Transport Systems In Multicellular Animals Flashcards
Why are specialised transport systems needed?
- high metabolic demand.
- small surface area : volume ratio.
- molecules may be made in one place and required in another.
- waste products of metabolism need to be removed from cells and transported to excretory organs.
What do most circulatory systems have in common?
- they have a liquid medium that circulates around the blood.
- they have vessels that carry transport medium.
- pumping mechanism to move fluid around the system.
What is a mass transport system?
When substances are transported in a mass of fluid with a mechanism for moving the fluid around the body.
What is an open circulatory system?
None or few vessels to contain the transport medium.
Transport medium is pumped from the heart into the body cavity (haemocoel) of the animal.
Is the transport medium in the haemocoel under high or low pressure?
Low pressure.
Where are open circulatory systems found?
Mainly in invertebrate animals.
Where does gas exchange take place in insects?
In the tracheal system.
What is insect blood called?
Haemolymph.
What does haemolymph carry?
Food and nitrogenous waste products and the cells involved in defence against disease.
What is a close circulatory system?
The blood is enclosed in blood vessels and does not come directly into contact with cells of the body.
Where are closed circulatory systems found?
Many different animal phyla.
- vertebrates.
Where are single closed circulatory systems sound?
Fish and annelid worms.
What is a single circulatory system?
Blood travels only once through the heart for each complete circulation of the body.
Why does the activity levels of animals with single closed circulations tend to be low?
As blood passes through narrow vessels, blood pressure in the system drops and the blood returns to the heart slowly. Limits the efficiency of the exchange processes.
What circulatory system does a fish have?
Single closed.
