BIOL10004 Lecture Notes - Lecture 17: Body Fluid, Semipermeable Membrane, Osteichthyes
10 Jun 2018
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Department
Course
Professor
Osmosis and tonicity
Osmosis: water diffuses through a semi-permeable membrane from area of low
osmotic concentration (high water potential), to high osmotic conc.
Osmolarity = osmoles
○
Solutes can move in or out of cells by active transpot against conc gradients
○
-
Tonicity: like osmolarity, except takes into account only non-permeable solutes
Measure of effective osmotic pressure, exerted by non-permeate solutes only,
across a semi-permeable membrane
○
-
Hypertonic solution -> plasmolysed
-
Isotonic
-
Hypotonic -> turgid
-
Why regulate water and solutes?
To achieve homeostasis
-
Terrestrial animals - lose water by evaporation from body surface (sweat) and from
breathing
-
Aquatic animals - gain/lose water by osmosis + gain/lose solutes by passive diffusion
across body surface
-
Strategies for regulating body fluid
Aquatic animals
Osmoconformers: osmotic conc of internal environment = external
Most marine INVERTEBRATES
○
Stenholaine: tolerates narrow range - Usually cannot cope with large change
in body salinity
○
-
Osmoregulators: osmotic conc of internal not equal to external environment
Most marine VERTEBRATES + freshwater and terrestrial animals
○
Euryhaline: tolerates wide range of environments (salinities)
○
Marine vertebrate osmoregulators (SEAWATERS)
Eg. Bony fish, birds, mammals, etc.
§
Loss of water from body fluid to seawater (by osmosis)
§
Body fluid is hypotonic to seawater
§
Gain water by drinking seawater
Seawater contains lots of ions
□
§
ADAPTATIONS (not enough water, too much salt)
Produce small amount of concentrated urine □
Actively excrete ions (across gills, or by kidneys or salt glands)□
§
○
-
Freshwater osmoregulators
Body fluid hypertonic to freshwater
§
Must osmoregulate
§
Gain water by osmomsis, lose solutes by diffusion
§
ADAPTATION (too much water, too few solutes)
Lots of dilute urine□
Don’t drink water□
Have organs that actively retain salts (eg. Kidneys, gills)□
§
○
Salmon: osmoregulator & osmoconformer during life cycle
Born in fresh water (river) -> migrate to ocean
○
1-8 years maturing at sea
○
Return to river to breed
○
Kidneys and gills must cope with both marine and freshwater conditions
○
Acclimatisation: need several days/weeks to adjust
Spend time at river mouth in brackish water
§
Kidney function must change and Na+/Cl- gill pumps must reverse
direction
§
○
-
Freshwater Seawaters
Water flows in Water flows out
Hypertonic to environment Hypotonic to environment
Don’t drink Drink several litres/day
Lots of dilute urine Concentrate urine - small
amount
Gill epithelial cells pump Na+ and Cl- from water
flowing over gills INTO BLOOD - increase solute conc. Of
blood
Pump Na+ and Cl- from blood
INTO WATER flowing over gills
Terrestrial animals
OBLIGATE OSMOREGULATOR
-
No issues with ion conc
-
Not enough water in environment
-
Lose water by evaporation and in urine and faeces
-
ADAPTATIONS
Drink or get water from food
Also have METABOLIC WATER PRODUCTION
§
○
Keep respiratory surfaces inside
○
Some absorb water through skin
○
Insulate skin with hair
○
Minimise water loss during excretion - concentrate urine
○
-
Eg. Thorny devil
Scales surround by channels that attract water -> water funnelled to mouth
○
-
Excretion of nitrogenous wastes
Excretion: process of removal of substances in urine
-
Elimination: process of removal of substances in faeces
-
Guanine: produced in spiders and scorpions - less-toxic form
-
Kidney/nephron function -Loop of Henle and countercurrent multiplication
Nephron: individual excretory tubule within the kidney specialised in water and
solute retention and excretion
-
Juxtamedullary nephrons allow terrestrial mammals to concentrate urine
-
Loop of Henle: part of nephron that comprises thin descending loop that is water
permeable and a thick ascending limb that actively pumps out ions
-
Countercurrent multiplication: process that can establish a solute conc gradient in
medulla of kidney
-
Filtration: all blood plasma except blood cells + large proteins enters tubule 1.
Reabsorption: Na+, Cl-, glucose, amino acids, vitamins re-enter blood 2.
Secretion: some ions (K+, NH4+, H+) secreted from blood into tubule 3.
Osmosis: osmodilution and osmoconcentration4.
Osmoconcentration
Establish a high osmotic concentration in the inner medulla
-
Thick ascending limb actively pumps ions out of filtrate
Water moves out by osmosis -> reabsorbed by the body
○
-
Especially long in desert animals to reabsorb water
-
Vasa recta -supply to renal medulla that provides nutrients + removes wastes
-
Regulating body fluids
Wednesday, 30 May 2018
2:48 pm
Osmosis and tonicity
Osmosis: water diffuses through a semi-permeable membrane from area of low
osmotic concentration (high water potential), to high osmotic conc.
Osmolarity = osmoles
○
Solutes can move in or out of cells by active transpot against conc gradients
○
-
Tonicity: like osmolarity, except takes into account only non-permeable solutes
Measure of effective osmotic pressure, exerted by non-permeate solutes only,
across a semi-permeable membrane
○
-
Hypertonic solution -> plasmolysed
-
Isotonic
-
Hypotonic -> turgid
-
Why regulate water and solutes?
To achieve homeostasis
-
Terrestrial animals - lose water by evaporation from body surface (sweat) and from
breathing
-
Aquatic animals - gain/lose water by osmosis + gain/lose solutes by passive diffusion
across body surface
-
Strategies for regulating body fluid
Aquatic animals
Osmoconformers: osmotic conc of internal environment = external
Most marine INVERTEBRATES
○
Stenholaine: tolerates narrow range - Usually cannot cope with large change
in body salinity
○
-
Osmoregulators: osmotic conc of internal not equal to external environment
Most marine VERTEBRATES + freshwater and terrestrial animals
○
Euryhaline: tolerates wide range of environments (salinities)
○
Marine vertebrate osmoregulators (SEAWATERS)
Eg. Bony fish, birds, mammals, etc.
§
Loss of water from body fluid to seawater (by osmosis)
§
Body fluid is hypotonic to seawater
§
Gain water by drinking seawater
Seawater contains lots of ions
□
§
ADAPTATIONS (not enough water, too much salt)
Produce small amount of concentrated urine □
Actively excrete ions (across gills, or by kidneys or salt glands)□
§
○
-
Freshwater osmoregulators
Body fluid hypertonic to freshwater
§
Must osmoregulate
§
Gain water by osmomsis, lose solutes by diffusion
§
ADAPTATION (too much water, too few solutes)
Lots of dilute urine□
Don’t drink water□
Have organs that actively retain salts (eg. Kidneys, gills)□
§
○
Salmon: osmoregulator & osmoconformer during life cycle
Born in fresh water (river) -> migrate to ocean
○
1-8 years maturing at sea
○
Return to river to breed
○
Kidneys and gills must cope with both marine and freshwater conditions
○
Acclimatisation: need several days/weeks to adjust
Spend time at river mouth in brackish water
§
Kidney function must change and Na+/Cl- gill pumps must reverse
direction
§
○
-
Freshwater Seawaters
Water flows in Water flows out
Hypertonic to environment Hypotonic to environment
Don’t drink Drink several litres/day
Lots of dilute urine Concentrate urine - small
amount
Gill epithelial cells pump Na+ and Cl- from water
flowing over gills INTO BLOOD - increase solute conc. Of
blood
Pump Na+ and Cl- from blood
INTO WATER flowing over gills
Terrestrial animals
OBLIGATE OSMOREGULATOR
-
No issues with ion conc
-
Not enough water in environment
-
Lose water by evaporation and in urine and faeces
-
ADAPTATIONS
Drink or get water from food
Also have METABOLIC WATER PRODUCTION
§
○
Keep respiratory surfaces inside
○
Some absorb water through skin
○
Insulate skin with hair
○
Minimise water loss during excretion - concentrate urine
○
-
Eg. Thorny devil
Scales surround by channels that attract water -> water funnelled to mouth
○
-
Excretion of nitrogenous wastes
Excretion: process of removal of substances in urine
-
Elimination: process of removal of substances in faeces
-
Guanine: produced in spiders and scorpions - less-toxic form
-
Kidney/nephron function -Loop of Henle and countercurrent multiplication
Nephron: individual excretory tubule within the kidney specialised in water and
solute retention and excretion
-
Juxtamedullary nephrons allow terrestrial mammals to concentrate urine
-
Loop of Henle: part of nephron that comprises thin descending loop that is water
permeable and a thick ascending limb that actively pumps out ions
-
Countercurrent multiplication: process that can establish a solute conc gradient in
medulla of kidney
-
Filtration: all blood plasma except blood cells + large proteins enters tubule 1.
Reabsorption: Na+, Cl-, glucose, amino acids, vitamins re-enter blood 2.
Secretion: some ions (K+, NH4+, H+) secreted from blood into tubule 3.
Osmosis: osmodilution and osmoconcentration4.
Osmoconcentration
Establish a high osmotic concentration in the inner medulla
-
Thick ascending limb actively pumps ions out of filtrate
Water moves out by osmosis -> reabsorbed by the body
○
-
Especially long in desert animals to reabsorb water
-
Vasa recta -supply to renal medulla that provides nutrients + removes wastes
-
Regulating body fluids
Wednesday, 30 May 2018
2:48 pm
Osmosis and tonicity
Osmosis: water diffuses through a semi-permeable membrane from area of low
osmotic concentration (high water potential), to high osmotic conc.
Osmolarity = osmoles
○
Solutes can move in or out of cells by active transpot against conc gradients
○
-
Tonicity: like osmolarity, except takes into account only non-permeable solutes
Measure of effective osmotic pressure, exerted by non-permeate solutes only,
across a semi-permeable membrane
○
-
Hypertonic solution -> plasmolysed
-
Isotonic
-
Hypotonic -> turgid
-
Why regulate water and solutes?
To achieve homeostasis
-
Terrestrial animals - lose water by evaporation from body surface (sweat) and from
breathing
-
Aquatic animals - gain/lose water by osmosis + gain/lose solutes by passive diffusion
across body surface
-
Strategies for regulating body fluid
Aquatic animals
Osmoconformers: osmotic conc of internal environment = external
Most marine INVERTEBRATES
○
Stenholaine: tolerates narrow range - Usually cannot cope with large change
in body salinity
○
-
Osmoregulators: osmotic conc of internal not equal to external environment
Most marine VERTEBRATES + freshwater and terrestrial animals
○
Euryhaline: tolerates wide range of environments (salinities)
○
Marine vertebrate osmoregulators (SEAWATERS)
Eg. Bony fish, birds, mammals, etc.
§
Loss of water from body fluid to seawater (by osmosis)
§
Body fluid is hypotonic to seawater
§
Gain water by drinking seawater
Seawater contains lots of ions
□
§
ADAPTATIONS (not enough water, too much salt)
Produce small amount of concentrated urine
□
Actively excrete ions (across gills, or by kidneys or salt glands)
□
§
○
-
Freshwater osmoregulators
Body fluid hypertonic to freshwater
§
Must osmoregulate
§
Gain water by osmomsis, lose solutes by diffusion
§
ADAPTATION (too much water, too few solutes)
Lots of dilute urine
□
Don’t drink water
□
Have organs that actively retain salts (eg. Kidneys, gills)
□
§
○
Salmon: osmoregulator & osmoconformer during life cycle
Born in fresh water (river) -> migrate to ocean
○
1-8 years maturing at sea
○
Return to river to breed
○
Kidneys and gills must cope with both marine and freshwater conditions
○
Acclimatisation: need several days/weeks to adjust
Spend time at river mouth in brackish water
§
Kidney function must change and Na+/Cl- gill pumps must reverse
direction
§
○
-
Freshwater Seawaters
Water flows in Water flows out
Hypertonic to environment Hypotonic to environment
Don’t drink Drink several litres/day
Lots of dilute urine Concentrate urine - small
amount
Gill epithelial cells pump Na+ and Cl- from water
flowing over gills INTO BLOOD - increase solute conc. Of
blood
Pump Na+ and Cl- from blood
INTO WATER flowing over gills
Terrestrial animals
OBLIGATE OSMOREGULATOR
-
No issues with ion conc
-
Not enough water in environment
-
Lose water by evaporation and in urine and faeces
-
ADAPTATIONS
Drink or get water from food
Also have METABOLIC WATER PRODUCTION
§
○
Keep respiratory surfaces inside
○
Some absorb water through skin
○
Insulate skin with hair
○
Minimise water loss during excretion - concentrate urine
○
-
Eg. Thorny devil
Scales surround by channels that attract water -> water funnelled to mouth
○
-
Excretion of nitrogenous wastes
Excretion: process of removal of substances in urine
-
Elimination: process of removal of substances in faeces
-
Guanine: produced in spiders and scorpions - less-toxic form
-
Kidney/nephron function -Loop of Henle and countercurrent multiplication
Nephron: individual excretory tubule within the kidney specialised in water and
solute retention and excretion
-
Juxtamedullary nephrons allow terrestrial mammals to concentrate urine
-
Loop of Henle: part of nephron that comprises thin descending loop that is water
permeable and a thick ascending limb that actively pumps out ions
-
Countercurrent multiplication: process that can establish a solute conc gradient in
medulla of kidney
-
Filtration: all blood plasma except blood cells + large proteins enters tubule 1.
Reabsorption: Na+, Cl-, glucose, amino acids, vitamins re-enter blood 2.
Secretion: some ions (K+, NH4+, H+) secreted from blood into tubule 3.
Osmosis: osmodilution and osmoconcentration4.
Osmoconcentration
Establish a high osmotic concentration in the inner medulla
-
Thick ascending limb actively pumps ions out of filtrate
Water moves out by osmosis -> reabsorbed by the body
○
-
Especially long in desert animals to reabsorb water
-
Vasa recta -supply to renal medulla that provides nutrients + removes wastes
-
Regulating body fluids
Wednesday, 30 May 2018 2:48 pm
Document Summary
Osmosis: water diffuses through a semi-permeable membrane from area of low osmotic concentration (high water potential), to high osmotic conc. Solutes can move in or out of cells by active transpot against conc gradients. Tonicity: like osmolarity, except takes into account only non-permeable solutes. Measure of effective osmotic pressure, exerted by non-permeate solutes only, across a semi-permeable membrane. Terrestrial animals - lose water by evaporation from body surface (sweat) and from breathing. Aquatic animals - gain/lose water by osmosis + gain/lose solutes by passive diffusion across body surface. Osmoconformers: osmotic conc of internal environment = external. Stenholaine: tolerates narrow range - usually cannot cope with large change in body salinity. Osmoregulators: osmotic conc of internal not equal to external environment. Most marine vertebrates + freshwater and terrestrial animals. Loss of water from body fluid to seawater (by osmosis) Actively excrete ions (across gills, or by kidneys or salt glands) Gain water by osmomsis, lose solutes by diffusion.
