Renal (SUGER) Flashcards
(208 cards)
1
Q
what is the kidney derived from
A
mesoderm
2
Q
where is the kidney located
A
between t12 & l3
3
Q
why is the right kidney lower than left
A
pushed down by liver
4
Q
what does a renal corpuscle consists of
A
glomerulus
bowman’s capsule
PCT
DCT
5
Q
does the medulla have renal corpuscles
A
no
6
Q
are there glomeruli in the medulla
A
no
7
Q
what is the renal pelvis
A
space that urine drains into
- continuous w collecting ducts proximally n ureteres distally
8
Q
where do the tips of the medullary pyramids project into
A
renal pelvis
9
Q
where does the renal artery come off the abdominal aorta
A
L1
10
Q
what is the path from the abdominal aorta to afferent arterioles?
A
abdominal aorta –> renal artery –> segmental arteries –> arcuate arteries –> interloper arteries –> interlobular arteries –> afferent arterioles
11
Q
what does a lobe consist of
A
a medullary pyramid and the overlying cortex
12
Q
what is the diff btwn cortex and medulla
A
cortex: PCT/DCT & renal corpuscles
medulla: loop of Henle & collecting ducts
13
Q
what is the function of the renal corpuscle
A
filter
14
Q
what is the role of the PCT
A
for reabsorbing solutes (bulk reabsorption)
15
Q
what is the role of the loop of henle
A
for concentrating urine (urinary dilution)
16
Q
what is the role of the DCT
A
for rebabsorbing water and solutes (selective reabsorption)
17
Q
what is the role of the collecting duct
A
for reabsorbing water and controlling acid, base and ion balance (like DCT)
18
Q
what are the granular cells
A
endothelium of afferent arteriole is expanded to form a mass of granular cells; detect BP and secrete renin
19
Q
what are macula densa cells
A
expansion of cells at juxtaglomerular apparatus: detects SODIUM levels
20
Q
what does the juxtaglomerular apparatus consist of
A
afferent arteriole
DCT
21
Q
what do the cells of the PCT have lots of and why
A
mitochondria; actively transport ions from glomerular filtrate (inc 2/3 of Na/K)
22
Q
what is the loop of henle supplied by
A
rich vasa recta (straight capillaries)
23
Q
where does the loop of henle travel
A
each loop dips down into medulla then returns to form the DCT and returns to same nephron it left
24
Q
why is the loop of hell prone to ischaemia (temp loss of blood supply)
A
bc vasa recta are quite far from glomerulus so before blood has reached, it has already lost some oxygen
25
is the descending limb of the loop of henle permeable to water
yes
26
is the ascending limb of the loop of henle permeable to water
no
27
what is the ascending loop of henle permeable to
salt
28
what is the DCT involved in
regulating acid base balance
29
how does DCT acidify urine
by secreting H+ ions
30
what are the 2 cell types of the collecting duct
- principal cells
| - intercalated cells
31
what do principal cells do
```
responds to aldosterone (exchanging Na+ for K+)
n ADH (increases water reabsorption by insertion of aqua porin 2)
```
32
what can a mutation in aquaporin 2 gene cause
diabetes insipidus
33
what are intercalated cells responsible for
exchanging acid for base
34
what do alpha and beta intercalated sells secrete
alpha - acid
| beta - bicarbonate
35
what kind of epithelium is the renal pelvis
urothelium (transitional epithelium)
36
what drains into the renal pelvis
collecting duct
37
what does the surface layer of urothelium consist of
umbrella cells that have tight junctions to prevent urine from getting btwn cells
38
what is the inner and outer layer of muscle in the ureters (n how is this diff to GI)
inner: longitudinal
outer: circular
opposite in GI
39
how is urine propelled along ureter
peristalsis
40
what are the 3 main functions of the kidneys
1. endocrine function (hormone secretion)
2. maintain balance of salt, water & pH
3. excretion of waste products
41
what % of blood supply does each kidney receive
20%
42
what is the total renal blood flow
1L/min
43
what is total urine flow
1ml/min
44
each nephron has 2 capillary beds; where?
1 at the glomerulus
| 1 at the peritubular area
45
what are the 2 sets of capillaries in the kidneys and what are they connected by
glomerular capillaries
peritubular capillaries
connected by an efferent arteriole
46
what wraps around capillaries in kidney
podocytes
47
what is bowman's space
fluid-filled space within bowman's capsule (protein free fluid filters from glomerulus into here)
48
what is the filtration barrier in the bowman's capsule
1. single celled capillary endothelium
2. basement membrane aka basal lamina
3. single celled epithelial lining of bowman's capsule
49
what are peritubular capillaries at the loop of Henle aka
vasa recta
50
what is the glomerulus
a cluster of capillaries (basic filtration unit)
51
what are the 2 types of nephrons (and respective %)?
15% - juxtamedullary
| 85% - cortical
52
briefly describe juxtamedullary nephrons
- LOH of nephrons plunge deep into medulla
| - responsible for generating an osmotic gradient
53
briefly describe cortical nephrons
- renal corpuscles lie in outer cortex and LOH do not penetrate deep into medulla
- do not contribute to hypertonic medullary interstitium
54
what is the juxtaglomerular apparatus (JGA)
combinationn of macula densa & juxtaglomerular cells
55
what is the flow of the glomerular filtrate
glomerular capsule --> pct --> nephron loop --> dct --> collecting duct --> papillary duct --> minor calyx --> major calyx --> renal pelvis --> ureter --> urinary bladder --> urethra
56
from tubular lumen --> peritubular capillary
tubular reabsorption
57
peritubular capillary plasma --> tubular lumen
tubular secretion
58
what is measured GFR
conc of M in urine x urine flow rate/conc of M in plasma - creatinin
59
what is renal clearance
vol of plasma from which a substance is completely removed by the kidney
60
does the bowman's capsule have oncotic pressure
no bc no proteins
61
what factors affect filtration rate
- size of molecule
- charge of the molecule (basement membrane is neg)
- rate of blood flow
- binding to plasma proteins
62
what impact does constricting afferent arterioles have on hydrostatic pressure in glomerular capillaries
decreases thus decreases GFR
63
how do you increase GFR
constrist efferent arterioles which increases hydrostatic pressure in glomerular capillaries
64
how can GFR be measured
by marking the excretion of a marker substance (M)
65
what must a marker substance be
- freely filtered
- not secreted/absorbed in tubules
- not metabolised
66
is the GFR a good measure of kidney function
if a disease = less nephrons, GFR will fall so good measure of kidney function but only 1 aspect. can still have other problems eg w secretion so no
67
what is often used to estimate GFR (used as M)
creatinine
68
if macula densa cells detect a reduction in NaCl, what do they release (tubuloglomerular feedback)
prostaglandins --> act on granular cells --> triggers renin release --> activation of RAAS
69
what is PCT responsible for
bulk reabsorption - leaky
70
what is DCT responsible for
fine tuning - impermeable
71
what is autoregulation?
incr blood flow in afferent arteriole --> wall stretch --> smooth muscle contracts --> arteriolar constriction
systemic circulation BP change doesn't affect renal circulation
72
what can easily cross filtration barrier
small and positively charged molecules
73
what charge does the glomerular basement membrane have
negative
74
what is the diff btwn osmolarity and osmolality
conc of solute in LITRES vs KG
75
what are the 3 main things that happen in PCT
1. basolateral Na/K pump establishes conditions for mass reabsorption
2. glucose and phosphate absorbed with sodium - symporter
3. sodium reabsorbed as H+ excreted - antiporter
76
what are the 4 steps of bicarb reabsorption in PCT
1. H+ combines w/ bicarb --> carbonic acid (h2co3)
2. converted to carbon dioxide/water by carbonic anhydrase
3. carbon dioxide diffuses into cell --> carbonic acid reformed
4. bicarb pumped into capillary through basolateral membrane
77
how many Na+ are actively transported out in exchange for how many K+ ions
3Na+ OUT for 2K+ IN
78
why is Na+ exchanged for K+
keeps intracellular conc of Na+ low compared to lumen so Na+ moved downhill out of lumen into tubular epithelial cells --> other substances eg glucose/phosphate also follow (Cotransported)
79
as Na+ moved into proximal tubule cells, what moves outing the lumen?
H+
80
what does Na+ reabsorption promote?
H+ secretion
81
what else are there cotransporters in PCT for
reabsorption of diff amino acids
82
what is the transport maximum
many oft he mediated-transport-reabsorptive systems have limit to amounts of material they can transfer per unit time bc binding sites become saturated when conc of transported substance incr to a certain level
83
does a greater GFT result in a higher or lower osmotic pressure and thus reabsorption?
increased both
84
what is the diff btwn descending and ascending limb of LOH
descending - water absorption
| ascending - solute absorption
85
how does LOH generate a hyper osmotic interstitium
via countercurrent multiplication
86
where is there higher osmolarity (which limb)
down descending limb
87
what is the diff in osmolarity btwn top and bottom of LOH
```
top = low osmolarity
bottom = high osmolarity
```
88
why is there a diff in osmolarity btwn LOH
creates conditions for selective reabsorption in collecting duct
89
what is countercurrent multiplication
opposing flows in 2 limbs
90
what is the NKCC2 pump
transports 1Na+, 1K+ + 2Cl- into ascending limb
91
are cotransporters present in lower ascending limb
no, reabsorption there occurs via simple diffusion
92
why don't medullary capillaries cancel out the countercurrent system
vasa recta form hairpin loops that run parallel to LOH: minimise excessive loss
93
what does DCT do
continues urine dilution - reabsorption of Na, impermeable to water
94
what cotransporter does DCT have
NCC (Na Cl cotransporter) - helps reabsorption of both
95
what does the collecting duct do
similar to DCT, also acid secretion and regulation of water reabsorption (conc urine)
96
what is collecting duct surrounded by
hypertonic medullary intersititum set up by LOH
97
what do principle cells contain
ENaC (epithelial Na channel)
98
what does aldosterone mean in collecting duct
more ENaC channels --> incr Na reabsorption/K excretion
99
what does ADH do in collecting duct
V2 receptors --> aquaporins in apical membrane --> increased water permeability --> incr water reabsorption --> more concentratedurine
100
what do intercalated cells do
secrete acid
- ATPase pumps out H+ --> byproduct of bicarb production in renal cell
- ammonia diffuses into tubular fluid --> combines with H to form NH3
101
what is water distribution in ICF/ECF
ICF: 2/3
ECF: 1/3
102
what is water distribution in ECF?
75%: interstitial fluid
| 25%: plasma
103
what is the major cation in ECF
Na
104
what is the major cation in ICF
K
105
what is intracellular pH
7.0
106
what is extracellular pH
7.4
107
is pH lower in inside or outside of cells
inside
108
how do u calculate plasma osmolality
2(Na+K) + glucose + urea
109
how is fluid movement regulated
by controlling Na movement
110
how is tonicity (osmotic pressure gradient) regulated
by controlling water movement
111
where is ADH synthesised
hypothalamus (supraoptic nuclei)
112
where is ADH secreted from
posterior pituitary
113
what is the release of ADH controlled by
hypothalamic osmoreceptors
114
name 2 locations where baroreceptors are located
aortic arch
| carotid sinus
115
what impact does an increased cardiovascular pressure have in ADH secretion
decreased ADH secretion
116
what is thirst stimulated by
increase in plasma osmolarity and by a decrease in ECF volume --> ADH secretion --> increased water reabsorption
117
where is Na reabsorbed in specific parts of the kidney and what %
60%: PCT
25%: LOH
10%: DCT
4%: collecting duc
118
does urinary excretion increase or decrease with an excess of Na in the body
increases
119
is Na actively reabsorbed or secreted
actively reabsorbed
120
if Na+ is low, what impact does this have in net glomerular filtration pressure (and why)
decreases
- bc of decreased arterial pressure
- reflexes acting on renal arterioles (vasoconstriction)
121
for long-term regulation of Na+ excretion: is control of Na+ reabsorption more important or control of GFR
control of Na+ reabsorption
122
which hormone has a major impact on determining rate of Na+ reabsorption
aldosterone
123
what releases renin
juxtaglomerular cells of kidney
124
where is angiotensinogen produced
liver
125
where is ACE produced
lungs
126
what does ACE do
converts angiotensin I to angiotensin II
127
what does renin do
cleaves angiotensinogen --> angiotensin I
128
what does angiotensin II do
stimulates cells of zona glomerulosa (adrenal cortex or adrenal glands) to secrete aldosterone
129
what is aldosterone
a vasoconstrictor (esp at efferent arteriole) which incr pressure --> increases GFR --> increases Na+ reabsorption in PCT --> stimulates ADH release
130
which cells does aldosterone act on
principal cells of collecting ducts
131
if u reabsorb more Na+, what will leak out more of
K+
132
which cells synthesis and secrete ANP
cells in the cardiac atria
133
what does ANP stand for
atrial natriuretic peptide
134
what does ANP do to glomerular arterioles
dilates --> increases GFR --> increases Na+ excretion
135
how does ANP inhibit Na+ reabsorption
blockis ENaC's in collecting ducts
136
how does ANP impact ADH secretion
directly inhibits --> increases Na+ excretion
137
how does ANP secretion increase when there is excess Na+ in body
bc excess Na+ = excess water in vessels = increased blood volume = stretched atria = ANP secreted
138
what ion concentration is the resting membrane potentials of excitable tissues eg nerves/muscles directly related to
K+
139
does ANP stimulate or inhibit renin secretion
inhibits
140
what are the 2 main hormones that affect the renal system
PTH
| ANP
141
how does PTH impact reabsorption of phosphate/Ca
- blocks phosphate reabsorption in PCT
| - increases calcium reabsorption everywhere else
142
what does PTH stimulate
active form of vit d (calcitriol)
143
what does 25-hydroxyvitamin D hydrolysed to in the kidneys
1,25dihydroxyvitamin D (active)
144
where is 90% of filtered K+ reabsorbed
pct
145
what is the main cause of changes in K+ excretion
cortical collecting ducts can secrete K+
146
how does a high K+ diet result in enhanced K+ secretion?
plasma K+ conc increases --> enhanced basolateral uptake K+ via NaKATPase pump --> enhanced secretion
147
how does aldosterone affect K+ secretion
enhances
148
what is base excess
quantity of acid required to return plasma pH to normal
149
what is standard base excess
quantity of acid required to return ECF back to normal
150
what is the anion gap
diff btwn measured anions and cations ([Na+] + [K+] - [Cl-] + [HCO3-])
151
name 2 urinary buffers
urinary phosphate buffer
| ammonia buffer
152
what is the purpose of hydrogen ion secretion
- to reabsorb bicarb
| - to excrete daily acid load
153
what is the minimum urine pH
4.5
154
what Is the commonest urinary buffer
alkaline phosphate
155
what is the urinary ammonia buffer purpose
it's an adaptive response to acid load
156
describe the phosphate buffer briefly
- most common
| - impermeable to apical membrane
157
describe the ammonia buffer briefly
- adaptive response to acid load --> synthesised from glutamine
- ammonia diffuses into tubular fluid --> ammonium ions impermeable to apical membrane
- PCT --> reabsorbed in LOH --> intercalated disc in collecting duct
158
what can cause resp acidosis
hypoventilation
- -> hypercapnia (can't get rid of CO2)
- -> eqm shifts right
- more H+
159
what is renal compensation for resp acidosis
- increased H+ secretion
- increased bicarb production
- increased ammonia secretion
160
what can cause resp alkalosis
hypoventilation
- -> hypocapnia
- -> elm shifts left
- less H+
161
what is renal compensation for resp alkalosis
- decreased H+ secretion
| - increased bicarb secretion
162
what is metabolic acidosis caused by
excess acid production
| or decreased bicarb concentration
163
what is resp compensation for metabolic acidosis
- low pH stimulates chemoreceptors
| - increased ventilation --> decreased pCO2
164
what can cause metabolic alkalosis
vomiting = acid loss
165
what is resp compensation for metabolic alkalosis
- high pH stimulates chemoreceptors
| - decreased ventilation --> increased pCO2
166
what is the diff in shape of R vs L adrenal gland
```
R = pyramidal
L = semilunar
```
167
what 3 regions is the adrenal cortex divided into
zona Glomerulosa
zona Fasiculata
zona Reticularis
168
what is the adrenal gland divided into
adrenal cortex (--> 3) and adrenal medulla
169
what does the adrenal cortex secrete
zG - mineralocorticoids eg aldosterone
zF - glucocorticoids eg cortisol
zR - androgens eg testosterone
170
what does the adrenal medulla secrete
catecholamines eg adrenaline
171
what are the steroid hormones prod in adrenal glands derived from
cholesterol
172
what receptors do mineralocorticoids act on
only on mineralocorticoid receptors
173
what receptors do glucocorticoids act on
mineralocorticoid and glucocorticoid receptors
174
what receptors do androgens act on
only androgen receptors
175
what does zona glomerulosa secrete
mineralocorticoids
176
what does zona fasciculata secrete
glucocorticoids
177
what does zona reticularis secrete
sex hormones and small amounts of cortisol
178
what is an example of a mineralocorticoid
aldosterone
179
what is an example of a glucocorticoid
cortisol
180
what is an example of an androgen
testosterone
181
what is an example of a catecholamine
adrenaline
182
what is cortisol released in response to (2)
- stress
| - low blood glucose levels
183
what does cortisol do
increases gluconeogenesis
| increases fat/protein metabolism
184
what type of hormones are catecholamines released from adrenal medulla
peptide hormones
185
what is the function of adrenaline (3)
1. gluconeogenesis
2. lipolysis
3. increased heart rate
186
what do alpha receptors in smooth muscle involve
vasoconstriction/dilation
187
what do the 3 beta receptors do
beta 1 - amylase secretion
beta 2 - bronchodilation
beta 3 - lipolysis in adipocytes
188
where do the superior, middle and inferior adrenal arteries come from
superior - inferior phrenic
middle - abdominal aorta
inferior - renal artery
189
where do the left L and R renal vein drain into
right - IVC
| left - left renal vein
190
what is the nerve supply of adrenal glands
splanchnic nerves
191
all 3 zones of adrenal cortex produce steroids classed under the band of what
corticosteroids
192
which type of feedback is important for glucocorticoids and mineralocorticoids
neg
193
what is the precursor for all corticosteroids
cholesterol
194
list 3 features of corticosteroids
1. lipid soluble (pass through bio membranes easily)
2. bind to specific intracellular receptors
3. alter gene expression
195
what is the role of mineralocorticoids
regulate body electrolytes
196
what is aldosterone important for (2)
maintaining salt balance and BP
197
will problems with hypothalamus or pituitary impact aldosterone secretion
no bc triggered by release of renin by juxtaglomerular cells of afferent arterioles of kidney
198
why is cortisol called a glucocorticoid
has important impact on metabolism of glucose
199
how is cortisol release stimulated
1. stress is detected and transmitted neurally to hypothalamus
2. stimulates secretion of CRH (corticotropin releasing hormone) from hypothalamus
3. carried to anterior pituitary --> ACTH released
4. ACTH circulates in blood and travels to adrenal cortex --> cortisol released
200
why is cortisol important in foetal and neonatal life
responsible for diff of numerous tissue and glands
201
what hormone is essential for surfactant production
cortisol!
202
what is the most abundant (yet weak) adrenal steroid
DHEA (dehydroepiadrosterone)
203
which NS is adrenal medulla part of
autonomic
204
what do alpha receptors have a high affinity for (adrenaline or noradrenaline)
noradrenaline
205
what do beta receptors have a high affinity for (adrenaline or noradrenaline)
adrenaline
206
is resp compensation for acidosis/alkalosis slow or fast
fast
207
is renal compensation for acidosis/alkalosis slow or fast
slow
208
what are the 3 layers of kidney tissue (outer to inner)
1. renal fascia
2. perirenal fat capsule
3. fibrous capsule
