what is the job of specialist exchange surfaces?
absorb nutrients absorb respiratory gasses absorb excretory products
state two factors that make it more likely that an organism will have a specialised transport medium or a circulatory pump
surface area to volume ratio how active the organism is lower SA to V ratio and more active - a greater need for specialised transport system with a pump
list the common features of a transport system
a suitable medium in which to carry material e.g. blood - normally water-based liquid as water good solute
a form of mass transport - transport medium moved around in bulks over large distances - more rapid than diffusion
a closed system of tubular vessels containing transport medium and forms branching network
the mechanism for moving transport medium - requires pressure difference - in animals = muscular contraction and in plants = evaporation
mechanism to maintain mass flow movements in one direction - valves
a mechanism for the mass flow of water or gasses - in animals - intercostal muscles
means of controlling the flow of the transport medium to suit the changing needs of different parts of the organism
a closed double circulatory system
why does the blood pass twice through the heart?
when blood passes through the lungs, the pressure is reduced, and if low-pressure blood passed immediately to the rest of the body, circulation = very slow
why is it necessary that substances are delivered to the rest of the body quickly?
mammals have a high body temperature - high rate of metabolism
what are the vessels that make up the circulatory system of a mammal?
arteries veins capillaries
what is the process that transports blood from vessels to cells?
why is diffusion rapid?
large SA to V ratio short distance steep diffusion gradient
diagram of the mammalian circulatory system
what is the name of the blood vessel that joins the right ventricle of the heart to the capillaries?
what is the name of the blood vessel that carries oxygenated blood away from the heart?
what is the name of the blood vessel that carries deoxygenated blood away from the kidney?
what is the name of the first main blood vessel that an oxygen molecule reaches after being absorbed from an alveolus?
what is the name of the blood vessel that has the highest blood pressure?