7.3- CIRCULATORY SYSTEM OF A MAMMAL

Question 1

What is diffusion fast enough for?

Answer 1

transport over short distances

Question 2

What does the efficient supply of materials over larger distances require?

Answer 2

mass transport system

Question 3

What do all organisms exchange materials between?

Answer 3

between themselves and their environment

Question 4

Where does exchange of materials happen in small organisms?

Answer 4

takes place over surface of the body

Question 5

What happens to SA:V with increasing size?

Answer 5

SA:V decreases

Question 6

Why are specialist exchange surfaces needed in larger organsims?

Answer 6

to absorb nutrients + respiratory gases, + remove excretory products

Question 7

What is a transport system required to do?

Answer 7

take material from cells to exchange surfaces + from exchange surfaces to cells

Question 8

Where do materials have to be transported between? (2)

Answer 8

between exchange surfaces + environment

between different parts of organism

Question 9

As organisms have evolved into larger + more complex structures, what happens to tissues + organs?

Answer 9

tissues + organs of which they’re made have become more specialised + dependent upon one another

Question 10

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?

Answer 10

makes transport system all the more essential

Question 11

What two factors determine whether or not there’s a specialised transport medium, or whether or not it’s circulated by a pump?

Answer 11

SA:V

how active organism is

Question 12

What two factors mean the greater need for a specialised transport system with a pump?

Answer 12

lower the SA:V

more active the organism

Question 13

Common features of transport systems of many organisms: medium? #1

Answer 13

suitable medium to carry material e.g. blood

normally a liquid based on water

Question 14

Common features of transport systems of many organisms: why is the medium normally based on water? #1

Answer 14

as water readily dissolves substances + can be moved around easily, but can be a gas i.e. air breathed in + out of lungs

Question 15

Common features of transport systems of many organisms: transport medium moved around in bulk over large distances? #2

Answer 15

form of mass transport in which transport medium moved around in bulk over large distances- more rapid than diffusion

Question 16

Common features of transport systems of many organisms: closed system? #3

Answer 16

closed system of tubular vessels that contains transport medium + forms branching network to distribute it to all parts of organsim

Question 17

Common features of transport systems of many organisms: mechanism? #4

Answer 17

mechanism for moving transport medium within vessels

Question 18

Common features of transport systems of many organisms: what does the mechanism for moving transport medium within vessels require? #4

Answer 18

requires pressure difference between one part of system + another

Question 19

How is the mechanism for moving transport medium within vessels achieved in animals?

Answer 19

animals use muscular contraction either of body muscles or of specialised pumping organ i.e. heart

Question 20

What do plants rely on for the mechanism of moving transport medium within vessels?

Answer 20

rely on natural, passive processes i.e. evaporation of water

Question 21

Common features of transport systems of many organisms: mass flow? #5

Answer 21

maintain mass flow movement in one direction e.g. valves

Question 22

Common features of transport systems of many organisms: controlling flow of transport medium? #6

Answer 22

means of controlling flow of transport medium to suit changing needs of different parts of organism

Question 23

Common features of transport systems of many organisms: mechanism for mass flow of water/ gases? #7

Answer 23

mechanism for mass flow of water or gases e.g. intercostal muscles + diaphragm during breathing in mammals

Question 24

What kind of circulatory system do mammals have?

Answer 24

closed, double circulatory system

Question 25

What is a closed, double circulatory system?

Answer 25

blood confined to vessels + passes twice through heart fir each complete circuit of body

Question 26

Why does blood pass twice through the heart for each complete circuit of the body? (3)

Answer 26

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

Question 27

As the blood passes twice through the heart for each complete circuit of the body, what happens?

Answer 27

substances delivered to rest of body quickly, which is necessary as mammals have high bdy temp. + hence high rate of metabolism

Question 28

What are the vessels that make up the circulatory system of a mammal divided into? (3)

Answer 28

arteries
veins
capillaries

Question 29

What is the process of the final part of the transport system to cells?

Answer 29

diffusion

Question 30

Why is the final exchange from blood vessels to cells rapid? (3)

Answer 30

it happens over large SA, across short distances + there’s a steep diffusion gradient