7.3- CIRCULATORY SYSTEM OF A MAMMAL Flashcards
What is diffusion fast enough for?
transport over short distances
What does the efficient supply of materials over larger distances require?
mass transport system
What do all organisms exchange materials between?
between themselves and their environment
Where does exchange of materials happen in small organisms?
takes place over surface of the body
What happens to SA:V with increasing size?
SA:V decreases
Why are specialist exchange surfaces needed in larger organsims?
to absorb nutrients + respiratory gases, + remove excretory products
What is a transport system required to do?
take material from cells to exchange surfaces + from exchange surfaces to cells
Where do materials have to be transported between? (2)
between exchange surfaces + environment
between different parts of organism
As organisms have evolved into larger + more complex structures, what happens to tissues + organs?
tissues + organs of which they’re made have become more specialised + dependent upon one another
As organisms have evolved into larger + more complex structures, tissues + organs of which they’re made have become more specialised + dependent upon one another, what does it make more essential?
makes transport system all the more essential
What two factors determine whether or not there’s a specialised transport medium, or whether or not it’s circulated by a pump?
SA:V
how active organism is
What two factors mean the greater need for a specialised transport system with a pump?
lower the SA:V
more active the organism
Common features of transport systems of many organisms: medium? #1
suitable medium to carry material e.g. blood
normally a liquid based on water
Common features of transport systems of many organisms: why is the medium normally based on water? #1
as water readily dissolves substances + can be moved around easily, but can be a gas i.e. air breathed in + out of lungs
Common features of transport systems of many organisms: transport medium moved around in bulk over large distances? #2
form of mass transport in which transport medium moved around in bulk over large distances- more rapid than diffusion
Common features of transport systems of many organisms: closed system? #3
closed system of tubular vessels that contains transport medium + forms branching network to distribute it to all parts of organsim
Common features of transport systems of many organisms: mechanism? #4
mechanism for moving transport medium within vessels
Common features of transport systems of many organisms: what does the mechanism for moving transport medium within vessels require? #4
requires pressure difference between one part of system + another
How is the mechanism for moving transport medium within vessels achieved in animals?
animals use muscular contraction either of body muscles or of specialised pumping organ i.e. heart
What do plants rely on for the mechanism of moving transport medium within vessels?
rely on natural, passive processes i.e. evaporation of water
Common features of transport systems of many organisms: mass flow? #5
maintain mass flow movement in one direction e.g. valves
Common features of transport systems of many organisms: controlling flow of transport medium? #6
means of controlling flow of transport medium to suit changing needs of different parts of organism
Common features of transport systems of many organisms: mechanism for mass flow of water/ gases? #7
mechanism for mass flow of water or gases e.g. intercostal muscles + diaphragm during breathing in mammals
What kind of circulatory system do mammals have?
closed, double circulatory system
What is a closed, double circulatory system?
blood confined to vessels + passes twice through heart fir each complete circuit of body
Why does blood pass twice through the heart for each complete circuit of the body? (3)
when blood passed through lungs, its pressure recued
if it were to pass immediately to rest of body its low pressure would make circulation very slow
blood returned to heart to boost its pressure before being circulated to rest of tissues
As the blood passes twice through the heart for each complete circuit of the body, what happens?
substances delivered to rest of body quickly, which is necessary as mammals have high bdy temp. + hence high rate of metabolism
What are the vessels that make up the circulatory system of a mammal divided into? (3)
arteries
veins
capillaries
What is the process of the final part of the transport system to cells?
diffusion
Why is the final exchange from blood vessels to cells rapid? (3)
it happens over large SA, across short distances + there’s a steep diffusion gradient
