Osmoregulation and Excretion Flashcards
What is osmoregulation?
homeostasis regulation of how to save or remove body water
How is osmoregulation conducted?
organs regulate solute concentration to influence the movement of water
What is excretion?
disposal of nitrogenous metabolites and waste products from the body
What is osmolarity?
The solute concentration of a solution which determines the movement water across a membrane
What does it mean to be isomotic?
both sides of the membrane have the same osmolarity, there is equal movement of water in both directions
What is osmosis?
movement of water molecules through a semipermeable membrane, solutes are blocked and water passes
What is dialysis?
movement of solute molecules form high to low concentration through a membrane, select solutes are allowed to pass
What are osmoconformers?
internal body osmolarities are isosmotic with their natural surroundings
only seen in marine animals
What are euryhalines?
animals that tolerate a great deal of osmolarity change
osmoconformers
What are Osloregulators?
expend energy to control water uptake and loss in either hyperosmotic or hyposmotic areas
What are stenohalines?
animals that cannot tolerate much osmolarity change
Most marine invertebrates are…
osmoconformers
Most marine vertebrates are…
osmoregulators
Most freshwater animals are…
osmoregulators
hyperosmotic to freshwater and need to lose excess water
they gain water by osmosis and lose salt by diffusion
drink almost no water and excrete dilute urine and uptake needed salt through food and gills
Marine animals lose water by…
osmosis and gain salt by diffusion from food
they drink seawater and excrete extra salt
What is anhydrobiosis?
a dormant state in which an organism survives being very desiccated (dehydrated)
seen in temporary water animals like tardigrades
How do land animals osmoregulate?
drink water, consume moist food and use metabolic water to replenish their water stores
What are important breakdown products?
nitrogenous wastes like ammonia
What is transport epithelia?
all osmoregulation/excretory systems use layers of epithelial cells that move specific solutes in specific directions
What are the steps of the Tubular Theme?
Filtration: pressure forces water/solutes from blood/hemolymp into Tubule
Reabsorption: valuable solutes from the filtrate are reclaimed into the body
Secretion: depositing toxins and solutes from body fluids to the filtrate
Excretion: removal of filtrate from the system (urine)
What controls osmoregulation and excretion in vertebrates?
kidneys
What tubules in kidneys called?
Nephrons
closely associated with capillaries
What is the kidney supplied with?
the renal artery and renal vein
What exits the kidney?
urine, through the ureter which drains into the bladder, where urine is expelled through urethra
What are the two distinct regions of the kidney?
outer renal cortex
inner renal medulla
What is the nephron made of?
a single long tubule and a ball of capillaries called the glomerus
What is Bowman’s Capsule?
collection of duct surrounding glomerulus, which receives filtrates from the blood brought by capillaries
What allows exchange in the kidney?
extensive network of capillaries
How are blood vessels and nephrons arranged?
situated in a countercurrent exchange
increases the efficiency of exchange between the fluids
What ensures that water can always be absorbed?
Salt and Urea form a osmotic gradient in the kidney
water always exits filtrate since the kidney tissue is always hyperosmotic
In what direction does osmolarity increase?
moving inward from cortex to medulla
How does blood pressure affect nephron excretory function?
forces fluid from the glomerulus into Bowman’s Capsule
What do the semipermeable membranes between capillaries and epithelium do?
filtrates based on size
allows: salts, glucose, amino acid, nitrogenous waste, and small molecules
blocks: RBCs and large molecules
