Ion And Water Balance Flashcards
1
Q
What is osmotic regulation
A
Control of tissue osmotic pressure
The driving force of water across the cell membrane
2
Q
What is ionic regulation
A
Control of ion concentrations
Control of ion balance in ECF and ICF
3
Q
What is nitrogen excretion
A
Excretion of ammonia which is toxic
Can be excreted as ammonia, urea, or uric acid
4
Q
What are ionoconformers
A
Whatever the ion concentration of the environment is, the ion concentration of that organism matches
5
Q
What are osmoconformers
A
Whatever the osmolarity of the environment is, the osmolarity of the organism will match
6
Q
What are characteristics of ammonia
A
High solubility in water
Increased tonicity with increased concentration
Aquatic organisms
7
Q
What are characteristics of urea
A
Less toxic
Good solubility in water
Terrestrial animals
8
Q
What are characteristics of uric acid
A
No soluble in water
Non toxic
Good at excreting nitrogenous waste without wasting water
Reptiles
More energetically expensive
9
Q
What are osmoregulators
A
Maintain osmolarity that is different than the surrounding environment
10
Q
What are ion regulators
A
Maintain ion concentration that is different from surrounding environments
11
Q
What is the barrier between the animal and environment
A
Epithelial tissue
12
Q
What is the difference between paracellular and transcellular transport
A
Paracellular is the transport between epithelial cells
Transcellular is transport through the epithelial
13
Q
What regulates ion and water balance in vertebrates
A
Kidneys
14
Q
What are extrarenal structures
A
Structures that assist the kidney in ion and water balance
15
Q
What regulates movement of water across the membrane
A
Ionic concentrations and osmotic pressure
16
Q
What is a conformer
A
Internal conditions are similar to external conditions
17
Q
What are regulators
A
They maintain a constant internal state
18
Q
What is stenohaline
A
Ability to tolerate narrow range of salt concentrations
19
Q
What is euryhaline
A
Ability to tolerate wide range of salt concentrations
20
Q
What is dietary water
A
Water obtained from plant and animal tissues
Not all water can be obtained because feces need a certain consistency to move through GI tract
21
Q
What is metabolic water
A
Water generated as a bi product of oxidative phosphorylation
22
Q
What are pertruding solutes
A
Disrupt macromolecule function at normal concentrations
Concentrations are different in the ECF vs ICF
23
Q
What are compatible solutes
A
Little affect on macromolecule function and can accumulate in high levels
24
Q
What are counteracting solutes
A
Antagonistic relationship between two solutes
25
What type of regulators are bony fish
Ionoregulators and osmoregulators
26
What happens to water and concentration in saltwater vs freshwater bony fish
In saltwater they gain water and lose ions, they drink to account for water loss and pump ions through gills
Freshwater they gain ions and lose water, get rid of excess water via the kidneys and uptake ions in the gills
Water and ions transferred between fish and environment through gills, gut, and skin
27
What is diadromous
Part of life in freshwater and part of life in seawater
28
What is anadromous
Adult life in seawater and migrate to freshwater for reproduction
29
What is catadromous
Adult life in freshwater and migrate to saltwater for reproduction
30
What are some terrestrial characteristics in regards to ion and water balance
They need to limit the amount of water loss
Can’t exchange ions with environment and can’t excrete metabolic waste into water
Integument prevents water loss and there are different ways to excrete ammonia
31
What hydrophobic molecule covers the surface of the integument
Mucus which traps water between the mucus and integument
32
What are keratinocytes
Secrete keratin to form dense hydrophobic ECM
Made up of Stratum corneum and cornification
33
What does the glycolipid layer of the integument do
Covers the stratum corneum and is most prominent in birds and mammals
34
How can desert animals conserve water
They can consume it in excess
They have a thicker stratum corneum
35
How can respiratory water loss be reduced
Through countercurrent heat exchange through enlarged nose
36
What is ammoniotelism
Excretion of ammonia as ammonia
Usually done in amphibians and fish
37
What is ureotelism
Excretion of ammonia as urea
Usually in mammals
38
What is uricotelism
Excretion of ammonia as uric acid
Usually in birds and reptiles
39
When is ammonia typically released
During the breakdown of amino acids
40
What is deamination
Removal of ammonia
Some amino acids are deaminated directly and others are transferred to glutamate then glutamate is deaminated
This is energetically more expensive
41
NH3 is a form that can dissolve in water, what is this dependent on
Partial pressure, solubility, and temperature
Once dissolved it becomes NH4 and the reaction is dependent on pH
Most ammonia is in the form of NH4
42
How can NH3 and NH4 pass through the membrane
NH3 uses passive diffusion
NH4 passes through an NH4/H+ anti port channel and K+ channels
43
What excretes ammonia through epithelial tissue
Ammonioteles
44
True or false: uric acid can accumulate without toxic effects
True
45
What can uric acid be converted into in some mammals
Urea
46
How can urea be produced and from where
Produced through ornithine urea cycle
Made in the liver and released in the blood
Higher in protein rich diets
Can accumulate to maintain osmotic pressure
47
How many atp per nitrogen in urea and uric acid
In urea it’s 2.5 atp per nitrogen
In uric acid it’s 1.75 atp per nitrogen
48
What does the kidney regulate
Ion and osmotic balance, blood pressure, ph balance, excretion, hormone production
49
What is a nephron and what is it made of
Functional unit of the kidney
Made of renal corpuscle, renal tubule, glomerulus, bowman’s capsule, proximal tubule, loop of henle, distal tubule, and collecting duct
50
What is the renal corpuscle
Bowman’s capsule and glomerulus combined
Its where filtration takes place
51
The bowman’s capsule is made of a visceral and parietal layer, what makes up the visceral layer
The visceral layer is made of podocytes which have foot processes which loop around the blood vessel
Small slits in between the podocytes are called filtration slits
52
What is the equation for amount secreted
Amount secreted = amount filtered+amount secreted-amount reabsorbed
53
What does hydrostatic pressure of blood vessels do to water? What about hydrostatic pressure of the bowman’s capsule
HP of blood pushes water out of blood into capillary space
HP of bowman’s capsule pushes stuff into blood vessel
54
What does the osmotic pressure of the blood vessel and bowman’s capsule do
OP of blood vessel pulls stuff inward
OP of bowman’s capsule takes stuff out
55
What is the glomerular filtration rate
Driven by hydrostatic pressure of capillary
When HP increase GFR increases
56
What happens when blood flow increases in relation to GFR
Blood pressure increases which leads to vasoconstriction
This decreases blood flow so a decrease in GFR mechanism
57
Where does filtration occur and how is blood filtered
Occurs at glomerulus
Blood is filtered through fenestrations and filtration slits of podocytes
58
What do bowman’s capsules surround and what are podocytes
Surround fenestrated capillaries
Podocytes make up the visceral layer of the bowman’s capsule
59
What is the juxtaglomerular apparatus
Macula densa monitors blood pressure and leads to vasoconstriction of afferent blood vessel
Mesengial cells detect blood pressure and cause vasoconstriction of capillaries and decrease GFR
60
What happens when afferent arterials constrict
Decrease blood flow so decrease HP of capillaries and decrease GFR
61
What happens when the efferent arterials constrict
Increase blood volume of glomerulus so increase in HP of capillaries and increase in GFR
62
What do outward pressures do and what are they
Promote filtrate formation
HP in glomerular capillaries and colloid osmotic pressure in capsular space
63
What are inward pressures and name the two
Oppose filtrate formation
Hydrostatic pressure in capsular space
Colloid osmotic pressure in glomerular capillaries
64
What is oncotic pressure
Colloid osmotic pressure when it is referred to as a single pressure because it equals zero
65
How do you find net filtration
Outward - inward pressures
66
What is tubuloglomerular feedback
Macula densa cells detect increase flow in distal tube so vasoconstriction of afferent arteriole
67
What is mesangial control
Mesangial cells detect increase in blood pressure
Vasoconstriction of glomerular capillaries reduces surface area for filtration
68
What are proximal convoluted tubules
Location where urine modification starts
Made of epithelium
Secretes carbonic anhydrase
Water and CO2 can be reabsorbed in PCT so they can be converted into bicarbonate and that goes to ECF via Cl antiport channel
69
True or false: a majority of primary urine is reabsorbed
True
70
What is solute reabsorption limited by
Transport capacity
The renal threshold where blood plasma levels result in ALL recovery of substances
71
What do proximal tubules do
Reabsorb salts and organic metabolites
Secrete organic molecules and certain drugs
72
In the loop of henle what is the descending and ascending limbs permeable to
Descending limb is permeable to water but not ions, water reabsorbed here
Ascending limb is permeable to ions but not water unless vasopressin is present, NaCl reabsorbed here
73
What does the single affect in the loop of henle create
An osmotic gradient between the loop and surrounding ECF
These forces counteract each other causing the other to do more but they DO NOT do countercurrent exchange
74
What is the transmedullary osmotic gradient
Established in the medulla
Present in mammals
Creates high osmotic gradient so more water can be absorbed in collecting ducts
75
What does a longer loop of henle mean
Stronger gradient and higher osmolarity of urine
76
What can final urine products be
Hyperosmotic to blood plasma
77
What does the distal tubule do
Mediates K+ secretion
Mediates NaCl reabsorption
Hormone sensitive water recovery
78
How does urea recycling work
Urea serves as osmolyte in kidneys
Enters filtrate at ascending limb and enters ECF in collecting duct
79
What does the collecting duct do
Involved with water retention
Secretes K+ and reabsorbs Na+
Intercalated cells secrete H+ or HCO3-
Responds to vasopressin which stimulates water retention with aquaporin type II
80
What does vasopressin do
Increases the number of aquaporins in the collecting ducts
81
What are vasa rectas
Blood vessels that surround the nephron loop
They are permeable to water and solutes so blood in vasa recta is isoosmotic with surrounding ECF
82
What is micturition
Urination
Detruser muscle contracts
Internal urethral sphincter opens and external urethral sphincter opens
83
What is aldosterone
Regulates Na and K balance
Targets principle cells of distal tubule and collecting ducts
Upregulates transcription of transport proteins
84
What is the renin angiotensin aldosterone pathway
Regulates blood pressure
Juxtaglomerular cells secrete renin in response to low BP
Renin converts angiotensinogen into angiotensin I
Angiotensin I converted to angiotensin II via angiotensin converting enzyme (ACE)
Angiotensin II stimulates release of aldosterone from adrenal medulla
85
How does angiotensin II work
It acts on the hypothalamus to release vasopressin and make aquaporin type II channels which increases water retention and leads to increase in blood volume and BP
It acts on adrenal cortex to release aldosterone which increases Na retention and increase water retention which leads to increase blood volume and BP
86
What do natriuretic peptides favor and what is an example of one
Favor appearance of Na in urine
Atrial natriuretic peptide which is released by the heart in response to stretch which increase BP and blood volume
ANP increases GFR by causing vasodilation of afferent arteriole and causes relaxation of mesangial cells increasing surface area for filtration
87
What is the largest source of acid during aerobic respiration
Production of CO2
Blood pH decreases and causes hyperventilation causing PCO2
Decrease in pH causes increase in secretion of H+ and NH4+
88
What does low BP cause, what do baroreceptors cause, and what does a decrease in stretch cause
Reduction in filtration and fluid remains in the blood
Increase vasopressin release
Stimulates juxtaglomerular cells to release renin
89
How do chondrichthyan kidneys work
90% urine recovered
Body fluids maintained with high urea concentrations
Sharks in dilute waters need to produce more urine
90
How do fish kidneys work
Glomerulus large in freshwater species
Produce large volume of hypoosmotic urine
91
How do amphibian kidneys work
Pronephros in larvae filtrate from coelom
Mesonephros in adults
92
How do fish gills regulate ions
Chloride cells present in gills
Pavement cells regulate Na
Use active transport mechanisms
93
Where are salt glands present and what do they secrete
Present in birds and reptiles
Secrete hypoosmotic solution of NaCl
94
What are rectal glands
Present in sharks and rays
Function similar to chloride cells in fish
