B: Breathing

Question 1

Alveoli

Answer 1

Tiny air sacs in the lungs with very think membranes and a large surface area, where gas is exchanged between the blood and air.

Question 2

Asthma

Answer 2

Disease involving breathlessness due to constriction of the bronchioles.

Question 3

Bronchi

Answer 3

The two major air tubes, one leading to each lung [singular = bronchus]

Question 4

Bronchioles

Answer 4

The many small, branching tubes from the bronchi to the alveoli.

Question 5

Carbon dioxide

Answer 5

Gaseous compound of carbon and oxygen which is a by-product of respiration, and which is needed by plants for photosynthesis.

Question 6

Carbon monoxide

Answer 6

Poisonous gas present in tobacco smoke; Carbon binds to haemoglobin, taking the place of oxygen.

Question 7

Diaphragm

Answer 7

A large sheet of muscle that separates the lungs from the abdominal cavity.

Question 8

Emphysema

Answer 8

Lung disease in which the alveoli gradually fuse together, losing their large surface area, so less and less gas exchange is possible.

Question 9

Epiglottis

Answer 9

Small flap behind the tongue; it closes the trachea when we swallow so that food does not go down the ‘wrong way’.

Question 10

Exhalation

Answer 10

Breathing out: caused by relaxation of the diaphragm and external intercostal muscles (aided by contraction of internal intercostals).

Question 11

Gas exchange

Answer 11

Transfer of oxygen from the air to blood and carbon dioxide from blood to air; in the alveoli. The purpose of breathing!

Question 12

Inhalation

Answer 12

Breathing in: caused by the contraction of the diaphragm and external intercostal muscles.

Question 13

Intercostal muscles

Answer 13

Muscles between the ribs. The external fibres contract to raise the ribcage during inhalation. The internal fibres only contract when forceful exhalation is needed (e.g. in a cough or sneeze).

Question 14

Mucus/mucus membranes

Answer 14

Mucus is the slippery fluid which lines the respiratory system and alimentary canal, produces y goblet cells in mucus membranes.

Question 15

Nitrogen

Answer 15

A colourless and odourless gas that makes up around 79% of the atmosphere.

Question 16

Oxygen

Answer 16

Gaseous element making up about 20% of the air, which is needed by living organisms for aerobic respiration.

Question 17

Pleural membranes

Answer 17

Slippery mucus membranes covering the outside of the lungs and the inside of the thorax, to reduce friction when we breathe.

Question 18

Tar

Answer 18

Oily mixture of >400 chemicals in tobacco smoke, many of which cause cancer and other diseases linked with smoking.

Question 19

Thorax

Answer 19

The chest, containing the heart and lungs and encased by the ribs.

Question 20

Trachea

Answer 20

The windpipe or tube from the back of the mouth to the top of the lungs

Question 21

Ventilation

Answer 21

The flow of air into and out of the lungs, caused by the physical movement of breathing. Without this flow there would be no concentration gradients to cause gas exchange in the alveoli.