Chapter 50 - Osmotic Regulation and Urinary System Flashcards
To maintain osmotic balance, the animal’s body must
- Be able to take out from the environment
- Excrete excess water into the environment
- Exchange solutes to maintain homeostasis
The measure of a solution’s tendency to take in water by osmosis
Osmotic Pressure
The measure of a solution’s ability to change the volume of a cell by osmosis
Tonicity
Solutions may be _________
hypertonic, hypotonic, or isotonic
More solutes and less water, will take in water from the surrounding
Hypertonic
Less solute and more water, will lose water to surroundings
Hypotonic
Equal water exchange with surroundings
Isotonic
Water always moves from
Hypotonic to hypertonic
Organisms that are in osmotic equilibrium (isotonic) with their enviorment
Osmoconformers
What organisms are the osmoconformers?
- Most marine invertebrates
2. Chondrichthythes
Maintain a constant blood osmolarity different than their environment (hypertonic/hypotonic)
Osmoregulators
What organisms are the osmoregulators?
- Most vertebrates
2. All terrestrial animals
Produced when amino acids and nucleic acids are broken down
Nitrogenous Wastes
The amino acid group is removed, resulting in _________
Ammonia (NH3)
When is ammonia safe?
In dilute concentrations
Excessive accumulation of ammonia derivatives in joints causes __________ in humans
Gout
How do bony fish and immature amphibians eliminate nitrogenous waste?
By diffusion via gills
How do chondrichthyes, adult amphibians, and mammals eliminate nitrogenous waste?
Convert ammonia into urea, which is dissolved in water.
How do birds, reptiles, and insects get rid of nitrogenous waste?
Convert ammonia into the water insoluble uric acid.
- Uses more carbon, but does not need water
What do vacuoles do and who uses them?
- Single celled protists use contractile vacuoles
- Pump out excess water to ensure cell does not buret
- Nitrogenous wastes excreted through membrane
______ are a network of tubes which branch into the ______
- Protonephridia
2. Flame Cells
Removes solutes and excess water from the body in flatworms
Flame Cells
Open to the outside of the body through a pore in flatworms
Protonephridia
What species use protonephridia and flame cells?
Flatworms
A series of convoluted tubules that remove excess water and solutes from blood and urine (earthworms)
- Urine excreted through a pore
Nephridia
Who use nephridia?
Earthworms
- In insects
- Extensions of the digestive tract
Malpighian tubules
How do Malpighian tubules work?
- H2O and K+ are secreted into the tubules by active transport
- Create an osmotic gradient that draws H2O into the tubules by osmosis
- H20 and K+ are reabsorbed into the open circulatory system through hindgut
- Wastes left behind to be excreted
Who are isotonic to seawater?
Cartilaginous Fish
What does it mean to be isotonic to seawater?
- Instead of excreted most urea in urine, much urea is reabsorbed and pooled in blood
- The solute concentration in the blood is equal to that of the sea water
Shark blood has 100 times the amount of ________ as a mammal
Urea
Who are hypotonic to seawater?
Saltwater bony fish
Hypotonic to seawater means
Water wants to leave their bodies by osmosis across their gills
The process of being hypotonic to seawater
- Drink large amounts of seawater
- Seawater ions become dissolved in the blood
- Actively eliminate those ions across the gill surface
- Have a kidney that produces urine isotonic to body fluids
Who are hypertonic to fresh water?
Freshwater bony fish
What does it mean to be hypertonic to fresh water?
Water wants to enter body from environment
The result of being hypertonic to fresh water
- Kidneys produce large amounts of dilute urine
- Solutes want to leave the body
- Therefore, they reabsorb ions across nephrons
__________________ absorb much of the salt and water in their blood in their kidney
Terrestrial Reptiles
How do terrestrial absorb salt and water into their blood in their kidney?
- Move the dilute urine into the cloaca
2. Water is reabsorbed in the cloaca
_______ and ________ are the only vertebrates that can produce urine that is hypertonic to body fluids in kidney
Mammals and Birds
How can mammals and birds produce urine that is hypertonic to body fluids in kidney?
Renal Tubules
Each mammalian kidney is made up of about 1 million functioning ______
Nephrons
Where urine is produced from the blood
Nephrons
In the nephron, blood is carried into the ______
Glomerulus
The result of plasma being filtered as it is forced through porous capillary walls
Filtrate
Filtrate enters ________
Bowman’s Capsule
Where do cells and large proteins go when filtrate is made?
Stay behind and drain out
Filtrate moves through the __________
Renal Tubules
By the time filtrate exits the collecting duct, it is now ____
Urine
Blood plasma is filtered out of the glomerulus into the tubule sytem
Filtration
Selective movement of substances out of the filtrate back into the blood (H20, Na, Cl, K, Ca, HCO3)
Reabsorption
Active movement of substances from the blood into the filtrate (H, K, Toxins)
Secretion
The three jobs the kidney has
- Regulate electrolyte balance in the blood by reabsorption and secretion of (Na, Cl, Ca, K, H, and HCO3)
- Eliminates toxins and metabolic wastes
- Maintain relatively constant levels of blood, volume, pressure, and osmolarity
Hormones secreted by the pituitary gland
Antidiuretic Hormone
What are antidiuretic hormones?
- Stimulated by an increase of osmolarity of blood
- Causes walls of distal tubule and collecting ducts to become more permeable to water
- Increase reabsorption of water
Is secreted by the adrenal cortex
Aldosterone
What are aldosterone hormones?
- Stimulated by low levels of Na in blood
- Causes distal tubule and collecting ducts to reabsorb Na
- Reabsorption of Cl and water follows
What do marine reptiles and birds do to regulate salt?
- Drink seawater and excrete an isotonic urine
- Solutes concentration in blood will be too high
- Eliminate excess salt via salt glands
