Excretory System Flashcards
1
Q
What is osmoregulation?
A
Process of controlling solute concentrations and balancing water gain or loss
2
Q
How marine birds and fishes regulate water?
A
They conserve more body water and eliminating excess salts.
3
Q
How fresh water animals regulate water balance?
A
They conserve more solute and absorbing salts from surroundings
4
Q
Thermoregulation
A
Balancing heat loss and heat gain
5
Q
Osmoregulation
A
Balancing uptake and loss of water and solutes
also important to excrete nitrogenous waste(i.e. Ammonia,Urea)
6
Q
When osmosis takes place?
A
2 solutions of different solute concentrations are separated by a membrane
7
Q
What is osmolarity
A
unit for measurement of total solute concentration
8
Q
What is isosmotic solutions?
A
2 solutions with same osmolarity
There is no net movement of water
9
Q
Water enters and leaves cells by ______
A
Osmosis
10
Q
What is hypoosmotic solution?
A
More dilute solution
Solution with less solute concentration
Water will diffuse out of the solution
11
Q
What is hyperosmotic solution?
A
More concentrated solution
Solution with more solute concentration
Water will diffuse into the solution
12
Q
Osmoconformer
A
Animal that maintain isoosmotic with its surroundings.
internal osmolarity နဲ့ surrounding osmolarity နဲ့တူတူပဲ
13
Q
Osmoregulators
A
Animal that control internal osmolarity independent to that of the environment
Hypoosmotic environment မှာဆိုwater discharge လုပ်
Hyperosmotic environment မှာဆို water take in
14
Q
Which type have constant internal osmolarity?
Osmoconformer or Osmoregulator?
A
Osmoconformer
15
Q
_____ are osmoconformer.
A
Most marine animals
**Marine invertebrates **
16
Q
______ are osmoregulator.
A
Fresh water animals and land animals
17
Q
Stenohaline animals
A
most animals cannot tolerate substantial changes in external osmolarity
18
Q
Euryhaline animals
A
animals that can survive even large fluctuation in external osmolarity
19
Q
Osmoregulation in marine bony fishes
A
They constantly loss water by osmosis so they balance water loss by drinking sea water.
The excess salt in sea water is eliminated through gills and kidneys
20
Q
High concentrations of urea in blood can cause____
A
denaturation of proteins
21
Q
Sharks have higher concentrations of urea in their body but their protein are well-functioned.Why?
A
Sharks contains organic molecules called trimethylamine oxide(TMAO)that protect proteins from denaturing
TMAO also regulates osmoregulation (sharksမှာinternal solute concနည်းပေမဲ့TMAOပေါင်းနေလို့solute concများသလိုဖြစ်နေ——>water diffuse in)
22
Q
Most marine invertebrates are _____ but marine bony fishes and sharks a
has_____ than their environment
A
Osmoconformer (same osmolarity as environment)
less internal solute concentration (hypoosmotic)
23
Q
Do sharks drink sea water?
A
No
24
Q
The body fluids of fresh water animals is ____
A
hyperosmotic(more solute conc than environment)
so they have high osmolarity than environment
25
How fresh water animals regulate water balance?
They excrete large amount of very dilute urine(soluteနည်းနည်းပဲပါ) and drinking almost no water.
They also lost salts by diffusion and in urine but they replenished by eating
26
How land animals prevent dehydration?
body coverings of land animals can prevent dehydration and also reduce evaporative water loss
eg.keratinized skin cells covering most land vertebrates including humans
27
Most land animals lost water through_____ , _____ and _____
in urine and feces
across skin
from the surfaces of gas exchange
28
Most land animals replenish water by_____ and ____
drinking and eating
by producing water metabolically through cellular respiration
29
Most animals relies on _____ for osmoregulation and metabolic waste disposal
transport epithelia
Arranged into tubular networks with large surface area
30
Most significant waste products are ______ which are products of breakdown of _____ and _____
Nitrogenous waste(ammionia,urea and uric acid)
proteins and nuclei acids
31
Metabolic waste are insoluble.True or false?
False
The wastes must be dissolved in water in order to excreted from body
32
Why ammonia is very toxic?
Its ion,ammonium(NH4+) can interfere with oxidative phosphorylation
33
Why there are different forms of nitrogenous waste?
b/c of their toxicity and the energy cost to producing them differ
34
Ammonia excretion is most common in _____
aquatic species b/c they have large access of water
ammonia is highly soluble and forms its ions and easily pass through membrane and lost by diffusion into surrounding water
35
Is ammonia excretion suitable for land animals?
No
It cannot safely transported in less volume of water in surrounding
36
What nitrogenous base is excreted by most land animals and marine species?
Urea b/c they do not have sufficient access to excrete ammonia
37
In vertebrates,urea is the product of____
energy-consuming metabolic cycle that binds ammonia with CO2 in liver
ammonia to ureaပြောင်းဖို့energyအများကြီးလို
38
What is main advantage and disadvantage of urea excretion?
Main adv-urea has very low toxicity
Main disadv-animals must expand more energy to produce urea from ammonia
39
Uric acid is primary nitrogenous waste of_____
insects,land snails and reptiles including birds
40
Why birds excrete as semisolid paste?
Because uric acid is nontoxic but is insoluble in water so they excrete with water as semisolid paste
41
Do ATO require to convert ammonia to uric acid?
Yes
uric acid is more energetically expensive than urea,more ATP needed
42
Kidney functions in both _____ and______ in vertebrates.
osmoregulation
excretion
43
Tubules of kidney are _____ and are ______ with a network of capillaries
highly organized
closely associated
44
Vertebrate kidney is segmented or nonsegmented ?
nonsegmented
in some species,it is segmented
45
Parts of urinary system
Kideny—->ureter——>urinary bladder——>urethra
Kidney-urine production
Ureter-transport urine
Bladder-store urine
Urethra-Expels urine
46
Parts of the kindey
Outer renal cortex
Inner renal medulla
Both regions are supplied with blood by renal artery and drained by renal vein
47
How many blood is reach to kidney?
About 20% of cardiac output
if cardiac output is 5L/min only 1L is transported
48
How many blood is filtrated in kidney?
If 1L(1000ml) of blood reaches the kidney,it contains 400 ml of proteins and cells + 600 ml of plasma
Only 20% of this 600ml is filtered in kidney
so only 120ml/min is filtrated
49
Is all filter excreted?
No, nearly 99% of filtrate is reabsorbed by kidney and only 1% is excreted
50
What is the functional unit of kidney?
Nephron
51
Types of nephron
1)Cortical nephrons(85%) that reach short distance into medulla.
2)Juxtamedullary nephrons (15%) that reach deep into medulla.
Juxtamedullary nephrons are essential for water conservation in mammals
52
Parts of nephron
Afferent arterioles form ball of capillaries form GLOMERULUS which is surrounded by BOWMAN’S CAPSULE.(within cortex)
PROXIMAL CONVOLUTED TUBULES(within cortex)
LOOP OF HENLE-Descending loop and ascending loop(within medulla)
DISTAL CONVOLUTED TUBULES(within medulla)
COLLECTING DUCT
53
Site of filtration
Glomerulus and Bowman’s capsule
54
Forces that driven filtration
1)Hydrostatic pressure caused by blood pressure
2)Oncotic pressure is a osmotic pressure exerted on fluid in the presence of proteins in blood or tissue
55
Filtrate produced in capsules contains______
Water
Salts
HCO3-
H+
Urea
Glucose,amino acids
Some drugs and toxins
56
Reabsorption in proximal tubules
Proximal tubule reabsorb ions,water and nutrients.
1)NaCl is reabsorbed together by water via passive or active transport
2)Glucose,K+,amino acids also reabsorbed
3)90% of Bicarbonate is reabsorbed
4)H+ and NH3+ is secreted to maintain constant pH
5)some drugs and toxins are excreted
57
Reabsorption in Descending loop
WATER is mainly absorbed because
1)the medulla region is increasingly salty than cortex region that can cause osmosis
2)presence of numerous aquaporin channels
58
Ascend loop lacks____
Aquaporin channels
59
Reabsorption in ascending loop
1)Thin segment-reabsorption of NaCl(waterပါ)
2)Thick segment-active transport of NaCl(waterမပါ)
60
Reabsorption in distal tubules and collecting ducts is depend on _____
ADH hormones
61
Reabsorption in Distal tubule
1)NaCl is reabsorbed
2)K+ is secreted
Distal tubule also regulates pH by control secretion of H+ and reabsorption of HCO3-
62
Reabsorption in collecting duct
Mainly NaCl but its reabsorption is depending on hormone
and some urea is reabsorbed
63
Osmolarity of blood is
300mOsm/L
64
Tha maximum concentrated urine in human kidney is
1200mOsm/L-the osmolarity of inner medulla
65
Production of hyperosmotic urine occur in ____
thick segment of ascending loop of Henle
66
Production of concentrated urine based on_____ and requires____
active transport of solute
ATP/energy
67
Primary solutes that affects the osmolarity are_____ and _____
NaCl and urea
68
Filtrate from Bowman’s capsule and proximal tubule has _____ osmolarity as blood.
same
69
Osmolarity in descending loop of Henle
water leaves by osmosis(aquaporin) so more NaCl is concentrated in filtrate and INCREASES OSMOLARITY
70
Countercurrent exchange system of loop of Henle based on ______ and requires ____
Active transport
Energy
71
Countercurrent system that requires energy to create concentration gradient is called
countercurrent multiplier systems
72
Osmolarity in cortex and medulla
Medulla has higher osmolarity than cortex
(Active transport of NaCl and Diffusion of urea from collecting duct)
အောက်ရောက်လေOsmolarity များလေ
73
Osmolarity in collecting duct
The filtrate that pass the ascending loop have higher solute concentration than intestial fluid(hypoosmotic).
Collating duct is permeable to water and not to solute so more water will diffuse into the intestial fluid making filtrate hyperosmotic urine(more concentrated)
74
Kidney is one of the ______ metabolic rate of any organ
highest
75
Kidney concentrates urine maximally,the urine reaches
1200mOsm/L-the osmolarity of inner medulla
urine is isoosmotic to inner medulla but
hyperosmotic to blood and other intestial fluid
76
What will happen to urine concentration if our diet contains more salt intake and less water intake?
Hyperosmotic urine will produce
(urine with more urea and salts with minimal water loss)
77
What will happen to urine concentration if our diet contains less salt intake and more water intake?
Hypoosmotic urine
(Urinw with excess water and little salt)
78
Key hormone of kidney is____
antidiuretic hormone or vasopressin
79
ADH hormones released from_____
Posterior pituitary gland
80
Action of Vasopressin
When ADH binds to membrane receptors of the collecting ducts, the receptors initiate a signal transduction cascade that directs insertion of aquaporin proteins on the membrane of collecting ducts.
More aquaporin channels —->more water reabsorption
81
ADH responds to_____
1)Increased blood osmolarity ***
2)excessive dehydration
3)less water intake
82
How ADH responds if blood osmolarity rises above set point?
When blood osmolarity rises above,the osmoreceptor in hypothalamus triggers increased release of ADH from posterior pituitary leading to more water reabsorption.
83
How ADH responds if blood osmolarity falls below set point?
When blood osmolarity fall below ,the osmoreceptor in hypothalamus triggers decreased release of ADH from posterior pituitary leading to less water reabsorption.
84
ADH action is controlled by ____
Negative feedback loop
When blood osmolarity reaches to set point,hypothalamus reduces ADH release
85
____,_____ and_____ are linked in feedback circuit.
Blood osmolarity,ADH release and water reabsorption
Eg.Alcohol inhibits ADH release, leading to excessive water excretion
86
Excessive loss of both salt and body fluids lead to _______
reduce blood volume without increasing osmolarity
***ADH is not responding in such situations *****
87
How body responds when blood volume of pressure is dropped?
Responds by endocrine circuit called RENIN-ANGIOTENSIN ALDOSTERONE SYSTEM
88
Function of RAAS
To increase both Na+ and water reabsorption
89
RAAS involves_____
juxtaglomerular apparatus
,a specialized tissue around afferent arterioles
Afferent arterioles-supplies blood to glomerulus
90
How RAAS works?
1)When blood vol or pressure drops in afferent arterioles,JGA releases enzyme renin.
2)Renin cleaves plasmas protein called angiotensin into peptide angiotensin II.
3)Angiotensin II cause vasoconstriction, so increasing blood pressure and decreasing blood flow to kidney.
4)Angiotensin II stimulates aldosterone which causes distal tubules and collecting duct to more Na+ and water —->increasing blood vol and pressure
91
RAAS is also controlled by _____
Negative feedback
When blood vol and pressure reaches the normal point,JGA reduces release of renin enzyme.
92
Drugs that block angiotensin II is widely used to treat _____
Hypertension
These drugs are specific inhibitors of angiotensin converting enzyme (ACE).
93
Both ADH and RAAS increase____
water reabsorption
but ADH alone can cause lower Na+ reabsorption and RAAS maintain blood osmolarity by increasing Na+ reabsorption
94
Hormone that oppose RAAS is ____
atrial natriuretic peptide(ANP)
95
ANP is released from___
walls of atria of the heart
96
ANO responds to_____
increased blood vol and pressure
97
Action of ANP
1)inhibits release of renin from JGA
2)inhibits Na+ reabsorption in collecting ducts
3)inhibits aldosterone release from adrenal glands
All of these actions lead to lower blood vol and pressure
98
Mammals excrete_____
most hyperosmotic urine
99
Mammals have many____
Juxtamedullary nephrons with loops of Hanle deep into medulla
100
Aquatic mammals have mostly____
cortical nephrons
so they have lower ability to concentrate urine
101
Land animals living in moist condition have _____
nephrons that contains loop of Henle with intermediate length
So their ability to concentrate urine is intermediate
102
Main water conservation in animals is presence of
juxtamedullary nephrons
103
Kidneys of birds contains juxtamedullary nephrons but they can’t concentrate urine into high osmolarity.Why?
loop of Henle is less deep into medulla
104
Birds can produces _____
hyperosmotic urine
Uric acidကိုexcreteလုပ်တော့water conserveပိုလုပ်နိုင်
105
Kidney of reptile contains only_____
cortical nephrons
So their urine is isoosmotic or hypoosmotic to body fluids
106
Fresh water fishes produce urine with____
large vol of very dilute urine(less salt)
their kidney contains cortical nephrons(salt reabsorption သိပ်မလုပ်နိုင်)
So salt conservation relies on reabsorption of ions from distal tubules
107
Amphibian excrete____
dilute urine as fresh water fishes
and their salt conservation relies on skin (accumulates salts from water of surrounding)
108
Marine fishes have ____ and _____ nephrons and also lack_____.
And their kidney have_____ or no at all.
fewer-smaller-distal tubule
glomeruli
109
Main function of kidney in marine fishes
to eliminate divalent ions(Mg2+,O2-)
110
Water moves from the ——— to ———
Hypoosmotic to hyperosmotic
111
Osmolarity is the number of solutes per———
Liter of the solution
112
Osmoconformer means ———
To be isoosmotic with the surroundings
113
Osmosis is the diffusion of water across a membrane in response to ——— caused by the imbalance of molecules on either side of the membrane
Osmotic pressure
114
What is osmotic pressure
Pure water- has the osmotic pressure of 0
If some solutes is added to it, the osmotic pressure becomes negative (lower)
If more solutes are added to it, the osmotic pressure becomes even more negative
Therefore, water, high osmotic pressure to low osmotic pressure, low osmolarity to high osmolarity
The pressure that must be applied to stop the flow of water down its concentration gradient is called the osmotic pressure
115
The concentration of electrolytes is measured by ———-
Milliequivalence
Millimoles of the ion concentration / divided by the number of charg on the ion
116
Setnohaline and euryhaline
Stenohaline- cannot tolerate changes in external osmolarity Euryhaline- can survive large fluctuations in external osmolarity
117
Osmoregulation is frequently coupled to the elimination of__________
Urea. Bcuz high concentration of urea can denature proteins thus disrupt cellular functions
118
Why isn’t high concentration in shark bodies harmful?
Bcuz they contain TMAO , trimethylamine oxide, produced by shark tissues, the TMAO protects proteins from denaturing effect of urea
119
TMAO in shark also function as ————
Osmoregulation.
Shark’s internal salt concentration is lower than that of its environment, therefore in hyperosmotic solution, salt enters the body through the gills. TMAO together with the salt, urea and other compounds result in a solute concentration in shark tissues somewhat higher than 1000 milliosmo. Therefore, the water enters the body. The small influx of water into shark’s body is disposed in the urine, the urine also removes some of the salt that diffuses into the water
120
Salmons migrate between between fresh water and seawater. How do they osmoregulate in each environment ?
In fresh water——-> water= hypoosomotic ——> salmon produces dilute urine , and replenish the salt loss through their gills.
In marine water——> water= hyperosmotic——> secrete through concentrated urine with little water, and excrete excess salt from their gills
121
Some organisms can lose all the water from the body and still survive. T or F
T. With an adaptation called anhydrobiosis. These organisms even survive when they dehydrate to less than 2 percent.
How? By containing a lot of sugar, in particular, trehalose, a disaccharide protect the cell by replacing water.
In freezing temp——> trehalose protect the membrane as well
122
Water can be lost from the ————————-
Urine, feces, surface of the skin through sweating as well as surfaces of the gas exchange organs
123
Maintaining osmolarity difference between an animal body and its surroundings require ————
Energy .
Maintaining osmotic gradient for water to move in and out, the active transport must be used to manipulate solute concentration
124
Fresh water fishes have ———— than marine fishes
Lower solute concentration
125
Nitrogenous waste can be excreted as ——,——,——
Nitrogenous waste comes from proteins and nucleic acid breakdown or converted to carbohydrates. The enz removes nitrogen and converted to nitrogenous waste
Ammonia, urea ,uric acid
Their toxicity and energy cost of producing them are differently
126
Ammonia excretion
Ammonia excretion requires access to lots of water ———> bcuz ammonia is toxic and can only tolerate at low conc ——-> therefore seen in aquatic animals
Interconversion between ammonia and ammonium ions ——> can be lost by diffusion readily to the surrounding water
127
Urea excretion
Energy consuming metabolic cycle——> ammonia+ CO2 in liver——> urea
Found in animals with no access to sufficient water to routinely excrete ammonia
Urea advantage= low toxicity Disadvantage= energy consuming
Animals that spend part of their lives on land and water===> switch urea and ammonia excretion for energy saving
In lands- urea
In marine- ammonia
128
Uric acid
Uric acid- non- soluble in water / non-toxic / energetically more expensive than urea / have to be excreted in semi-solid paste with very little water loss
Birds dropping/ feces- uric acid+ brown feces
Human and mammals not primarily uric acid producers, but a small accumulation of uric acid from metabolism ——> sometimes disease
In dogs- uric acid stones in gall bladders In human- uric acid crystals d
129
The type of the nitrogenous waste a species produce depends on ————,———,———
Environment
Embryo- absence or presence of shell around the egg
Absence of shell- ammonia or urea can easily diffuse out of the egg, she soluble waste produced by embryos can be carried away to mother.
With shell- urea or ammonia can be dangerous if accumulated in egg, therefore- Nitrogenous waste are unharmful uric acid, which can be left behind when the egg hatches
Diet- predators which derive much of the energy from protein——> more nitrogen , excrete more nitrogenous waste
130
Where is renal corpuscle located?
In the renal cortex. Contains glomerulus and bowman’s capsule
131
Where are proximal/ distal convulated tubules and loop of henle
The first part emerging from glomerulus is called proximal convoluted tubule, and it is located in the renal cortex/
Loop of henle is located in the renal medulla
Distal convoluted tubule is also located in the renal cortex
132
Function of descending loop of henle
Water reabsorption, along the tubule ——> numerous water Channels aquaporins present+ , only allow water, low permeability to solutes
133
Func of the ascending loop of Henle
Present thick and thin segment
Aquaporins absent unlike descending loop, transport epithelia facing the filtrate is insoluble to water
Thin segment——> diffuses NaCl out of the tubule
Thick segment———> continue diffusing NaCL into the ECF
Interstitial fluid ——> increased NaCl, maintain the osmolarity of ECF
134
Func of collecting duct
Presence of aquaporins channels, when the kidney want to preserve water, water diffuses out of the aquaporin channels into the ECF/ salt are left behind .
Transport epithelium is impermeable to the water and urea, urea also diffuses out of the tubule . Filtrate increasingly concentrated ====> result is hyperosmotic to the general body fluids
If kidney needs dilute urea——> aquaporin channels are blocked,
water cannot move out of the duct, NaCl are actively transported out
of the epithelium into the ECF
135
The ——— channels in ——- is controlled by ———
Aquaporins channels in the collecting ducts Hormones
136
Osmolarity of blood is ——- milliosmo/L
300
137
Kidneys can excrete urine more than the blood osmolarity t or f
True, blood osmolarity- 300 milliosmo/l
Urine osmolarity- can be up to 1200 milliosmo and more
138
Glomerular filtration filters
Almost all the solute, except for the proteins are filtered out into the glomerulus by a process known as glomerular filtration
139
Glomerular filtration requires ———
No energy
140
Glomerulus filter filtrate by ——-
Blood pressure and specialized membranes of the
afferent arterioles
141
The glomerulus blood pressure is dependent on the systemic blood pressure
False, independent
142
What kind of products are excreted through the tubular secretion and where does it occur?
Undesirable waste products such as urea, uric acid, certain drugs
Most of them occur in the distal convulated tubule, some occur in the early part of the collecting duct , also in the proximal convulaed
143
——- and ——- contribute the osmolarity of ECF
NaCl and urea
144
Hyperosmotic urine is possible to be excreted by the kidney due to the ———
Energy expenditure of reabsorption of NaCl into the ECF , can maintain the osmotic gradient to extract water from the filtrate
145
Why doesnt vasa recta dissipate the concentration gradient and aftect osmolarity
Down the loop of henle and uphill , the flow of blood are in different direction, with the different substances coming in and out in opposite directions.
Thus, the vasa recta can supply the kidney with nutrients and other important substances carried by the blood without interfering with the osmolarity gradient in the inner and outer medulla.
146
How is osmotic gradient maintained throughout the life in the kidney for excretion?
The gradient will be gone without the energy expenditure to maintain the gradient.
The energy is mainly spent in the thick segments of the ascending loop where the NaCl are actively reabsorbed into the ECF and peritubular capillaries .
Do not need to spend energy at the thin segments bcuz NaCl diffuses out of the tubule at the thin segment
147
Some urea leak out of ———the ——— and contribute to the ——- of the ——-
Collecting duct/ constant leakage supplies high osmotic pressure to the ECF
148
When the kidney fully concentrates urine, urine is isoosmotic to ———- and hyperosmotic to ——-
Isoosmotic to the ECF of the medulla but hyperosmotic to the blood and interstitial fluid throughout the body, this allows solutes to be remained in the urine with the minimal water loss
149
——— and ——— system regulate the osmoregulation function of the kidneys
Hormones and nervous system
150
In addition to the hormonal release from the posterior pituitary ADH production, what does the hypothalamus do?
Increases thirst——> water intake——> decreases osmolarity of the blood
151
What happens when you drink a lot of water and blood osmolarity is low?
Collecting ducts less permeable to water, and reduces the water reabsorption ——-> dilute urine large amount
152
Why does alcohol makes urinate a lot ?
Alcohol inhibits ADH release, and hence causing dehydration and water loss
153
What happens when there is the mutation in the ADH production or inactivate the ADH receptor ?
No ADH production ——> large secretion of diluted urine——> dehydration
Called diabete insipidus
154
When there is diarrhea or a major wound what happens?
Diarrhea or major wound——> loss of both fluids and solute ——> no osmolarity change ——> no ADH——> so kidney performs sodium and water reabsorption by RAA ( renin- angiotensin- aldosterone system )
RAA system contains the juxtaglomerular apparatus, when the blood pressure or blood volume of the afferent arterioles drop , which supply blood to the glomerulus drops ——> justaglomerular apparatus releases renin ——> angiotensionogen ——> angiotensin 1 ——> angiotensin 2 ——> constrict of the blood vessels to the kidney and increasing the blood pressure ——> Also stimulate the adrenal glands to secrete aldosterone ———> acts on the distal and collecting tubules to reabsorb the sodium and water——> increasing blood volume and pressure
155
——— inhibits RAAS system
ANP acts as vasodilator
ANP ( atrial natriuretic peptide ) is secreted from the blood in high pressure and high blood volume
ANP inhibits renin secretion by juztaglomerular system
ANP reduces the aldosterone production by the adrenal glands ANP reduces the reabsorption of sodium and water by the collecting duct
156
What is transport epithelia
Transport epithelia contain specialized epithelial cells that control the solute movements required for waste disposal and osmoregulation.
157
Aldosterone is the hormones from ——— and apart from sodium and water reabsoprtion, it also———
Adrenal cortex
Secretes potassium out of the body, if the daily potassium is not secreted, retention of K+ can cause a dangerous increase in plasma K+ concentration
Addison’s disease- failing adrenal cortex—-> no aldosterone——> no potassium secretion, no sodium reabsorption——> sodium in urine—— > consequences fatal
