Module 3 Definitions

Question 1

Exchange surface

Answer 1

A specialised area adapted to make it easier for molecules to cross from one side of the surface to the other

Question 2

Gaseous exchange

Answer 2

The movement of gases by diffusion between an organism an its environment across a barrier e.g. the alveoli

Question 3

Tissue

Answer 3

A group of similar, specialised cells working together to perform a common function

Question 4

Tidal volume

Answer 4

The volume of air moved in and out of the lungs with each breath at rest

Question 5

Vital capacity

Answer 5

The largest volume of air that can be moved in and out of the lungs in one breath

Question 6

Residual volume

Answer 6

The volume of air that always remains in the lungs even after the biggest possible exhalation

Question 7

Inspiratory reserve volume

Answer 7

The volume of air that can be breathed in above the normal tidal volume

Question 8

Expiratory reserve volume

Answer 8

The volume of air that can be breathed out above the normal tidal volume

Question 9

Transport

Answer 9

The movement of oxygen, nutrients, hormones, waste and heat around the body

Question 10

Open circulatory system

Answer 10

Blood does not always remain in vessels

Question 11

Closed circulatory system

Answer 11

The blood always remains in vessels

Question 12

Single circulatory system

Answer 12

Blood passes through the heart once for each circuit of the body

Question 13

Double circulatory system

Answer 13

Blood flows through the heart for one circuit of the body. Contains a pulmonary circuit and a systemic circuit

Question 14

Cardiac cycle

Answer 14

The sequence of events in one heartbeat

Question 15

Myogenic

Answer 15

Muscle tissue that generates its own contractions

Question 16

Fibrillation

Answer 16

The chambers of the heart contracting out of rhythm

Question 17

Endothelium

Answer 17

Tissue that lines the inside of a structure e.g. a blood vessel

Question 18

Partial pressure

Answer 18

The amount of pressure exerted by a gas relative to the total pressure exerted by all the gases in the mixture

Question 19

Dissociation

Answer 19

The breakdown of a molecule into 2 molecules e.g. oxyhaemoglobin into oxygen and haemoglobin

Question 20

The Bohr effect

Answer 20

The change in shape of the oxyhaemoglobin dissociation curve when carbon dioxide is present. Carbon dioxide causes oxyhaemoglobin to release more readily.

Question 21

Transpiration

Answer 21

The loss of water by evaporation out of the leaves via the stomata

Question 22

Xerophyte

Answer 22

A plant that is adapted to reduce water loss by transpiration so that it can survive in very dry conditions

Question 23

Translocation

Answer 23

The transport of assimilates between the sources and sinks of a plant in the phloem tissue. This requires energy

Question 24

Source

Answer 24

Where sucrose and other assimilates are loaded into the phloem e.g. leaf

Question 25

Sink

Answer 25

Where sucrose and other assimilates are unloaded from the phloem e.g. flower

Question 26

Assimilates

Answer 26

Carbon containing compounds produced by a plant using the carbon from carbon dioxide