mammalian heart Flashcards
Diffusion is fast enough for
transport over short distances
larger distances requires a…..
The efficient supply of materials over larger distances requires a mass transport system.
small organism can
exchange materials directly from the surface of the body.
what does increasing size causes
, the surface area to volume ratio to decrease
to a point where the needs of the organism cannot be met by the body surface alone
what do transport systems do
To take materials from cells to exchange surfaces and from exchange surfaces
to cells.
Materials have to be transported between exchange surfaces and the environment.
They also need to be transported between
different parts of the organism.
what do larger organism need to get nutrients and respiratory gases to the cells
). Specialist exchange surfaces are
therefore required to absorb nutrients and respiratory gases, and
remove excretory products.
where are exchange surfaces located ?
These exchange surfaces are located in specific regions of the organism.
what increases the needs for an organism to have specialised structures for mass transports
the surface area to volume ratio,
• how active the organism is.
4 required factors for increasing exchange rates
A suitable medium
- A form of mass transport
- A closed system of tubular vessels
A mechanism
A suitable medium
A suitable medium in which to carry materials,
This is normally a liquid based on water because water readily
dissolves substances and can be moved around easily,
gases such as air breathed in and out of the lungs.
• A form of mass transport
• A form of mass transport in which the transport medium is moved
around in bulk over large distances - more rapid than diffusion.
• A closed system
• A closed system of tubular vessels that contains the transport
medium and forms a branching network to distribute it to all parts
of the organism.
• A mechanism
• A mechanism for moving the transport medium within vessels.
This requires a pressure difference be tween one part of the system
and another.
mechanism in animals
Animals use muscular contraction.
Either from body muscles or specialist pumping organs such as the heart.
plant mechanism
Plants rely on natural, passive processes such as the evaporation of water
valves mechanism
maintains the mass flow movement in one
direction,
intercostal muscles and diaphragm in breathing
• A mechanism for the mass flow of water or gases, for example,
closed double circulatory system
closed -
blood is confined in organs such as heart and in vessels
double- blood passes through the heart twice.
why does the blood passes through the heart twice
the heart pumps deoxygenated and nutrient lacking blookd to the lungs. The lungs oxygenate the blood. The blood is at a low pressure. this low pressure would cause the circulation rate to be too slow. The blood passes through the heart which increases pressure and speeds up circulation rate.
since mammals have high temperatures the must have
high metabolism
kidney
renal artery
renal veins
body exchange surfaces
body vena cava right atrium right ventricles pulmonary arteries lungs pulmonary veins left atrium left ventricle aorta body
the heart
two closely associated pumps the left pump deals with oxygenated blood from lungs the right deals with deoxygenated blood from the body
atrium
thin-walled and elastic and stretches as it collects
blood.
