Circulatory System Of A Mammal Flashcards
Why do larger organisms have a transport system?
They have a low surface area to volume ratio, this means that the needs of the organism cannot be met by the body-surface alone.
What does the transport system do?
It takes materials from cells to exchange services and from exchange services to cells. Materials also have to be transported between exchange services and the environment and between different parts of the organism.
What has happened as organisms have evolved into larger and more complex structures?
The tissues and organs of which they are made have become more specialised and dependent upon one another.
What two factors determine whether or not there is a specialised transport medium and whether or not to circulated by a pump?
Surface area to volume ratio:
How active the organism is
Why may a specialised transport system with the pump be needed?
If the surface area to volume ratio is low and the organism is active.
What do the transport systems of many organisms have in common?
They have a suitable medium in which to carry materials;
A form of mass transport in which the transport medium is moved around in bulk over large distances;
A closed system of tubular vessels that contain the transport medium and form a branching network to distribute it to all parts of the organism;
A mechanism for moving the transport medium within vessels.
What is the suitable medium normally like?
It is normally liquid based on water.
Why is the liquid medium normally based on water?
Water readily dissolves substances and can be moved around easily, but can be a gas such as air breathed in and out of the lungs.
Why is a form of mass transport needed?
It is faster than diffusion.
What does the mechanism for moving the transport medium within vessels require?
Pressure difference between one part of the system and another.
What do you animals use to run their transport systems?
The contraction of either body muscles are of specialised pumping organs.
What do plants use to transport substances?
They rely on natural, passive processes such as the evaporation of water.
What three things are important in transport systems?
Mechanism to maintain the mass flow movement in One Direction;
A means of controlling the flow of transport medium to suit the changing needs of different parts of the organism;
A mechanism for the mass flow of water or gases, for example intercostal muscles and diaphragm during breathing in mammals.
Give an example of a mechanism that maintains the mass flow movement in One Direction.
Valves
What type of circulatory system do mammals have?
Are closed, double circulatory system in which blood is confined to Bessels and passes twice through the heart for each complete circuit of the body.
