breathing exam qs

Question 1

describe the features of the lungs that make them effective organs for gas exchange

Answer 1

many alveoli to produce large surface area;
thin barrier;
good blood supply / many capillaries;
to carry dissolved gases to and from the alveoli;
ventilation / air movement to refresh the air in the alveoli;
(contains) elastic tissue to stretch and recoil to help expel air;

Question 2

what happens to bronchus wall in smokers? (3)

Answer 2

cilia, destroyed / damaged;
(epithelium replaced by) scar tissue / scarring;
smooth muscle becomes thicker;
larger/ more goblet cells;
inflammation of connective tissue;

Question 3

why do alveoli walls contain elastic fibres? (2)

Answer 3

stretch as air is inhaled / allow alveoli to expand during inhalation;
to increase lung volume / surface area;
prevents alveoli bursting;
(elastic fibres) recoil, as exhale;
more complete / rapid expulsion (from the alveoli);

Question 4

how does loss of elasticity of alveoli walls affect emphysema sufferers? (4)

Answer 4

tidal volume is reduced / less air inhaled and exhaled / residual volume is larger / air trapped in alveoli / vital capacity smaller;

more difficult to exhale;
(as) alveoli cannot, stretch / recoil;

rapid / shallow, breathing / breathlessness / wheezing;

alveoli may burst;

leaves gaps in tissue / larger air spaces / AW;

less surface area (for gaseous exchange);

blood / haemoglobin, less well oxygenated / less carbon dioxide removed;

Question 5

function of cartilage

Answer 5

1 in, trachea / bronchi;
2 holds airway open / prevents collapse;
3 prevents bursting (of trachea / bronchi as air pressure changes);
4 low resistance to air movement;

Question 6

function of ciliated epithelium

Answer 6

move mucus;
ref to how movement brought about;
e.g. metachronal rhythm / wave / sweep / waft

Question 7

function of goblet cells

Answer 7

7 secrete mucus;
8 trap, bacteria / dust / pollen / particles;
9 remove particles from lungs;

Question 8

function of blood vessels

Answer 8

10 supply, oxygen / nutrients (to tissues of lung);
11 surround alveoli / good blood supply to alveoli;
12 deliver carbon dioxide / pick up oxygen;
13 ref to wall of capillary being thin;
14 ease of / rapid, gaseous exchange or short diffusion pathway;

Question 9

function of smooth muscle

Answer 9

15 adjust size of airways (in, exercise / asthma);
connective tissue / elastin / elastic tissue
16 stretch (inhalation);
17 prevents alveoli bursting;
18 recoil; R contract
19 helps exhalation / forces air out (of lungs);

Question 10

function of squamous epithelium in alveolus wall

Answer 10

20 alveolus wall thin;
21 ease of / rapid, gaseous exchange or short diffusion pathway;
22 AVP; e.g. ref to large surface area of numerous alveoli
23 AVP; ref to macrophages removing pathogens

Question 11

what happens during an asthma attack?

Answer 11

histamine released;
mucus is not moved;
more goblet cells;
goblet cells produce excess mucus;
fewer cilia (per cell);

thicker / more, (smooth) muscle;
(muscle) contracts;
connective tissue, swells / enlarges / fills with fluid;
lining of bronchiole thrown into deeper folds;