Protonephridia - excretion, Biology

Protonephridia - Excretion

Protonephridia are more primitive and occur mainly in acoelomate and pseudocoelomates animals. An animal may have two or more extensively branched protonephridia, each internally terminating in several bulb-like structures called flame cells or flame bulbs. In the lumen of each flame cell is found a tuft of cilia.

905_Protonephridia - Excretion.png

Figure:  Excretory system of planarian

 

 

Flame cells are common in flatworms and nemertines. In some of the coelomate worms that have protonephridia (e.g., polychaetes), the flame bulbs are Excretory pore replaced by a solenocytes. The solenocytes have a single flagellum projecting into the lumen instead of the ciliary tuft as found in the flame cells. It has been suggested that the undulating movements of the ciliary tuft or flagellum generate sufficient negative pressure for filtration and the force required to propel the fluid through the tubules. Flame cell system functions in animals without a circulatory system and pick up substances only from the tissue fluids.

 

 

Posted Date: 1/16/2013 1:28:06 AM | Location : United States







Related Discussions:- Protonephridia - excretion, Assignment Help, Ask Question on Protonephridia - excretion, Get Answer, Expert's Help, Protonephridia - excretion Discussions

Write discussion on Protonephridia - excretion
Your posts are moderated
Related Questions
Vitamin B 2 (Riboflavin) Riboflavin is a yellow to orange-yellow, crystalline powder of faint odour and intensely bitter taste. Its solubility in water is very slight and depe


Define fluorides Metabolism? Soluble fluorides, even at high intake levels are almost completely absorbed from gastrointestinal tract. These include aqueous solutions of fluori

Define the Micronutrient Deficiencies? In the previous section, we learnt about macronutrient deficiencies i.e. protein energy malnutrition in children. We are now aware that t

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4

1. How often should she have Glycated hemoglobin (HgbA1C) drawn?  What percentage is desired? 2. How often should she see an ophthalmologist or optometrist? 3. What should be

In which chloroplast structure are chlorophyll molecules found? Chlorophyll molecules are placed in an organized manner in order to increase the exposure to light on the thylak

Define Prevention of Iron Deficiency? Iron deficiency anaemia accounts for approximately one-half or more of all the anaemia's seen worldwide. Iron deficiency without anaemia a

The human immune system has developed diverse, coordinated methods of resisting and destroying viruses. a.  Describe the typical composition of a virus. Why are viruses not clas

Explain Common Concerns during Pregnancy? Many of the physiological changes that occur during pregnancy affect the digestive tract and may cause discomfort to the mother. Most