Component 3.2 - Features Of A Transport System Flashcards
What 3 features do all transport systems in animals have?
1) A suitable medium in which to carry materials
2) A pump, such as the heart, for moving blood
3) valves to maintain the flow in one direction
What 2 features do some transport systems have?
1) A respiratory pigments, such as in vertebrates and some invertebrates, which increases the volume of oxygen which can be carried
2) A system of vessels with a branching network to distribute the transport medium to all parts of the body
What is an open circulatory system?
The blood does not move around the body in blood vessels but it bathes the tissue directly while held in a cavity called then haemocoel.
Describe the circulatory system in an insect
They have a open blood system.
They have a long, dorsal tube-shaped heart. It pumps blood out at low pressure into the haemocoel where materials are exchanged between the body and blood cells.
There is no respiratory pigment and therefore lack of respiratory gases in blood.
What is a closed circulatory system?
The blood moves in blood vessels
Describe the circulation in an earth worm
1) It has a single, closed circulation system
2) Respiratory gases carried in blood by haemoglobin
3) Blood moves forward in the dorsal vessel and is pumped into the ventral vessel by pseudohearts which are muscular blood vessels (vascularisation)
Describe the circulation in a fish
It has a closed, single circulatory system
The ventricle of the heart pumps deoxygenated blood to the gills. Oxygenated blood is carried to the tissues and then deoxygenated blood returns to the atrium of the heart
Why do mammals need a double circulation system?
The blood passes through the heart twice - blood pressure is reduced in the lungs and would be too low to provide the the body’s tissues with nutrients quickly enough. Instead the blood is returned to the heart which raises its pressure again, to make sure circulation is efficient.
