Renal Flashcards
1
Q
why do we need the kidneys
A
to control what is in the blood and how much blood we have
2
Q
what is the main function of kidneys
A
filter blood
3
Q
what do our kidneys regulate
A
blood osmolarity, volume and pressure, red blood cell production, pH
4
Q
what waste do the kidneys eliminate
A
nitrogen (from breaking down amino acids) and drugs/toxins
5
Q
the __ kidney is slightly higher than the other
A
left
6
Q
what do juxtamedullary nephrons do
A
concentrate and dilute urine
7
Q
what do cortical nephrons do
A
regulatory functions
8
Q
is the afferent arteriole the higher or lower arteriole on the glomerulus
A
lower
9
Q
each kidney contains how many nephrons
A
1 million
10
Q
the renal tubules are lined with
A
epithelial cells
11
Q
where is the apical side of the cell
A
facing into the lumen (inside)
12
Q
where is the basolateral side of the cell
A
faces the interstitial fluid (outside)
13
Q
what are epithelial cells in the nephron joined by
A
tight junctions
14
Q
what is the path of reabsorption
A
lumen, apical side, through/between cells, basolateral side, interstitial space, bloodstream
15
Q
what are the capillaries surrounding the nephrons called
A
peritubular capillaries
16
Q
what is the transcellular pathway, what does it require
A
through the cells, requires permeability (transport proteins etc), driving force (gradient or energy), can be automatic or controlled by hormones
17
Q
what is the paracellular pathway and what does it require
A
between cells, transport proteins not required, permeability depends on tightness of junction
18
Q
diffusion/osmosis travels in which pathways
A
through the membrane or tight junction driven by a gradient
19
Q
how is facilitated diffusion possible
A
through a channel or transporter
20
Q
primary active transport uses
A
ATP for energy
21
Q
secondary active transport uses
A
the movement of one substance down its gradient to drive the movement of another substance against its concentration gradient (these may be moving in the same direction but gradients are opposite)
22
Q
what is an electrical gradient
A
positive attracted to negative and vice versa
23
Q
water moves to where there is more
A
solute
24
Q
which molecules need a channel or transporter
A
larger and not lipid soluble or have a charge
25
which molecules are able to pass through or between cells on their own
very small or lipid soluble
26
when there is leaky tight junctions, which pathway can water move through
both trans and para cellular
27
when there are tight tight junctions, which pathway can water move through
has to go through the transcellular pathways using aquaporins
28
what are aquaporins
channels in the transcellular pathways for water to move through
29
what do the adding or removing of aquaporins result in
more reabsorption or more excretion of water
30
reabsorption uses which forms of transport
all of them
31
pressure is __ in the capillary than in the capsular space so things move __ of the capillary __ the capsular space
higher, out, into
32
why do things move out of the capillary into the capsular space
pressure gradient, higher in the capillary, lower in the capsular space
33
what molecules from the blood become filtrate
water, ions, glucose, amino acids, hormones
34
what molecules are too big to become filtrate
red and white blood cells, plasma proteins
35
how much blood do the kidneys filter per min
125mL
36
how much blood do the kidneys filter per day
180L
37
how many times is your entire blood supply filtered per day
36
38
how much urine do we produce a day
1.5L (500mL-20L min and max)
39
why is our blood filtered so any times per day
if something in the body changes they can change the way it is filtered accordingly
40
the absorption of 90% water, 90% Na+ and 100% nutrients (glucose, amino acids) by the proximal tubule is an __ process
automatic (obligatory reabsorption), they absorb this regardless
41
which type of epithelia are in the proximal tubule
leaky
42
what type of pathways are used in the proximal tubule
both trans and para cellular
43
describe the Na+ and K+ concentrations in and out of cells
low Na+ inside cell and high outside, high K+ inside cell and low outside
44
glucose and amino acids are reabsorbed through the apical membrane using __ driven by __
sodium coupled secondary active transport driven by the sodium electrochemical gradient created by the Na+/K+ ATPase pump
45
glucose and amino acids are reabsorbed through the basolateral membrane using __ driven by __
facilitated diffusion driven by concentration gradients created by the secondary active transport of glucose and AA's through the apical membrane
46
reabsorption of glucose and AA's causes __ reabsorption as well
sodium, this is a big contributor to the 90% of sodium reabsorption that has to happen
47
once sodium is reabsorbed _ follows
water by osmosis
48
where sodium goes __ follows via the paracellular pathway, down its electrical gradient (all of the positive ions that have just be reabsorbed are going to attract the negative ion chloride into the bloodstream)
chloride, helped by leaky junctions (paracellular)
49
the distal tube regulates blood volume, osmolarity and pH by determining how much ______ is reabsorbed
water, Na+, H+/HCO3-
50
the distal tubule is regulate by
hormones
51
what type of epithelia lines the distal tubule
tight epithelia
52
what pathway is the only one used in the distal tubule
transcellular
53
what do tight tight junctions let through
nothing
54
what do leaky tight junctions let through
some things
55
how do hormones regulate reabsorption of water and sodium
if need more/less of something they add/take away channels/transporters fro sodium and water
56
which tubule is under hormonal control
distal
57
what hormone regulates water reabsorption
ADH
58
what hormone regulates sodium reabsorption
aldosterone
59
is ADH a fast or slow response
fast
60
what type of hormone is ADH and where is it released from
peptide hormone, from the posterior pituitary
61
what type of hormone is aldosterone and where is it released from
steroid hormone, from adrenal cortex
62
is aldosterone a fast or slow response
slow, long term response
63
ADH needs which driving force
osmotic gradient
64
water can only use the
transcellular pathway
65
water needs __ to enter and exit the nephron cells
aqauporins
66
water cannot use the
paracellular pathway
67
what is the osmolarity of the blood, ICF, ECF and renal cortex
300mosmol/L
68
is the osmolarity in the Rena medulla higher or lower than the cortex
much higher
69
the gradient of osmolarity from the renal cortex to medulla is the driving force for
water to be reabsorbed in the distal tubule
70
what is an increase/decrease in ECG osmolarity detected by
osmoreceptors in the hypothalamus
71
an increase in ECF osomolarity leads to more or less ADH being released
more
72
increase in ADH results in increase of
aquaporins in the apical membrane of distal tubule cells
73
ADH and aldosterone acts on the __ tubule
distal
74
what is the driving force for sodium reabsorption
electrochemical gradient
75
sodium cannot use the _ pathway
paracellular, they must use the transcellular pathway just like water
76
what does sodium need to enter the cells
sodium channels
77
how does sodium leave the cells
pumped out by Na+/K+ ATPase pump
78
what is ADH stimulated by
change in osmolarity
79
what is aldosterone stimulated by
loss of water and ions - isosmotic fluid loss e.g. blood loss, vomiting or diarrhoea (this is not a change in osmolarity as both water and ions have been lost) there is no gradient for water to move in or out of cells due to this, only a change in ECF and therefore blood volume and pressure
80
what is a decrease in blood volume detected by
pressure receptors in the kidney
81
what is the response to a decrease in blood pressure (due to a loss of isosmotic fluid) detected by pressure receptors in the kidney
increased released of aldosterone from the adrenal cortex and increased release of ADH from the posterior pituitary
82
why are both aldosterone and ADH released after a drop in blood pressure
blood pressure drops due to a loss of both water and ions (isosmotic fluid) in the ECF so need to stimulate the increased reabsorption of both
83
aldosterone levels cause the addition/reduction of
sodium channels
84
does ADH affect driving force for water reabsorption in the kidney
no the driving force is the osmolarity gradient, ADH increases permeability
85
when the body loses water does ECF or ICF volume change
both change
86
when the body loses water and ions does ECF or ICF volume change
just ECF
87
why is ADH fast and aldosterone is slow
blood osmolarity is an emergency, blood volume is less urgent
88
sweat is hypo osmotic, this means it is __ salty than plasma
less
89
what is hyponatremia
sodium deficiency, over hydration
90
ADH is released at anticipation of water loss during exercise, this process is called
feedforward
91
if the feedforward of the body releasing ADH during exercise is combined with the athlete drinking a lot of water this will lead to
the body keeping too much water, over hydration (hyponatremia), body can't release the extra water as ADH has been released to conserve this
92
which is more dangerous, dehydration or overhydration
overhydration
93
why is blood volume less urgent for the body
because there is another system that can rapidly adapt to changes in volume and pressure (CVS), when we lose isosmotic fluid there is no change in cell volume only a change in blood (ECF) volume
94
what is the fast and slow response to replacing isosmotic fluid loss
fast - CVS, slow - kidneys (increase sodium and water reabsorption to replace blood volume), this is longer term
95
what is the neutral pH range of the ECF
7.35-7.45
96
what is too much acid called
acidosis
97
what is too much base called
alkalosis
98
plasma below 6.8 or above 7.7 is usually
lethal
99
acid is a H+
donor, releases H+, lowering pH
100
base is a H+
aceptor, binds to and removes H+, increasing pH
101
the body produces how much acid per day
1300mmol
102
to keep pH normal we have to
buffer the acid, remove excess acid
103
what processes are pH sensitive
enzyme activity, ion transport mechanisms, cell metabolism, DNA synthesis and growth
104
the acidity of the body is increased by
gaining H+ or losing HCO3-
105
how is H+ gained
from CO2 production by metabolism, protein breakdown (amino acids), lactic acid, ketones
106
how is HCO3- lost
diarrhoea (GI fluid)
107
the acidity of the body is decreased by
loss of H+ by vomit (acid from the stomach) or medications that cause H+ loss, hyperventilation (decreased CO2)
108
which three systems work together to control the pH of the body
buffering systems (fast response), respiratory system (fast response), urinary system (long term)
109
what is a buffer
a substance that minimises changes in pH, when H+ concentration is altered
110
when the H+ concentration increases, buffers __ the excess H+ molecules to__ the amount of acid (__ the pH)
bind, decrease, increase
111
when the H+ concentration decreases, buffers __ H+ molecules to__ the amount of acid (__ the pH)
release, increase, decrease
112
when there is too much H+, it is converted to __ until equilibrium is reestablished
water, through carbonic acid resulting in CO2 and H2O it is then diffused out of the blood into the lungs and is breathed out (blown off)
113
the partial pressure of CO2 in the blood affects the
pH of tissues, when CO2 increases it increases H+ and when CO2 decreases, it decreases H+
114
when body pH is normal (7.35-7.45) how much bicarbonate is reabsorbed back into the blood
all of it
115
how much acid do the kidneys secrete per day
4-5000mmol
116
what is the kidneys response to metabolic acidosis
increasing excretion of acid
117
what is a metabolic source of acid
breaking down proteins
118
is increasing HCO3- absorption in the GI tract related to buffering
no
119
what is metabolic acidosis due to
increased acid production from metabolism (increased ATP production leading to increased CO2 and H+ production) or loss of HCO3-
120
why do the kidneys kick in to help the respiratory system get rid of acidosis
the lungs don't want to be continuously increased breathing to get rid of it (this is ok for short term e.g. running for bus)
121
how is H+ excreted into the urine and HCO3- reabsorbed to counteract acidosis
combine to make carbonic acid and then H2O and CO2 which can get into cells, then once in the cells, reassemble to H+ and HCO3-, HCO3- is reabsorbed into the blood, H+ is excreted back into the urine to increase pH to normal range
122
what is metabolic alkalosis caused by
loss of H+ or increased HCO3- production due to vomiting or medication
123
what does the pH need to be less than to be acidosis
7.35
124
what does the pH need to be more than to be alkalosis
7.45
125
how does CO2 cause a increase in H+
CO2 and water is combined to make carbonic acid which is broken down to make H+ and HCO3-
126
how does breathing increase H+
decrease ventilation to increase CO2 and H+ back to within the normal range
127
how is HCO3- excreted in the urine and H+ reabsorbed to counteract alkalosis
the same way as the reverse, they are combined in to carbonic acid and then broken into CO2 and H2O to go into renal tubule cells, then reassembled to carbonic acid and broken into H+ and HCO3-, H+ is reabsorbed and HCO3- is excreted in urine to decreased pH to normal range
128
simple terms how to counteract acidosis
secrete H+ in urine, generate/reabsorb HCO3-
129
simple terms how to counteract alkalosis
secrete HCO3- in urine, generate/reabsorb H+
