?
activates cAMP, triggering the insertion of aquaporins into the DCT membrane
63
where is ADH released from?
posterior pituitary
64
what molecule inhibits aldosterone when blood volume is too high?
ANP
65
what does a high concentration of K+ cause?
more production of aldosterone via the adrenal cortex
66
what does low sodium/blood pressure trigger?
renin-angiotensin-aldosterone pathway
67
what does high K+ cause?
a decrease in resting membrane potential, lowering AP threshold, causing hyperexcitability of the heart (arrhythmias)
68
what does lower K+ cause?
increase in resting membrane potential. leading to hyperpolarization, skeletal muscle weakness, abnormal heart conduction etc.
69
region 5
juxtaglomerular apparatus
70
what does an increased flow rate cause the macula densa cells to do?
secrete a vasoactive chemical to contract smooth muscle
71
macula densa cells
detect blood flow rate; release a chemical that helps restrict the afferent arteriole if GFR is too high
72
vasoconstriction
decreases blood flow to the glomerulus
73
vasodilation
increases blood flow to the glomerulus
74
granular cells
detect low bp, and [Na+] to release return
75
hypertension
bp is greater or equal to 140-180
abnormally high increase in the renin-angiotensin-aldosterone activity
76
glomerulonephritis
thickening of podocytes, fall of GFR, too much water leading to hypertension
77
congestive heart failure
blood volume is elevated (15%-20% more)
excess ECF
78
albuminuria
protein in urine
79
pseudonephritis
after extreme exercise, protein in urine
80
edema
fluid retention
81
inappropriate triggers to heart failure (1/2)
activates autoregulation, sympathetic control to try and get GFR back up
82
inappropriate triggers to heart failure (2/2)
stimulates renin to increase H2O reabsorption and increase Na/K pumps to stabilize
83
patient treatments
low salt diet
diuretic drug therapy
ACE inhibitors
ANP treatment
84
ACE does what?
converts angiotensin I to angiotensin II
85
ANP (atrial natriuretic peptide)
acts to decrease bp, increase urine output, and increase Na+ loss
86
acute renal failure
rapid reduction in urine, only 500 or less in a day
reversible
87
chronic renal failure
slow, progressive loss of nephron function
undetectable
up to 75% of nephrons are not functioning
88
end stage renal failure
90% or more nephrons are not working
every organ is affected
irreversible loss
fatal
89
two treatments for end stage renal failure
transplant
dialysis
90
CAPD
continuous ambulatory peritoneal dialysis
91
advantages of dialysis
1. 4x faster than normal
2. increase life from 15-20 years
3. feed individuals
92
disadvantages of dialysis
1. not great quality of life
2. 4-6 hours three times a week
3. still affects organs
4. take anticoagulants
