Renal Flashcards
(107 cards)
1
Q
What is the order of the filtration membrane from inner to outer?
A
Fenestrated epithelium -> Basal Lamina -> Slit membrane
2
Q
What does the fenestrated epithelium allow through?
A
Large, medium and small proteins
3
Q
What does the basal lamina allow through?
A
Medium and small proteins
4
Q
What does the slit membrane allow through?
A
Small proteins
5
Q
What do none of the layers of the filtration membrane allow through?
A
Cells
6
Q
What cells make up the visceral layer of the glomerular capsule?
A
Podocytes
7
Q
After passing through the 3 layers of filtration, where is the filtrate?
A
Urinary/capsular space
8
Q
How does blood enter the renal corpuscle?
A
Through the afferent arteriole
9
Q
How does blood exit the renal corpuscle?
A
Through the efferent arteriole
10
Q
What is the glomerulus?
A
Network of capillaries
11
Q
What is the glomerular/bowmans capsule?
A
The pouch that covers the glomerulus
12
Q
Describe the path of filtrate from the urinary space to the bladder
A
Proximal convoluted tubule -> thick descending LOH -> thin descending LOH -> thin ascending LOH -> thick ascending LOH -> distal convoluted tubule -> collecting duct -> papillary duct -> calyx -> renal pelvis -> ureter -> bladder
13
Q
What are the 3 layers of protection around the kidney from outer to inner?
A
Renal fascia -> adipose capsule -> renal capsule
14
Q
What separates lobules?
A
Interlobular arteties
15
Q
What separates lobes?
A
Interlobar artieries
16
Q
Describe the path of blood from the interlobular artery to the interlobular vein
A
Interlobular artery -> afferent arteriole -> glomerular capillaries -> peritubular capillaries of the cortex -> descending vasa recta -> peritubular capillaries of the medulla -> ascending vasa recta -> interlobular bein
17
Q
Approx. how many nephrons are in each kidney?
A
~1 million
17
Q
What controls the flow of blood into the glomerulus?
A
Afferent arterioles
18
Q
How many lobes do human kidneys have?
A
8-12
19
Q
How much does each kidney weigh?
A
150g
20
Q
What are the protective layers of the kidneys made of?
A
Connective tissue
21
Q
How is osmolarity calculated?
A
Molarity x dissociation factor
22
Q
Does osmolarity measure solute or water?
A
Solute
23
Q
What happens to a cell in a 150mM NaCl solution?
A
Nothing - it is isotonic
24
What is meant by hypotonic and what happens to a cell placed in a hypotonic solution?
A solution with a higher POsm than another - cell will shrink as water moves out
25
What happens to a cell in a 300mM urea solution?
Swells - cell is hypotonic to solution
26
What is meant by hypertonic and what happens to a cell placed in a hypertonic solution?
A solution with a lower POsm than another - cell will swell as water moves in
27
What is meant by isotonic and what happens to a cell placed in a isotonic solution?
2 solutions with the same POsm - no net water movement
28
What percent (and volume) of the body is fluid (70kg male)
60% - 42L
29
How much of the body's fluid is intracellular (include approx. volume)?
2/3 - 28L (2/3 of 42)
30
How much of the body's fluid is extracellular (include approx. volume)?
1/3 - 14L (1/3 of 42)
31
What makes up extracellular fluid, including approx percentages and volumes
20% plasma - 2.8L
80% interstitial - 11.2L
32
What are the 3 major sources of water intake?
Drinks, foods, metabolism
33
What are the 4 major sources of water output?
Urine, skin, lungs, feces
34
What ions have higher extracellular concentrations?
Na+ (142mM EC, 10mM IC), Cl- (103mM EC, 4mM IC), Ca2+
35
What ion has a higher intracellular concentration?
K+ (140mM IC, 4mM EC)
36
What percentage of body mass is the kidney?
0.5%
37
What percentage of cardiac output does the kidney receive at rest?
20-25%
38
What is the blood flow through the kidney per minute (in a 70kg male)?
1100ml/min
39
How many litres of blood are filtered through the kidneys each day?
180L
40
How much urine is produced every day?
1.4L
41
What is the equation that represents urine production?
Excretion = filtration - reabsorption + secretion
42
What is not reabsorbed at all?
Creatinine
43
What is the major driving force in the glomerular?
Glomerular capillary hydrostatic pressure
43
What are the 4 pressures in the glomerular capillaries and their approximate values?
PGC - glomerular capillary hydrostatic pressure (55mmHg)
πBS - Bowman space oncotic pressure (
PBS - Bowman space hydrostatic pressure (15mmHg)
πGC - Glomerular capillary oncotic pressure (30mmHg)
44
What 2 forces drive filtrate out of the glomerular capillaries?
PGC & πBS
45
What 2 forces drive filtrate into the glomerular capillaries?
πGC & PBS
46
What is the approx. value of net filtration pressure?
10mmHg
47
What is the equation for net filtration pressure?
NFP = GBHP - CHP - BCOP
48
What are the 2 autoregulation mechanisms of the kidneys?
Myogenic and tubuloglomerular feedback
49
What effect does constriction of the afferent arteriole have on PGC/GBHP and GFR?
Decreased pressure and GFR
49
What effect does constriction of the efferent arteriole have on PGC/GBHP and GFR?
Increased pressure and GFR
49
What are the 3 ways in which glomerular filtration is regulated?
Autoregulation, neural, hormonal
50
What are the 2 main things impacting GFR?
GBHP (PCG) and surface area
51
What is the neural regulation of GFR?
Sympathetic nerve activity causing vasoconstriction of afferent arteriole(baroreflex)
52
What is the overall effect of angiotensin 2 on GFR?
Maintained
53
What are the 2 hormonal mechanism of GFR regulation?
Angiotensin 2 and ANP
54
What does angiotensin do to the arterioles in the glomerular?
Constriction of both (however, tubuloglomerular feedback counteracts the constriction of afferent arteriole)
55
What does ANP stand for?
Atrial Natriuretic Peptide
56
What does ANP cause?
Relaxation of mesangial cells, leading to increased surface area for filtration -> more sodium release into the urine, leading to more water in the urine and an overall decrease in blood volume
57
What causes ANP release?
Stretching of the atria
58
What is the effect of SNS on GFR?
Decrease
58
What is the effect of ANP on GFR?
Increase
59
What is urine output directly proportional to?
Renal pressure
60
Describe tubuloglomerular feedback
Increased GFR -> increased Na+, Cl- and water content sensed by the macula densa cells in the distal tubule -> Juxtaglomerular cells in afferent arteriole sense macula densa cells -> decreased release of NO from juxtaglomerular cells -> afferent arteriole vasoconstriction -> decreased GBHP and GFR -> slower flow promotes more Na+ reabsorption
61
What are corticol nephrons involved in the production of?
Dilute urine
62
What are juxtamedullary nephrons involved in the production of?
Concentrated urine
63
The cells of which part of the nephron have microvilli?
Proximal convoluted tubule
64
Describe the cells in the loop of henle
Thin
65
Where does the majority of reabsorption occur?
Proximal convoluted tubule
66
What percentage of glomerular filtrate is reabsorbed in the proximal tubule?
60%
67
What percentage of NaCl & water is reabsorbed in the proximal tubule?
60%
67
What percentage of glucose is reabsorbed in the proximal tubule?
100%
68
Describe the osmolarity of the fluid in the lumen of the proximal tubule at the start and end
Isosmotic (Na+ and water both reabsorbed together, ~290mOsmol/L)
69
Describe the movement of ions and solutes in the proximal tubule
Na+ moved into cells along with glucose via symporter (both down conc. grad)
Na+ is pumped out of basement membrane by Na+/K+ ATPase (creating a concentration gradient for Na+ uptake)
Glucose diffuses through the transporter across the basement membrane
Water follows Na+ (osmosis)
70
What is reabsorbed in the descending limb of Henle?
Only water
71
Describe the filtrate at the bottom of the LOH
Very concentrated, 1200mOsmol/L
72
What is reabsorbed in the thick ascending limb of Henle?
Only ions (NOT water)
73
Describe the movement ions in the ascending LOH
Na+, Cl- and K+ all actively pumped into cell through symporter
Cl- diffuses out of cell across BM
Na+ pumped out of cell across BM
74
Where is the interstitial fluid most concentrated?
Tip of the medulla
75
What occurs in the distal convoluted tubule?
Additional reabsorption of NaCl & water (if ADH is present)
76
What does the absence of ADH produce?
Dilute urine
77
Where is glucose reabsorbed?
Proximal convoluted tubule
78
What part of the nephron cannot reabsorb water?
Ascending LOH
79
What releases renin?
Juxtaglomerular cells of afferent arteriole
80
What hormone has the greatest influence on water retention?
ADH
81
What part of the nephron does ADH act on?
Distal convoluted tubule and collecting duct
82
What does ADH cause to happen in the apical membranes?
Insertion of aquaporin 2 channels via exocytosis
83
What releases ANP?
Cardio myocytes
84
What enzyme converts angiotensinogen to angiotensin 1?
Renin
85
What is the effect of angiotensin 2 on the PCT?
Increased Na+ uptake via Na+/H+ antiporter
86
What is the overall effect of ADH?
Increased water reabsorption through aquaporin 2 channels in the DCT and CD leading to increased water reabsorption, increased urine concentration and decreased urine production
87
What is the overall effect of ANP?
Reduced renin, ADH and aldosterone
Increased GFR
Reduced Na+ and water reabsorption -> increased urination and decreased BV and BP
88
What is the overall effect of Aldosterone?
Increased transcription of Na+/K+ ATPase in DCT and CD to increase Na+ and water reabsorption (and K+ secretion)
89
What is the overall effect of Renin?
Maintenance of Na+ balance and blood pressure
90
What is the overall effect of Angiotensin 2/ what does it do?
Vasoconstriction of blood vessels (predominantly efferent) to help maintain GFR
Increase Na+/H+ antiporters in PCT to increase Na+ and water reabsorption
Stimulates release of aldosterone from adrenal cortex -> increased Na+ reabsorption in DCT
Acts centrally to stimulate thirst and salt intake, release ADH and stimulate SNS
91
What stimulates the release of ADH?
Increased Na+/Osmolarity - sensed by osmoreceptors in the hypothalamus
Decreased BP and BV (baroreceptors)
92
What stimulates the release of Renin?
Decreased NaCl sensed by Macula Densa cells -> increased prostaglandin secretion
Decreased BP or BV. in afferent arteriole
Increased SNS stimulation
93
How do osmoreceptors work?
Via stretch-activated ion channels, which are opened when ECF is hypertonic and cell shrinks, allowing Na+ ions to enter and an AP to be triggered
94
What is the effect of an increase in plasma osmolality on ADH level?
Increased ADH release
95
What is the effect of increased thirst on ADH?
Increased ADH release
96
Name a common ACE inhibitor
Lisinopril
97
What is the effect of increased salt intake on angiotensin 2?
Decrease
98
What is the effect of ANP on the arterioles?
Dilation of afferent, constriction of efferent
99
What is the normal GBHP?
55mmHg
100
What is the normal BCOP in the glomerulus?
30mmHg
101
What is the normal CHP?
15mmHg
