Osmoregulation Flashcards
What is osmoregulation?
Maintaining homeostasis of water content
Control of tissue osmotic pressure
cannot pump water, so requires movement of solutes
Ionic Regulation
Control osmotic composition of body fluids
Nitrogen excretion
Pathway by which animals excrete ammonia
how to get rid of waste
Two types of osmotic exchange processes and what are they?
Obligatory:
- based on physical processes animal cannot control
- cannot control diffusion and osmosis
Regulated:
- Controlled by the animal
- uses energy
Challenges of osmoregulating in marine envs?
- High level of ions and mostly Na+ and Cl-
- must expel ions against electrochemical gradients: hypoosmotic
- obtaining water against osmotic gradients
What are Conformers
Internal conditions are similar to external conditions, even when external conditions change
What are Regulators
Defend a nearly constant internal state, distinct from external conditions
Maintain osmotic balance by control
Ionoconformer
exerts little control over solute profile within its extracellular space
Solutes in body similar to envs
Ionoregulators
Control levels of most ions in extracellular fluids
employs a combination of ion absorption and excretion
osmoconformer
internal osmolarity is same as external envs
if external conditions change the internal osmolarity changes
Osmoregulators
maintains internal osmolarity within narrow range regardless of external envs
depending ion conditions, animals could have an osmolarity higher or lower than surrounding water.
Stenohaline
Tolerate narrow range of salt concentrations
Euryhaline
Tolerate widely variant osmolarities
Nitrogenous wast
Ammonia is produced riding amino acid breakdown. It is toxic solution that must be excreted, either as ammonia, uric acid, or urea.
What happens if you don’t excrete ammonia?
Toxic in body and results in water loss
What are the different form that nitrogenous waste is excreted and what animals use those types?
Fish ammonia
birds and reptiles: uric acid
Mammals: urea
Ammonia costs?
Cheapest nitrogenous wast: does not need to be further metabolized after protein metabolism
Cost lots of water lost
Uric Acid pros and cons?
Pro: can accumulate in body fluids with few toxic effects
- cares water bc excreted as anhydrous white crystals
Cons: synthesis requires metabolic energy
Urea pros and cons?
Pros: pathway allows greater control of over the fate of metabolites
-made in the liver, released into blood, where fate depends on species
Cheaper than uric acid
less cheap than ammonia
Cons: synthesis requires metabolic energy
Integument
protective layer that decreases water los and gain
Restricts osmosis to small areas
limits water loss to skin tissues
Transcelluar transport
Movement of solutes( water) through epithelial cells
Paracellurar transport
: movement of solutes (or water) between adjacent cells
What are the three main nitrogenous waste excretion strategies?
Ammonium, uric acid, urea
What is the difference between ionoconformer and osmoconformer
Ionocoformer: ionic composition same as envs
Osmoconformer: osmotic conditions as envs
What are the 6 roles the kidney plays in maintenance of homeostasis?
- Ion balance
- Osmotic Balance
- Blood pressure
- Ph balance
- Excretion
- Hormone production
What is the functional unit of the kidney called and what does it do, draw anatomy and name areas?
Nephron
place at which all filtration occurs, excretion takes place
Nephrons are composed of what two elements?
Glomerulu: twisted ball of capillaries that deliver fluid to the tubule
Renal tubule: composed of a single layer of cells with transport properties that allow them to reclaim specific solutes and expel others
Kidneys have two major parts:
Renal Cortex, Renal medulla
How does the Bowman’s capsule filter blood?
It is a size filter only
What are the four regulatory factors involved in uric formation?
Filteration
Reabsorption
secretion
excretion
Where does filtration occur?
Glomerulus
What factors influence an animals ability to concentrate urine?
Medullary thickness: Thicker may be better
The amount of long loops of Henle: mammals can produce urine with an osmolarity 5x greater than plasma
What influences the strength of the loop of henle?
the length; longer loops more concentrating abilities
What osmoregulatory challenges do fresh water fish have to deal with?
excessive water gain and loss of ions
What osmoregulatory challenge to marine fish have to deal with?
Solutes are higher outside than internally have to deal with ion gain and reduce water loss.
How do marine fish reduce ion gain and where does it happen?
Gills are primary site of osmotic regulation: chloride cells are essential for excreting ions
What is a hypo osmotic environment/
Fresher water inside than outside the body.
What are the advantages of marine mammals having evolved on land with regards to osmoregulation?
Evolved to conserve water.
What is the shape of the marine mammals kidney called and what is its function?
Reniculated kidney increases surface area of medulla.
What are the 3 ways mammals gain water
- Ingestion of sea water
- from food
- from metabolism of fat
How is water loss reduced in Marine mammals?
Apneu like breathing
Nasal turbinates
What are some adaptations or strategies that marine mammals use to maintain osmolarity?
Highly concentrated urine produced by their reniculated kidney and Long loops of henle.
Metabolism of fat
drink sea water
reduction in water loss through apnea like breathing
nasal turbinates
How do marine mammals get rid of nitrogenous waste?
Through kidney excitement of urea
Salt gland fucntion
excrete slats and is the main way that birds do so.
