Osmoregulation

Osmolarity

The number of osmotically active moles of solute per litre of solution

Tonicity

The ability of a solution to change the volume of a cell by osmosis

If a cell is put in a hypertonic solution it will

lose water and shrink

If a cell is put in a hypotonic solution it will

take in water and swell

If a cell is put in an isotonic solution

there will be no movement of water

Osmotic gradient

The difference in concentration on both sides of a semipermeable membrane.

Osmoconformers

Have body fluids that are isotonic to seawater preventing an osmotic gradient. Most marine invertebrates

Osmoregulators

Maintain constant blood osmolarity while having different concentrations than their surroundings. All other vertebrates

Bony fish and tadpoles excrete ammonia through

diffusion through their gills

Cartilaginous fish, adult amphibians, and mammals excrete

urea

Flatworm excratory system

Have protonephridia (tubules) that branch throughout their body into flame cells. Cilia in the flame cells move fluid throughout the body. Water and metabolites are reabsorbed in flame cells and wastes are excreted through pores

Annelid excratory system

Have nephridia that open to both the inside and outside of the body. Coelomic fluid is filtered into the funnel shaped nephrostomes. As filtrate is moved salt is reabsorbed through active transport

Malpighian tubules

Found in insects, draw waste molecules and potassium ions through active transport. The resulting gradient draws water into the tubule and is later reabsorbed with the potassium ion in the hindgut.

Nitrogenous waste in insects

uric acid

Nephron

The structural unit of the vertebral kidney. Filters blood under pressure to create tubular fluid, wastes are secreted into the fluid, and other molecules, ions, and water are reabsorbed. Molecules are them secreted from the blood

What is the advantage to the vertebrate unrinary system?

It can be adapted to many environments and unknown wastes can still be filtered out of the system

Amphibian kidneys are the same as

Freshwater fish, they produce dilute urine and retain electrolytes through active transport of sodium ions across the skin from the water

Frogs have a large bladder where they

store urine and reabsorb water while they are in terrestrial environments

Due to their environment marine reptiles lose \_______ and absorb \_________

Water, salt

How do marine reptiles eliminate salt?

salt glands located around the nose or eyes.

True or false, marine reptiles produce isotonic urine?

True

Terrestrial reptiles nitrogenous waste

uric acid, this requires little water that is later absorbed by their cloaca