Circulatory Systems (pages 78 - 79)

Question 1

Multicellular Organisms need what systems?

Answer 1

they need Transport Systems

Question 2

How do Organisms get substances?

Answer 2

they get substances that they need by diffusion across their outer membrane.

Question 3

Why is it harder for multicellular organisms to get the substances they need?

Answer 3

if you’re multicellular it is a bit harder to supply all your cells with everything they need. Mulcicellular organisms are relatively big, they have a low surface area to volume ratio and a high metabolic rate (the speed at which chemical reactions take place in the body} so this makes it harder to get the substances they need.

Question 4

A lot of multicellular organisms (e.g. mammals) are not very active, what do this mean?

Answer 4

This means that a large number of cells are respiring very quickly, so they need a constant, rapid supply of glucose and oxygen. (this also it a bit harder to supply all the cells with everything they need by diffusion).

Question 5

To make sure that every cell/multicellular organisms has a good enough supply of the substances, what do they need?

Answer 5

they need a transport system

Question 6

What is the transport system called in mammals?

Answer 6

the circulary system.

Question 7

What do the circulatory system for mammals do?

Answer 7

the circulatory system uses blood to carry glucose and oxygen around the body. It also carries hormones, antiboidies (to fiight disease) and wast (like CO²)

Question 8

Not all organisms have the same type of circulatory system.

What circulatory system does
a) fish have?
b) mammals have?

Answer 8

a) fish have a single circulatory system
b) mammals have a double circulatory system.

Question 9

What is the difference between a single and a double circulatory system?

Answer 9

1) a single circulatory system, blood only passes through the heart ONCE for each complete circuit of the body.
2) a double circulatory system, the blood passes through the heart twice for each complete circuit of the body.

Question 10

Explain how a single circulatory system in fish works?

Answer 10

in fish, the heart pumps blood to the gills (to pick up oxygen) and then on through the rest of the body (to deliver the oxygen) in a single circuit. (see diagram 1 on page 78).

Question 11

Explain how a double circulatory system in mammals works?

Answer 11

In mammals, the heart is divided down the middle, so it’s really like two heart pumps joined together.

1) the right side of the heart pumps blood to the lungs (to pick up oxygen)
2) from the lungs it travels to the left side of the heart, which pumps it to the rest of the body.
3) when blood returns to the heart, it enters the right side again.

(the right and left side of the heart are reversed in the diagram 2 on page 78, because it’s the right and left of the person the heart belongs to).

Question 12

Our circulatory system is really two linked loop.

a) one sends blood to the lungs - what is this system called?
b) the other sends blood to the rest of the body - what is this system called?

Answer 12

a) pulmonary system (sends blood to the lungs)
b) systemic system (sends blood to the rest of the body).

Question 13

What is an advantage of the mammalian double circulatory system? and why?

Answer 13

is that the heart can give the blood an extra push between the lungs and the rest of the body. This makes the blood travel faster, so oxygen is delivered to the tissues more quickly.

Question 14

All verbebrates (e.g. fish and mammals) have open or closed circulatory systems?

Answer 14

they have CLOSED circulatory systems - the blood is enclosed inside blood vessels.

Question 15

All vertebrates have closed circulatory systems - the blood enclosed inside blood vessels.

explain what this means?

Answer 15

1) the heart pumps blood into arteries. These branch out into millions of capilliaries (see page 80).

2) Substances like oxygen and glucose diffuse from the blood in the capillaries into the body cells, but the blood stays inside the blood vessels as it circulates.

3) Veins take the blood back to the heart.

Question 16

Some invertebrates (e.g. insects) have an open or closed circulatory system?

Answer 16

some inverebrates have an open circulatory system - blood isn’t elnclosed in blood vessels all the time. Instead, it flows freely through the body cavity.

Question 17

In some invertebrates (e.g. insects) have an open circulatory system - blood isnt enclosed in the blood vessels all the time. instead, it flows freeley through the body cavity, how?

Answer 17

1) The heart is segmented. It contracts in a wave, starting from the back, pumping the blood into a single main artery.

2) That artery opens up into the body cavity.

3) The blood flows around the insect’s organs, gradually making its way back into the heart segments through a series of valves.

The circulatory system supplies the insect’s cells with nutrients, and transports things like hormomes around the body. It doesn’t supply the insect’s cells with oxygen though - this is done by a system of tubes called the tracheal system (see page 77 for more).

see diagram 1 on page 79.

(segmentated means the division of some animal and plant body plans into a linear series of repetitive segments that may or may not be interconnected to each other)

Question 18

Give three reasons why multicellular organisms usually need a transport system, but unicellular organisms dont?

Answer 18

Multicellular organisms need efficent transportation systems because simple diffusion would be too slow to transport nutrients and remove waste. In single celled organisms, simple diffusion carries metabolic wast out of the cell and allow for the transport of nutrients into the cell.

Multicellular organisms are much larger and can be composed of billions of cells, thus, they need efficient transport systems to deliver nutrients to all cellsand remove waste in a systamatic way. for example, animals have circulatory systems that delivers oxygen and nutrients to the body and brings metabolic waste to the kidney and lungs to be removed.

Question 19

Explain why the mammalian circulatory system is described as a double circulatory system?

Answer 19

the heart can give the blood an extra push between the lungs and the rest of the body. This makes the blood travel faster, so oxygen is delivered to the tissues more quickly.

It is called a double circulatory system because blood passes through the heart twice per circuit. The right pump sends deoxygeneted blood to the lungs where it becomes oxygenated and returns back to the heart. The left pump sends the newly oxygenated blood around the body.

Question 20

What is an open circulatory system?

Answer 20

Organisms have different forms of circulatory systems. Humans have a closed circulatory system, while many mollusks and other inverebrates have an open system - blood isn’t enclosed in blood vessels all the time, instead it flows freely through the blood cavity.

the heart is segmented, it contract in a wave from the back, pumping the blood into a single main artery.
the artery opens up into the body cavity, then blood flows around the insets organs, gradually making its way back into the heart segments through a series of valves.

Question 21

Explain why the circulatory system of a trout is described as being closed (1 mark)

(trout is a fish)

Answer 21

The blood flows through the body in vessels (1 mark)

Question 22

Briefly describe the circulatory system of a beetle (2 marks)

Answer 22

Beetles are insects, so they have an open circulatory system [1 mark]. The blood is pumped into the body cavity where it circulates freeley [1 mark].

Question 23

The Atlantic salmon (salmo salar) and the red fox (Vulpes vulpes) have circulatory systems. Describe one way in which the circulatory system of the Atlantic Salmon is:

a) similar to that of the red fox (1 mark)
b) different from that of the red fox (1 mark)

Answer 23

a) It is a closed system [1 mark]
b) It is a single circulatory system, not a double one [1 mark]