Chapter 39.2-Excretion of wastes Flashcards
Why is execertion important for animals?
it helps animals maintain homeostasis
What are excretory organs and what are their functions?
Osmoregulation: maintance of water balance in the body
Excretion: Removal of metabolic waste by using water
What are the differences between gastrointenstinal tract and excretory organs?
gastrointestinal tract: contact with the outside
vertebrate kidneys: seperates toxic compounds from toxic compounds from essiential nutrients
Why is ammonia considered a form of nitrogenous waste?
- can distrub the Ph level of a cell
- damage neurons
- can be lethal to organisms
How did the migration of animals from water to land lead to the evolution of excreting nitrogenous waste?
Initially fishes secreted ammonia into water directly because the surrounding water allowed for a diluted less toxic ammonia. But moving to lands meant that ammonia could not be directly excreted out of the cell. Animals now have to convert ammonia into less toxic forms
One of the three ways to handle nitrogenous wastes: Excrete ammonia directly
- Very toxic
- requries alot of water and body of water
- Fishes
One of the three ways to handle nitrogenous wastes: Convert to Urea
- less toxic means it can be more concentrated
- Requires alot of energy
- Requires water
- Mammals humans amphibians sharks
One of the three ways to handle nitrogeneous wastes: Convert to uric acid
- the least toxic form can be stored at a high concentrated
- bird, arthropods, land snails
- Not dissolved in water or osomatic pressure
- Requires alot of energy
What is a central vacoule?
it is where unicellular and simple multicellular isolate their waste
The fusion of the contrctile vacuole with the cell membrane
How does excertory organs work?
- Filtration
- Reabsoprtion
- Secretion
Filtration:
Blood passes through blood capillary pores small molecules passes through.
The filtrate passes through exectrory tubules containing amino acids and glucose
Reabsoprtion:
uses active or passive transport in order to useful solutes lost from filtration
Secretion:
active or passive of waste and electrolytes from the blood to the filter
What is the function of a protonephridia?
When an organism lacks a circulatory system, pressure from the ciliary flow moves fluids into the protonephridia. (flatworms)
serves mostly as a way to maintain water amount in the cell less effective form of excertion
How does the protonephridia function in flatworms?
- Fluid gets filtered through large fenstrae
- Once the fluid reaches the tubules it undergoes secretion and reabsorption (minor amount)
