Lesson 6 - Specialised transport systems in mammals

Question 1

What can supply everything the cell needs to import and export via:

Answer 1

• Diffusion
• Osmosis
• Active transport
• Exocytosis
• Endocytosis

Question 2

Why do multicellular organisms need transport systems?

Answer 2

• Metabolic demands of most multicellular animals are high, so diffusion over long distances is not enough to supply quantities needed and remove waste.
• SA:V smaller as multicellular organisms get bigger. Smaller SA to absorb or remove substances becomes relatively smaller.
• Molecules (hormones & enzymes) may be in one place but need to be transported to another
• Food digested in one organ, but needs to be transported to every cell in the body for aerobic respiration and other aspects of cell metabolism.
• Waste products of metabolism need to be removed from cells and transported to excretory organs.

Question 3

Features of circulatory system:

Answer 3

• Have liquid transport medium that circulates around the system
• Vessels that carry transport medium
• Pumping mechanism to move the fluid around the system

Question 4

When substances are transported in a mass fluid with a mechanism moving the fluid around the body

Answer 4

Mass transport system

Question 5

Open circulatory system:

Answer 5

Blood is not enclosed in vessels, and it circulates in open space.

Question 6

How open circulatory system works?

Answer 6

• Very few blood vessels to contain transport medium
• Pumped straight from heart into body cavity
• In haemocoel transport medium is under low pressure
• Comes into direct contact with cells and tissues
• Transport medium returns to heart through an open ended vessel

Question 7

What is the body cavity called?

Answer 7

Haemocoel

Question 8

Where does gaseous exchange take place in the open system?

Answer 8

Haemocoel

Question 9

Where are open-ended vessels found?

Answer 9

Invertebrate animals:
- Insects
- Molluscs

Question 10

Insect blood =

Answer 10

Haemolymph

Question 11

What doesn’t haemolymph carry and why?

Answer 11

Oxygen and carbon dioxide:
- Gaseous exchange occurs in tracheoles

Question 12

What does haemolymph carry in the blood?

Answer 12

• Food
• Nitrogenous waste products
• Cells involved in defence against disease

Question 13

How is the open system of an insect structured?

Answer 13

Haemocoel split by a membrane and heart extends along length of the thorax and the abdomen of the insect.

Question 14

Haemolymph flow?

Answer 14

Circulates but steep concentration gradient can not be maintained for efficient diffusion. The amount of haemolymph flowing to a particular tissue can not be varied to meet changing demands.

Question 15

Closed circulatory system:

Answer 15

Blood enclosed in blood vessels and does not come directly into contact with cells of the body.

Question 16

How does closed circulatory system work?

Answer 16

• Heart pumps blood around body under pressure and relatively quickly, and blood returns directly to heart.

Question 17

How does gaseous exchange occur in a closed system?

Answer 17

Substances leave and enter blood by diffusion through the walls of the blood vessels.

Question 18

How is quantity of blood delivered to cells altered in a closed system?

Answer 18

Widening / narrowing the blood vessels

Question 19

What is the blood pigment for?

Answer 19

To carry respiratory gases.

Question 20

Where are closed systems found? (what phyla)

Answer 20

• Echinoderms
• Cephalopod molluscs
• Annelid worms
• Vertebrate groups

Question 21

Echinoderms:

Answer 21

Sea urchins and starfish

Question 22

Cephalopod molluscs:

Answer 22

Octopods and Squids

Question 23

Annelid worms:

Answer 23

common earthworms

Question 24

Where are single closed circulatory systems found?

Answer 24

Annelids and fish

Question 25

Single closed circulatory system:

Answer 25

Blood flows through the heart once for every complete circulation.

Question 26

How many sets of capillaries does the blood pass through in one circuit in a single closed circulatory system?

Answer 26

two

1: exchange oxygen and carbon dioxide
2: Different organ systems. Substances exchanged between blood and cells.

Question 27

What is the result of passing through 2 sets of capillaries in a single closed circulatory system?

Answer 27

Blood pressure decreases and blood returns to the heart very slowly.
This limits limits the efficiency of the exchange processes, so the activity levels of animals with a single closed circulatory system needs to be relatively low.

Question 28

What is the exception to the low activity level rule for single closed circulatory systems?

Answer 28

Fish

Question 29

How is a fish’s metabolic rate decreased?

Answer 29

• Efficient gaseous exchange (counter-current flow)
• Body weight is supported by the water
• Do not need to maintain body temperature due to water

Question 30

Double closed circulatory system is present in?

Answer 30

Birds and most mammals

Question 31

How does double closed circulatory system work?

Answer 31

• Blood is pumped from the heart to the lungs to pick up oxygen and unload carbon dioxide, and then returns to the heart.
• Blood flows through the heart and is pumped out to travel all around the body before returning again.

Question 32

Pulmonary circulation:

Answer 32

heart and lungs

Question 33

Systemic circulation:

Answer 33

heart and body / other organs

Question 34

Definition of double circulatory system:

Answer 34

Blood travels through the heart twice for each complete circulation.

Question 35

How is high pressure and fast flow maintained?

Answer 35

Blood only passes through one network of capillaries in each circuit.