Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Animal Physiology Exam 1 > Water and Solute Balance > Flashcards

Water and Solute Balance Flashcards

1
Q

properties of water

A
  • dipole moment
  • ability to form hydrogen bonds
  • high specific heat (good for regulating body temp)
  • high latent heat of evaporation(good for cooling body)
  • high latent heat of fusion (water is hard to freeze)
  • bodies of water expand when frozen
  • good solvent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

colligative properties

A

characteristics of a solution that depend on the number of molecules dissolved in a given volume
- all related to concentration of solute in water
- more solutes in water= higher boiling point, lower freezing point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

osmosis

A

diffusion of solvent molecules into are of high solute concentration
- water will flow to more concentrated side of membrane
- higher osmotic pressure= more concentrated solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

flux

A

water movement, rate of flow of matter or energy across a unit area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

permeability

A

rate at which a substance penetrates a membrane under a given set of conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

diffusion rates depend on

A
  • concentration gradient (greater concnetration gradient= greater diffusion)
  • electrical (ionic gradient)
  • temperature ( greater temp= greater diffusion)
  • membrane area (greater area = greater diffusion rate)
  • size of solute (smaller size = greater diffusion rate)
  • polar substance has minimal diffusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

3 routes by which substances cross membranes

A

1) through aqueous channels/pores
2) dissolves into lipid bilayer and diffuses across
3) molecule combines with a carrier molecule dissolved in the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

lipid bilayer

A
  • phospholipids arrange in a bilayer
  • polar heads outward
  • non-polar tails inward away from water
  • membrane is impermeable to polar molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

extrinsic

A

attached to surface
- more polar R groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Intrinsic

A

more nonpolar R groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

liquid-crystalline state

A
  • range of temp is dependent on type of fatty acid in phospholipid
  • more unsaturated FA have greater tolerance of membrane to lower temps
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

passive diffusion

A
  • down a concentration gradient
  • no carrying or energy involved
  • occurs through pores in membrane (polar molecules) or directly through lipid bilayer (nonpolar molecules)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

active transport

A

involves a carrier molecule (probably a protein) which carries the molecule from one side to the other
- exhibits saturation kinetics
- can occur against a concentration gradient
- pumps maintain gradients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

saturation kinetics

A

as concentration of solute increases, the protein carrier gets saturated and rates of diffusion level off

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

facilitative transport/facilitated diffusion

A

passive diffusion with a carrier molecule
- down an electrical/concentration gradient
- no direct energy is required
- exhibits saturation kinetics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

exchange diffusion

A

involves a carrier
- no energy directly required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

codiffusion

A

involves a carrier
- no direct energy, but indirectly there is

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

iso-osmotic cell

A

osmotic concentrations are the same inside and outside of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

hypo-osmotic cell

A

cell has lower osmotic concentration inside than out
- cell will shrink

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

hyperosmotic cell

A

osmotic concentration outside is less than inside (cell will swell)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

isotonic cell

A

volume is constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

hypotonic cell

A

volume inside decreasing
- water flows in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

hypertonic cell

A

volume inside increases
- water flows out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

euryhaline

A

cells that tolerate high salt concentrations (extracellular and intracellular)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

stenohaline

A

narrow tolerance to salt
- a lot of effort is put into maintaining gradients, if salt balance is thrown off the cell will have a hard time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

osmoconformers

A

allow their osmolarity to vary with salt water
- includes most marine invertebrates
- their environment is relatively stable
- quite tolerant of high salinity (euryhaline)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

osmoregulator

A
  • will maintain a relatively constant osmolarity, in spite of external environment
  • includes most freshwater invertebrates, most vertebrates and terrestrial invertebrates and vertebrates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

concentrations for both Osmo conformers and regulators

(Na+ and K+ for blood vs inside cell)

A
  • blood concentration normally high Na+, low K+
  • inside cell normally high K+, low Na+
  • also high organic molecules
  • some insects have unusually high K+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

adaptations in freshwater teleost fish

A
  • plasma is hyperosmotic to surrounding water
  • water tends to flow in and ions flow out
    must get rid of water and retain ions
  • low permeability of body surface to limit influx of water
  • kidney is designed to get rid of water, produces a large volume of hypotonic and hypoosmotic urine
  • active uptake of ions from water (use of chloride cells in epithelia of gills–> actively transport Cl- and Ma+ out of water, water still follows
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

vasotocin(freshwater)

A

vasoconstrictor of efferent arterioles
- increases GFR, inc urine volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

corticosteroids

A

increase urine volume by increasing GFR
- also inc Na+ uptake

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

prolactin

A

very important to FW fish to increase Na+ retention at gills
- helps promote active transport in gills

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Salt water fish

A
  • fish plasma is hypo-osmotic to SW
  • water leaves fish and ions tend to diffuse in
    fish need to retain water and get rid of ions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

vasotocin (SW)

A

vasoconstricts afferent arterioles to decrease GFR–> limits urine production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

adaptations in SW fish

body surface, srink, kidney, chloride cells

A
  • low permeability in body surface
  • drink SW–> inc in water, but also inc Na+, Cl-, and K+ concentrations
  • Kidney has low volume output for water concentration (secrete isosmotic urine, divalent ions excreted by gut/kidney, monovalent via gills)
  • chloride cells excrete salts through outward active transport against conc/electrical gradients without loss of water–> Cl pump is electrogenic (pumps Cl- out, creating charge for net ion fluc, Na+ follows)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

cortisol (SW)

A
  • very important to SW fish
  • increases Na+ transport at gills
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

amphibians in aquatic environments

A
  • kidney similar to fish
  • use skin and bladder
  • active transport of Na+ out of bladder, with water following
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

marine mammals

A
  • drink salt water
  • efficient kidney that can secrete inc ions in a small urine volume
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

reptiles and birds in an aquatic environment

drink, how do they get rid of salts

A
  • drink salt water
  • don’t have as efficient of a kidney as mammals
  • rely on other organ to get rid of salt (SALT GLANDS/RECTAL GLANDS)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

salt glands

A

active transport of NaCl into tubule lumen to be excreted down nasal canal
- strong electrogenic Cl- pump with Na+ passively following

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

rectal glands

A

in elasmobranchs produces hypertonic Na+ solution
- also electrogenic Cl- pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

water gain

A
  • drink
  • skin/body surfaces (amphibians)
  • metabolic water, water in food
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

water losses

A
  • urine
  • feces
  • evaporation over the body surface and across respiratory surfaces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

kangaroo rat

A
  • nocturnal
  • doesn’t drink water or eat succulent plants (diet is only dry seeds)
  • gets most of water metabolically
  • long loop of Henle–> more efficient kidney so they can excrete a greater osmolarity urine with same volume
  • low volume, highly concentrated urine
  • has long, narrow trachea that cools air as it is exhaled (air holds less water)–> water condenses and is reabsorbed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

intermittent countercurrent heat exchange

A
  • separate in time, not space
  • during inhalation, walls lose heat to inhaled air, become cooler
  • exhalation, warm lung air passes over cool surface and water condenses
  • decreases water loss
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

camel physiological adaptations

A
  • hump of camel contains lipid which animal draws from ro metabolize for energy and water
  • kidney will concentrate urine
  • very tolerant to dehydration
  • avoids explosive heat death
  • stores heat (during day stores heat to dec heat flux and water loss), unloaded at night (when temp is lower)
  • high insulation to avoid heat loss
  • can stop urination and store urea in tissues
  • countercurrent heat exchanger (temporally–> same as kangaroo rat)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

steps to explosive heat death

A
  • as water is lost, volume of blood decreases and viscosity increases–> makes heart work harder (inc pumping)–> still have dec circulation so heat won’t dissipate–> inc body heat leads to death
    (less blood = heart has to work harder to pump blood around= dec circulation = elevated temp)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

nephridia

A

most common type of excretory organ among invertebrates
- simple branching tube opening to outside via a pore
- 2 types: protonephridia and metanephridia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

protonephridia

A
  • inner portion of tubule is closed off
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

metanephridia

A
  • inner portion is open
  • with nephrostome: open, funnel like, ciliated end
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

3 mechanisms of kidney

A
  • ultrafiltration
  • reabsorption
  • secretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

glomerulus

A

capillary bed in Bowman’s capsule
- responsible for first step in urine filtration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

ultrafiltration

A
  • blood pumped into glomerulus
  • walls are premeable and blood is filtered
  • filtrate accumulates in lumen of Bowman’s capsule
  • salts, sugars filter through
  • large proteins, RBC won’t
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

at proximal tubule

A
  • lumen contains urinary filtrate, composition of fluid in tubule is isosmotic to blood plasma
  • contains glucose, amino acids, salts, but no RBC or proteins
  • needs to be a way to reabsorb these things
  • requires active transport systems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

net movement of water from plasma to tubule

what is it caused by

A

results from: hydrostatic blood pressure, back pressure in tubule, pressure due to excess of proteins –> net filtration pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

vasoconstriction of afferent arteriole

A

less urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

vasoconstriction of efferent arteriole

A

more urine

57
Q

reabsorption

where does it occur

A

99% of water and most salts, sugars are reabsorbed
- occurs through length of tubule
- involves active transport and diffusion
- distal tubule: most electrolytes reabsorbed here
- proximal tubule: most of glucose

58
Q

secretion

A

-involves active transport
- secretion of ammonia ion, H+, K+
- important in regulation of blood H= and pH buffers (bicarb)

59
Q

freshwater fish kidneys

A
  • designed to lose lots of water
  • have high number of glomeruli for filtration –> so urine is of high volume but low osmolarity
  • # of electrolytes are being reabsorbed
  • urine is hypotonic to blood
60
Q

salt water fish kidneys

include structure of kidney

A
  • must remove slats and retain water
  • less glomeruli–> lose less water
  • no distal tubule to prevent uptake of salts
  • SW fish excrete isosmotic urine (divalent ions excreted out by kidney, monovalent at gills)
  • some SW fish are aglomerular–> kidney doesn’t use filtration (uses diffusion and active transport_
  • not a lot of reabsorption
61
Q

kidney of amphibians and reptiles

A
  • essentially like a FW teleost kidney
  • 3 processes
  • glomeruli and tubules
  • importance of bladder, salt glands, and skin
62
Q

kidney of aves and mammals

A

problem with water loss–> have to reabsorb most of it
- able to secrete a concentrated urine

63
Q

cortex

A

outer layer of kidney
- contains malpighian bodies and proximal and distal tubules

64
Q

medulla

A
  • inner portion of kidney
  • contains Loop of Henle and collecting duct
65
Q

loop of Henle

A

connects proximal and distal tubule
- contains thin descending limb, thin ascending limb, and thick ascending limb

66
Q

thin descending limb

A
  • No NaCl active transport
  • low permeability to NaCl; urine is concentrated–> hypertonic fluid
  • permeable to water
  • entirely passive
  • urine vol dec
  • urea and NaCl conc inc
  • as it turns loop at bottom = isosmotic to “inner medulla” fluid
67
Q

thin ascending limb

A
  • Permeable to NaCl and urea, not to water
  • NaCl diffuses out, urea diffuses in (passive)
  • inc urea conc inside
  • lower osmolarity inside
68
Q

thick ascending limb

A
  • impermeable to water, not to urea
  • active transport of Cl- (Na+ passively follows)
  • Use of Na-K-2Cl cotransporter
  • lowers osmolarity
  • hyposmotic/iosmotic to interstitial fluid
69
Q

2 types of kidney nephrons

A

Juxtamedullary (penetrates inner medulla) and Cortical (does not penetrate)

70
Q

proximal convoluted tubule

A
  • concentrates glomerular filtrate
  • 75% of Na+ is removed (act transport)–> 75% water and Cl- follows passively
  • water permeable membrane, presence of aquaporins
  • glucose and organics reabsorbed (AA, glucose: carrier mediated)
  • reabsorbed HCO3-, increases H+ secretion (dec pH)
  • leads to fluid of reduced volume which is isosmotic with plasma
71
Q

distal convoluted tubule

A
  • volume dec further
  • impermeable to urea–> urea conc inc more
  • secretion of K+, H+, and NH3 (active transport)
  • some reabsorption of Na+ and Cl-, HCO3-
  • water permeable (influenced by vasopressin)
72
Q

collecting duct

A
  • water reabsorbed (influenced by ADH)–> passive diffusion into hypertonic interstitial fluid, urine volume dec further
  • NaCl is reabsorbed (influenced by ADH
  • initially impermeable to urea, but in lower regions the epithelium becomes permeable to urea–> urea then passively diffuses out
  • Medulla region inc in osmolarity (from urea and NaCl)
73
Q

interstitial hyperosmolarity due to…

A
  • active salt transport in thick ascending limb (cl- with Na+ passively following)
  • Urea leaving lower collecting duct, increasing osmolarity
  • high salt in thin ascending loop and diffuses out
74
Q

electrogenic pump

A

1 ion gives rise to electric current and another passively follows

75
Q

electrotonic pump

A

with counterion and no net charge

76
Q

important points about kidney

A
  • water is being reabsorbed (because if high osmolarity in interstitial fluid, vasopressin)
  • urine volume decreases and urea is being concentrated (leads to hypertonic urine, high urea in collecting duct will diffuse into interstitial fluid and maintain high osmolarity)
77
Q

vasa recta

A

countercurrent mechanism
- water is removed from the area by entering the vasa recta which removes it to the general circulation
- water is drawn out as blood descends–> concentrates proteins–> draws a lot of water into vessels upon ascent and removes it
- passive diffusion of Na+, urea–> draws water in–> Na+, urea recirculated to maintain high osmolarity (rids area of excess salt and water)

78
Q

Glomerular Filtration Rate (GFR)

A

dependent on blood pressure (greater BP= greater GFR)

79
Q

reabsorption

A
  • mostly by active transport
  • ex: glucose codiffusion with Na+ (requires carrier which can become saturated)
80
Q

tubular maximum

A

max rate which tubules can transport and reabsorb a solute

81
Q

renal thresholds

A

blood concentration when active transport systems are saturated]8

82
Q

insect excretory system

A
  • Malpighian Tubules
  • how they secrete hypertonic urine
  • mechanism based on transport of K+ and Cl- –> creates an osmotic gradient to bring H2O into lumen, generates concentration gradient between blood and fluid inside MT–> water drains into gut
  • reabsorption of solutes in rectum
  • circulatory system is not very important, so BP is low
  • filtration isn’t very important
83
Q

Malpighian Tubules

A
  • vary in number
  • blind ended tubules attached behind the midgut and before the hindgut
84
Q

control of excretory system for vertebrates

hormonal systems

A
  • variation in rates of urine production
  • control from 2 hormonal systems–> Posterior Pituitary (ADH) and adrenal glands (aldosterone and corticosteroids)
85
Q

Antidiuretic Hormone

A
  • secreted by Posterior pituitary gland
  • produced in hypothalamus, stored in posterior pituitary until release
  • 2 types of ADH found in vertebrates: AVP and AVT
86
Q

AVP (arginine vasopressin)

A
  • found in mammals
87
Q

AVT (arginine vasotocin)

A
  • all lower vertebrates
88
Q

effects of ADH

A
  • main effect on collecting duct epithelium and distal tubules
  • inc water permeability
  • may also inc Na+ uptake
  • net effect to inc water uptake–> decrease urine volume
  • increase in water uptke, and decrease in urine volume–> inc ECF (extracellular fluids)–> inc blood pressure, dec blood osmolarity, dec blood viscosity
  • except for FW fish, ADH dec urine volume by dec GFR or inc water reabsorption
89
Q

AVT, vasotocin (In reptiles, amphibians, and SW teleost)

A
  • dec GFR (constricts glomerili afferent arterioles, dec blood flow through glomerilus)–> dec urine volume
90
Q

AVT (anurans)

A
  • also affects skin–> to inc Na+ transport across skin into animal and inc water permeability
  • also influences epithelium of urinary bladder to make it more permeable to water–> reabsorbs more water and excretes less
91
Q

AVT (teleost)

FW vs SW

A
  • Freshwater: AVT inc urine production by inc GFR–> vasoconstricts efferent arterioles; inc Na+ uptake across gills (also role for cortisol and prolactin)
  • Saltwater: AVT dec urine volume–> dec GFR–> vasoconstricts afferent arteriole
92
Q

control of ADH

osmolarity, BP, Angiotensin II, Baroreceptors

A
  • cells in hypothalamus which are sensitive to changes in osmolarity
  • inc in osmolarity->inc in ADH secretion-> water conservation-> dec urine production, inc ECF-> dec osmolarity of ECF
    Baroreceptors: sensory organs located in large veins, measure changes in ECF volume, sensitive to changes in BPP
  • Inc BP-> dec ADH-> inc urine vol-> dec ECF vol-> dec BP
  • low BP-> sensed by Baroreceptors-> inc ADH release-> inc water reabsorption in kidney-> inc ECF volume-> inc BP
  • Angiotensin II-> inc in vasopressin release
93
Q

effect of alcohol on urine production

A
  • inc alcohol-> inc urine production
  • inc volume of ECF-> dec ADH
  • dec osmolarity of ECF-> dec ADH
  • alcohol acts on brain to dec ADH
94
Q

Water toxicity death

A

Inc ECF volume-> inc BP
- dec osmolarity-> gradient challenges (cells swell and lyse)

95
Q

arid species

ADH

A
  • greater need to retain water
  • tend to maintain larger pituitary stores of ADH per unit body fat
  • can synthesize ADH faster
96
Q

Diabetes insipidus

A
  • inc urine production due to hyposecretion of ADH
97
Q

protein hormone

A
  • binds to surface receptor on target cell (receptor is hormone and target cell specific)
  • Receptor is G-protein linked receptor
  • activated G-protein activates the enzyme adenyl cyclase–> converts ATP to cAMP
  • cAMP becomes send messenger (activates specific protein kinase: cytosolic))
98
Q

2nd messenger

A
  • ex: cAMP
  • provides amplification of signal and brings about a specific action on the part of the target cell
  • ex: stimulates or inhibits enzymes or processes that are specific for a type of target cell
99
Q

ADH at collecting duct

A
  • binds membrane receptor, activates cAMP–> cell inserts AQP2 water pores into apical membrane–> water permeability and uptake occurs
  • in absence of ADH, pores are withdrawn and stored in cytosolic vesicles
100
Q

cAMP levels

A
  • depends on rates at which it is synthesized and rates in which it is inactivated by phosphodiesterase
  • enzyme converts cAMP to 5’ AMP
  • inhibitors of phosphodiesterase inc cAMP levels
101
Q

cortex tissue

A

synthesizes and secretes steroid hormones

102
Q

medullary tissue

A

of neural origin, and secretes epinephrine and norepinephrine

103
Q

3 levels of adrenal cortex

A

Zona Glomerulosa, Zone fasiculata, and Zona Reticularis

104
Q

Zona Glomerulosa

A

produces the mineralocorticoid: aldosterone

105
Q

Zona fasciculata

A

produces glucocorticoids

106
Q

Zona Reticularis

A

produces estrogens and androgens

107
Q

glucocorticoids

A

effect on carbohydrate metabolism
- glucose affecting steroids
- hyperglycemia: produces an inc in blood glucose, by breakdown of liver glycogen and conversion of AA and fats to glucose

108
Q

ACTH

A

adrenal corticotropic hormone
- glucocorticoid
- regulated by CRH (corticotropin releasing hormone from the hypothalamus)

109
Q

Mineralcorticoids

A
  • effect osmoregulation and water balance
  • primary effect: Na+
  • impacts water retention and K+ secretion
110
Q

Aldosterone

A
  • inc Na+ reabsorption (active transport) indistal tubules of kidney nephron–> inc water reabsorption–> dec urine volume
  • also inc K+ secretion into urine (active transport indistal tubules–> Na+ uptake favors K+ secretion
111
Q

aldosterone effect in birds

A

inc salt gland efficiency (Na+ secretion)A

112
Q

aldosterone in Amphibians

A
  • inc Na+ reabsorption from bladder
  • inc Na+ transport in skin
113
Q

cortisol

A
  • mineralocorticoid in teleost
  • acts in osmoregulation
  • FW fish: inc Na+ uptake across gills–> inc water uptake–> inc urine volume
  • SW fish: inc Na+ transport out of gills
114
Q

Renin-angiotensin System

A

renin is a proteolytic enzyme which is release by the juxtaglomerular apparatus (JGA)
- cells composed of macula densa cells at beginning of distal tubule and special renin secreting afferent arteriole cells in smooth muscle layer- renin released-> cleaves angiotensin-> angiotensin I-> converted in lungs by ACE-> angiotensin II

115
Q

Angiotensin II

A
  • hormone that affects the adrenal cortex to release aldosterone
  • potent vasoconstrictor
  • constricts arterioles, dec GFR–> inc water retention and BP
  • also inc vasopressin release
116
Q

aldosterone

A

released in response to Angiotensin II
- Inc Na+ uptake (active transport)
- Inc water uptake passively

117
Q

triggers for Renin-Angiotensin, Aldosterone

A
  • change in BP (dec distenstion of arteriole because of dec BP-> inc renin release-> aldosterone release-> Na+ uptake, water uptake, inc ECF vol-> higher BP)
  • Macula densa cells are senstive to amt of Na+ transport across tubules (renin secretion is inversely proportional to rate of Cl- or Na+ transport across distal tubule: inc renin release because of dec Na+ in plasma OR inc Na+ in distal tubule)
  • cells in adrenal ccortex (zona glomerulosa) are directly sensitive to changes in Na+ in plasma (dec in Na+ plasma-> inc aldosterone secretion-> inc Na+ uptake
118
Q

Low BP

A

inc ADH and increase aldosterone release–> inc BP

119
Q

High osmolarity

effect on ADH and aldosterone

A

inc ADH (which inc water uptake), dec aldosterone

120
Q

low osmolarity

ADH, renin, aldosterone

A

ADH decrease (dec in water uptake)–> dec in blood volume–> renin inc–> aldosterone release–> inc Na+ uptake–> inc blood volume

121
Q

Atrial Natriuretic Peptide

A
  • opposite effects of aldosterone
  • produced by heart muscle
  • targets distal tubules to dec Na+ reabsorption, and inc Na+ excretion
  • inc GFR
  • inhibits ADH, renin, and aldosterone release
  • inc Na+ ecretion from gills
122
Q

steroid mode of action

A
  • pass through cell membrane
  • bind to intracellular receptor
  • hormone/receptor complex moves into nucleus
  • interacts with specific DNA sequences
  • steroid hormones are slower acting than protein hormones
123
Q

aldosterone mode of action

A

inc rates of synthesis of mRNAs which are used for certain transport enzymes participating in Na+ uptake

124
Q

de-amination

A

when AA is metabolized
- the amino group (NH2) is removed and forms ammonia (NH3)–> NH4+ (ammonium ion= toxic)

125
Q

transamination

A

when an amino group is transferred to another AA
- usually transferred to glutamate which is then converted to glutamine (which is deaminated in kidney or gills and ammonia is liberated)

126
Q

forms of nitrogen excretion

A

1) ammonia
2) urea
3) uric acid

127
Q

ammoniotelic

A
  • animals use ammonia
  • NH3 (NH4+)
  • NH4+ is very toxic, and extremely soluble in water
  • formed by deamination of proteins and AA
  • used by animals with access to lots of water
128
Q

Ureotelic

A
  • urea
  • less toxic
  • quite soluble
  • readily diffuses across membranes
  • synthesis via urea cycle
  • animals with more of problem with water balance will use this and get by with less water loss
129
Q

uricotelic

A
  • uric acid
  • only slightly soluble in water
  • pathway for purine synthesis
  • metabolized by some to allantoin and allantoic acid
  • used by animals in very dry habitats
130
Q

ammoniotelic disadvantages

A

-NH4+ is very toxic
- only lose 1 Na

131
Q

ammoniotelic advantages

A
  • very soluble in water
  • no eleborate pathways requires
  • no energy is required to produce NH4+
132
Q

uriotelic disadvantages

A
  • needs extra pathways and enzymes for its synthesis
  • takes 3 ATPs per 1 molecule synthesized
  • lose 1 carbon atom
133
Q

ureotelic advantage

A
  • less toxic
  • removal of 2N–> for same inc in osmolarity, you get rid of twice as much
134
Q

uricotelic disadvantages

A
  • lots of pathways involved
  • high amount of energy expenditure
  • 4-5 ATPs/uric acid molecules
  • loss of 5 carbons
135
Q

Uricotelic advantages

A
  • insoluble–> aniimals can get rid of N2 excretion products without losing much water
  • less toxic than even urea
  • removal of 4 N groups
  • won’t contribute to osmolarity concentration
136
Q

determining factors of excretion method

A
  • water availability
  • embryonic factors: animals that excrete uric acid produce a cleidoic egg; embryos are isolated and build up of uric acid can be tolerates, can be metabolized by some organisms into allantoin and allantoic acid
  • diet
  • life stage
137
Q

ammoniotelic animals

A
  • FW and SW invertebrate
  • FW and SW teleosts
138
Q

Ureotelic animals

A
  • mammals
  • elasmobranch fishes
  • some lungfish release both NH4+ and urea
  • amphibians switch from NH4 to urea in developmental process
139
Q

uricotelic organisms

A
  • terrestrial gastropods
  • insects
  • squamates (reptile) lizards
  • birds
  • all with water balance problems
140
Q

mixed animals

A
  • chelonids (turtles)–> urea and uric acid (some een NH4)
  • crocodiles–> ammonia (mostly in water), uric acid
141
Q

guanotelic animals

A
  • arachnids, scorpions, some ticks
  • excrete mainly guanine material
  • similar to uric acid (purine), extremely insoluble, very dry

Animal Physiology Exam 1 (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions