renal physiology Flashcards
(131 cards)
1
Q
in order for cells to survive, the composition of _______ must remain within well defined limits
A
extracellular fluid
2
Q
organ that is the primary organ for stabilization of ion concentration and volume of extracellular fluid
A
kidney
3
Q
organ that enables mammals to survive under conditions of highly variable access to water and salts
A
kidney
4
Q
production of glucose
A
gluconeogenesis
5
Q
importance of resorbing filtered substances in the kidney
A
to maintain a constant extracellular fluid osmolarity and volume
6
Q
functions of the kidneys
A
- filter blood
- produce urine
- resorb from filtered substance
- excretion of metabolic wastes and xenobiotics
- water and acid-base balance – buffer ion into blood stream
- produce glucose
- endocrine things
7
Q
3 hormones produced in the kidney
A
- calcitriol
- renin
- erythropoietin
8
Q
stimulated by PTH in response to hypocalcemia
A
calcitriol
9
Q
chemical name for calcitriol
A
1,25-(OH)2-D2
10
Q
a hormone activator used for renal regulation of blood pressure and is an essential part of the RAA system
A
renin
11
Q
trigger of erythropoietin
A
low tissue oxygen tension
12
Q
location of the kidneys
A
adjacent to the upper abdominal wall
13
Q
functional unit of the kidney
A
nephron
14
Q
T/F
nephrons can regenerate themselves
A
FALSE – partially…cannot be replaced
15
Q
type of nephron with short loop of henle that is supplied by the peritubular capillaries
A
cortical nephrons
16
Q
nephron located near the cortex/medulla junction with extremely long loops of henle
A
juxtamedullary nephron
17
Q
critical for urine concentration
A
long loops of henle
18
Q
PART OF NEPHRON:
located in the renal cortex, consists of glomerulus and is surrounded by the Bowmans capsule
A
Malpighian body
19
Q
PART OF NEPHRON:
longest part
A
Proximal tubules – has a convoluted and straight part
20
Q
PART OF NEPHRON:
consists of a thick descending limb extending into the renal medulla, a thin descending limb, a thick descending limb (in nephrons with long loops), and a thick ascending limb
A
loops of henle
21
Q
T/F
Distal tubules have both a straight and a convoluted part
A
TRUE
22
Q
T/F
collecting ducts only extend through the renal cortex
A
FALSE – extend through the renal cortex and medulla
23
Q
leading cause of death worldwide
A
ischemic heart disease
24
Q
5-30% of patients undergoing cardiac or vascular surgeries will develop this
A
acute renal failure
25
interruption of blood supply to a tissue
ischemia
26
re-establishment of blood flow to a tissue
reperfusion
27
what are reactive oxygen species (ROS)
highly reactive molecules that damage DNA, lipids, and proteins
28
T/F
| nephrons can regenerate
FALSE
29
T/F
| tubular cells can regenerate
TRUE
30
T/F
| brush border is lost during ischemia/reperfusion
TRUE
31
What is the first step in urine formation
filtration of large amounts of fluid through the glomerular capillaries into bowmans capsule
32
compact network of capillaries that retains cellular components and proteins
glomerulus
33
what does the glomerulus produce
glomerular filtrate
34
T/F
| the glomerular filtrate is nearly identical to plasma
TRUE
35
the rate the kidney is perfused with blood
renal plasma flow
36
three components of the filtration barrier
1. fenestrated capillary endothelial cells
2. glomerular basement membrane
3. visceral epithelium (podocytes)
37
The layers of the glomerular basement membrane
1. lamina rara interna
2. lamina densa
3. lamina rare externa
38
T/F
| the glomerular filtrate contains many proteins
FALSE --
basically IMPERMEABLE to proteins and is relatively protein free
39
T/F
| albumin is freely filterable
FALSE -- filterability is almost 0
40
List 3 freely filterable substances
water
sodium
glucose
41
Which charge of ions are filtered more easily through the barrier
cations filtered more than anions
42
What is the main driving force for filtration?
the glomerular capillary hydrostatic pressure
43
What percent of the GFR returns to the extracellular compartment via tubular reabsorption
99%
1% excreted as urine
44
2 substances that can be used to measure renal clearance (GFR)
creatinine and inulin
45
byproduct of muscle metabolism
creatinine
46
regulatory mechanism for changes in systemic blood pressure
RAAS
47
Autoregulatory mechanism for changes in glomerular perfusion
Myogenic reflex/ bayliss effect
48
Autoregulatory mechanism for changes in tubule fluid delivery
tubuloglomerular feedback
**inhibits renin release
49
Where is Renin produced
in the wall of cells located in the afferent arterioles (juxtaglomerular cells)
**released by kidney when there is a decrease in arterial pressure
50
T/F
| endothelin is a vasodilatory agent
FALSE --
it is a constricting factor
51
the ultrafiltrate that accumulates in the capsular space between the glomerulus and bowmans capsule and contains the same concentration salt and glucose as plasma
primary urin
**made in the glomerulus after blood is filtered
52
an indicator of functional integrity in the renal tubules
fractional excretion rate
53
The net rate of reabsorption and secretion of a filtered substance
fractional excretion rate
54
reabsorbs most of the filtered solutes
Proximal tubule
55
maintain medullary hypertonicity
thin limbs of loop of henle
56
T/F
| proximal tubule cells are polarized
TRUE
**apical and basolateral ends -- also have brush borders and tight junctions
57
transport in PT fueled directly by ATP consumption
Primary Active Transport
*basolateral Na/K ATPase
58
movement in PT mainly by carrier-mediated transport across the apical membrane -- through the cytoplasm -- into the interstitial fluid then peritubular capillary
Transcellular pathway
59
tubule fluids pass through the epithelium across the tight junctions. The substances enter the lateral intercellular space and then the interstitial fluid and peritubular capillaries
Paracellular pathway (PT)
**solvent drag / passive diffusion
60
driven by the electrochemical gradient produced by the primary active transporter
secondary active transport
**tertiary driven by secondary's gradient then (H+ grad)
61
Substances that the secondary active transport system transports in the PT for reabsorption
```
glucose
amino acids
phosphate
sulfate
citrate
```
62
process in the PT for low-molecular-weight proteins reabsorption
receptor mediated endocytosis
**receptors are in the plasma membrane of the PT cells (megalin and cubilin)
63
T/F
| receptor-mediated endocytosis is saturable
TRUE
can lead to an elevated plasma concentration of filterable proteins or increased filtration of proteins / glomerular filter damage
64
pathological presence of protein in the urine
proteinuria
65
pre-renal proteinuria
if the concentration of free filterable proteins is increased
**hyperproteinemia
66
intrarenal proteinuria
if the glomerular filter is damaged
**glomerular damage
67
post-renal proteinuria
tubular loss of proteins (inflammatory processes)
**tubular cell death or UTI
68
K+ uptake in the PT is mainly by ______
transcellular
69
Ca++ uptake in the PT is by _____ and _____
paracellular and solvent drag
70
Cl- ion uptake in the PT occurs by ____ and _____
paracellular and transcellular
71
examples of organic anions secreted by the PT
```
PAH
Oxalate
Drugs like penicilin, diuretics
herbicides
glucuronic acid
```
**done by using OATS and MRP-2
72
examples of organic cations secreted by the PT
epinephrine
choline
histamine, serotonin
drugs like atropin and morphine
**done by using OCT and MDR-1
73
presence of glucose in the urine
glucosuria
74
"concentrates" the tubule fluid segment of the loop of henle
Thin descending limb
**water is reabsorbed because it is highly permeable here due to AQUAPORINS but NaCl does not flow
75
"diluting" segment of the loop of henle
mTAL -- thick ascending limb
**reabsorbs NaCl but water cannot flow because it is impermeable to water
76
transport system used in the mTAL
NKCC (for Na, K, Cl)
**can be inhibited by furosemide, a common diuretic
77
where is angiotensin produced
the liver
78
T/F
| cortical nephrons have thin ascending loops
FALSE
79
Three things that glomerular filterability depends on
1. size
2. electrical charge
3. plasma protein binding
80
2 forces that oppose filtration
1. bowmans space hydrostatic pressure
| 2. blood plasma oncotic pressure
81
T/F
| hemaglobin is freely filterable
FALSE
82
GFR units
mL/min/Kg
83
4 properties indicator substances must have
1. must not alter renal funciton
2. must be freely filterable
3. must not be metabolized in the kidney
4. amount filtered must not be changed due to secretion or reabsorption
84
renal clearance
Volume of plasma from which a substance is completely removed by the kidney in a given amount of time.
85
vasodilatory agents
NO and PGE2
86
steps of myogenic reflex
1. Arteriolar wall tension increases
2. Smooth muscle cells depolarize and calcium enters into the cell
3. Contraction of smooth muscle occurs in the afferent arteriole
4. Results in decreased blood flow to nephron
87
steps of tubuloglomerular feedback
1. GFR and tubular fluid increase
2. Macula Densa suppresses renin release and afferent arteriole is constricted by mesangial cells
3. GFR decreases
88
result of the RAA system
Upregulation of Aldosterone secretion via Angiotensin II acting on the Adrenal Gland
89
functions of the Distal Tubule
Reabsorbs sodium, chloride, calcium, and magnesium. Regulates pH. Excretion of ammonia, water, and some electrolytes
90
functions of the Collecting Duct
Regulates ammonia, urea, and water excretion/reabsorbtion. Regulates pH
91
two cell types of the CD
1. principal
| 2. intercalated
92
cells of the CD that absorb NaCl through apical epithelial Na channels (ENaC)
Principal cells
**few mitochondria and small apical projections
93
cells of the CD that have many membrane folds (microplicae) on the apical surface and also many mitochondria
intercalated cells
**types A and B -- important for acid base homeostasis
94
T/F
| ENaC can be induced by aldosterone
TRUE
95
CD cells that control the net renal K+ excretion through ROMK
principal cells
**intracellular K+ leaves through the apical end (down the gradient)
96
intercalated cell type A and B transporters
secretes H+ and reabsorbs HCO3- on type A
type B is opposite functions and opposite side of the membrane
**acid base homeostasis
97
inhibits the apical NaPi transporters in the proximal tubule
parathyroid hormone (PTH)
98
functions of the hormone angiotensin II
increases Na+ reabsorption in the PT, TAL, and DCT
99
functions of the hormone aldosteron
increases Na+ reabsorption in the CD
**hyperkalemia also stimulates aldosterone release
100
hormone that stimulates NKCC in the TAL
ADH
101
increases Na+ excretion through inhibition of
| NHE3, Na,K ATPase, NKCC, and ENaC
NO
**regulation of systemic extracellular fluid and blood pressure
102
endothelin-1 hormone inhibitory effects
increases Na+ excretion through inhibition of
| NHE3, Na,K ATPase, NKCC, ENaC
103
Atrial Natriuretic Peptide (ANP) hormonal effects
inhibits aldosterone and renin release and increases Na+
| excretion
104
effects of hypercalcemia
triggers PTH to stimulate the apical uptake of Ca++ through channels in the TAL and DCT
105
Vitamin D effects?
PTH also stimulates Vit D synthesis in the kidney
Vitamine D hormone stimulates
calcium reabsorption from the
intestine and kidney stimulating
calcium channels
106
increase RBF =
increases GFR
107
increase systemic pressure =
increases GFR
108
increase afferent arteriole tone =
decreases GFR
109
increase efferent arteriole tone (slight) =
increases GFR
110
increase efferent arteriole tone (strong) =
decreases GFR
111
increase hydrostatic pressure =
decreases GFR
112
the main way some drugs and toxins are excreted from the body
active transport in the PT
113
if water is being removed from the fluid, but the NaCl stays, what is happening to the tubular fluid
concentrates
114
if NaCl is being reabsorbed but water cannot flow, what is happening to the tubular fluid?
it is being diluted
115
T/F
within the autoregulatory window, the GFR increases proportionally with the blood pressure
FALSE
116
what is the autoregulatory window?
80-180mmHg
117
where is aldosterone produced?
the cells of the adrenal cortex
118
What is PAH used to measure and why?
it measures RPF because it is filtered and additionally secreted
119
what is creatinine used to measure and why?
it measures GFR because it is only filtered and never secreted!
120
changes in arteriole resistance will alter the pressures where?
glomerular and peritubular capillaries
121
mechanism that prevents a flow rate that would exceed transport capacity
tubuloglomerular feedback
122
increase in aldosterone leads to what
increased renal reabsorption of Na+
**high angiotensin II in plasma leads to increase in aldosterone
123
T/F
| saturation of carriers leads to more reabsorption
FALSE
less reabsorption --> excreted in urine
124
Where does receptor-mediated endocytosis occur and what does it transport
proximal tubules ..low molecular weight proteins like insulin, PTH, and glucagon
125
Thiazide diuretics acts on NCC channels in which tubule
Distal tubules
126
What is the effect of ADH and which tubules does it act on?
increases water reabsorption in the Distal tubule and CD
127
How does ADH control the amount of water in the collecting ducts?
increases the amount of aquaporins in the CD
128
where is urea reabsorbed?
collecting duct
129
where is urea excreted?
thin descending limb
130
T/F
if organic ions are protein bound, they will be poorly filtered by the glomerulus
TRUE
131
are the ENaC located apically or basolaterally?
apically on principal cells for NaCl reabsorption
