Transport system in multicellular animals

Question 1

How do single celled organism transport material?

Answer 1

Osmosis Diffusion Active transport Exocytosis Endocytosis

Question 2

Why do multicellular organisms need a specialised transport system?

Answer 2

High metabolic demands Small surface area to volume ratio There is a need to transport hormones and enzymes from the place of their production to the place where they are needed. Transportation of food molecules from the an organ system to different cells. Large amount of waste products are produced by cells which need to be transported to excretory organs

Question 3

What are the names of the two types of circulatory systems?

Answer 3

Open circulatory system Closed circulatory system

Question 4

What are the three common features of a circulatory system?

Answer 4

A liquid transport medium that circulates around the system (blood) Vessels that carry the transport medium A pumping mechanism to move the fluid around the system

Question 5

What does the term ‘mass transport system’ mean?

Answer 5

It is used to describe a system that requires substances to be transported in a mass of fluid with a mechanism for moving the fluid around the body.

Question 6

What type of organisms usually have open circulatory systems?

Answer 6

Invertebrate animals (insects and molluscs)

Question 7

Describe the process of an open circulatory system

Answer 7

There are very few vessels to contain the transport medium, so instead it is pumped straight from the heart into the body cavity. Inside the body cavity the the transport medium is under low pressure. It comes into direct contact with the tissues and cells. Exchange tales place between the transport medium and the cells before the transport medium moves back to the heart through an open-ended vessel

Question 8

What is the name of the body cavity of an invertebrate?

Answer 8

Haemocoel

Question 9

What is the name of the transport medium inside of invertebrates?

Answer 9

Haemolymph

Question 10

What does the haemolymph transport inside invertebrates?

Answer 10

food, nitrogenous gas and the cells that fight against disease

Question 11

How is the body cavity split inside vertebrates?

Answer 11

Via a membrane

Question 12

Were is the heart located inside an insect?

Answer 12

along the thorax and abdomen

Question 13

Why is the open circulatory system inefficient when there is a change in demand?

Answer 13

The open circulatory system is inefficient because the amount of haemolymph flowing to a particular tissue can not vary according to the change in demands.

Question 14

Why is there not efficient diffusion from the haemolymph?

Answer 14

A steep diffusion gradient cannot be maintained (so although it circulates the cavity, it does not circulate well).

Question 15

In what organisms would you find a closed circulatory system?

Answer 15

• Echinoderms
• cephalopods
• molluscs
• annelid worms
• vertebrates

Question 16

Describe the process of a closed circulatory system

Answer 16

The blood is enclosed in vessels and so does not come into direct contact with the cells of the body. The blood is pumped around the body under pressure via the heart. The blood then circulates and then returns to the heart. Substances leave and enter the blood via diffusion through the walls of the blood vessels.

Question 17

How can the body adjust the amount of blood flowing to a particular tissue?

Answer 17

By widening or narrowing the blood vessels

Question 18

In most circulatory systems how is the respiratory gas carried?

Answer 18

Via a blood pigment

Question 19

What is the name of the blood pigment in vertebrates?

Answer 19

Hemoglobin

Question 20

In what organisms are a single closed circulatory system found?

Answer 20

Fish and annelid worms

Question 21

Why is a single closed circulatory system less efficient?

Answer 21

As the blood has to pass between two sets of vessels with only having been pumped once the blood pressure drops dramatically. This means that the blood returns too the heart relatively slowly.

Question 22

How does the efficiency of the single closed circulatory system effect the organism?

Answer 22

It means that the activity levels of the animals have to be relatively low

Question 23

How comes fish can be very active despite the fact that they have a single closed circulatory system?

Answer 23

They have a copuntercurrent gaseous exchnage system which allows them to take in a lot of oxygen from the water. Their body weight is supported by the water They do not maintain there own body temperature. All of this greatly reduces the metabolic activities of the fish and along with there efficient gaseous exchange allows them to be more active.

Question 24

What types of animals would have a double closed circulatory system?

Answer 24

Birds and most mammals

Question 25

What are the two separate circulations of a double circulatory system?

Answer 25

1st- The blood is pumped via the heart to the lungs. Here the blood picks up oxygen and drops of carbon dioxide. The blood then returns to the heart. 2nd- The blood flows through the heart to then be pumped around the body before returning back to the heart.

Question 26

Why is the double circulatory system more efficient?

Answer 26

The blood travels through the heart for each circulation. Each circulation only passes through one capillary network. As a result there is relatively high pressure and the blood flows a lot faster.

Question 27

Why do birds and most mammals need an efficient circulatory system?

Answer 27

They are very active, so have a high metabolic rate, and maintain there own body heat. This means that they need a faster blood supply.